12.07.2015 Views

Journal of Emerging Technologies in Web Intelligence Contents

Journal of Emerging Technologies in Web Intelligence Contents

Journal of Emerging Technologies in Web Intelligence Contents

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

<strong>Journal</strong> <strong>of</strong> <strong>Emerg<strong>in</strong>g</strong> <strong>Technologies</strong> <strong>in</strong> <strong>Web</strong> <strong>Intelligence</strong>ISSN 1798-0461Volume 2, Number 2, May 2010Special Issue: <strong>Emerg<strong>in</strong>g</strong> <strong>Technologies</strong> <strong>in</strong> Internet Security and NetworksGuest Editors: Himanshu Aggarwal and Vishal Goyal<strong>Contents</strong>Guest EditorialHimanshu Aggarwal and Vishal Goyal79SPECIAL ISSUE PAPERSPerformance <strong>of</strong> Dom<strong>in</strong>at<strong>in</strong>g and Adaptive Partial Dom<strong>in</strong>at<strong>in</strong>g Sets <strong>in</strong> AODV Rout<strong>in</strong>g Protocol forMANETsA. Nagaraju, S. Ramachandram, and B. EswarBee-Inspired Rout<strong>in</strong>g Protocols for Mobile Ad Hoc NetworkDeepika ChaudharyDistance and Frequency based Route Stability Estimation <strong>in</strong> Mobile Adhoc NetworksAjay Koul, R. B. Patel, and V. K. BhatInvestigation <strong>of</strong> Blackhole Attack on AODV <strong>in</strong> MANETAnu Bala, Raj Kumari, and Jagpreet S<strong>in</strong>ghCopyright Protection <strong>of</strong> Gray Scale Images by Watermark<strong>in</strong>g Technique us<strong>in</strong>g (N,N) Secret Shar<strong>in</strong>gSchemeSushma Yalamanchili and M. Kameswara RaoBroadband Integrated Services over Proposed Open CPE ArchitectureKushal RoyRecovery Based Architecture to Protect Hids Log Files us<strong>in</strong>g Time StampsSur<strong>in</strong>der S<strong>in</strong>gh Khurana, Divya Bansal , and Sanjeev S<strong>of</strong>atS<strong>of</strong>tware RadioVarun Sharma and Yadv<strong>in</strong>der S<strong>in</strong>gh MannSDR and Error Correction us<strong>in</strong>g Convolution Encod<strong>in</strong>g with Viterbi Decod<strong>in</strong>gShriram K. Vasudevan, Siva Janakiraman, and Subashri Vasudevan<strong>Web</strong><strong>in</strong>ar – Education through Digital CollaborationAnuradha Verma and Anoop S<strong>in</strong>ghEfficient Visual CryptographySupriya A. K<strong>in</strong>ger80868996101106110115122131137


Multistage Interconnection Networks: a Transition from Electronic to OpticalR<strong>in</strong>kle Rani Aggarwal, Lakhw<strong>in</strong>der Kaur, and Himanshu Aggarwal<strong>Web</strong> Based H<strong>in</strong>di to Punjabi Mach<strong>in</strong>e Translation SystemVishal Goyal and Gurpreet S<strong>in</strong>gh LehalProtect<strong>in</strong>g Data from the Cyber Theft – a Virulent DiseaseS. N. Panda and Vikram Mangla142148152


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 79Special Issue on <strong>Emerg<strong>in</strong>g</strong> <strong>Technologies</strong> <strong>in</strong> Internet Security and NetworksGuest EditorialComputer systems have been the core <strong>of</strong> <strong>in</strong>formation technology to provide signal process<strong>in</strong>g and storage capabilitiesand form the basis for the Internet connectivity. Computer systems act as the fundamental core hardware forimplementation <strong>of</strong> the physical layer <strong>of</strong> today's worldwide <strong>in</strong>formation super highways. Network<strong>in</strong>g technologiesprovide end-users with the facilities for network connection, data access, and communications through wired andwireless IP-based networks. On the other hand, communication technologies provide means for signal transmission andreception via efficient multiple access capability through various media, <strong>in</strong>clud<strong>in</strong>g copper wires, optical fibers, radi<strong>of</strong>requency (RF) and other approaches (such as <strong>in</strong>frared, laser, etc.). Integration <strong>of</strong> computer systems, networks, andcommunications is an important trend for future <strong>in</strong>formation technologies (ITs).With the advances <strong>in</strong> the communication and <strong>in</strong>ternet technologies the Information security, data <strong>in</strong>tegrity and safeexchange <strong>of</strong> data and Information are most important and contemporary issues <strong>in</strong> the today’s world. With a mission toreport emerg<strong>in</strong>g a state-<strong>of</strong>-the-art research <strong>in</strong> <strong>Technologies</strong> <strong>in</strong> Network security and Computer Networks, the mostimportant areas <strong>of</strong> <strong>in</strong>formation technology, a special issue <strong>of</strong> JEWTI has been dedicated The research contributionshave been collected through the National Conference –Cum- Workshop on Information Security and Network (ISAN).The mission <strong>of</strong> ISAN was to promote research, development and new <strong>in</strong>ventions <strong>of</strong> Information Security and Networks<strong>in</strong>clud<strong>in</strong>g mobile and wireless technologies DCAS, <strong>in</strong>trusion detection etc.This Issue <strong>of</strong> the <strong>Journal</strong> is designed for researchers, developers, practitioners, policy-makers, pr<strong>of</strong>essional tra<strong>in</strong>ers,educators, and other specialists.Guest Editors:Dr. Himanshu Aggarwal, Punjabi University, India.Dr. Vishal Goyal, Punjabi University, India.Himanshu Aggarwal, Ph.D., is Reader <strong>in</strong> Computer Eng<strong>in</strong>eer<strong>in</strong>g at Punjabi University, Patiala. Hehas more than 15 years <strong>of</strong> teach<strong>in</strong>g experience and served academic <strong>in</strong>stitutions such as Thapar Institute<strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g & Technology, Patiala, Guru Nanak Dev Eng<strong>in</strong>eer<strong>in</strong>g College, Ludhiana and TechnicalTeacher’s Tra<strong>in</strong><strong>in</strong>g Institute, Chandigarh. He is an active researcher who has supervised many M.Tech.Dissertations and contributed 40 articles <strong>in</strong> various Research <strong>Journal</strong>s and Conferences. He is on theeditorial Board <strong>of</strong> several journals <strong>of</strong> repute. His areas <strong>of</strong> <strong>in</strong>terest are Information Systems, ERP andParallel Comput<strong>in</strong>g. Himanshu Aggarwal can be contacted at: himagrawal@rediffmail.com.Vishal Goyal, MCA, M.Tech., is senior lecturer at Department <strong>of</strong> Computer Science, PunjabiUniversity Patiala, Punjab, India. He has more than 10 years <strong>of</strong> teach<strong>in</strong>g, research and s<strong>of</strong>tware <strong>in</strong>dustryexperience. He has about 50 publications <strong>in</strong> various journals and conferences <strong>of</strong> national and <strong>in</strong>ternationalrepute. He is member <strong>of</strong> editorial board <strong>of</strong> various journals <strong>of</strong> computer science <strong>of</strong> national and<strong>in</strong>ternational repute. He is Technical team member <strong>of</strong> E&R Department <strong>of</strong> Infosys <strong>Technologies</strong>. DST hasfunded him research project worth Rs 28Lakhs for development <strong>of</strong> Punjabi Grammar checker. He is veryactive researcher <strong>in</strong> the field <strong>of</strong> Natural Language Process<strong>in</strong>g. He has guided approx. 25 M.tech. studentsand 15 M.Phil Students for their research work. He has been honored with Young Scientist award byPunjab Academy <strong>of</strong> Sciences <strong>in</strong> 2005. He is be<strong>in</strong>g regularly <strong>in</strong>vited by colleges and universities for hisexpert talks. He can be reached at vishal.pup@gmail.com or http://www.punjabiuniversity.ac.<strong>in</strong>.© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.79-79


80 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Performance <strong>of</strong> Dom<strong>in</strong>at<strong>in</strong>g and Adaptive PartialDom<strong>in</strong>at<strong>in</strong>g Sets <strong>in</strong> AODV Rout<strong>in</strong>g Protocol forMANETsA. Nagaraju *, Dr. S. Ramachandram**, B. Eswar**** Head & Associate Pr<strong>of</strong> <strong>in</strong> I.T , Kamala Institute <strong>of</strong> Tech & Science, Huzurabad, Karimnagar, A.P** Head & Pr<strong>of</strong> <strong>in</strong> CSE , Osmania University , Hyderabad. A.P, INDIA***Assistant Pr<strong>of</strong> <strong>in</strong> I.T, Kamala Institute <strong>of</strong> Tech & Science, Huzurabad, Karimnagar, A.P. INDIAAbstract— A mobile ad hoc network (MANET) is a wirelessnetwork that does not rely on any fixed <strong>in</strong>frastructure (i.e.,rout<strong>in</strong>g facilities, such as wired networks and access po<strong>in</strong>ts),and whose nodes must coord<strong>in</strong>ate among themselves todeterm<strong>in</strong>e connectivity and rout<strong>in</strong>g. The broadcast can targeta portion <strong>of</strong> the network (e.g. gather<strong>in</strong>g neighborhood<strong>in</strong>formation), or the entire network (e.g., discover<strong>in</strong>g routes ondemand). Broadcast<strong>in</strong>g <strong>of</strong> signal<strong>in</strong>g and data <strong>in</strong> MANETs raiseredundant transmission <strong>of</strong> control packets to overcome theseproblems we applied dom<strong>in</strong>at<strong>in</strong>g set and Adaptive partialDom<strong>in</strong>at<strong>in</strong>g (APDP) approach to exist<strong>in</strong>g rout<strong>in</strong>g protocolssuch as Ad-hoc On-demand Distance Vector (AODV). Thefocus <strong>of</strong> this paper is to apply the concept <strong>of</strong> DS and APDP toAODV and evaluate the performance <strong>of</strong> dom<strong>in</strong>at<strong>in</strong>g sets <strong>in</strong>AODV that improve broadcast<strong>in</strong>g, End-to-End Delay, Networkload, Packet Latency, and also ma<strong>in</strong>ta<strong>in</strong>s secure packettransmission.IndexTerms—Adaptive partial dom<strong>in</strong>at<strong>in</strong>g, Dom<strong>in</strong>at<strong>in</strong>g sets,AODVI. INTRODUCTIONMobile IP and wireless networks access<strong>in</strong>g the fixednetworks have provided support for the mobility. But it isstill restrictive <strong>in</strong> forc<strong>in</strong>g the connectivity at least to thecore network. It puts impediments on support<strong>in</strong>g the truemobility <strong>in</strong> the network. In this connection, one areawhich is gett<strong>in</strong>g much attention <strong>in</strong> last couple <strong>of</strong> years isMobile Ad Hoc Networks (MANETs). A MANET(Mobile Ad-Hoc Network) is a type <strong>of</strong> ad-hoc networkwith rapidly chang<strong>in</strong>g topology. S<strong>in</strong>ce the nodes <strong>in</strong> aMANET are highly mobile, the topology changesfrequently and the nodes are dynamically connected <strong>in</strong> anarbitrary manner.As def<strong>in</strong>ed <strong>in</strong> [1] a MANET is an autonomoussystem <strong>of</strong> mobile nodes. MANET nodes are equippedwith wireless transmitters and receivers us<strong>in</strong>g antennawhich may be omni directional, highly-po<strong>in</strong>t-to-po<strong>in</strong>t,possibly steerable, etc. At a given po<strong>in</strong>t <strong>in</strong> time,depend<strong>in</strong>g on the positions <strong>of</strong> the nodes and theirtransmitters and receivers coverage patterns,transmission power levels and co-channel <strong>in</strong>terferencelevels, a wireless connectivity <strong>in</strong> the form <strong>of</strong> a random,multi hop graph or ad hoc network exists among thenodes. This ad hoc topology may change with time as thenodes move or adjust their transmission and receptionparameters. There is current and future need for dynamicad hoc network<strong>in</strong>g technology. The emerg<strong>in</strong>g field <strong>of</strong>mobile and nomadic comput<strong>in</strong>g, with its currentemphasis on mobile IP operation, should graduallybroaden and require highly-adaptive mobile network<strong>in</strong>gtechnology to effectively manage multi hop, ad-hocnetwork clusters which can operate autonomously or,more than likely, be attached at some po<strong>in</strong>t(s) to thefixed Internet.There are two broad categories <strong>of</strong> unicast rout<strong>in</strong>gprotocols for MANETs, proactive and reactive. Withproactive rout<strong>in</strong>g (e.g., OLSR [21]), nodes keep rout<strong>in</strong>g<strong>in</strong>formation to all nodes <strong>in</strong> the network, not subject to anyexist<strong>in</strong>g data flow. OLSR is a l<strong>in</strong>k state protocol us<strong>in</strong>g anoptimized broadcast mechanism for the dissem<strong>in</strong>ation <strong>of</strong>l<strong>in</strong>k state <strong>in</strong>formation. In reactive rout<strong>in</strong>g (e.g., AODV[3]), routes are found on demand and nodes f<strong>in</strong>d routes totheir dest<strong>in</strong>ations as they are needed. Route discoverystarts by broadcast<strong>in</strong>g a route request (RREQ) messagethroughout the network. This message is relayed until itreaches a node with a valid route to the dest<strong>in</strong>ation, or thedest<strong>in</strong>ation itself. Once this happens, a routereply (RREP)message is sent back to the source by revers<strong>in</strong>g the pathtraversed by the RREQ message. Only after receiv<strong>in</strong>g thecorrespond<strong>in</strong>g RREP message can the source startsend<strong>in</strong>g packets to the dest<strong>in</strong>ation. Reactive and proactiverout<strong>in</strong>g can be comb<strong>in</strong>ed, result<strong>in</strong>g <strong>in</strong> hybrid protocols(e.g., ZRP 20]). In this case, routes to some nodes(usually the nearest ones) are kept proactively, whileroutes to the rema<strong>in</strong><strong>in</strong>g nodes are found on-demand.Neighbor-knowledge-based methods ma<strong>in</strong>lydepend on the follow<strong>in</strong>g idea: To avoid flood<strong>in</strong>g thewhole network, a small set <strong>of</strong> forward nodes is selectedsuch that the forward node set forms a connecteddom<strong>in</strong>at<strong>in</strong>g set (CDS). A node set is a connecteddom<strong>in</strong>at<strong>in</strong>g set if every node <strong>in</strong> the network is either <strong>in</strong>that set or the neighbor <strong>of</strong> a node <strong>in</strong> that set. Then thechallenge is to select a small set <strong>of</strong> forward nodes <strong>in</strong> theabsence <strong>of</strong> global network <strong>in</strong>formationIn our proposed paper we focused on apply<strong>in</strong>gAPD to AODV and to evaluate the performance <strong>of</strong>Dom<strong>in</strong>at<strong>in</strong>g sets <strong>in</strong> Ad-hoc On Demand Distance VectorRout<strong>in</strong>g algorithm(AODV) that improve broadcast<strong>in</strong>g, Endto-EndDelay, Network load, Packet Latency, and alsoMa<strong>in</strong>ta<strong>in</strong>s secure packet transmission . To do this, conceptsfrom dom<strong>in</strong>ation <strong>in</strong> graphs have been explored (i.e.© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.80-85


82 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010messages are handled may differ among differentprotocols, but their functionality rema<strong>in</strong>s the same: arequest is relayed until it reaches a node with a valid routeto the dest<strong>in</strong>ation or the dest<strong>in</strong>ation itself, which triggers areply message sent back to the orig<strong>in</strong>ator. Severalparameters (such as how long to keep requests <strong>in</strong> a cache,timeouts for requests, timeouts for hellos) are subject totun<strong>in</strong>g, and the choices made may result <strong>in</strong> improvements<strong>in</strong> the protocol performance. However, RREQs arepropagated us<strong>in</strong>g either an unrestricted broadcast or anexpand<strong>in</strong>g r<strong>in</strong>g search. In either case, the result<strong>in</strong>gflood<strong>in</strong>g operation causes considerable collisions <strong>of</strong>packets <strong>in</strong> wireless networks us<strong>in</strong>g contention-basedchannel access.In addition to apply<strong>in</strong>g DP to reduce the number <strong>of</strong>nodes that need to propagate RREQs transmitted onbroadcast mode, <strong>in</strong>formation regard<strong>in</strong>g prior routes to adest<strong>in</strong>ation is used to unicast RREQs to a region close tothe <strong>in</strong>tended dest<strong>in</strong>ation, so that broadcast RREQs arepostponed as much as possible and occur (if necessary)only close to the dest<strong>in</strong>ation, rather than on network-widebasis. This RREQ Algoritm presents the pseudo-code forthe modified RREQ. A route request (RREQ) is handledas follows:• If the source <strong>of</strong> a RREQ does not have any previousknowledge about the route to the dest<strong>in</strong>ation or is retry<strong>in</strong>gthe RREQ, it calculates its forwarder list us<strong>in</strong>g DP, andbroadcasts the packet (L<strong>in</strong>es 8, 9, and 14).• On the other hand, if the source <strong>of</strong> a RREQ hasknowledge about a recently expired route to thedest<strong>in</strong>ation, and there is a valid route to the next hoptowards the dest<strong>in</strong>ation (L<strong>in</strong>es 2, 3, and 4), the nodecalculates the forwarder list us<strong>in</strong>g DP (L<strong>in</strong>e 9), but <strong>in</strong>stead<strong>of</strong> broadcast<strong>in</strong>g the RREQ packet, the node unicasts thepacket to the last known next hop towards the dest<strong>in</strong>ation(L<strong>in</strong>e 12).Upon receiv<strong>in</strong>g a route request, a forwarder thatcannot respond to this request calculates its ownforwarder list us<strong>in</strong>g the <strong>in</strong>formation provided <strong>in</strong> theRREQ packet (i.e., forwarder list, second to previousforwarder list, and source node) and broadcasts or unicaststhe packet (depend<strong>in</strong>g on which one <strong>of</strong> the two first casesapply) after updat<strong>in</strong>g it with its own forwarder list.RREQ AlgorithmData : n i, dest<strong>in</strong>ation D, B i , U iResult : Unicast the RREQ, or Broadcast the RREQBeg<strong>in</strong>1 if recently expired route to D and not retry<strong>in</strong>gthen2 NextHop ← previous_nextHop(D)3 if validRoute(NextHop) then4 result←Unicast5 else6 result←Broadcast7 else8 result←Broadcast9 F i ←DP( n i, B i , U i )10 Update RREQ packet with F i11 if result== Unicast then12 Unicast the RREQ packet to NextHop13 else14 broadcast the RREQ packetendEventually, the RREQ reaches a node with a route tothe dest<strong>in</strong>ation or the dest<strong>in</strong>ation itself. Our approachattempts to reduce the delay <strong>of</strong> the route discovery byunicast<strong>in</strong>g a RREQ towards the region where thedest<strong>in</strong>ation was previously located. The success <strong>of</strong> thisapproach depends on how fresh the previous known routeto the dest<strong>in</strong>ation is, and how fast the dest<strong>in</strong>ation node ismov<strong>in</strong>g out <strong>of</strong> the previous known location. If an<strong>in</strong>termediate node has completely removed any route tothe dest<strong>in</strong>ation, the RREQ is then broadcasted. The<strong>in</strong>tended effect is to postpone the broadcast <strong>of</strong> a RREQ tothe region closest to the dest<strong>in</strong>ation. In the case that theunicast approach fails, or there is no previous route to thedest<strong>in</strong>ation, the source broadcasts by default.Because <strong>of</strong> topology changes, nodes may not havecorrect two-hop neighborhood <strong>in</strong>formation, which mayresult <strong>in</strong> forward<strong>in</strong>g lists that do not cover all nodes <strong>in</strong>the neighborhood. However, this is not a major problemwhen the request is broadcasted, because a node<strong>in</strong>correctly excluded from the forwarder list may alsoreceive the request and is able to respond <strong>in</strong> the case it hasa route to the dest<strong>in</strong>ation.C. Enhanced Dom<strong>in</strong>ant Prun<strong>in</strong>g AlgorithmIn their paper [6], wei Lou and Jie Wu proposed twoenhanced dom<strong>in</strong>ant prun<strong>in</strong>g algorithms: the TotalDom<strong>in</strong>ant prun<strong>in</strong>g (TDP) algorithm and ParatialDom<strong>in</strong>ant Prun<strong>in</strong>g (PDP).In TDP algorithm, if node v can receive a packetpiggybacked with N(N(v)) from node u , the 2-hopneighbour set that needs to be covered by v’s forwardnode list F is reduced to U = N(N(v)) – N(N(u)). Thema<strong>in</strong> objective <strong>of</strong> the TDP algorithm is that 2-hopneighbourhood <strong>in</strong>formation <strong>of</strong> each sender is piggybacked<strong>in</strong> the broadcast packet which results <strong>in</strong> consumption <strong>of</strong>more bandwidth.D. Partial Dom<strong>in</strong>ant Prun<strong>in</strong>g Algorithm:Just like the DP algorithm, <strong>in</strong> PDP, noneighbourhood <strong>in</strong>formation <strong>of</strong> the sender is piggybackedwith the broadcast packet. Apart from exclud<strong>in</strong>g N (u)and N (v) from N (N (v)) as <strong>in</strong> the DP algorithm, we canhere exclude some more nodes from neighbours <strong>of</strong> eachnode <strong>in</strong> N (u) ∩ N (v). Such a node set is denoted by P(u,v) (or simply P) = N(N(u) ∩ N(v)). Then 2-hopneighbour set U <strong>in</strong> the PDP algorithm can be given by U= N(N(v)) – N(u) – N(v) – P s<strong>in</strong>ce P is a subset <strong>of</strong>N(N(u)), we can easily see P can be excluded fromN(N(v)). Also it can be proved that U is subset <strong>of</strong> N(B),when P = N(N(u)∩N(v)), U = N(N(v)) – N(u) – N(v)-Pand B = N(v) – N(u).E Adaptive Partial Dom<strong>in</strong>ant Prun<strong>in</strong>g Algorithm[19]Adaptive dom<strong>in</strong>ant prun<strong>in</strong>g algorithm (APDP) issimilar to PDP. However, besides exclud<strong>in</strong>g N (u), N (v)and P from N (N (v)) as mentioned <strong>in</strong> PDP algorithm,adjacent nodes <strong>of</strong> U are elim<strong>in</strong>ated from U.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 83APDP Algorithm1 Node v uses N(N(v)) ,N(u), and N(v) to obta<strong>in</strong> P= N (N(u) ∩ N(v) ), U 1 = U – E where U =N(N(v)) – N(u) – N(v) – P and E is the set <strong>of</strong>equivalent and adjacent nodes <strong>in</strong> U and B =N(v) – N(u)2 Node v calls the selection process to determ<strong>in</strong>eF.Now consider Fig 1 <strong>in</strong> the example <strong>of</strong> sample ad-hocnetwork with 12 nodes. Table 1 shows each node <strong>in</strong> Fig 11-hop and 2-hop neighbor nodes. Here we illustrate thedifference between PDP and APDP algorithms.Table 2: PDP algorithmu v P U B FØ 6 Ø 1,3,4,8,10,11 2,5,7,9 7,2,96 7 1,3,6,7 10,12 4,8,11 116 2 2,4,6,8,11 Ø 1,3 [ ]6 9 1,6,9 9 10 107 11 Ø 9 10,12 109 10 Ø 7,12 11 11Table 3: APDP algorithmU V P U B FØ 6 Ø 1,4,8,11 2,5,7,9 7,26 7 1,3,6,7 10,12 4,8,11 116 2 2,4,6,8,11 Ø 1,3 [ ]6 9 1,6,9 9 10 107 11 Ø 9 10,12 109 10 Ø 7,12 11 11The lower bound as per the AMCDS (ApproximationM<strong>in</strong>imum Connected Dom<strong>in</strong>at<strong>in</strong>g Set) reduces them<strong>in</strong>imum connected dom<strong>in</strong>at<strong>in</strong>g set to {2, 6, 7, 11}m<strong>in</strong>imiz<strong>in</strong>g the number <strong>of</strong> forward nodes to 4. Accord<strong>in</strong>gto our proposed model number <strong>of</strong> total forward<strong>in</strong>g nodes<strong>in</strong>clud<strong>in</strong>g source node is 5 i.e. {2, 6, 7, 10, 11} where as itis 6 <strong>in</strong> PDP.Fig 1 An Ad-hoc Network with 12 nodes.Table 1: Two hop neighbors <strong>of</strong> each nodeV N(v) N(N(v))1 1,2,5 1,2,3,5,6,7,92 1,2,3,6,7 1,2,3,4,5,6,7,8,9,113 2,3,4 1,2,3,4,6,7,84 3,4,7,8 2,3,4,6,7,8,11,125 1,5,6,9 1,2,5,6,7,9,106 2,5,6,7,9 1,2,3,4,5,6,7,8,9,10,117 2,4,6,7,8,11 1,2,3,4,5,6,7,8,9,10,11,128 4,7,8,12 2,3,4,6,7,8,11,129 5,6,9,10 1,2,5,6,7,9,10,1110 9,10,11 5,6,7,9,10,11,1211 7,10,11,12 2,4,6,7,8,9,10,11,1212 8,11,12 4,7,8,10,11,12For PDP algorithm, node 6 aga<strong>in</strong> has same forwardnode list F (Ø,6) = [7,2,9]. From P(6,7) = {1,3,6,7 }, wehave U(6,7) = N(N(7)) – N(6) – N(7) – P(6,7) = { 10,12 }.The forward node list for 7 is F(6,7) = {11 }, Similarly ,from P(6,2)= { 2,4,6,8,11} , we have U(6,2) = N(N(2)) –N(6) –N(2) –P(2,6) = Ø and , then , F(6,2) = {10 }.Therefore, the total number <strong>of</strong> forward nodes is 1+3+2 =6. The details <strong>of</strong> P, U, B and F are represented <strong>in</strong> thefollow<strong>in</strong>g Table 2.The total number <strong>of</strong> forward<strong>in</strong>g nodes accord<strong>in</strong>g toPDP is <strong>in</strong> the give example is 6 <strong>in</strong>clud<strong>in</strong>g source node i.e.{ 6,2,7,9,11,10 }.In our proposed model APDP, an enhanced version <strong>of</strong>PDP, the def<strong>in</strong>ition <strong>of</strong> exist<strong>in</strong>g U has been broadened to anew U to check and exclude if it conta<strong>in</strong>s any adjacentnodes. The results <strong>of</strong> the proposed model are presented <strong>in</strong>Table 3IV. SIMULATIONS RESULTS AND SIMULATIONPARAMETERSWe used the simulator glomosim-2.03,[8] to run thesimulation Table 3 summarizes the simulation parameterswe used. The simulation time was 15 m<strong>in</strong>utes accord<strong>in</strong>gto simulator clock. A total <strong>of</strong> 45 nodes were randomlyplaced <strong>in</strong> field <strong>of</strong> 500 X 500 m 2 and <strong>in</strong> field <strong>of</strong> 2000 X2000 m 2 . Power range <strong>of</strong> each node is 250m. Weperformed the simulation for AODV with DP algorithm.Table 3 Simulation ParametersParameter Value DescriptionNumber <strong>of</strong> nodes 160 and 40 Simulation NodesField range x 500m and 2000 X-DimensionField range y 500m and 2000 Y-DimensionPower range 250m Nodes power rangeMac protocol IEEE 802.11 MAC layer protocolNetwork Protocol AODV &RoughAODVTransport Layer UDPProtocolPropagationfunctionFREE-SpaceNetwork LayerTransport LayerPropagationFunctionNode placement Random Nodes aredistributed <strong>in</strong>random mannerSimulation time 15M Accord<strong>in</strong>g tosimulation clockMobility Interval 10-30sec Pause time <strong>of</strong> node© 2010 ACADEMY PUBLISHER


84 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010We run each simulation four times with different nodepause time vary<strong>in</strong>g from 15 to 30sec with a step <strong>in</strong>terval<strong>of</strong> 5 sec. The graphs are presented <strong>in</strong> results section.ResultsThe performance <strong>of</strong> proposed protocol is evaluated us<strong>in</strong>gthe follow<strong>in</strong>g metrics:Packet delivery ratio (Throughput): Packet deliveryfraction is the ratio between the number <strong>of</strong> packetsorig<strong>in</strong>ated by the application layer CBR sources and thenumber <strong>of</strong> packets received by the CBR s<strong>in</strong>ks at the f<strong>in</strong>aldest<strong>in</strong>ations. Packet delivery Ratio is higher for AODVwith Dom<strong>in</strong>at<strong>in</strong>g Sets than that <strong>of</strong> conventional AODV(figure 3 & 7 )Number <strong>of</strong> Control Packets: The total number <strong>of</strong>control packets occurred by different nodes is less <strong>in</strong>AODV with Dom<strong>in</strong>at<strong>in</strong>g Sets than that <strong>of</strong> conventionalAODV(figure 4 & 8).Number <strong>of</strong> Route requests: It is the number <strong>of</strong> controlpackets generated by all the nodes <strong>in</strong> the simulation. Thenumber <strong>of</strong> Route Request packets is less <strong>in</strong> AODV withDom<strong>in</strong>at<strong>in</strong>g Sets (figure 2 & 6 ) compare to conventionalAODV.End-to-End Delay: The End-to-End Delay <strong>of</strong> AODVwith Dom<strong>in</strong>at<strong>in</strong>g Sets is better when compared withconventional AODV (figure 5 & 9).Performance <strong>of</strong> AODV with Dom<strong>in</strong>at<strong>in</strong> sets andAODV <strong>in</strong> the Terra<strong>in</strong> Dimensions (500, 500)RouteThroughputs <strong>in</strong>Requests(persecondsnodes)Comparision Route Requests <strong>in</strong> AODV and AODV withDom<strong>in</strong>at<strong>in</strong>g sets700600500400300200100020 40 60 80 100 120 140 160No <strong>of</strong> NodesAodvAodvdomFig 2 Route Request packet ComparisonComparision <strong>of</strong> Throughputs <strong>in</strong> AODV and AODV withDom<strong>in</strong>at<strong>in</strong>g sets14000120001000080006000400020000AodvdomAodv20 40 60 80 100 120 140 160No <strong>of</strong> NodesAODVAODVDOMAODVAODVDOMEnd-to-End Delay<strong>in</strong> secondsComparision <strong>of</strong> End-to-End Delay <strong>in</strong> AODV and AODVwith Dom<strong>in</strong>at<strong>in</strong>g sets0.050.040.030.020.010Aodv1 2 3 4 5 6 7 8No <strong>of</strong> NodesAodvdomFig 5 End-to-End Delay <strong>in</strong> SecAODVAODVDOMPerformance <strong>of</strong> AODV with dom<strong>in</strong>at<strong>in</strong>g sets andAODV <strong>in</strong> the Terra<strong>in</strong> (2000, 2000) up to 40 nodesRouteRequestpackets sentThroughputs(<strong>in</strong>Control Packetsseconds)Compar<strong>in</strong>g Route Request packets sent <strong>in</strong> AODV andAODV with dom<strong>in</strong>at<strong>in</strong>g sets2000Aodv15001000500010 15 20 25 30 35 40No <strong>of</strong> NodesAodvdomFig 6 Route Request packet ComparisionComparision <strong>of</strong> Throughputs <strong>in</strong> AODV and AODV withdom<strong>in</strong>at<strong>in</strong>g sets80007000Aodvdom60005000400030002000Aodv1000010 15 20 25 30 35 40No <strong>of</strong> nodes2000150010005000Fig 7 Throughput comparisonComparision <strong>of</strong> CTRL Packets <strong>in</strong> AODV and AODV withDom<strong>in</strong>at<strong>in</strong>g setsAodvAodvdom10 15 20 25 30 35 40No <strong>of</strong> nodesFig 8.Control Packets ComparisonAODVAODVDOMAODVAODVDOMAODVAODVDOMControl Packets800600400200Fig 3 Throughput comparisonComparision <strong>of</strong> Control Packets <strong>in</strong> AODV and AODV withDom<strong>in</strong>at<strong>in</strong>g sets020 40 60 80 100 120 140 160No <strong>of</strong> NodesAodvAodvdomFig4.Control Packets ComparisonAODVAODVDOMEnd-to-End delay <strong>in</strong>secondsComparision <strong>of</strong> End-to-End Delay <strong>in</strong> AODV and AODVwith Dom<strong>in</strong>ant sets0.350.3Aodv0.250.2AODV0.15AODVDOM0.1Aodvdom0.05010 15 20 25 30 35 40No <strong>of</strong> nodesFig 9 End-to-End Delay <strong>in</strong> Sec© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 85V. CONCLUSIONS AND FUTURE WORKWe presented an enhanced dom<strong>in</strong>ant prun<strong>in</strong>g approachthat allows prun<strong>in</strong>g redundant broadcasts even more thanthe conventional dom<strong>in</strong>ant prun<strong>in</strong>g heuristic. Redundantbroadcasts <strong>in</strong>crease the number <strong>of</strong> packet collisions, andconsequently delay the response for RREQs <strong>in</strong> the routediscovery process. DP is shown to reduce the number <strong>of</strong>broadcast transmissions when compared to standard DP.Because DP requires the two-hop neighborhood todeterm<strong>in</strong>e the forwarder list, we built a neighbor protocolas part <strong>of</strong> AODV. By mak<strong>in</strong>g the neighbor protocol part<strong>of</strong> AODV, the result is a more accurate view <strong>of</strong> the localtopology, and therefore more accurate is thedeterm<strong>in</strong>ation <strong>of</strong> the forwarder list. We also proposed aAPDP algorithm which is an enhanced version <strong>of</strong> PDP.Here we have shown the performance comparison <strong>of</strong>AODV with DP algorithm. Future scope <strong>of</strong> the work is tocompare to the performance <strong>of</strong> AODV with PDPalgorithm and compare the performance <strong>of</strong> both.REFERENCES[1] Brad Williams and Tracy Camp. Comparison <strong>of</strong>broadcast<strong>in</strong>g techniques for mobile adhoc networks. InMobiHoc ’02: Proceed<strong>in</strong>gs <strong>of</strong> the 3rd ACM <strong>in</strong>ternationalsymposiumon mobile ad hoc network<strong>in</strong>g & comput<strong>in</strong>g,pages 194–205. ACM Press, 2002.[2] C. Perk<strong>in</strong>s. Ad-hoc on-demand distance vector rout<strong>in</strong>g. InProceed<strong>in</strong>gs <strong>of</strong> the IEEE workshop on mobile comput<strong>in</strong>gsystems and applications, pages 90–100, 1999.[3] Charles E. Perk<strong>in</strong>s and Elizabeth M.Royer. Ad-hoc ondemanddistance vector rout<strong>in</strong>g. Technical report, SunMicro Systems Laboratories, Advacnced DevelopmenetGroup, USA.[4] David B Johnson and David A Maltz. Dynamic sourcerout<strong>in</strong>g <strong>in</strong> ad hoc wireless networks.In Mobile Comput<strong>in</strong>g,volume 353, pages 153–179. Kluwer AcademicPublishers,1996.[5] Dipti Joshi, Sridhar Radhakrishnan, and ChandrasekheranNarayanan. A fast algorithm for generalized networklocation problems. In Proceed<strong>in</strong>gs <strong>of</strong> the ACM/SIGAPPsymposium on applied comput<strong>in</strong>g, pages 701–8, 1993[6] H. Lim and C. Kim. Flood<strong>in</strong>g <strong>in</strong> wireless ad hoc networks.Computer Communications, 24(3–4):353–363, February2001[7] Jie Wu and Fei Dai. Broadcast<strong>in</strong>g <strong>in</strong> ad hoc networks basedon self-prun<strong>in</strong>g. In IEEE INFOCOM, pages 2240–2250,2003.[8] Jorge Nuevo, “A comprensible glomosim tutorial”,March4,2004http://appsrv.cse.cuhk.edu.hk\~hndai\research.[9] Katia Obraczka, Kumar Viswanath, and Gene Tsudik.Flood<strong>in</strong>g for reliable multicast <strong>in</strong> multi-hop ad hocnetworks. Wireless Networks, 7(6):627–634, 2001.[10] Marco A. Spohn and J. J. Garcia-Luna-Aceves. Enhanceddom<strong>in</strong>ant prun<strong>in</strong>g applied to the route discovery process <strong>of</strong>on-demand rout<strong>in</strong>g protocols. In Proceed<strong>in</strong>gs <strong>of</strong> the 12thIEEE <strong>in</strong>ternational conference on computercommunications and networks, pages 497–502, October2003[11] Mobile Ad Hoc Network<strong>in</strong>g:Rout<strong>in</strong>g Protocol PerformanceIssues and Evaluation Considerations Request ForComments 2501 available at http://www.ietf.org[12] N<strong>in</strong>g.P. and Sun.K. How to misuse aodv: a case study <strong>of</strong><strong>in</strong>sider attacks aga<strong>in</strong>st mobile ad-hoc rout<strong>in</strong>g protocols.Technical report, Comput. Sci. Dept., North Carol<strong>in</strong>a StateUniv., Raleigh, NC, USA, 2003.[13] Peng-Jun Wan, Khaled M. Alzoubi, and Ophir Frieder.Distributed construction <strong>of</strong> connected dom<strong>in</strong>at<strong>in</strong>g set <strong>in</strong>wireless ad hoc networks. In IEEE INFOCOM, pages1597–1604, June 2002.[14] Rajive Bagrodia. README GloMoSim S<strong>of</strong>tware.University <strong>of</strong> California, Los Angeles - Department <strong>of</strong>Computer Science. Box 951596, 3532 Boelter Hall, LosAngeles-CA 90095-1596 / rajive@cs.ucla.edu.[15] Teresa W. Haynes, Stephen T. Hedetniemi, and Peter J.Slater, editors. Fundamentals <strong>of</strong> Dom<strong>in</strong>ation <strong>in</strong> Graphs.Marcel Dekker, Inc., 1998.[16] Xiaoyan Hong, Kaix<strong>in</strong> Xu, and Mario Gerla. Scalablerout<strong>in</strong>g protocols for mobile ad hoc networks. 2002.[17] Yu-Chee Tseng, Sze-Yao Ni, Yuh-Shyan Chen, and Jang-P<strong>in</strong>g Sheu. The broadcast storm problem <strong>in</strong> a mobile ad hocnetwork. Wireless Networks, 8:153–167, 2002. H. Lim andC. Kim. Flood<strong>in</strong>g <strong>in</strong> wireless ad hoc networks. ComputerCommunications,24(3–4):353–363, February 2001-04-15).[18] Z. Haas. A new rout<strong>in</strong>g protocol for the reconfigurablewireless network. In Proceed<strong>in</strong>gs<strong>of</strong> the IEEE <strong>in</strong>ternationalconference on universal personal communications, pages562–566, October 1997.[19] A Nagaraju , Dr S.Ramachandram “Adaptive PartialDom<strong>in</strong>at<strong>in</strong>g Set Algorithm For Mobile Ad-Hoc Networks”, Presented <strong>in</strong> the <strong>in</strong>ternational conference ACM,COMPUTE-09, Jan 9 th -11 th ,2009,Banglore.[20] J.Hass and M.R.Pearlman, “The Zone Rout<strong>in</strong>gProtoco(ZRP) for Ad Hoc Networks,” draft-ietf-manetzone-zrp-02.txt,work<strong>in</strong> progress,June 1999[21] T.Clausen, P.Jacquet,A.Laouiti, P.Muhlethaler,A. Q andL.Viennot. Optimized l<strong>in</strong>k state rout<strong>in</strong>g protocol for adhocnetworks. In Proceed<strong>in</strong>gs <strong>of</strong> the IEEE <strong>in</strong>ternat multitopics conferences. 2001© 2010 ACADEMY PUBLISHER


86 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Bee-Inspired Rout<strong>in</strong>g Protocols for MobileAd HOC Network (MANET)Deepika ChaudharyChitkara Institute <strong>of</strong> Engg & Technology JhanslaTeh. Rajpura,Distt Patiala-140401,Punjabdeepika.chaudhary@chitkara.edu.<strong>in</strong>Abstract – Mobile AdHoc networks( MANETs) are receiv<strong>in</strong>ga significant amount <strong>of</strong> attention from researchers. Thispaper provides a high light on a new and very energyefficient algorithm for rout<strong>in</strong>g <strong>in</strong> Manets BeeAdHoc. Thisalgorithm is a reactive source rout<strong>in</strong>g algorithm andconsumes less energy as compared to other exist<strong>in</strong>g state <strong>of</strong>art rout<strong>in</strong>g algorithms because a fewer control packets forrout<strong>in</strong>g are sent as compared to other networks.I. INTRODUCTIONMobile Ad HOC networks (MANET’S) are networks <strong>in</strong>which all nodes are mobile and communicate with each other viawireless connections. Nodes can jo<strong>in</strong> or leave the network at anytime. There is no fixed <strong>in</strong>frastructure. All nodes are equal andthere is no centralized control or overview. There no designatedrouters all nodes can serve as routers for each other and datapackets are forwarded from node to node <strong>in</strong> multihop fashion.S<strong>in</strong>ce a few years researcher’s <strong>in</strong>terest <strong>in</strong> MANETS havebeen grow<strong>in</strong>g and especially the design <strong>of</strong> MANET rout<strong>in</strong>gprotocols has received a lot <strong>of</strong> attention. One <strong>of</strong> the reasons isthat rout<strong>in</strong>g <strong>in</strong> MANETS is particularly challeng<strong>in</strong>g task due tothe fact that the topology <strong>of</strong> the network changes constantly andpaths, which were <strong>in</strong>itially efficient, can quickly become<strong>in</strong>efficient or even <strong>in</strong>feasible. Moreover control <strong>in</strong>formation flow<strong>in</strong> the network is very restricted. This is because the bandwidth<strong>of</strong> the wireless medium is very limited and the medium isshared: nodes can only send or receive data if no other node issend<strong>in</strong>g <strong>in</strong> their radio neighborhood. It is therefore important todesign algorithm that are adaptive robust & self-heal<strong>in</strong>g. Natureself-organiz<strong>in</strong>g systems like <strong>in</strong>sect societies show precisely thesedesirable properties. Mak<strong>in</strong>g use <strong>of</strong> a number <strong>of</strong> relativelysimple biological agents like ants, a variety <strong>of</strong> differentorganized behavior are generated at the system level from thelocal <strong>in</strong>teraction among the agents and with the environment.The robustness and effectiveness <strong>of</strong> such collective behaviorswith respect to variations <strong>of</strong> environment conditions are keyaspects <strong>of</strong> their biological success. This k<strong>in</strong>d <strong>of</strong> systems are<strong>of</strong>ten referred to with the term swarm <strong>in</strong>telligence. Swarmsystems have recently become a source <strong>of</strong> <strong>in</strong>spiration for design<strong>of</strong> distributed & adaptive algorithms.II. DESIGN ISSUES OF ROUTING ALGORITHMSThe most important challenge <strong>in</strong> design<strong>in</strong>g algorithms forMANETs are mobility and limited battery capacity <strong>of</strong> nodes.Mobility <strong>of</strong> nodes results <strong>in</strong> cont<strong>in</strong>uously evolv<strong>in</strong>g newtopologies and consequently the rout<strong>in</strong>g algorithms have todiscover or update the routes <strong>in</strong> real time but with small controloverhead . The limited battery capacity requires that the packetsif possible be distributed on multiple paths , which would result<strong>in</strong> the depletion <strong>of</strong> batteries <strong>of</strong> different nodes at an equal rateand hence as a result the life time <strong>of</strong> networks would <strong>in</strong>crease[1].Therefore an important challenge <strong>in</strong> Manets is to design arout<strong>in</strong>g algorithm that is not only energy effieicent but alsodelivers performance same or better than exist<strong>in</strong>g state <strong>of</strong> artrout<strong>in</strong>g protocols.III. CLASSIFICATION OF ROUTING ALGORITHMS INMANETSThe rout<strong>in</strong>g algorithms for Manets can be broadly classifiedas proactive algorithms or reactive algorithms. Proactivealgorithms periodically launch control packets which collect thenew network state and update the rout<strong>in</strong>g tables accord<strong>in</strong>gly. Onthe other hand, reactive algorithms f<strong>in</strong>d routes on demand only.Reactive algorithms looks more promis<strong>in</strong>g from the prespective<strong>of</strong> energy consumption <strong>in</strong> Manets. Each category <strong>of</strong> abovementioned algorithms can further be classified <strong>in</strong>to host<strong>in</strong>telligent or router <strong>in</strong>telligent algorithms . A few reactivealgorithms are DSR ( Dynamic Source Rout<strong>in</strong>g ) which is host<strong>in</strong>telligent algorithm while AODV( AdHoc On DemandDistance Vector Rout<strong>in</strong>g) which is a router –<strong>in</strong>telligentalgorithm.However these algorithms are not designed for energyefficient rout<strong>in</strong>g. Here <strong>in</strong> this study an deep <strong>in</strong>sight is providedon BeeAdHoc which delivers performance same as better thanthat <strong>of</strong> DSR,AODV but consumes less energy as compared tothem. The algorithm achieves these objectives by transmitt<strong>in</strong>gfewer control packets and by distribut<strong>in</strong>g data packets onmultiple paths.IV. EXISTING WORK ON NATURE –INSPIRED MANETROUTING PROTOCOLSThe first algorithm which presents a detailed scheme forMANET rout<strong>in</strong>g based on ant colony pr<strong>in</strong>ciples is ARA [3]. Thealgorithm has its roots <strong>in</strong> ABC AND AntNet Rout<strong>in</strong>g algorithmsfor fixed networks and are <strong>in</strong>pired by the pheromone lay<strong>in</strong>gbehavior <strong>of</strong> ant colonies . AntHocNet, which is hybrid algorithmhav<strong>in</strong>g both reactive and proactive components have also beenproposed.This algorithm tries to keep most <strong>of</strong> features <strong>of</strong> theorig<strong>in</strong>al AntNet and shows promis<strong>in</strong>g results <strong>in</strong> simulationcomared to AODV Termite is another MANET rout<strong>in</strong>galgorithm <strong>in</strong>spired by termite behaviour .Here no special agentsare needed for updat<strong>in</strong>g the rout<strong>in</strong>g tables rather data packets aredelegated this task.V. OVERVIEW OF BEEADHOC ARCHITECTUREBeeAdHoc is an on-demand multi path rout<strong>in</strong>g algorithm formobile adhoc networks <strong>in</strong>spired from the forag<strong>in</strong>g pr<strong>in</strong>ciples <strong>of</strong>honey bees[4]. BeeAdHoc works with types <strong>of</strong> agents: packers,scouts foragers and swarms. The packers locate a forager andhand over the data packet to the discovered forager. Scoutsdiscover new routes from the launch<strong>in</strong>g node to the dest<strong>in</strong>ation© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.86-88


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 87node through broadcast<strong>in</strong>g pr<strong>in</strong>ciple and an expand<strong>in</strong>g time tolive (TTL) timer. Foragers, the ma<strong>in</strong> workers.The architecture <strong>of</strong> the hive is shown <strong>in</strong> Fig 1 where theentrance floor is an <strong>in</strong>terface to the lower MAC layer, while thepack<strong>in</strong>g floor is an <strong>in</strong>terface to the upper transport layer. Thedance floor conta<strong>in</strong>s the foragers and the rout<strong>in</strong>g <strong>in</strong>formation toroute locally generated packets. The functional characteristics <strong>of</strong>each floor compos<strong>in</strong>g the hive are expla<strong>in</strong>ed <strong>in</strong> the follow<strong>in</strong>g.floor from the MAC layer. If the packet is the forager and th ecurrent node is its dest<strong>in</strong>ation, then the forager is forwarded tothe pack<strong>in</strong>g floor.; otherwise, it is directly routed to the MAC<strong>in</strong>terface <strong>of</strong> the next hop node. If the packet is a scout, it isbroadcast to the neighbor nodes if its TTL timer has not expiredyet or if the current node is not its dest<strong>in</strong>ation. The <strong>in</strong>formationabout the ID <strong>of</strong> the scout and its source node is stored <strong>in</strong> a locallist. If a replica <strong>of</strong> previously received scout arrives at theentrance floor , it is removed from the system. If a forager withthe same dest<strong>in</strong>ation as the scout already exists on the dancefloor, then the forager’s route to the dest<strong>in</strong>ation is given to thescout by append<strong>in</strong>g it to the route held so far by the scout.Fig 1. Overview <strong>of</strong> BeeAdHoc ArchitectureVI. PACKING FLOORThe pack<strong>in</strong>g floor is an <strong>in</strong>terface to the upper transport layer(e.g, TCP or UDP) . Once a data packet arrives from transportlayer, a match<strong>in</strong>g forager for it is looked up on the danced floor .If a forager is found then the data packet is encapsulated <strong>in</strong> itspayload . Otherwise, the data packet is temporary bufferedwait<strong>in</strong>g for a return<strong>in</strong>g forager. If no forager comes back with<strong>in</strong>a certa<strong>in</strong> predef<strong>in</strong>ed time, a scout is launched which isresponsible for discover<strong>in</strong>g new routes to the packet dest<strong>in</strong>ation .Figure 2 expla<strong>in</strong>s the series <strong>of</strong> action performed at pack<strong>in</strong>g floor.Fig 3: The EntranceVIII. DANCE FLOORFig 2 : The Pack<strong>in</strong>g FloorVII. ENTRANCEThe function performed <strong>in</strong> the entrance are shown <strong>in</strong> figure.3. The entrance is an <strong>in</strong>terface to the lower level MAC layer.The entrance handles all <strong>in</strong>com<strong>in</strong>g and out go<strong>in</strong>g packet. Actionon the dance floor depends on the type <strong>of</strong> packet entered theThe dance floor is the heart <strong>of</strong> the hive because it ma<strong>in</strong>ta<strong>in</strong>sthe rout<strong>in</strong>g <strong>in</strong>formation <strong>in</strong> the form <strong>of</strong> foragers. The dance flooris populated with rout<strong>in</strong>g <strong>in</strong>formation by means <strong>of</strong> mechanismrem<strong>in</strong>iscent <strong>of</strong> the waggle dance recruitment <strong>in</strong> natural bee hivesonce a forager returns after its journey, it recruits new forager by“danc<strong>in</strong>g” accord<strong>in</strong>g to the quality <strong>of</strong> the path it traversed.A lifetime forager evaluates the quality <strong>of</strong> its route based onthe average rema<strong>in</strong><strong>in</strong>g battery capacity <strong>of</strong> the nodes along itsroute. The central activity <strong>of</strong> the dance floor module consists <strong>of</strong>send<strong>in</strong>g a match<strong>in</strong>g forager to the pack<strong>in</strong>g floor <strong>in</strong> response to arequest from a packer. The foragers whose lifetime has expiredare not considered for match<strong>in</strong>g. If multiple path be identifiedfor match<strong>in</strong>g, then a forager is selected <strong>in</strong> a random way. Thishelps <strong>in</strong> distribut<strong>in</strong>g the packets over multiple paths, which <strong>in</strong>turn serves two purpose : avoid<strong>in</strong>g congestion under high loadsand deplet<strong>in</strong>g batteries <strong>of</strong> different nodes at comparable rate. Aclone <strong>of</strong> the selected forager is sent to the pack<strong>in</strong>g floor and thenumber <strong>of</strong> permitted clones. If the dance number is 0 then theorig<strong>in</strong>al forager is sent to the pack<strong>in</strong>g floor remov<strong>in</strong>g it <strong>in</strong> thisway from the dance floor. This strategy aims at favor<strong>in</strong>g youngover old foragers.If the last forager for a dest<strong>in</strong>ation leaves ahive then the hive does not have any more route to thedest<strong>in</strong>ation. Nevertheless if a route to the des<strong>in</strong>ation still existsthen soon a forager will be return<strong>in</strong>g to the hive if no foragercomes back with<strong>in</strong> reasonable amount <strong>of</strong> time, then the node has© 2010 ACADEMY PUBLISHER


88 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010probably lost its connection to the dest<strong>in</strong>ation node. In this wayfewer control packets are transmitted result<strong>in</strong>g <strong>in</strong> less energyexpenditure.packets over different routes rather then always send<strong>in</strong>g them onthe best routes.X. FUTURE ASPECTSDesign and development <strong>of</strong> rout<strong>in</strong>g protocols for Mobile AdHoc Networks (MANETs) is an active area <strong>of</strong> research. Thestandard practice among researchers work<strong>in</strong>g <strong>in</strong> this emerg<strong>in</strong>gdoma<strong>in</strong> is to evaluate the performance <strong>of</strong> their rout<strong>in</strong>g protocols<strong>in</strong> a network simulator. In future a mathematical models <strong>of</strong> twokey performance metrics, rout<strong>in</strong>g overhead and route optimality,<strong>of</strong> BeeAdHoc MANET rout<strong>in</strong>g protocol us<strong>in</strong>g a simulator can bestudied . One <strong>of</strong> the key components <strong>of</strong> our BeeAdHoc model isthe collision model at Medium Access Control (MAC) layer. Todesign the mathematical expressions <strong>of</strong> the performance metricscan also provide <strong>in</strong>sight about the behavior <strong>of</strong> BeeAdHoc <strong>in</strong>particular, and a typical ad hoc rout<strong>in</strong>g protocol <strong>in</strong> general.REFERENCESIX. CONCLUSIONThe simplicity <strong>of</strong> BeeAdHoc which results from its simplerarchitecture and its us<strong>in</strong>g a smaller number <strong>of</strong> control packetspay <strong>of</strong>f once we look at the energy consumption <strong>in</strong> transpot<strong>in</strong>gthe packets from their source to their dest<strong>in</strong>ation. BeeAdHocnetwork employs a simple bee behavior to monitor the validity<strong>of</strong> the routes.When compared to other algorithms the batterylevel <strong>of</strong> BeeAdHoc is better because it tries to spread the data[1] Formal Model<strong>in</strong>g <strong>of</strong> BeeAdHoc : A Bio-<strong>in</strong>spired Mobile AdHoc Network Rout<strong>in</strong>g Protocol, Muhammad Saleem 1 , SyedAli Khayam 2 and Muddassar Farooq 3.[2] The wisdom <strong>of</strong> the hive applied to mobile ad-hoc networksWedde, H.R.; Farooq, M.[3] BeeAdHoc: an Efficient, Secure and Scalable Rout<strong>in</strong>gFramework for Mobile AdHoc Networks , Pr<strong>of</strong>. Dr. HorstF. Wedde (wedde@ls3.cs.uni-dortmund.de) ME MuddassarFarooq (muddassar.farooq@ls3.cs.uni-dortmund.de)[4] M. Farooq, “From the Wisdom <strong>of</strong> the Hive to IntelligentRout<strong>in</strong>g <strong>in</strong> Telecommunication Networks” PhD Thesis,Dortmund University, 2006.[5] H. F. Wedde and M. Farooq. “The wisdom <strong>of</strong> the hiveapplied to mobile ad-hoc networks.” In Proceed<strong>in</strong>gs <strong>of</strong> theIEEE Swarm <strong>Intelligence</strong> Symposium, pages 341–348,2005.[6] P. K. Visscher, “Dance Language”, Encyclopedia <strong>of</strong>Insects, Academic Press, 2003© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 89Distance and Frequency based Route StabilityEstimation <strong>in</strong> Mobile Adhoc NetworksAjay KoulSMVD University/ School <strong>of</strong> computer Science and Eng<strong>in</strong>eer<strong>in</strong>g, Katra, IndiaEmail:ajay.kaul@smvdu.ac.<strong>in</strong>R. B. Patel and V. K. BhatM.M.University/Department <strong>of</strong> Computer Science and Eng<strong>in</strong>eer<strong>in</strong>g, Ambala, IndiaSMVD University/School <strong>of</strong> Applied Physics and Mathematics, Katra, IndiaEmail :{ patel_r_b, vijaykumarbhat2000}@yahoo.comAbstract-This paper discusses the l<strong>in</strong>k stability estimationfor Mobile Ad hoc Networks (MANETs). In this approachthe total time for which the l<strong>in</strong>k rema<strong>in</strong>s connected with theneighbor<strong>in</strong>g nodes is estimated. This helps to predict thestability <strong>of</strong> the route which is required to forward thepackets to the dest<strong>in</strong>ation. This method does not use theselection <strong>of</strong> the next hop on the basis <strong>of</strong> shortest distance,but is based on the time period for which the next hop l<strong>in</strong>krema<strong>in</strong>s connected. The parameters we use, are the distanceand frequency and signal quality. These provide the way fora node to decide the best next hop neighbor and hence aperfect Quality <strong>of</strong> Service (QoS) is also obta<strong>in</strong>ed.The rest <strong>of</strong> the paper is organized as follows.In Section II we discuss the related works. In Section III,the node distance, position and mobility is estimated.The quality <strong>of</strong> signal along with the algorithms to beexecuted on <strong>in</strong>termediate and dest<strong>in</strong>ation nodes arepresented <strong>in</strong> Section IV. In Section V the practicalscenario <strong>of</strong> estimat<strong>in</strong>g the parameters like distance,frequency, mobility, RSSI, etc. and their performanceresults are obta<strong>in</strong>ed. F<strong>in</strong>ally the article is concluded <strong>in</strong>Sections VI.Index Terms— Route stability, frequency, distance,MANETs, QoS.I. INTRODUCTIONAn ad hoc network is a dynamic multihop wirelessnetwork that is established by a set <strong>of</strong> mobilenodes. Such networks are, therefore, suitable for theenvironments where it is a difficult to create a fixed<strong>in</strong>frastructure. In this network, mobile nodes randomlymove and communicate over radio channels. If twomobile nodes are <strong>in</strong> a radio transmission range, they cancommunicate with each other directly, otherwise, thesource node sends/receives the packets via some<strong>in</strong>termediate nodes. Hence a proper rout<strong>in</strong>g algorithm isrequired to route the packets from source to dest<strong>in</strong>ation.Most rout<strong>in</strong>g algorithms, like <strong>in</strong> [1] estimate the l<strong>in</strong>kstability based on the distance between the twoneighbor<strong>in</strong>g nodes. In [2] the electric field as a parameteris used to f<strong>in</strong>d the stable route to the dest<strong>in</strong>ation. Thealgorithm given <strong>in</strong> [3], f<strong>in</strong>ds the best route to thedest<strong>in</strong>ation based on l<strong>in</strong>k perdurability. These, however,do not lead to the reliable solution <strong>in</strong> Mobile Ad hocNetworks (MANETs), as the environments are dynamicand hence the route estimation depends on the factors likemobility and direction as well. In this paper we havetaken these factors <strong>in</strong>to account and the next hop route isselected not on the basis <strong>of</strong> distance only but on mobilityas well. The quality <strong>of</strong> strength is also taken <strong>in</strong>toconsideration. Our results show that our method can alsobe applied <strong>in</strong> the selection <strong>of</strong> the best neighbor<strong>in</strong>g node.II. RELATED WORKMany rout<strong>in</strong>g protocols <strong>in</strong> the past have been proposed onroute stability. In [4] the technique <strong>of</strong> signal stability isused for adaptive rout<strong>in</strong>g <strong>in</strong> Mobile Ad hoc networks. Inthis approach the on demand longer lived routes arediscovered based on signal strength and location stability.The signal strength <strong>of</strong> the neighbor<strong>in</strong>g nodes are detectedby send<strong>in</strong>g beacons, and based on that, the classification<strong>of</strong> strong and weaker channels are established. This isfurther strengthened by choos<strong>in</strong>g a channel which hasexisted for a longer period <strong>of</strong> time. This signal strengthfeature <strong>in</strong> comb<strong>in</strong>ation with the location stability helps <strong>in</strong>selection <strong>of</strong> the next hop neighbor and hence the overallroute is established. The protocol mentioned even thoughgives good results <strong>in</strong> establish<strong>in</strong>g stable route, however,fails when the node density <strong>in</strong>creases or the node mobility<strong>in</strong>creases. The Global position<strong>in</strong>g system based reliableroute discovery proposed <strong>in</strong> [5] used a different approach.The algorithm discovers routes based on two zones, thestable zone and the caution zone. The zones are decidedbased on the location and the mobility <strong>of</strong> the nodes us<strong>in</strong>gthe Global position<strong>in</strong>g system (GPS). The stable zone andthe caution zone change dynamically depend<strong>in</strong>g on themobile nodes speed and direction <strong>in</strong>formation. Themobile nodes speed, direction and position is estimatedbased on GPS system. This method is the perfect method<strong>of</strong> determ<strong>in</strong><strong>in</strong>g the stability <strong>of</strong> the route as the criticalparameters like direction and mobility is determ<strong>in</strong>ed. Themethod mentioned however, has a serious drawback <strong>of</strong>additional cost <strong>in</strong>volvement and more power requirementfor the GPS based device. In [6] a model to f<strong>in</strong>d the best© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.89-95


90 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010route based on l<strong>in</strong>k lifetime has been proposed. In thismodel the edge effect has been explored to f<strong>in</strong>d morestable route to the dest<strong>in</strong>ation. The lifetime and thestability <strong>of</strong> the route is calculated by elim<strong>in</strong>at<strong>in</strong>g the edgeeffect to reduce route ma<strong>in</strong>tenance and route overheads.The disadvantage <strong>of</strong> this model however is that eachmethod proposed under the model requires either pilotsignal generation and monitor<strong>in</strong>g <strong>of</strong> the pilot signal <strong>of</strong> theother nodes or monitor<strong>in</strong>g <strong>of</strong> signal strength <strong>of</strong> the othernodes. With these weaknesses, the stable route still getsestablished and performance <strong>of</strong> the network also gets<strong>in</strong>creased. Lifetime Prediction Rout<strong>in</strong>g (LPR) proposed <strong>in</strong>[7] also was suggested to f<strong>in</strong>d the stability <strong>of</strong> the route. Inthis the service life <strong>of</strong> the MANET is predicted andcorrespond<strong>in</strong>gly the route is established. The servicelifetime is predicted based on the past activity <strong>of</strong> thebattery lifetime <strong>of</strong> the node. A simple mov<strong>in</strong>g averagepredictor is used to keep track <strong>of</strong> last N values <strong>of</strong> residualenergies and the correspond<strong>in</strong>g time <strong>in</strong>stances for the lastN packets received/ relayed by each mobile node. Thisway LPR not only captures the rema<strong>in</strong><strong>in</strong>g batterycapacity but also accounts for rate <strong>of</strong> energy discharge.This way the route stability and lifetime is estimatedbased on the battery life which is also an important factor.This method has some serious concerns like, when thenode mobility <strong>in</strong>creases it becomes difficult to predict thelifetime <strong>of</strong> the node and also the use <strong>of</strong> LPR <strong>in</strong>volvescerta<strong>in</strong> overheads. One more model to predict the l<strong>in</strong>kstability was proposed <strong>in</strong> [8]. This model was named asthe signal stability based rout<strong>in</strong>g protocol (SSA + ) model.SSA + is the enhanced version <strong>of</strong> SSA for f<strong>in</strong>d<strong>in</strong>g theroute stability <strong>in</strong> MANETs. In this method a route isma<strong>in</strong>ta<strong>in</strong>ed with the help <strong>of</strong> active neighbour<strong>in</strong>g nodes.The neighbours are considered active if it relays ororig<strong>in</strong>ates at least one packet with<strong>in</strong> the most recentactive timeout period. The SSA + solution was ma<strong>in</strong>ly<strong>of</strong>fered to remove the problems <strong>of</strong> high node density andhigh mobility and the low node density and low mobility.In high node density and high mobility scenario themobility is high, the probability <strong>of</strong> l<strong>in</strong>k failures rema<strong>in</strong>also high. To cater to the problem the signal strength <strong>of</strong>the l<strong>in</strong>k is estimated and classified <strong>in</strong>to the categories <strong>of</strong>weak, normal and strong signals. The nodes exchange<strong>in</strong>formation regard<strong>in</strong>g the signal strength by send<strong>in</strong>g thehello packets and based upon the signal strength valuestored <strong>in</strong> the l<strong>in</strong>k state table, the life time <strong>of</strong> the route isdeterm<strong>in</strong>ed. In low node density and low mobility thesignals <strong>of</strong> the nodes rema<strong>in</strong> weaker and the stability andthe route lifetime is ma<strong>in</strong>ta<strong>in</strong>ed based on two importantconditions.1) The distance between any two nodes getsshorter for the past few clicks.2) Secondly the distance between any two nodesgets longer but the distance changes largerslowly for the past few clicks (the condition <strong>of</strong>low mobility).The method above mentioned above, even thoughshowed better results compared to SSA <strong>in</strong> terms <strong>of</strong> lownode density and low mobility and high node density andhigh mobility has the drawback <strong>of</strong> predict<strong>in</strong>g the lifetime<strong>of</strong> the route <strong>in</strong> a complicated way as the node has toma<strong>in</strong>ta<strong>in</strong> the L<strong>in</strong>k stability table which adds lots <strong>of</strong>overheads <strong>in</strong> terms <strong>of</strong> route control and ma<strong>in</strong>tenance andwhich are difficult to ma<strong>in</strong>ta<strong>in</strong>. In [9] [10] and [11],algorithms are proposed as DV-Hop, Hop-TERRAIN,and l<strong>in</strong>k stability with dynamic delay prediction, todeterm<strong>in</strong>e the location <strong>of</strong> nodes based on hop counts andthe appropriate route to the dest<strong>in</strong>ation. The hop countsprovided an estimate for the overall distance between thenodes and the dynamic delay ensured stability. Thesehowever, were ma<strong>in</strong>ly focus<strong>in</strong>g on the Quality <strong>of</strong> service(QoS) based route establishment and hence were silent onthe route lifetime parameters like mobility and batterypower. A Novel route metric based on the fragility <strong>of</strong> theroute was also proposed <strong>in</strong> [12]. In this approach thedynamic nature <strong>of</strong> the route is captured by study<strong>in</strong>g thedistance variation <strong>of</strong> the next hop neighbor <strong>in</strong> terms <strong>of</strong>expansion and contraction. A distributed algorithm isexecuted <strong>in</strong> every node to calculate the relative speedestimate <strong>of</strong> the neighbours. The dest<strong>in</strong>ation node gets the<strong>in</strong>formation <strong>of</strong> every route and selects the best routebased on the route fragility coefficient (RFC) which <strong>in</strong>turn depends on the cumulative expansion metrics (CEM)and cumulative contraction metrics (CCM). Thisapproach f<strong>in</strong>ds the stability <strong>of</strong> the route and is good <strong>in</strong>terms <strong>of</strong> not requir<strong>in</strong>g time bound measurements, like theglobal position<strong>in</strong>g system. This method however, fails topredict the node mobility and <strong>in</strong>cludes the dest<strong>in</strong>ationlatency. The estimation <strong>of</strong> l<strong>in</strong>k quality and residual time<strong>in</strong> vehicular Adhoc networks proposed <strong>in</strong> [13] is also themethod to determ<strong>in</strong>e stability <strong>of</strong> the route <strong>in</strong> MANETs bypredict<strong>in</strong>g the active time <strong>of</strong> the l<strong>in</strong>k. In this method thesignal process<strong>in</strong>g along with empirical decompositionand robust regression is used to predict the l<strong>in</strong>k qualityand the residual time. This method unlike the methodproposed <strong>in</strong> this paper uses a three stage approach which<strong>in</strong>volves lots <strong>of</strong> complexity <strong>in</strong> terms <strong>of</strong> practicaldeployment. This also <strong>in</strong>volves additional burden <strong>of</strong>calculat<strong>in</strong>g the various essential parameters mentionedunder signal process<strong>in</strong>g, empirical decomposition androbust regression methods. The above mentionedliterature even though provides excellent way <strong>of</strong>estimat<strong>in</strong>g the distance and the location <strong>of</strong> neighbor<strong>in</strong>gnodes through different techniques, however, are mostlysilent on the mobility issue. This paper provides the routestability estimation based upon the neighbor<strong>in</strong>g nodedistance ,mobility and signal strength.III. DESCRIPTIONMobile Ad hoc Networks (MANETs) be<strong>in</strong>g dynamic <strong>in</strong>nature create challenges <strong>in</strong> terms <strong>of</strong> Quality <strong>of</strong> Service(QoS) at each level from application to physical. Inphysical layer level the mechanism to predict the lifetime<strong>of</strong> the neighbor<strong>in</strong>g node <strong>in</strong>creases reliability from sourceto dest<strong>in</strong>ation delivery. To achieve this we have identifiedthe follow<strong>in</strong>g three parameters for next hop path selection1) Node Distance and position2) Mobility3) Signal quality© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 91A. Node Distance and positionLet two circles with radii R 1 and R 2 <strong>in</strong>tersect <strong>in</strong> a regionas shown <strong>in</strong> Fig. 1 Let the circles be centered At A (0, 0)and B(d, 0). Then equations <strong>of</strong> the circles are( d )2 2 2x + y = R1(1)2 2 2x − + y = R2(2)This implies that2 2 2 2 2x − 2dx+ d − x = R2− R1(3)⎛ 2 2 2 ⎞⎜ d − R + Rx =2 1 ⎟⎜ 2d⎟⎝⎠Figure 1. Show<strong>in</strong>g the wireless range <strong>in</strong>tersection.(4)Now y is half <strong>of</strong> the length <strong>of</strong> chord connect<strong>in</strong>g the twocircles, we have2 2y = R1− x2 2 2 2 2 224dR1− ( d − R2+ R1)y = (5)24dTo f<strong>in</strong>d out d 1 and d 2 the distances from centre on nodesto the circle <strong>in</strong>tersection po<strong>in</strong>t, we use the relation22 2 2( d − R R )d2+11= (6)2dd22 2 2( d + R2− R1)= (7)2dTo f<strong>in</strong>d the distance d, and position parameters x, ywe assume the follow<strong>in</strong>g:1) That all the nodes are <strong>of</strong> equal strength andtechnical specifications2) That the radii are known and are same for allthe nodes because <strong>of</strong> same transmission power.With these assumptions and from (1-7), the distance canbe found us<strong>in</strong>g the method as given <strong>in</strong> [14], known asround trip time based method. This works on the conceptthat every data packet can be acknowledged. Under thiswork the time span from the moment at which a packetstarts to occupy the wireless medium to the time at whichthe immediate acknowledgment is received is measuredand denoted by T R . The time duration between thereception <strong>of</strong> a data packet and issu<strong>in</strong>g the correspond<strong>in</strong>gimmediate acknowledgment is also measured anddenoted by T L . The distance is computed based on therelation between the distance traveled and the speed <strong>of</strong>light as follows:( TR−TL)d = × C2(8)Where C= 3 × 10 8 is the speed <strong>of</strong> light. Now solv<strong>in</strong>gfor d1, d2, x,y from (7) and (8), the positionP ( α , β ) <strong>of</strong> the neighbor<strong>in</strong>g node can be estimated. Nowl<strong>in</strong>k stability L s is, given by:⎧1,if d < µ and | AP | ≤|AC |L s = ⎨⎩0,if d < µ and | AP | ≤|AC |WhereAP =2 2α + β2 2AC = m + nand µ and C(m, n) are respectively the maximumpermissible distance and maximum co-ord<strong>in</strong>ate positionallowed to communicate between the nodesB. MobilityMeasurement <strong>of</strong> distance and position as mentionedabove are easy to compute and provides the route stabilityespecially when the nodes are static. In case the nodes aredynamic the mobility plays an important factor. Thedistance and position <strong>in</strong> mobile environment will providethe feasibility <strong>of</strong> communication but will not provide thelife time <strong>of</strong> the route with the neighbor<strong>in</strong>g node. To f<strong>in</strong>dmobility, we calculate the frequency <strong>of</strong> the neighbor<strong>in</strong>gnode from the follow<strong>in</strong>g equations us<strong>in</strong>g [10].⎡ v ⎤f r = f e ⎢ ⎥(9)⎣v+ v sr ⎦Where <strong>in</strong> (9), f r is the received frequency, f e is theemitted frequency, v is the speed <strong>of</strong> the waves <strong>in</strong> themedium and v sr is the radial component <strong>of</strong> the velocity <strong>of</strong>the neighbor<strong>in</strong>g node with respect to the medium(positive if mov<strong>in</strong>g away from the observer, negative ifmov<strong>in</strong>g towards the observer). A similar analysis for amov<strong>in</strong>g observer and a stationary source yields theobserved frequency from the follow<strong>in</strong>g equation (thereceiver's velocity be<strong>in</strong>g represented as v r ):⎡ v ⎤f r = f e ⎢ ⎥(10)⎣ v + v r ⎦where the same convention applies. We note that v r ispositive if the observer is mov<strong>in</strong>g away from the sourceand negative if the observer is mov<strong>in</strong>g towards the© 2010 ACADEMY PUBLISHER


92 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010source. These can be generalized <strong>in</strong>to a s<strong>in</strong>gle equationwith both the source and receiver mov<strong>in</strong>g as given below:⎡ v ⎤f = ⎢ − srr f e 1 ⎥(11)⎣ v + v sr ⎦Where v sr is the source to receiver velocity radialcomponent. Now s<strong>in</strong>ce the source nodes have equalpower so frequency <strong>of</strong> transmission will rema<strong>in</strong> same forall the nodes with<strong>in</strong> the vic<strong>in</strong>ity. From (11) above we getthe velocity <strong>of</strong> the neighbor<strong>in</strong>g nodes as⎡ f − f ⎤v = e rsr v⎢⎥(12)⎣ f r ⎦Now overall time period for which the l<strong>in</strong>k rema<strong>in</strong>sestablished will depend on the follow<strong>in</strong>g relationdT = (13)v srwhere T <strong>in</strong> (13) is def<strong>in</strong>ed as the time period for whichthe l<strong>in</strong>k with the neighbor<strong>in</strong>g node will rema<strong>in</strong>established. The time period depends on d because if thenode covers the maximum distance away from the othernode, then a small velocity <strong>of</strong> it <strong>in</strong> the opposite directionwill disconnect the l<strong>in</strong>k. The time T will be more if it isnegative as the velocity will be hav<strong>in</strong>g +ve or –ve signdepend<strong>in</strong>g upon the direction <strong>of</strong> motion.C. Signal QualityThe distance, and position plays an important role <strong>in</strong>f<strong>in</strong>d<strong>in</strong>g mobility and hence the l<strong>in</strong>k stability. However,the stability <strong>of</strong> the l<strong>in</strong>k also depends on the quality <strong>of</strong>signal as well. In Mobile Adhoc Networks (MANETs)the signal quality plays an important role <strong>in</strong> select<strong>in</strong>g theroute to the dest<strong>in</strong>ation. The parameters like distance andmobility proposed above effects the signal quality,however <strong>in</strong> spite <strong>of</strong> the feasible distance and mobilitythreshold values, the node may not receive from theneighbor<strong>in</strong>g node the good quality signal due to noisysurround<strong>in</strong>gs. When there is a signal transmission from anode with certa<strong>in</strong> power <strong>in</strong> the noisy environment, the Biterror rate <strong>of</strong> the signal <strong>in</strong>creases apart from the normalpath loss <strong>in</strong> the medium. The receiver on the basis <strong>of</strong> thereceiver sensitivity, and the threshold Signal to NoiseRatio (SNR), predicts the quality <strong>of</strong> signal. Overall it isthe Receiver signal strength <strong>in</strong>dicator (RSSI) whichprovides the details <strong>of</strong> the quality <strong>of</strong> signal received.RSSI which is basically a measurement <strong>of</strong> how well theradio is receiv<strong>in</strong>g or 'hear<strong>in</strong>g' data to determ<strong>in</strong>e thequality <strong>of</strong> signal received. It's typically measured <strong>in</strong> -dBm, which is the power ratio <strong>in</strong> decibel (dB) <strong>of</strong> themeasured power referenced to one milliwatt (mW).Normally <strong>in</strong> the real test<strong>in</strong>g environments the RSSI above-60 dB is considered the threshold required to performgood network<strong>in</strong>g functions and any value higher than thatis the stable value. We denote this value by .Therefore overall l<strong>in</strong>k stability which is denoted by L SSOshould satisfy L S , T and M RSSI the three importantparameters to determ<strong>in</strong>e the stability <strong>of</strong> the route.IV. ROUTINGThe above parameters calculated can be used to enhancethe rout<strong>in</strong>g procedures already available. To <strong>in</strong>coorporatethe changes, the nodes needs to be modified.Below are the node level modifications suggested whenthe node behaves as, the <strong>in</strong>termediate and the dest<strong>in</strong>ationnode.A. Intermediate node operationWhen the <strong>in</strong>termediate node receives the RREQ packetfrom the source or from any <strong>of</strong> its neighbors it providesthe additional <strong>in</strong>formation <strong>of</strong> the distance and thefrequency <strong>in</strong> the RREQ packet and forwards it to thedest<strong>in</strong>ation. The Algorithm 1 provides the operationaldetails to be performed at each <strong>in</strong>termediate node.Algorithm 1 Algorithm to be executed <strong>in</strong> the node1 Set , (m, n), M RSSISet k stable l<strong>in</strong>k time threshold2 Measure d3 if d < µ L s = 1 Goto xElse d > µ L s = 0 stop.3 x: calculate RSSI4 if RSSI < M RSSI goto 8 else5 calculate v sr5 if vsr -ve calculate TElse if +ve calculate T6 if T < k reject6 Else if T > k select and modify RREQ7 stopB. Dest<strong>in</strong>ation node operationThe dest<strong>in</strong>ation node on receiv<strong>in</strong>g RREQ packets fromthe several nodes sends the reply to the source byselect<strong>in</strong>g the best path on the basis <strong>of</strong> the T, M RSSI value.Algorithm 2 provides the process details <strong>of</strong> thedest<strong>in</strong>ation node when RREQ arrives from differentnodes <strong>of</strong> the dest<strong>in</strong>ation node.Algorithm 2 Process execution when RREQ arrives1 Analyze RREQ2 Extract, d, v sr M RSSI*3 Compared with d* and M RSSI with M RSSI * and v sr with v sr*4 if d > d* and M RSSI < M RSSI*and v sr > v sr*Reject RouteElse select RouteThe source node when send<strong>in</strong>g the RREQ packet,calculates before, the distance, mobility and SNR <strong>of</strong> theneighbor<strong>in</strong>g nodes. It then embeds the <strong>in</strong>formation <strong>in</strong> theRREQ packet and sends it to the dest<strong>in</strong>ation via. Nexthop neighbor.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 93V. RESULTSThe experiments were performed <strong>in</strong> the <strong>in</strong>doorenvironments. In the experiment, we used one wirelessaccess po<strong>in</strong>t namely Wireless-G WAP54Gv.2 <strong>of</strong> L<strong>in</strong>ksysmake and a WLan laptop. The access po<strong>in</strong>t and theLaptop were support<strong>in</strong>g the wireless 802.11 b/g modelprotocols. For send<strong>in</strong>g the ICMP packets, we used aGraphic tool namely Multip<strong>in</strong>g Grapher to send the p<strong>in</strong>grequests every second.The payloads <strong>in</strong> bytes were keptconstant at 512bytes. The purpose <strong>of</strong> do<strong>in</strong>g so was to seethe graphic outcome <strong>of</strong> the response. Figures 2 and 3show the details <strong>of</strong> the p<strong>in</strong>g at a max <strong>of</strong> 6ms and 7ms byvary<strong>in</strong>g the <strong>in</strong>door distance from maximum to m<strong>in</strong>imumand vice versa.TABLE I.Velocity and Frequency Recorded Read<strong>in</strong>gsS.No velocity <strong>in</strong> m/s Frequency <strong>in</strong> GHz1 -2 2.41402 -3 2.42123 -4 2.42834 -5 2.43565 -6 2.44216 -7 2.44977 -8 2.45738 -9 2.46439 -10 2.471910 -11 2.479311 -12 2.4868Figure. 2 P<strong>in</strong>g Response at 6ms MaxThe physical and the operational mode rates have beenfixed at 802.11g and 54mbps, 11mbps. The distance d ascalculated <strong>in</strong> (8) is measured from the tool Snuffle.From this tool the and is computed from theMAC time stamps recorded on the transmitted requestand received acknowledgment packets and by subtract<strong>in</strong>gthe MAC time stamps <strong>of</strong> the received reply and the issuedacknowledgment packets.Figure. 3 P<strong>in</strong>g Response at 7 ms Max.Figure 4. shows the distance calculated vs the difference<strong>in</strong> MAC delay. The calculated distance is however not theactual physical distance. The <strong>in</strong>tension here is to checkthe distance between the nodes and to compare it with thethreshold maximum allowable radial distance <strong>in</strong> this casewe have fixed as . Now that the distance between thenodes is calculated, the mobility can be calculated byspecify<strong>in</strong>g the frequency <strong>of</strong> the source at rest which is 2.4GHz and wave velocity 300,000 Kms/second. Theexperiments were carried <strong>in</strong> the <strong>in</strong>doors were the speed <strong>of</strong>the access po<strong>in</strong>t were varied and the frequency it wascalculated by us<strong>in</strong>g the above equations and theDoppler’s effect calculator.Frequency <strong>in</strong> GHz2.52.482.462.442.422.42.382.361 2 3 4 5 6 7 8 9 10 11Speed <strong>in</strong> m/sFigure. 5 Frequency vs SpeedThe data collected are as shown <strong>in</strong> Figure 5. Thevelocities <strong>in</strong> the table 1 above are shown negative this<strong>in</strong>dicates that the node is approach<strong>in</strong>g the other nodewhich is record<strong>in</strong>g the frequency. By calculat<strong>in</strong>g thevelocity we can f<strong>in</strong>d the l<strong>in</strong>k stability as per the equationsgiven above <strong>in</strong> (13) and (14).A. Received Signal Strength IndicatorTo calculate the l<strong>in</strong>k stability based on RSSI parameter,we used a graphical tool called Wirelessmon. This toolprovided the details <strong>of</strong> the RSSI Value recorded and thesignal strength percentage which is proportional to theRSSI value. The more the percentage <strong>of</strong> signal strengththe more the RSSI value closer to zero. Some <strong>of</strong> theGraphs plotted are shown from Fig. 6 to Fig. 8. Thegraphs clearly show that the percentage <strong>of</strong> signal receivedis good when the distance is only 1m and hence the RSSIvalue approach<strong>in</strong>g –ve value towards zero. As soon as thenode is mov<strong>in</strong>g away from the access po<strong>in</strong>t and somealum<strong>in</strong>um wall partition <strong>in</strong>cluded <strong>in</strong> between, It showsthe decl<strong>in</strong>e <strong>in</strong> the signal and hence <strong>in</strong> the RSSI value aswell.Delay <strong>in</strong> µ SecSignal strength (%)Distance <strong>in</strong> Meters x10Figure. 4 Calculated distance vs DelayTime (Seconds)Figure. 6 Signal strength % vs time <strong>in</strong> seconds© 2010 ACADEMY PUBLISHER


94 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Signal strength (%)strength (%)SignalTime (seconds)Figure. 7 Signal strength % vs Time <strong>in</strong> seconds distance=3m and one alum<strong>in</strong>ium partition <strong>in</strong> between the nodesTime ( seconds )Figure. 8 Signal Strength % vs. time <strong>in</strong> sec with distance = 6m andtwo alum<strong>in</strong>um partitions between the nodes.VI. CONCLUSIONSWe have presented an approach on how to measure thedistance and position based on the propagation time <strong>of</strong>IEEE 802.11 packets. We used commercial WLAN card<strong>of</strong> l<strong>in</strong>ksys make support<strong>in</strong>g IEEE 802.11b and 802.11g.The distance and the position measure however is logicaland has no relation with the physical distance or position<strong>in</strong> the co-ord<strong>in</strong>ate system. The frequency measurementresults reveal the mobility <strong>of</strong> the neighbor<strong>in</strong>g nodes. Thedistance parameter can be used to detect the location <strong>of</strong>the node especially when two nodes are static and istherefore, sufficient to determ<strong>in</strong>e next hop l<strong>in</strong>k stability.The frequency measurement to determ<strong>in</strong>e the logicalmobility is however important to determ<strong>in</strong>e the next hoproute stability if any one or both <strong>of</strong> the nodes are mobile.The signal quality also adds the QoS factor. This paper <strong>in</strong>spite <strong>of</strong> explor<strong>in</strong>g three important factors like distanceand mobility RSSI value however is silent on the otherfactors like S/N ratio, BER and overall signal quality. Thedistance factor can somehow presume the strength <strong>of</strong>signal but cannot provide the details <strong>of</strong> the qualityparameters like S/N ratio, BER. These parameters S/Nratio and BER comb<strong>in</strong>ed with the above mentionedparameters like distance and frequency may be used t<strong>of</strong><strong>in</strong>d the best route life <strong>in</strong> near future. The algorithmsdepicted also will be <strong>in</strong>corporated <strong>in</strong> the nodes and arout<strong>in</strong>g protocol will be used to see the performanceenhancement <strong>of</strong> this method over others.REFERENCES[1] Nam T. Nguyen, Ady Wang, Peter Reiher, Ge<strong>of</strong>fKuenn<strong>in</strong>g “ Electric Field Based Rout<strong>in</strong>g : AReliable Framework for Rout<strong>in</strong>g <strong>in</strong> MANETs ”,ACM Mobile Comput<strong>in</strong>g and CommunicationsReview, USA, 8(2): 35-49, 2004.[2] Sun Xueb<strong>in</strong>, Zhou Zheng, “ L<strong>in</strong>k Perdurability basedRout<strong>in</strong>g for Mobile Ad hoc Networks ”, <strong>Journal</strong> <strong>of</strong>Electronics, Ch<strong>in</strong>a, 20(4): 299-304, 2004.[3] M. Royer and C.-K. Toh, “A Review <strong>of</strong> currentRout<strong>in</strong>g Protocols for Ad Hoc Mobile WirelessNetworks”, IEEE Personal Communication Magaz<strong>in</strong>e,6(2): 46-55, 1999.[4] Rohit Dube, Cynthia D. Rais, Kuang-Yeh Wang, andSatish K. Tripathi, “Signal Stability-Based AdaptiveRout<strong>in</strong>g (SSA) for Ad Hoc Mobile Networks,” IEEEPersonal Communications, 4(1): 36-45 1997.[5] Young Joo Soh, Won Kim, Dong Hee kwon, “GPS basedReliable Rout<strong>in</strong>g algorithms for Adhoc networks” <strong>in</strong>Proceed<strong>in</strong>gs <strong>of</strong> IEEE International Conference onCommunications, Hels<strong>in</strong>ki, F<strong>in</strong>land, June 11- 14, 2001,pp.3191-3195[6] G. Lim, K. Sh<strong>in</strong>, S. Lee, H. Yoon and J. S. Ma,“L<strong>in</strong>k Stability and route lifetime <strong>in</strong> ad hoc wirelessnetworks”, <strong>in</strong> Proceed<strong>in</strong>gs <strong>of</strong> International Conferenceon Parallel Process<strong>in</strong>g workshop (ICPPW’02),Vancouver, BC, Canada, August 18-21, 2002, pp. 116-123.[7] M. Maleki, K. Dantu, and M. Pedram, "Lifetimeprediction rout<strong>in</strong>g <strong>in</strong> mobile ad-hoc networks," IEEEWireless Communications and Network<strong>in</strong>g Conference,USA, March 16-20, 2003, vol.2, pp.1185–1190.[8] W.-F. Wang and P.-H. Shih, "Study on an enhanced l<strong>in</strong>kstabilitybased rout<strong>in</strong>g scheme for mobile ad hocnetworks," <strong>in</strong> Proceed<strong>in</strong>gs <strong>of</strong> 3rd Annual IEEECommunication Society Conference on Sensor and Ad HocCommunications and Networks (SECON'06), Reston, VA,USA, vol.3, September 25-28, 2006, pp. 797–802.[9] F. Erbas, J. E.Garcia, K. Jobmann, “Position- based QoSrout<strong>in</strong>g <strong>in</strong> mobile ad hoc networks problem statementand a novel approach”, <strong>in</strong> Proceed<strong>in</strong>gs <strong>of</strong> 3 rd IEEEInternational Conference on performance, Comput<strong>in</strong>gand communications, Pheonix, AZ, USA, April 15- 17,2004, pp. 619- 623.[10] S.R. Medidi, K.H. Vik, “Quality <strong>of</strong> service- Awaresource-Initiated ad-hoc rout<strong>in</strong>g ”, <strong>in</strong> Proceed<strong>in</strong>gs <strong>of</strong>IEEE SECON Conference Pullman, USA, October 4-7,2004, pp. 108-117.[11] Peng Yang, Biao Huang, "QoS Rout<strong>in</strong>g Protocol Based onL<strong>in</strong>k Stability with Dynamic Delay Prediction <strong>in</strong>MANET”, IEEE Pacific-Asia Workshop onComputational <strong>Intelligence</strong> and Industrial Application(PACII), Wuhan, Ch<strong>in</strong>a, vol. 1, December 19-20, 2008,pp.515-518..[12] O. Tickoo, S. Raghunath, Kalyanaraman S, “Routefragility: a novel metric for route selection <strong>in</strong> mobile adhoc networks”, <strong>in</strong> Procced<strong>in</strong>gs <strong>of</strong> the 11 th IEEE<strong>in</strong>ternational conference on networks (ICON), SydneyNSW, Austrailia, september 28- 1 st october 2003, pp. 537-542.[13] Nikoletta S<strong>of</strong>ra, K. K. Leung, “ Estimation <strong>of</strong> L<strong>in</strong>k qualityand Residual Time <strong>in</strong> VANETs”, <strong>in</strong> Proceed<strong>in</strong>gs <strong>of</strong> IEEEwireless communications and Network<strong>in</strong>g Conference(WCNC), Sydney, Austrailia, 31 March- 3 rd April, 2008,pp.2444-2449.[14] Murad Abusubaih, Berthold Rathke, and AdamWolisz, “A Dual Distance Measurement scheme forIndoor IEEE Wireless Local Area Networks”, <strong>in</strong>Proceed<strong>in</strong>gs <strong>of</strong> the 9 th IFIP/IEEE InternationalConference on Mobile and wireless CommunicationNetworks (MWCN’07), Ireland, Cork, September 9-21,2007, pp. 121-125.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 95[15] Branislav Kusy, Akos Ledeczi, Xen<strong>of</strong>on,Koutsoukos, “Track<strong>in</strong>g Mobile nodes us<strong>in</strong>g RF Dopplershifts”, <strong>in</strong> Proceed<strong>in</strong>gs <strong>of</strong> the 5 th InternationalConference on Embedded networked sensor systems,Sydney, NSW, Australia, November 6-9, 2007, pp.29-42.Ajay koul received his B.E. degree from BangaloreUniversity, Bangalore, Karnataka, India <strong>in</strong> Electrical& Electronics <strong>in</strong> 1997 and MTech from HyderabadUniversity, Hyderabad, Andhra Pradesh, India <strong>in</strong>Computer Science <strong>in</strong> the year 2001.He is currently a Ph.D. student <strong>in</strong> the School <strong>of</strong>Computer Science at SMVD University Katra, J&K,India. His research <strong>in</strong>terests <strong>in</strong>clude wirelessnetworks, Image process<strong>in</strong>g and data storage.Dr. R. B. Patel received his PhD from IIT Roorkee,Roorkee, Uttarakhand, India, <strong>in</strong> Computer Science &Eng<strong>in</strong>eer<strong>in</strong>g. PDF from Highest Institute <strong>of</strong>Education, Science & Technology (HIEST), Athens,Greece, MS (S<strong>of</strong>tware Systems) from BITS, Pilani,RajasthanHe is <strong>in</strong> teach<strong>in</strong>g and Research & Development s<strong>in</strong>ce 1991. Hehas supervised several M. Tech, M. Phil and PhD . He haspublished more than 95 research papers <strong>in</strong>International/National <strong>Journal</strong>s and Refereed InternationalConferences. His current research <strong>in</strong>terests are <strong>in</strong> Mobile &Distributed Comput<strong>in</strong>g, Mobile Agent Security and FaultTolerance, development <strong>in</strong>frastructure for mobile & Peer-To-Peer comput<strong>in</strong>g, Device and Computation Management,Cluster Comput<strong>in</strong>g, etc. He has written numbers books foreng<strong>in</strong>eer<strong>in</strong>g courses (These are “Fundamentals <strong>of</strong> Comput<strong>in</strong>gand Programm<strong>in</strong>g <strong>in</strong> C”, “Theory <strong>of</strong> Automata and FormalLanguages”, “Expert Data Structures with C,” out <strong>of</strong> these someare recommended by Indian Society for Technical Education(ISTE), India.Dr. Patel received several research awards, like best researchpaper award at BIS 2003 Colorado, Spr<strong>in</strong>g, USA and is amember <strong>of</strong> various International Technical Societies such asIEEE-USA, Elsevier-USA, Technology, Knowledge & Society-Australia, WSEAS, Athens.Dr. V.K. Bhat received his MscDegree from KashmirUniversity, Kashmir and Phd Degrees <strong>in</strong> Mathematics fromJammu University, Jammu, J&K, India.He is currently serv<strong>in</strong>g <strong>in</strong> the School <strong>of</strong> Mathematics at SMVDuniversity Katra India. He has supervised many researchstudents <strong>in</strong> the area <strong>of</strong> R<strong>in</strong>g theory, Load balanc<strong>in</strong>g anddistributed networks. He has published nearly 65 researchpapers mostly <strong>in</strong> <strong>in</strong>ternational journals and conferences <strong>of</strong>repute. His current research <strong>in</strong>terests <strong>in</strong>clude Graph theory andR<strong>in</strong>g theory.© 2010 ACADEMY PUBLISHER


96 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Investigation <strong>of</strong> Blackhole Attack on AODV <strong>in</strong>MANETAnu BalaUniversity Institute <strong>of</strong> Engg. & Tech Deptt, Panjab University, Chandigarh,IndiaEmail: anubala22@gmail.comRaj Kumari and Jagpreet S<strong>in</strong>ghUniversity Institute <strong>of</strong> Engg. & Tech Deptt, Panjab University, Chandigarh,IndiaGuru Teg Bahadur Khalsa Institute <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g and Technology, Malout, IndiaEmail:rajkumari_bhatia5@yahoo.com and drjagz@gmail.comAbstract—Mobile Ad Hoc Network (MANET) consists <strong>of</strong> acollection <strong>of</strong> wireless mobile hosts without the required<strong>in</strong>tervention <strong>of</strong> any exist<strong>in</strong>g <strong>in</strong>frastructure or centralizedaccess po<strong>in</strong>t such as base station. The dynamic topology <strong>of</strong>MANET allows nodes to jo<strong>in</strong> and leave the network at anypo<strong>in</strong>t <strong>of</strong> time. Wireless MANET is particularly vulnerabledue to its fundamental characteristics such as open medium,dynamic topology, distributed cooperation and constra<strong>in</strong>edcapability. In this paper we simulate the blackhole attackwhich is one <strong>of</strong> the possible attacks on AODV rout<strong>in</strong>gprotocol <strong>in</strong> mobile ad hoc networks by the help <strong>of</strong> networksimulator (NS-2). The simulation results show the packetloss, throughput, and end-to-end delay with blackhole andwithout blackhole on AODV <strong>in</strong> MANET. We analyzed thatthe packet loss <strong>in</strong>creases <strong>in</strong> the network with a blackholenode. We also observed that the throughput and end-to-enddelay decreases <strong>in</strong> the network with a blackhole node.Index Terms—<strong>in</strong>troduction, AODV rout<strong>in</strong>g protocol,blackhole attack <strong>in</strong> AODV, simulation environment andresults, conclusion, acknowledgement, referencesI. INTRODUCTIONWireless networks use some sort <strong>of</strong> radio frequencies<strong>in</strong> air to transmit and receive data <strong>in</strong>stead <strong>of</strong> us<strong>in</strong>g somephysical cables. Wireless networks are formed by routersand hosts. Ad-hoc networks are wireless networks wherenodes communicate with each other us<strong>in</strong>g multi-hopl<strong>in</strong>ks. Networks that support mobile wireless ad hocarchitecture are typically called mobile ad hoc networks(MANET). A mobile ad hoc network is formed bymobile hosts. There is no stationary <strong>in</strong>frastructure or basestation for communication. So the function<strong>in</strong>g <strong>of</strong> Ad-hocnetworks is dependent on the trust and co-operationbetween nodes. Ref. [1] Nodes help each other <strong>in</strong>convey<strong>in</strong>g <strong>in</strong>formation about the topology <strong>of</strong> the networkand share the responsibility <strong>of</strong> manag<strong>in</strong>g the network.Ref. [2] Each mobile node acts as a host whenrequest<strong>in</strong>g/provid<strong>in</strong>g <strong>in</strong>formation from/to other nodes <strong>in</strong>the network, and acts as router when discover<strong>in</strong>g andma<strong>in</strong>ta<strong>in</strong><strong>in</strong>g routes for other nodes <strong>in</strong> the network.Ref. [3] Based on the rout<strong>in</strong>g <strong>in</strong>formation updatemechanism, rout<strong>in</strong>g protocols <strong>in</strong> ad hoc wirelessnetworks can be classified <strong>in</strong>to three broad categories:Proactive (or table-driven) protocols, Reactive (or ondemand)protocols, and Hybrid rout<strong>in</strong>g protocols. Theseare further divided <strong>in</strong>to sub categories. Ref. [3] These arevulnerable to rout<strong>in</strong>g attacks. Rout<strong>in</strong>g attacks <strong>in</strong> ad hocwireless networks can also be classified <strong>in</strong>to five broadcategories: Attacks us<strong>in</strong>g Impersonation, Modification,Fabrication, Replay, and Denial <strong>of</strong> Service (DoS). In thispaper, we focus on blackhole attack that belongs tocategory <strong>of</strong> fabrication attacks.Ref. [4] There are three ma<strong>in</strong> rout<strong>in</strong>g protocolsproposed for MANET: Ad hoc On-demand DistanceVector (AODV) rout<strong>in</strong>g, Dynamic Source Rout<strong>in</strong>g(DSDV), and Dest<strong>in</strong>ation Sequence Distance Vectorrout<strong>in</strong>g protocols. AODV and DSR belong to on-demandrout<strong>in</strong>g protocols and DSDV is a table-driven rout<strong>in</strong>gprotocol. These protocols are vulnerable to differentsecurity attacks. In this paper, we use AODV rout<strong>in</strong>gprotocol because the AODV protocol is vulnerable to theblackhole attack. So we have simulated the behavior <strong>of</strong>blackhole attack on AODV <strong>in</strong> MANET.II.AODV ROUTING PROTOCOLRef. [5] Ad-Hoc On-Demand Distance Vector(AODV) is a reactive rout<strong>in</strong>g protocol <strong>in</strong> which thenetwork generates routes at the start <strong>of</strong> communication.Ref. [7] The Ad Hoc On-Demand Distance Vector(AODV) rout<strong>in</strong>g protocol described <strong>in</strong> builds on theDSDV algorithm. AODV is an improvement on DSDVbecause it typically m<strong>in</strong>imizes the number <strong>of</strong> requiredbroadcasts by creat<strong>in</strong>g routes on a demand basis, asopposed to ma<strong>in</strong>ta<strong>in</strong><strong>in</strong>g a complete list <strong>of</strong> routes as <strong>in</strong> theDSDV algorithm. Ref. [7] The authors <strong>of</strong> AODV classifyit as a pure on-demand route acquisition system, s<strong>in</strong>cenodes that are not on a selected path do not ma<strong>in</strong>ta<strong>in</strong>rout<strong>in</strong>g <strong>in</strong>formation or participate <strong>in</strong> rout<strong>in</strong>g tableexchanges.AODV builds routes us<strong>in</strong>g a route request / route replyquery cycle. When a source node desires a route to adest<strong>in</strong>ation for which it does not already have a route, itbroadcasts a route request (RREQ) packet across thenetwork. Nodes receiv<strong>in</strong>g this packet update their<strong>in</strong>formation for the source node and set up backwardspo<strong>in</strong>ters to the source node <strong>in</strong> the route tables. In additionto the source node's IP address, current sequence number,and broadcast ID, the RREQ also conta<strong>in</strong>s the mostrecent sequence number for the dest<strong>in</strong>ation <strong>of</strong> which the© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.96-100


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 97source node is aware. A node receiv<strong>in</strong>g the RREQ maysend a route reply (RREP) if it is either the dest<strong>in</strong>ation orif it has a route to the dest<strong>in</strong>ation with correspond<strong>in</strong>gsequence number greater than or equal to that conta<strong>in</strong>ed<strong>in</strong> the RREQ. If this is the case, it unicasts a RREP backto the source. Otherwise, it rebroadcasts the RREQ.Nodes keep track <strong>of</strong> the RREQ's source IP address andbroadcast ID. If they receive a RREQ which they havealready processed, they discard the RREQ and do notforward it. As the RREP propagates back to the source,nodes set up forward po<strong>in</strong>ters to the dest<strong>in</strong>ation. Once thesource node receives the RREP, it may beg<strong>in</strong> to forwarddata packets to the dest<strong>in</strong>ation. If the source later receivesa RREP conta<strong>in</strong><strong>in</strong>g a greater sequence number orconta<strong>in</strong>s the same sequence number with a smaller hopcount, it may update its rout<strong>in</strong>g <strong>in</strong>formation for thatdest<strong>in</strong>ation and beg<strong>in</strong> us<strong>in</strong>g the better route. As long asthe route rema<strong>in</strong>s active, it will cont<strong>in</strong>ue to bema<strong>in</strong>ta<strong>in</strong>ed. If a l<strong>in</strong>k break occurs while the route isactive, the node upstream <strong>of</strong> the break propagates a routeerror (RERR) message to the source node to <strong>in</strong>form it <strong>of</strong>the now unreachable dest<strong>in</strong>ation(s). After receiv<strong>in</strong>g theRERR, if the source node still desires the route, it canre<strong>in</strong>itiate route discovery.The rest <strong>of</strong> this paper is organized as follows. Insection II, we discuss the AODV rout<strong>in</strong>g protocol <strong>in</strong>detail. Section III describes the characteristics <strong>of</strong> theblackhole attack on AODV. Section IV provides thesimulation environment and results. F<strong>in</strong>ally we conclude<strong>in</strong> section V.III.BLACKHOLE ATTACK <strong>in</strong> AODVRef. [5] In a blackhole attack, a malicious node canimpersonates a dest<strong>in</strong>ation node by send<strong>in</strong>g a spo<strong>of</strong>edroute packet to a source node that <strong>in</strong>itiates a routediscovery. Ref. [2] A blackhole has two properties:1. The node exploits the ad hoc rout<strong>in</strong>g protocol,such as AODV, to advertise itself as hav<strong>in</strong>g a valid routeto a dest<strong>in</strong>ation, even though the route is spurious, withthe <strong>in</strong>tention <strong>of</strong> <strong>in</strong>tercept<strong>in</strong>g packets.2. The node consumes the <strong>in</strong>tercepted packets.In an ad hoc network that uses the AODV protocol, ablackhole node absorbs the network traffic and drops allpackets. To expla<strong>in</strong> the blackhole attack we add amalicious node that exhibits blackhole behavior <strong>in</strong> theFig. 1.node N8 <strong>in</strong> Fig. 1, and <strong>in</strong>itiates the route discoveryprocess. We assumed node N4 is a malicious node withno fresh enough route to dest<strong>in</strong>ation node N8. However,node N4 claims that it has the route to the dest<strong>in</strong>ationwhenever it receives RREQ packets, and sends theresponse to source node N1. The dest<strong>in</strong>ation node andany other normal <strong>in</strong>termediate nodes that have the freshroute to the dest<strong>in</strong>ation may also give a reply. If the replyfrom a normal node reaches the source node <strong>of</strong> theRREQ. First, everyth<strong>in</strong>g works well; but the reply frommalicious node N4 could reach the source node first, ifthe malicious node is nearer to the source node.Moreover, a malicious node does not need to check itsrout<strong>in</strong>g table when send<strong>in</strong>g a false message; its responseis more likely to reach the source node first. This makesthe source node th<strong>in</strong>k that the route discovery process iscomplete, ignore all other reply messages, and beg<strong>in</strong> tosend data packets. As a result, all the packets through themalicious node are simply consumed or lost. Themalicious node could be said to form a black hole <strong>in</strong> thenetwork. In this way the malicious node can easilymisroute a lot <strong>of</strong> network traffic to itself, and could causean attack to the network with very little efforts on its part.IV.SIMULATION ENVIRONMENT and RESULTIn this section we present a set <strong>of</strong> simulationexperiments to evaluate the effect <strong>of</strong> blackhole attack onAODV protocol <strong>in</strong> MANET. First I have expla<strong>in</strong>edblackhole attack <strong>in</strong> detail via simulation <strong>in</strong> NS-2.We havegenerated a small size network with7 nodes <strong>in</strong> a flat grid<strong>of</strong> 670m x 670m <strong>in</strong>clud<strong>in</strong>g blackhole node. We havegenerated a connection between nodes 1 and node 2. Wehave also <strong>in</strong>troduced some movements <strong>in</strong> our scenario.Duration <strong>of</strong> the scenario is 60 seconds. Node 1 is thesource node, node 2 is the dest<strong>in</strong>ation node and node 6 isthe blackhole node. Fig. 2 shows the data flow from node1 to node 2 via <strong>in</strong>termediate nodes 3 and 4. For someseconds, the l<strong>in</strong>k breaks and all data that is send fromnode 1 get lost as shown <strong>in</strong> Fig.3. Now Fig. 4 shows thatnode 1 aga<strong>in</strong> sends the RREQ to all nodes to f<strong>in</strong>d route.Nodes further rebroadcast the request if they are not thedest<strong>in</strong>ation nodes. Node 6,that is blackhole node, claimsthat it has the route to dest<strong>in</strong>ation whenever it receivesRREQ packets and sends the response to source node 1.All other nodes that have the fresh route also send areply. But the reply from node 6 reaches the source nodefirst. Node 1 accepts it and ignores all other replymessages and beg<strong>in</strong>s to send data packets to node vianode 3, 4, 5 and Node 6 be<strong>in</strong>g a blackhole node absorbsall the packets and traffic as shown <strong>in</strong> Fig. 5.Secondly, to calculate network performance, wesimulate blackhole node behavior <strong>in</strong> AODV <strong>in</strong> largenumber <strong>of</strong> nodes and connections with the help <strong>of</strong>Network Simulator 2 Ref. [6]. We set the parameters forour simulation as shown <strong>in</strong> Table 1.Figure 1: Blackhole attack <strong>in</strong> AODVIn Fig. 1, we assume that node N4 is the maliciousnode. Suppose node N1 wants to send data packets to© 2010 ACADEMY PUBLISHER


98 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Figure 2 : Data flow between Node 1 to Node 2 via Node 3 and Node 4Figure 3 : L<strong>in</strong>k breakage and Data LossFigure 4 : Route Discovery ProcessTable 1: Simulation ParametersSimulatorns-2 (ver.2.31)Simulation Time500(s)Number <strong>of</strong> Mobile Nodes 20Number <strong>of</strong> Blackhole Nodes 1Topology750m x750mTransmission Range250mRout<strong>in</strong>g ProtocolAODVTrafficConstant Bit Rate (CBR)Pause Time10(s)Maximum Connections 9Packet Size512 bytesData Rates10 KbitsWe have taken four scenarios <strong>of</strong> def<strong>in</strong>ed parametersfor our simulation with or without blackhole node. Wehave taken different positions and movements <strong>of</strong> nodesfor each scenario. Then we have varied the blackholenodes and simple nodes to evaluate the performance. Wehave also varied the mobility speed <strong>of</strong> mobile nodes.Themetrics are used to evaluate the performance are packetloss percentage, throughput and end-to-end delay. Wecalculate data loss percentage with blackhole and withoutblackhole node. Then we compare the results <strong>of</strong> thesetwo simulations to understand the network and nodebehaviors. The results <strong>of</strong> the simulation show that thepacket loss <strong>in</strong> the network with a blackhole <strong>in</strong>creasesbeyond that dropped by the blackhole node. This is due to<strong>in</strong>creased congestion <strong>in</strong> the routes toward the blackholenode.Table 2 shows the packet loss percentage on AODVwith the presence and absence <strong>of</strong> blackhole nodes forfour scenarios.Table 2: Simulation Results with blackhole effect and withoutblackhole effectScenarios Total Loss Total Loss Increase<strong>of</strong> AODV <strong>of</strong> BlackHoleAODVScenario1 3.37 90.54 87.17Scenario2 2.53 90.42 87.89Scenario3 2.35 98.54 96.19Scenario4 1.74 88.01 86.27Figure 5 : Node 1 found new route and Node 6(Blackhole Node)absorbs the DataOur simulation results show that AODV network hasnormally 2.50 % data loss and if a blackhole node is<strong>in</strong>troduc<strong>in</strong>g <strong>in</strong> this network data loss is <strong>in</strong>creased to 89.38%. As 2.50 % data loss already exists <strong>in</strong> this data traffic,blackhole node <strong>in</strong>creases this data loss by 86.88 %.We have also analyzed the throughput <strong>of</strong> receivedpackets with the presence and absence <strong>of</strong> blackhole nodewith respect to the simulation time <strong>of</strong> 450(s).Fig. 6 illustrates the graphic representation <strong>of</strong> packetloss percentage with and without blackhole node withrespect to simulation time (1=100seconds).© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 99Figure 7: Impact <strong>of</strong> Blackhole Node on Throughput <strong>of</strong> ReceivedPacketsFigure 6 : Shows the Packet Loss <strong>of</strong> AODV and blackholeAODVFig. 7 shows the effect <strong>of</strong> blackhole attack onthroughput <strong>of</strong> received packets <strong>of</strong> network. The resultshows both the cases with blackhole and withoutblackhole attack. With our simulation, we analysed thatthe throughput <strong>of</strong> received packets <strong>in</strong> AODV is very highthan the throughput <strong>of</strong> received packets <strong>in</strong>blackholeAODV. Because the packet loss <strong>in</strong>blackholeAODV is higher than the AODV protocol.We studied the performance with vary<strong>in</strong>g number <strong>of</strong>Blackhole Nodes. Number <strong>of</strong> Blackhole Nodes variesfrom 1 to 4 with the <strong>in</strong>crement <strong>of</strong> 1. Fig. 8 shows theimpact <strong>of</strong> number <strong>of</strong> Blackhole Nodes on throughput <strong>in</strong>the network.. Simulation results show that the throughputdecreases with the <strong>in</strong>crease <strong>of</strong> number <strong>of</strong> BlackholeNodes.We also studied the performance with vary<strong>in</strong>g thenumber <strong>of</strong> nodes. Fig. 9 shows the impact <strong>of</strong> number <strong>of</strong>nodes on throughput without blackhole attack. Thenumber <strong>of</strong> nodes is vary<strong>in</strong>g from 10 to 50 with the step <strong>of</strong>10. Simulation results show that when the number <strong>of</strong>nodes <strong>in</strong>creases, the throughput <strong>in</strong>creases for AODVprotocol.We have evaluated the End-to-End Delay with vary<strong>in</strong>gthe mobility speed <strong>of</strong> nodes without blackhole node andwith blackhole node. The mobility speed varies from10m/s to 50m/s with the <strong>in</strong>crease <strong>of</strong> 10.Fig. 10 illustrates the End-to-End Delay withblackhole attack and without blackhole attack. Weobserved that, there is <strong>in</strong>crease <strong>in</strong> the average end-to-enddelay without the effect <strong>of</strong> blackhole attack. This is dueto the immediate reply from the malicious node becauseit doesn’t check its rout<strong>in</strong>g table.Figure 8: Impack <strong>of</strong> Number <strong>of</strong> Blackhole Nodes on ThroughputFigure 9: Impact <strong>of</strong> Number <strong>of</strong> Nodes on Throughput© 2010 ACADEMY PUBLISHER


100 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010REFERENCESFigure 10: Impact <strong>of</strong> blackhole attack on End-to-End DelayV. CONCLUSIONIn this paper, we studied AODV <strong>in</strong> detail and theblackhole attack <strong>in</strong> AODV. We evaluate the effects <strong>of</strong>blackhole nodes on AODV <strong>in</strong> ad hoc networks. Wesimulate the blackhole behavior with the help <strong>of</strong> NetworkSimulator 2 and compared the performance <strong>of</strong>blackholeAODV with the orig<strong>in</strong>al AODV <strong>in</strong> terms <strong>of</strong>packet loss percentage. The simulation results show thatthe packet loss <strong>in</strong>creases <strong>in</strong> the network with a blackholenode. Simulation results also show that the throughput <strong>of</strong>the network is decreased with blackhole attack ascompared to without blackhole attack.. When the number<strong>of</strong> blackhole nodes <strong>in</strong>creases the throughput decreases.We observed that the End-to-end Delay withoutblackhole attack is slightly <strong>in</strong>creased as compared to theeffect <strong>of</strong> blackhole attack. The detection <strong>of</strong> blackhole <strong>in</strong>ad hoc networks is still to be a challeng<strong>in</strong>g taskACKNOWLEDGEMENTI would like to take the opportunity to thank peoplewho guided and supported me dur<strong>in</strong>g this process.Without their contributions, this project would not havebeen possible. I have a great pleasure <strong>in</strong> express<strong>in</strong>g mydeep sense <strong>of</strong> gratitude and <strong>in</strong>debtedness to Mr. JagpreetS<strong>in</strong>gh, Lecturer, Teg Bahadur Khalsa Institute <strong>of</strong>Eng<strong>in</strong>eer<strong>in</strong>g and Technology, Malout and Ms. Rajkumari,lecturer, University Institute <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g andTechnology, Panjab University, Chandigarh, mysupervisor for their cont<strong>in</strong>uous guidance and <strong>in</strong>valuablesuggestions at all the time dur<strong>in</strong>g the research work. Myspecial thanks to all my friends for be<strong>in</strong>g supportive <strong>in</strong>my hours <strong>of</strong> need. F<strong>in</strong>ally, I would not forget to thank myparents for their love and bless<strong>in</strong>gs that support andencouraged me at every moment I need. They were thefirst ones that <strong>in</strong>troduced the amaz<strong>in</strong>g world to me andencouraged me to explore the wonderful nature.[1] Latha Tamilselvan and Dr. V.Sankaranarayanan,“Solution to Prevent Rush<strong>in</strong>g Attack <strong>in</strong> Wireless Mobile Adhoc Networks”.[2] Latha Tamilselvan, Dr.V Sankaranarayanan, “Prevention <strong>of</strong>Blackhole Attack <strong>in</strong> MANET”. The 2 nd InternationalConference on Wireles Broadband and Ultra WidebandCommunications (AusWireless 2007) India, 2007 IEEE.[3] Mohammad O. Pervaiz, Mihaela Cardei, and Jie Wu,“Rout<strong>in</strong>g Security <strong>in</strong> Ad Hoc wireless Networks”, NetworkSecurity, 2005 Spr<strong>in</strong>ger.[4] Elizabeth M. Royer, and Chai-Keong Toh, “A Review <strong>of</strong>Current Rout<strong>in</strong>g Protocols for Ad Hoc Mobile WirelessNetworks,” IEEE Personal Communications, pp. 46-55,April 1999.[5] Satoshi Kurosawa, Hidehisa Nakayama, Nei Kato, AbbasJamalipour, and Yoshiaki Nemoto. “Detect<strong>in</strong>g BlackholeAttack on AODV based Mobile Ad hoc networks byDynamic Learn<strong>in</strong>g Method”. International <strong>Journal</strong> <strong>of</strong>Network Security, Vol.5, No.3, PP.338–346, Nov 2007.[6] ns-2 : http://www.isi.edu/nsnam/ns/[7] C. E. Perk<strong>in</strong>s and E. M. Royer, “Ad Hoc On-DemandDistance Vector Rout<strong>in</strong>g,” Proc. 2nd IEEE Wksp. MobileComp. Sys. and Apps., New Orleans, LA, Feb. 1999, pp.90–100.Anu Bala from Bhogpur (Jalandhar, India)and her date <strong>of</strong> birth is 22 nd August 1985. She isa ME (IT) student <strong>in</strong> Information Technologyat the University Institute <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g andTechnology, Panjab University, Chandigarh,India. She received her B.Tech (CSE) degreefrom Panjab Technical University, jalandhar,India <strong>in</strong> 2006. Her research <strong>in</strong>terests <strong>in</strong> the area <strong>of</strong> mobile adhoc networks, especially ad hoc network security. Her recentwork has focused on ad hoc rout<strong>in</strong>g protocol attacks.She has worked as Lecturer for one year at IITT college <strong>of</strong>engg., Pojewal, Punjab, India.Raj Kumari from chandigarh (India) and his date <strong>of</strong> birth is6 th June 1981. she received her M.Tech (IT) degree fromGNDU, Amritsar, India <strong>in</strong> 2006 and her B.Tech from PanjabTechnical University, Jalandhar, India <strong>in</strong> 2003.She has works as Lecture for one year at college <strong>of</strong> Engg.Tangori, India. She has been work<strong>in</strong>g <strong>in</strong> UIET, Chandigarh,India s<strong>in</strong>ce 2007Jagpreet S<strong>in</strong>gh from Malout (India) and his date <strong>of</strong> birth is5 th March 1983. He received his MS (S<strong>of</strong>tware System) degreefrom BITS Pilani, India and his B.Tech from Panjab TechnicalUniversity, Jalandhar, India. He has been engaged <strong>in</strong> researchon mobile adhoc network and he has enhanced algorithm <strong>of</strong>AODV protocol. He has been work<strong>in</strong>g <strong>in</strong> GTBIET, Malout,India s<strong>in</strong>ce 2003. Two <strong>of</strong> his papers has been published <strong>in</strong>National Conferences.1) Communication technology on UBI Quietestcomput<strong>in</strong>g2) Successful implementation <strong>of</strong> recruisiteimplementation <strong>of</strong> e-governance© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 101Copyright Protection <strong>of</strong> Gray Scale Images byWatermark<strong>in</strong>g Technique Us<strong>in</strong>g (N, N) SecretShar<strong>in</strong>g SchemeSushma YalamanchiliPr<strong>of</strong>essor & Head, Department <strong>of</strong> CSE,V.R.Siddhartha Eng<strong>in</strong>eer<strong>in</strong>g College, Vijayawada.Email: sushma_yalamanchili@yahoo.co.<strong>in</strong>M.Kameswara RaoLecturer, P.B.Siddhartha College, P.G.Centre, Vijayawada.Email: kamesh.manchiraju@gmail.comAbstract— S<strong>in</strong>ce the rise <strong>of</strong> the Internet one <strong>of</strong> the mostimportant factors <strong>of</strong> <strong>in</strong>formation technology andcommunication has been the security <strong>of</strong> <strong>in</strong>formation. Aspecial case <strong>of</strong> <strong>in</strong>formation hid<strong>in</strong>g is digital watermark<strong>in</strong>g.Digital watermark<strong>in</strong>g is the process <strong>of</strong> embedd<strong>in</strong>g<strong>in</strong>formation <strong>in</strong>to digital multimedia content such that the<strong>in</strong>formation (the watermark) can later be extracted ordetected for a variety <strong>of</strong> purposes <strong>in</strong>clud<strong>in</strong>g copy preventionand control. Among numerous cryptographic solutionsproposed <strong>in</strong> the past few years, secret shar<strong>in</strong>g schemes havebeen found sufficiently secure to facilitate distributed trustand shared control <strong>in</strong> various communication applications.In this paper, a new image watermark<strong>in</strong>g algorithm isdeveloped us<strong>in</strong>g (n,n) secret shar<strong>in</strong>g scheme for copyrightprotection. The proposed method embeds the copyrightimage <strong>in</strong>to orig<strong>in</strong>al image and is to be shared among nparticipants. Then the copyright image could be recoveredus<strong>in</strong>g simple XOR operations without any loss.Experimental simulations are provided us<strong>in</strong>g MATLAB 7.1to demonstrate the efficient performance <strong>of</strong> the developedtechnique <strong>in</strong> terms <strong>of</strong> reliability <strong>of</strong> watermark embedd<strong>in</strong>gand extraction. The scheme conta<strong>in</strong>s three phases: thecopyright image embedd<strong>in</strong>g phase, embedded image secretshar<strong>in</strong>g phase, copyright image extraction phase. Theexperimental results show that the proposed scheme canresist several attacks such as JPEG compression, resize andnoise addition.Index Terms— copyright protection, secret shar<strong>in</strong>g,watermark<strong>in</strong>g, steganography.I. INTRODUCTIONOn the Internet today it is possible to duplicate digital<strong>in</strong>formation a million-fold and distribute it over the entireworld <strong>in</strong> seconds. These issues worry creators <strong>of</strong><strong>in</strong>tellectual property to the po<strong>in</strong>t that they do not evenconsider to publish on the Internet. To solve the problem<strong>of</strong> publish<strong>in</strong>g digital images, researchers have come upwith digital image watermark<strong>in</strong>g [1]. Digitalwatermark<strong>in</strong>g is a method <strong>of</strong> embedd<strong>in</strong>g identify<strong>in</strong>g<strong>in</strong>formation <strong>in</strong> an image, <strong>in</strong> such a manner that it cannoteasily be removed .An application <strong>of</strong> watermark<strong>in</strong>g iscopyright control, <strong>in</strong> which an image owner seeks toprevent illegal copy<strong>in</strong>g <strong>of</strong> the image. A digital watermarkis a code that is embedded <strong>in</strong>side an image. It acts as adigital signature, giv<strong>in</strong>g the image a sense <strong>of</strong> ownershipor authenticity. Digital watermark<strong>in</strong>g <strong>of</strong> an image hasalso been proposed for the prevention <strong>of</strong> copy<strong>in</strong>g <strong>of</strong> animage by unauthorized persons.To a computer, an image is a collection <strong>of</strong> numbersthat constitute different light <strong>in</strong>tensities <strong>in</strong> different areas<strong>of</strong> the image [4]. This numeric representation forms agrid and the <strong>in</strong>dividual po<strong>in</strong>ts are referred to as pixels.Most images on the Internet consists <strong>of</strong> a rectangular map<strong>of</strong> the image’s pixels (represented as bits) where eachpixel is located and its colour [5]. Digital colour imagesare typically stored <strong>in</strong> 24-bit files and use the RGB colourmodel, also known as true colour [6]. All colourvariations for the pixels <strong>of</strong> a 24-bit image are derivedfrom three primary colours: red, green and blue, and eachprimary colour is represented by 8 bits [4].Secret shar<strong>in</strong>g [2] refers to method for distribut<strong>in</strong>g asecret amongst a group <strong>of</strong> participants, each <strong>of</strong> which isallocated a share <strong>of</strong> the secret. The secret can bereconstructed only when the shares are comb<strong>in</strong>edtogether; <strong>in</strong>dividual shares are <strong>of</strong> no use on their own.Secret image shar<strong>in</strong>g is a technique for protect<strong>in</strong>g imagesthat <strong>in</strong>volves the dispersion <strong>of</strong> the secret image <strong>in</strong>to manyshadow images. This endows the method with a highertolerance aga<strong>in</strong>st data corruption or loss than otherimage-protection mechanisms, such as encryption orsteganography.A secret kept <strong>in</strong> a s<strong>in</strong>gle <strong>in</strong>formation-carrier could beeasily lost or damaged. Secret shar<strong>in</strong>g (SS) schemes,called (n, n) schemes, have been proposed s<strong>in</strong>ce late1970s. To encode the secret <strong>in</strong>to n pieces (“shadows” or“shares”) that the pieces can be distributed to nparticipants at different locations. The secret can only bereconstructed from n pieces [2].II. PROPOSED METHODConsider an image A <strong>of</strong> NR ×NC. Each pixel <strong>of</strong> Acan take any one <strong>of</strong> c different colors or gray-levels.Image A is represented by an <strong>in</strong>teger matrix A:A = [aij ]NR×NC , where i = 1, 2, . . . , NR,j = 1, 2, . . . , Nc, and aij {0, 1, . . . , c − 1}.We have c=2 for a b<strong>in</strong>ary image, and c =256 for a grayscale image© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.101-105


102 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010with one byte per pixel. In a color image with one byteper pixel, the pixel value can be an <strong>in</strong>dex to a color table,thus c = 256. In a color image us<strong>in</strong>g an RGB model, eachpixel has three <strong>in</strong>tegers: R (red), G (green) and B (blue).If each R, G or B takes value between 0 and 255, we havec = 256 [2]. The proposed method <strong>in</strong>cludes the follow<strong>in</strong>gstepsStep 1: Consider two images - Orig<strong>in</strong>al image and thecopyright image - represented by <strong>in</strong>teger matrices.Step 2: Decide a value called weight_value between 0and 1.For <strong>in</strong>visible watermark weight_value must be nearto 0.Watermark Embedd<strong>in</strong>g :Step 3: Embed the copyright image <strong>in</strong>side the orig<strong>in</strong>alimage as followsEmbedded image=orig<strong>in</strong>al image + (resized copyrightimage * weight_value).(N,N) Secret Shar<strong>in</strong>g Scheme For the embedded Image :The output <strong>of</strong> a (n,n) scheme for embedded images isa set <strong>of</strong> n dist<strong>in</strong>ct NR×NC matrices A1, . . . , An, calledshares or shadow images. Each share image has the samenumber <strong>of</strong> pixels as the orig<strong>in</strong>al image A, but every pixel<strong>in</strong> a share may conta<strong>in</strong> m sub pixels. A can bereconstructed from the set {Ai1, . . . , Aik } and evencomplete knowledge <strong>of</strong> k − 1 shares reveals no<strong>in</strong>formation about A. The first condition above is calledprecision, and the second condition is called security [2].Step 4: Encode the embedded image <strong>in</strong>to n shadows orsecrets as follows andgenerate n − 1 random matrices B1, . . . , Bn−1,compute the shadow images as below:A1 = B1,A2 = B1 ⊕ B2,. . . . . .An−1 = Bn−2 ⊕ Bn−1,An = Bn−1 ⊕ A.In the generation <strong>of</strong> the shadow images and <strong>in</strong> thereconstruction <strong>of</strong> the secret, Boolean operation XOR(“ ⊕ ”) is used. For easy lookup, the truth-table <strong>of</strong> XORfor b<strong>in</strong>ary scalar <strong>in</strong>puts is given below.a=0 a=1b=0 0 1b=1 1 0a ⊕ bFor example, when a =125 and b =18, the XOR betweenthese two <strong>in</strong>tegers isa ⊕ b = (125)10 ⊕ (18)10 = (01111101)2 ⊕(00010010)2= (01101111)2 = (111)10.Step 5 : Reveal the embedded image from the n shadowimages as below:A’ = A1 ⊕ A2 ⊕ · · · ⊕ An.Because the “ ⊕ ” operation is associative and Bi ⊕ Biis a zero matrix for any i, we haveA = B1 ⊕ (B1 ⊕ B2) ⊕ · · · ⊕ (Bn−2 ⊕ Bn−1) ⊕(Bn−1 ⊕ A)= (B1 ⊕ B1) ⊕ · · · ⊕ (Bn−1 ⊕ Bn−1) ⊕ A = A.To demonstrate the computation steps <strong>in</strong> the reveal<strong>in</strong>gprocess, we give a trivial example for n = 3 and a s<strong>in</strong>glepixelsecret image A.Given: A = (231)10 = (11100111)2Generate: B1 = (46)10 = (00101110)2 andB2 = (188)10 = (10111100)2Compute: A1 = B1 = (46)10 = (00101110)2,A2 = B1 ⊕ B2 = (10010010)2, andA3 = B2 ⊕ A = (01011011)2Reconstruct: A1 ⊕ A2 ⊕ A3 = (11100111)2 = (231)10.An example for the proposed (n, n) scheme us<strong>in</strong>g a 3× 3 secret image A is given below:A = 209 214 225233 227 228222 221 226B1 = 136 169 28254 128 24596 108 49B2 = 8 94 65218 137 22846 71 222,A1 = B1 =,A2 = B1 ⊕ B2 =,A3 = B2 ⊕ A =, andA1 ⊕ A2 ⊕ A3 =136 169 28254 128 24596 108 49128 247 9336 9 1778 43 239217 136 16051 106 0240 154 60209 214 225233 227 228222 221 226= AWatermark Extraction :Step 6 : Extract the copyright image <strong>in</strong>side the embeddedimage as followscopyright image =(Orig<strong>in</strong>al image – embeddedimage)/weight_value.III. EXPERIMENTAL RESULTS ON GRAY SCALE IMAGESThe simulations were conducted on Intel mach<strong>in</strong>ewith 2.4 GHz processor and 512 MB <strong>of</strong> RAM. MATLAB7.1 was used for implementation <strong>of</strong> proposed scheme and© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 103image process<strong>in</strong>g operations respectively. Apply<strong>in</strong>g theproposed method on tree path image as orig<strong>in</strong>al imageand college logo image as copyright image under (n,n)scheme with n = 3.Figure 2(b)shadow image1Figure 1 (a) Orig<strong>in</strong>al imageFigure 1 (b) Copyright ImageFigure 2( c ) Shadow image 2Figure 1(c) Embedded ImageFig. 1 shows the orig<strong>in</strong>al image <strong>in</strong> part (a), copyrightimage <strong>in</strong> part (b) and the embedded image (Orig<strong>in</strong>alimage + Copyright Image) <strong>in</strong> part(c) .(n,n) Secret shar<strong>in</strong>g schemeA (n,n) secret shar<strong>in</strong>g scheme encodes a secret image<strong>in</strong>to n share images, which demonstrate randomly noisypatterns and hide the <strong>in</strong>formation about the secret image,are distributed to n recipients. The secret image can easilybe decrypted by XOR operation <strong>of</strong> the n share images <strong>in</strong>an arbitrary order without complicated arithmetic.Figure 2(a)Embedded ImageFigure 2(d) Shadow image 3Figure 2 (e) Reconstructed Embedded image us<strong>in</strong>g 3shadowsFig. 2(a) shows the embedded image <strong>in</strong> part (a), shadowimages <strong>in</strong> part(b-d)and the reconstructed embeddedimage us<strong>in</strong>g the 3 shadow images <strong>in</strong> part(e).Strength <strong>of</strong> the (n,n) SchemeThe reconstruction phase <strong>of</strong> our algorithm computes nshadow images us<strong>in</strong>g XOR operation. the proposed (n, n)scheme reconstructs the secret image exactly, and itsatisfies the security condition. That is, when fewer thann shadows are used, the orig<strong>in</strong>al secret image A will notbe revealed.© 2010 ACADEMY PUBLISHER


104 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Our experiments show that for group <strong>of</strong> attacks likeJPEG compression, resiz<strong>in</strong>g, add<strong>in</strong>g noise the proposedmethod can be able to extract the copyright image withless loss <strong>in</strong> the quality.Figure 3(a)Reconstructed image us<strong>in</strong>g shadowimage 1 and shadow image 2Figure 5(a) Resized Embedded ImageFigure 3(b)Reconstructed image us<strong>in</strong>g shadowimage 1 and shadow image 3Figure 5(b)Extracted Copyright image when the embeddedimage is resizedFig 5 shows the Resized embedded image <strong>in</strong> part(a) andthe extracted copyright image when the embedded imageis resized <strong>in</strong> part(b)Figure 3(c)Reconstructed image us<strong>in</strong>g shadowimage 2 and shadow image 3Fig 3 shows the Reconstructed image us<strong>in</strong>g shadowimages 2(a) and 2(b) <strong>in</strong> part(a) Reconstructed imageus<strong>in</strong>g shadow images 2(a) and 2(c) <strong>in</strong> part(b) andReconstructed image us<strong>in</strong>g shadow images 2(a) and 2(c)<strong>in</strong> part(c).Watermark extraction processFigure 6(a) Compressed Embedded ImageFigure 6(b)Extracted Copyright image when the embeddedimage is CompressedFig 6 shows the compressed embedded image <strong>in</strong> part (a)and the extracted copyright image when the embeddedimage is compressed <strong>in</strong> part (b)Figure 4(a) Embedded imageFigure 7(a) Embedded Image with added noiseFigure 4(b)Extracted copyright imageFig 4 shows the embedded image <strong>in</strong> part (a) and theextracted copyright image <strong>in</strong> part (b)Attacks on the Proposed MethodFigure 7(b)Extracted Copyright image when the embeddedimage is added with noise© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 105Fig 7 shows the embedded image with added noise <strong>in</strong>part (a) and the extracted copyright image when theembedded image is added with noise <strong>in</strong> part (b)IV. PSNR MEASUREMENTOne commonly used measure to evaluate theimperceptibility <strong>of</strong> the watermarked image is the peaksignal to noise ratio (PSNR) which is given byPSNR = 10 * log10( ( 255 )^2 / mean_square_error )WhereOrig<strong>in</strong>alImage_x_size = size( Orig<strong>in</strong>alImage, 2);Orig<strong>in</strong>alImage_y_size = size( Orig<strong>in</strong>alImage, 1);CopyrightImage_x_size = size( CopyrightImage, 2);CopyrightImage_y_size = size( CopyrightImage, 1);mean_square_error = sum( sum( sum( ( CopyrightImage– Extracted CopyrightImage ).^2 ) ) ) / double(CopyrightImage_x_size * CopyrightImage_y_size * 3);[4]Johnson, N.F. & Jajodia, S., “Explor<strong>in</strong>g Steganography:See<strong>in</strong>g the Unseen”, Computer <strong>Journal</strong>, February 1998 .[5]“Reference guide: Graphics Technical Options andDecisions”, http://www.devx.com/projectcool/Article/1997[6] Owens, M., “A discussion <strong>of</strong> covert channels andsteganography”, SANS Institute, 2002.TABLE I.PSNR VALUESType <strong>of</strong> Operation on ImagePSNROrig<strong>in</strong>al Embedded Image 32.6737After resiz<strong>in</strong>g embedded Image 29.0508After compress<strong>in</strong>g the Embedded image to a .jpg 28.4083After add<strong>in</strong>g random noise to the Embedded image 33.4338Table I illustrates PSNR values between the Orig<strong>in</strong>alCopyright Image and the Extracted Copyright Imagetaken from various operationsV. CONCLUSIONSWe have demonstrated a new watermark<strong>in</strong>gtechnique that uses (n,n) secret shar<strong>in</strong>g scheme to embeda copyright image <strong>in</strong>to orig<strong>in</strong>al image . This techniqueworks well with images <strong>of</strong> all sizes. This techniqueprovides two layers <strong>of</strong> security. In the first step, acopyright image is embedded <strong>in</strong>to orig<strong>in</strong>al image forcopyright protection. Also, the embedded image is sharedamong n participants where all the n shares must be usedto reconstruct the embedded image. This makes thesystem more secure. The method can with stand attackslike JPEG compression, resize and add<strong>in</strong>g noise with lessloss <strong>in</strong> quality <strong>of</strong> the image. Further this work can beextended by calculat<strong>in</strong>g the hash value <strong>of</strong> the image andencrypt the hash value us<strong>in</strong>g either symmetric key orpublic key and embed the hash value <strong>in</strong>side the image sothat at the receivers end the authentication and <strong>in</strong>tegrity<strong>of</strong> the image can be verified by recalculat<strong>in</strong>g the hashand verify<strong>in</strong>g it. Similarly digital signatures can begenerated for images and can be verified. Also (k,n)threshold secret shar<strong>in</strong>g schemes can be implemented formuch security.VI. REFERENCES[1] Adrian Perrig Andrew Willmott, ”Digital ImageWatermark<strong>in</strong>g <strong>in</strong> the Real World" Extended Abstract, March 9,1998.[2] DaoshunWang, Lei Zhang, N<strong>in</strong>g Ma, Xiaobo Li,“Two secretshar<strong>in</strong>g schemes based on Boolean operations”, Science Direct–Pattern Recognition 2007.[3] A. Shamir, “How to share a secret”, Commun. Assoc.Comput. Mach. 22 (11) (1979) 612–613.© 2010 ACADEMY PUBLISHER


106 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Broadband Integrated Services over ProposedOpen CPE ArchitectureKushal RoyPr<strong>in</strong>cipal Investigator to DST Government <strong>of</strong> India and faculty,Department <strong>of</strong> Electronics and Communication Eng<strong>in</strong>eer<strong>in</strong>gHaldia Institute <strong>of</strong> Technology, ICARE Complex, PO H.I.T HaldiaPIN- 721657, West Bengal, IndiaEmail: pr<strong>of</strong>kushalroy@hotmail.comAbstract— Over the decades, due to technology limitationsand regulatory restrictions, <strong>in</strong>formation services have beendelivered to subscribers through multiple service providers.In recent years, however, the advancement <strong>of</strong> digitalcommunication technology, the pass<strong>in</strong>g <strong>of</strong> the 1996Telecommunications Act <strong>in</strong> the U.S., and the emergence <strong>of</strong>the Internet are driv<strong>in</strong>g network convergence. As a result,the <strong>in</strong>dustry is call<strong>in</strong>g for the consolidation <strong>of</strong> an <strong>in</strong>tegratedCustomer Premises Equipment (CPE) <strong>in</strong> the customer’spremises to provide <strong>in</strong>tegrated services, such as multimedia,voice, and data services. However, the ever-chang<strong>in</strong>gnetwork standards and compet<strong>in</strong>g technologies not onlyconfuse carriers, but also prevent them from committ<strong>in</strong>g tomassive CPE deployment.In this paper, the problems carriers face <strong>in</strong> the deployment<strong>of</strong> <strong>in</strong>tegrated services over broadband are first described. Inorder to remove these deployment obstacles, and also tocreate new value-added services, service models are<strong>in</strong>vestigated and an open CPE architecture is proposed thatwill support the wide range <strong>of</strong> broadband accesstechnologies and ever-chang<strong>in</strong>g network standards.Index Terms—Integrated Services, Broadband, VoIP, PSN,S<strong>of</strong>tSwitch Model.I. INTRODUCTIONThe convergence <strong>of</strong> voice and Internet data trafficalso calls for new Customer Premises Equipment (CPE)such as Digital Subscriber L<strong>in</strong>es (DSLs), modems, cablemodems, and wireless modems that provide users withbroadband access to the Internet. However, <strong>in</strong>stead <strong>of</strong>add<strong>in</strong>g new CPE to the home, the <strong>in</strong>dustry is mov<strong>in</strong>gtowards consolidat<strong>in</strong>g CPE <strong>in</strong>to an Integrated CPE (I-CPE) to help lower the cost, reduce network managementcomplexities, and improve the efficiency <strong>of</strong> networkresources. The I-CPE is also called an Integrated AccessDevice (IAD) and a Residential Gateway (RG) whenused <strong>in</strong> residential areas. In this paper, the term I-CPE isused, because I-CPE is <strong>in</strong>tended to serve multiple marketsegments <strong>in</strong>clud<strong>in</strong>g residential, Small Office HomeOffice (SOHO), and small bus<strong>in</strong>esses to provide<strong>in</strong>tegrated services such as voice, multi-media, andInternet access.While the upgrade <strong>of</strong> the network <strong>in</strong>frastructure iswell underway, the deployment <strong>of</strong> I-CPE rema<strong>in</strong>s a bigobstacle to the delivery <strong>of</strong> <strong>in</strong>tegrated services overbroadband due to the volume and time that are requiredfor the deployment. It was believed that the lack <strong>of</strong> autoconfigurationwas the ma<strong>in</strong> roadblock to massive I-CPEdeployment. However, the largest obstacle today is not somuch how to deploy I-CPE but rather, which type <strong>of</strong> I-CPE the carriers should be deploy<strong>in</strong>g, because thistelecommunication world is filled with too manystandards, e.g., Media Gateway Control Protocol(MGCP), H.248 [7], H.323, Session Initiation Protocol(SIP), Voice over Internet Protocol (VoIP), Voice overATM (VoATM), etc.; and compet<strong>in</strong>g technologies, e.g.,DSL, Cable, Wireless, Fiber, Ethernet, HomeRF ∗ , IEEE802.11, Bluetooth, etc. As a result, carriers are fac<strong>in</strong>ggreat difficulties <strong>in</strong> choos<strong>in</strong>g an I-CPE for deploymentbecause they fear it be<strong>in</strong>g replaced <strong>in</strong> the near future.II. THE NEXT-GENERATION NETWORKINFRASTRUCTUREUnlike the dial-up modem, the <strong>in</strong>troduction <strong>of</strong> I-CPEwill require major upgrades <strong>in</strong> the <strong>in</strong>frastructure <strong>of</strong> theexist<strong>in</strong>g network. The new network is <strong>in</strong>tended to supportthe convergence <strong>of</strong> the voice-centric Public SwitchedTelephone Network (PSTN) and the Internet, and it iscommonly referred as the Next-Generation Network(NGN). The NGN is based on the distributed S<strong>of</strong>tswitcharchitecture <strong>in</strong> which the call control is separated fromthe media transport. Figure 1 shows the role <strong>of</strong> I-CPE <strong>in</strong>the NGN <strong>in</strong>frastructure. It <strong>in</strong>dicates that an I-CPE is theportal to a customer’s premises and it acts as the gatewayto <strong>in</strong>terconnect the Local Area Network (LAN) with theWide Area Network (WAN), which consist <strong>of</strong> the AccessNetwork and the Core Network [6]. The Access Network,consist<strong>in</strong>g <strong>of</strong> Access Nodes, Regional BroadbandNetworks, Transit Gateways, and Because <strong>of</strong> the pass<strong>in</strong>g<strong>of</strong> the Telecommunications Act <strong>in</strong> 1996 and the FCC’songo<strong>in</strong>g adventures <strong>in</strong> local loop deregulation,companies, <strong>in</strong>clud<strong>in</strong>g Inter-eXchange Carriers (IXC),Incumbent Local Exchange Carriers (ILEC), CompetitiveLocal Exchange Carriers (CLEC), CATV serviceproviders, and many other emerg<strong>in</strong>g service providers,are all eager to enter this lucrative broadband accessbus<strong>in</strong>ess. Therefore, it is certa<strong>in</strong> that I-CPE will supportvarious broadband <strong>in</strong>terfaces, such as wireless, cable,xDSL, and fiber optics, to target different market sectorsdepend<strong>in</strong>g on price, performance, environment, or thetype <strong>of</strong> users. Then, the recent advancement <strong>of</strong> IEEE© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.106-109


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 10780.3ae 10 GigE standard [13] enables the Ethernet towork beyond the LAN. Thus, an I-CPE may also supportEthernet broadband <strong>in</strong>terface to the WAN. Access Nodesterm<strong>in</strong>ate the broadband <strong>in</strong>terfaces from I-CPE andaggregate multiple CPE traffic to the RegionalBroadband Networks. Regional Broadband Networksprovide transport and switch<strong>in</strong>g functions among AccessNodes and Transit Gateways. Transit Gateways mayconsist <strong>of</strong> Trunk<strong>in</strong>g Gateways and Signal<strong>in</strong>g Gatewaysthat perform signal<strong>in</strong>g and bearer <strong>in</strong>terwork<strong>in</strong>g functionsbetween Regional Broadband Networks and PSN/CSN.An MGC is also referred to as the Call Manager orS<strong>of</strong>tswitch that typically runs call control s<strong>of</strong>tware <strong>in</strong> aserver to provide call-process<strong>in</strong>g functions. In thedistributed S<strong>of</strong>tswitch architecture, the value-addedservices or applications can reside <strong>in</strong> an ApplicationServer. A Media Server is controlled by the S<strong>of</strong>tswitch toplay tonal announcements or perform media stream<strong>in</strong>gfunctions, such as Interactive Voice Response (IVR) andConference Bridge. The media stream<strong>in</strong>g is carried <strong>in</strong>bearer connections between the Access Node and theTransit Gateway for on-net calls, or between AccessNodes for <strong>of</strong>f-net calls, while call control functions areprovided by an MGC. GigaPoP (i.e., Po<strong>in</strong>t <strong>of</strong> Presence)aggregates the traffic from Ethernet CPE to PSN [14]. Itshould be noted that the NGN architecture shown aboveis meant to be logical, so the Access Nodes, TransitGateways, Media Server, Application Server, and MGCare logical functional blocks which may be implementedas stand-alone devices or embedded <strong>in</strong> other networkelements.The Media Gateway Controller (MGC), provides theramp to Packet-Switched Networks (PSN) and Circuit-Switched Networks (CSN).Figure 1: Next-Generation Network <strong>in</strong>frastructureIII OPEN CPE ARCHITECTUREBroadband access is, for many, the solution to the“World Wide Wait” problem (slow <strong>Web</strong> performance),and it would also enable the creation <strong>of</strong> many newservices that promise enormous benefits to subscribersand service providers. However, service providers arefac<strong>in</strong>g many challenges dur<strong>in</strong>g the deployment <strong>of</strong>broadband access networks, not least <strong>of</strong> which is how todeploy the greatest number <strong>of</strong> Customer PremisesEquipment (CPE) <strong>in</strong> the timeliest manner..A. I-CPE CharacteristicsThe follow<strong>in</strong>g characteristics <strong>of</strong> the IntegratedCustomer Premises Equipment (I-CPE) architecture areimportant to the resolution <strong>of</strong> these deployment problems.• Open Architecture–In the past several decades,open architecture has become the trend <strong>in</strong> the<strong>in</strong>dustry. It started with the computer <strong>in</strong>dustry <strong>in</strong>the early 80s, and it gradually spread to thetelecommunication <strong>in</strong>dustry, where the monolithiccentral <strong>of</strong>fice switch is under great pressure fromthe Internet telephony to open up. The broadbandCPE <strong>in</strong>dustry will not buck this trend s<strong>in</strong>ceopenness will only foster new services and productcompetition, which, <strong>in</strong> turn, will lower CPE cost,reduce time-to-market, and <strong>in</strong>spire <strong>in</strong>novation [3].• Flexibility–The ever-chang<strong>in</strong>g network standardsand <strong>in</strong>frastructures, the wide range <strong>of</strong> accessnetwork technologies, and the uncerta<strong>in</strong>ty <strong>of</strong>which value-added service will emerge <strong>in</strong> thefuture make it very difficult to have a fit-it-all CPEarchitecture. Thus, the I-CPE should be flexible toconta<strong>in</strong> the must-have core features needed tosupport today’s services, yet it should still be ableto accommodate future upgrades. Flexiblearchitecture will lower CPE costs, someth<strong>in</strong>g thatis crucial to I-CPE be<strong>in</strong>g accepted <strong>in</strong> the costsensitiveconsumer market. For example, an I-CPEmight be designed to provide home automationand security services, but the <strong>in</strong>terface standardsas well as the functionalities to control homeappliances have yet to be def<strong>in</strong>ed. The flexiblearchitecture needs to be able to accommodate aBluetooth wireless modem plug-<strong>in</strong> and thenecessary s<strong>of</strong>tware that will need to be added tothe CPE to support this feature when the standardand technology become available.• Value-Added Services - Each time a new serviceor technology is <strong>in</strong>troduced, it needs to beperceived by the public as add<strong>in</strong>g value <strong>in</strong> orderthat it will be bought and used. Due to thecompetition from Internet telephony, the cost <strong>of</strong>toll telephony services is cont<strong>in</strong>ually decreas<strong>in</strong>g.Soon, it is believed, you will be charged a flatmonthly rate for telephone services <strong>in</strong>stead <strong>of</strong>be<strong>in</strong>g billed on a per-m<strong>in</strong>ute basis. Therefore, thedriver for the Next-Generation Network (NGN) isnot about <strong>in</strong>vent<strong>in</strong>g a new way to provide exist<strong>in</strong>gservices, but focus<strong>in</strong>g on value-added servicessuch as Presence, Voice <strong>Web</strong>, Voice Portal,Unified Messag<strong>in</strong>g, and Voice Virtual PrivateNetwork (VPN), which hold great potential forgenerat<strong>in</strong>g additional revenue for serviceproviders.© 2010 ACADEMY PUBLISHER


108 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010B. Integrated CPE Functional DecompositionFigure 2 shows the Open CPE architecture that is<strong>in</strong>tended to fulfill the requirements as listed above and tosupport multiple broadband access technologies andtelephony protocol standards. It is composed <strong>of</strong> a CPEController Module (CCM), LAN Interface Modules(LIM), and WAN Interface Modules (WIM). The CCMconsists <strong>of</strong> a CPE Controller, Flash, ROM, and RAM thatconta<strong>in</strong> a Real-Time Operat<strong>in</strong>g System (RTOS) ands<strong>of</strong>tware to implement telephony call control, networkmanagement, and service logic functions, as well as thirdpartyapplications. The CCM may also <strong>in</strong>clude a DigitalSignal<strong>in</strong>g Processor (DSP) to implement media stream<strong>in</strong>gprocess<strong>in</strong>g functions, such as vocoder, echo cancellation,tone generation and detection. The CCM can be reconfiguredto support different protocols or telephonystandards through s<strong>of</strong>tware download<strong>in</strong>g.Figure 2: Open CPE architectureWIM and LIM conta<strong>in</strong> plug-<strong>in</strong>s to support variousWAN and LAN <strong>in</strong>terfaces. WIM may consist <strong>of</strong> aWireless Modem , a Cable Modem, a DSL Modem, aFiber Modem, and a 10 Gigabit Ethernet module thatprovide <strong>in</strong>terfaces to the broadband access network. LIMmay <strong>in</strong>clude <strong>in</strong>terfaces to analog phones. There are twobuses responsible for the distribution <strong>of</strong> user data, realtimevoice stream<strong>in</strong>g, control signal<strong>in</strong>g, and themanagement data between the CCM Controller and theWIM/LIM. The <strong>in</strong>terface specification should meet therequirements <strong>of</strong> transport<strong>in</strong>g real-time and non-real-timedata. The open CPE architecture as described above isderived from the abstraction <strong>of</strong> multiple CPE platformsthat may use various broadband access technologies andstandards. The goal <strong>of</strong> the abstraction is to f<strong>in</strong>d out whatfunctions are common to all CPEs and therefore shouldbe implemented <strong>in</strong> CCM, and what functions are <strong>in</strong>terfacedependent. and therefore are more appropriatelyimplemented <strong>in</strong> plug-<strong>in</strong> modules. Figure 3 gives anexample <strong>of</strong> the CPE functional decomposition. It depictsthe protocol stacks <strong>of</strong> I-CPE support<strong>in</strong>g cable, xDSL, and10 Gigabit Ethernet broadband <strong>in</strong>terfaces to provide voiceand data convergence services.Figure 3: I-CPE protocol stackThe Cable CPE is <strong>in</strong>tended to provide VoIP services.It uses Network-based Call Signal<strong>in</strong>g (NCS) [4] as thesignal<strong>in</strong>g protocol to perform telephony call controlfunctions, while encapsulat<strong>in</strong>g the voice stream<strong>in</strong>g data <strong>in</strong>the Real-Time Protocol (RTP) packets to be sent to theCable Modem Term<strong>in</strong>ation System (CMTS). xDSL CPEprovides VoIP and Voice over AAL2 (ATM AdaptationLayer type 2) Loop Emulation Services (LES) [5]. It usesH.248 [7] and Channel Associated Signal<strong>in</strong>g (CAS)protocols to implement telephony call control functionsfor VoIP and VoAAL2, respectively. The voice stream<strong>in</strong>gdata are encapsulated <strong>in</strong> either RTP or AAL2 packets tobe sent to the DSL Access Multiplex (DSLAM). In thisexample, the Ethernet CPE acts as a SIP client to provideVoIP services. SIP is used to establish, modify, andterm<strong>in</strong>ate multi-media sessions and calls [10]. The voicestream<strong>in</strong>g is encapsulated <strong>in</strong> the RTP packets transmitt<strong>in</strong>gto the term<strong>in</strong>at<strong>in</strong>g party via the User Datagram Protocol(UDP) connection.In the Time Division Multiplex (TDM) networks,only call control and management functions areimplemented by s<strong>of</strong>tware <strong>in</strong> the processor, leav<strong>in</strong>g thevoice process<strong>in</strong>g to be handled by the hardware, because<strong>of</strong> the latency concern.However, the trend toward packet telephony, alongwith the advancement and <strong>in</strong>creas<strong>in</strong>g performance <strong>of</strong>processors <strong>in</strong> recent years, has made it possible for, andeven demanded that, voice stream<strong>in</strong>g be processed bys<strong>of</strong>tware. Thus, as Figure 3 <strong>in</strong>dicates, it makes good senseto locate the CCM-WIM <strong>in</strong>terface between Layer 2 andLayer 3 <strong>of</strong> the protocol stack. The CCM conta<strong>in</strong>ss<strong>of</strong>tware to implement voice process<strong>in</strong>g, the signal<strong>in</strong>gprotocol, and management functions. WIM shouldimplement Physical layer (PHY), Medium AccessControl (MAC), Logical L<strong>in</strong>k Control (LLC),Asynchronous Transfer Mode (ATM), and ATM.Adaptation Layer (AAL) functions that are closelycoupled with each broadband access <strong>in</strong>terface.IV. CONCLUSIONThe explosion <strong>of</strong> the Internet along with regulationand technology changes are reshap<strong>in</strong>g telecommunicationnetworks <strong>in</strong> many ways. The <strong>in</strong>dustry is mov<strong>in</strong>g towardthe convergence <strong>of</strong> PSTN and the Internet. The© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 109converged network, the NGN, will operate <strong>in</strong> a verysimilar way to the Internet topology <strong>in</strong> which central<strong>of</strong>fice switches are decomposed <strong>in</strong>to distributed systemsthat are based on the S<strong>of</strong>tswitch model. As a result, theNGN will no longer provide transport services betweentelephone equipment (as PSTN previously did), but willprovide personalized multi-media services. Thisconvergence <strong>of</strong> voice and Internet data traffic also callsfor the deployment <strong>of</strong> I-CPE to provide <strong>in</strong>tegratedservices. However, the ever-chang<strong>in</strong>g network standardsand compet<strong>in</strong>g technologies not only confuse carriers, butalso prevent them from committ<strong>in</strong>g to massive CPEdeployment, because they are afraid that the CPE justdeployed will have to be replaced <strong>in</strong> a few years.Hardware replacement is very common <strong>in</strong> the PC andcellular phone bus<strong>in</strong>ess when new standards ortechnologies are <strong>in</strong>troduced, but it presents a big threat tothe wirel<strong>in</strong>e broadband bus<strong>in</strong>ess because CPEdeployment is such a daunt<strong>in</strong>g task that it cannot becompleted easily. In this paper, I proposed an open CPEarchitecture to solve the CPE deployment dilemma. Thearchitecture is very flexible and can support multipleWAN/LAN technologies and IP Telephony standards. Italso <strong>in</strong>cludes a common API to allow users to customizeor even create new services and third-party developers tocreate new applications and services. The open CPEarchitecture will allow CPE vendors to lower costs andreduce time-to-market, and most importantly enableservice providers to provide many value-added servicesthat promise great potential for generat<strong>in</strong>g additionalrevenueREFERENCES[1] C. A. Elder<strong>in</strong>g, “Customer Premises Equipment forResidential Broadband Gateway,” IEEE CommunicationMagaz<strong>in</strong>e, , pp. 114-121, June 1997.[2] S. Moyer and A. Umar, “The Impact <strong>of</strong> NetworkConvergence on Telecommunications S<strong>of</strong>tware,” IEEECommunication Magaz<strong>in</strong>e, pp. 78-84, January 2001[3] C. Low, “Integrat<strong>in</strong>g Communication Services,” IEEECommunication Magaz<strong>in</strong>e, pp. 164-169, June 1997.[4] “PacketCable Network-based Call Signal<strong>in</strong>g ProtocolSpecification,” Pkt-SP-EC-MGCP-101-990312, Cable Lab,3/12/1999.[5] “Voice and Multimedia over ATM–Loop Emulation ServiceUs<strong>in</strong>g AAL2,” af-vmoa-145.000, ATM Forum, July 2000.[6] J. Chou, “The migration <strong>of</strong> LES to the Next GenerationNetwork based on H.248,” ATM Forum, atm00-164, SanFrancisco, May 2000[7] F. Cuervo, N. Greene, A. Rayhan, C. Huitema, B. Rosen,and J. Segers. “Megaco Protocol Version 1.0,” IETFRFC3015, November 2000.[8] J. Lennox, H. Schulzr<strong>in</strong>ne, “Call Process<strong>in</strong>g LanguageFramework and Requirements,” IETF RFC2824, May 2000.[9] J. Rosenberg, J. Lennox, H. Schulzr<strong>in</strong>ne, “Programm<strong>in</strong>gInternet Telephony Services,” IEEE Internet Comput<strong>in</strong>g,May-June 1999, pp. 63-72.[10] M. Handley, H. Schulzr<strong>in</strong>ne, E. Schooler, and J.Rosenberg, “SIP: Session Initiation Protocol,” IETF,RFC2543, March 1999.[11] “OpenCable,” http://www.opencable.com, Cable Labs.[12] J. Lennox, H. Schulzr<strong>in</strong>ne, J. Rosenberg, “CommonGateway Interface for SIP,” IETF RFC3050, January 2001.[13] IEEE P802.3ae 10Gb/s Ethernet Task Force,http://grouper.ieee.org/groups/802/3/ae/<strong>in</strong>dex.html.[14] “Light<strong>in</strong>g Internet <strong>in</strong> the WAN,” TelecommunicationMagaz<strong>in</strong>e, September, 2000, http://telecomsmag.com/issues/200009/tcs/light<strong>in</strong>g_<strong>in</strong>ternet.html.Kushal Roy, born <strong>in</strong> M.P Republic <strong>of</strong> India on December13 th 1979, received his Bachelors Degree with Honors <strong>in</strong>Electronics and Communication Eng<strong>in</strong>eer<strong>in</strong>g form GovernmentEng<strong>in</strong>eer<strong>in</strong>g College Ujja<strong>in</strong>, M.P India, <strong>in</strong> the year 2002,achieved his Master’s Degree M,Phil <strong>in</strong> Instrumentation fromIndian Institute <strong>of</strong> Technology Roorkee, U.A Republic <strong>of</strong> India<strong>in</strong> the year 2004 with nano scale <strong>in</strong>strumentation and opto<strong>in</strong>strumentation as major fields <strong>of</strong> study.He is <strong>in</strong>volved extensively <strong>in</strong>volved <strong>in</strong> Research educationand development s<strong>in</strong>ce 2004 with more than 5 years <strong>of</strong>experience <strong>in</strong> teach<strong>in</strong>g undergraduate as well as post graduatestudents <strong>in</strong> various renowned Institutes across the country.Presently he is serv<strong>in</strong>g as faculty <strong>in</strong> the Department <strong>of</strong>Electronics and communication Eng<strong>in</strong>eer<strong>in</strong>g, Haldia Institute <strong>of</strong>Technology ICARE (Indian Center for Advancement <strong>in</strong>Research and Education) Complex, Haldia, West BengalRepublic <strong>of</strong> India.Mr. Roy has contributed to more than 6 <strong>in</strong>ternationalconferences papers across the globe <strong>in</strong> Italy, S<strong>in</strong>gapore,Morocco, USA etc. He is also work<strong>in</strong>g as Pr<strong>in</strong>cipal Investigatorto a sponsored project on “Study and Development <strong>of</strong> nanoscale piezo electronic material Lead Zirconium Titanate,(popularly known as PZT) by sol-gel process.” (conferred videHonorable President <strong>of</strong> India Direct sanction orderSR/FTP/ETA-49/07) worth 0.522 million INR, Science andEng<strong>in</strong>eer<strong>in</strong>g Research Council, Department <strong>of</strong> Science andTechnology, M<strong>in</strong>istry <strong>of</strong> Science and Technology Government<strong>of</strong> India.© 2010 ACADEMY PUBLISHER


110 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Recovery Based Architecture To Protect HidsLog Files Us<strong>in</strong>g Time StampsSur<strong>in</strong>der S. KhuranaPunjab Engg. College, Chandigarh, Indiasur<strong>in</strong>ders<strong>in</strong>gh.cs07@pec.edu.<strong>in</strong>Divya Bansal , Pr<strong>of</strong>. Sanjeev S<strong>of</strong>atPunjab Engg. College, Chandigarh, IndiaAbstract – After the great revolution <strong>in</strong> the field <strong>of</strong>Information Technology, many applications made necessityto run computer systems (either servers or client mach<strong>in</strong>es)all the time. Along with improvements and new <strong>in</strong>ventions<strong>in</strong> technology, the threat <strong>of</strong> attacks through computernetworks becomes a large issue. Host Based IntrusionDetection is a part <strong>of</strong> security system that protects hostsfrom various k<strong>in</strong>ds <strong>of</strong> attacks. It also provides a greatdegree <strong>of</strong> visibility (<strong>of</strong> system activities). It is quite widestthat HIDS are vulnerable to attacks. An adversary, ifsuccessfully enters <strong>in</strong> a system can disable HIDS or modifyHIDS rules to hide its existence. One can easily evade HIDS.In [7] we propose a new architecture that protects HIDSfrom such attacks. In this paper, we have proposed a newmechanism to check <strong>in</strong>tegrity <strong>of</strong> log files. We have discussedits affects on performance <strong>of</strong> system.I. INTRODUCTIONIntrusion Detection System [5] is an imperative<strong>in</strong>gredient <strong>in</strong> network computer security which plays avital role <strong>in</strong> detect<strong>in</strong>g the <strong>in</strong>trusive activities before theyoccur. Intrusion Detection is usually done throughscann<strong>in</strong>g network traffic and/or hosts data and activities.These <strong>in</strong>trusive activities can be def<strong>in</strong>ed as - activitiesperformed by some adversary for ga<strong>in</strong><strong>in</strong>g unlawfulbenefits. The adverse affects <strong>of</strong> such <strong>in</strong>trusion activitiesare <strong>in</strong> terms <strong>of</strong> loss <strong>of</strong> confidentiality, <strong>in</strong>tegrity andavailability <strong>of</strong> resources or services.IDSs can be classified under various categories.Figure-1 illustrates the various classifications <strong>of</strong> IntrusionDetection Systems.Response BasedDoma<strong>in</strong> OfDetection BasedUnderly<strong>in</strong>gDetectionTechniqueBased• Active IDS• Passive IDS• HIDS• NIDS• Anomaly based IDS• Signature based IDSFigure-1: IDS ClassificationAn IDS can be active or passive. Passive IDS detectthe attacks and logs <strong>in</strong>formation or raise alarms. ActiveIDS takes action <strong>in</strong> response to an already detectedattack. Active IDSs are also known as IntrusionPrevention System.Section 2 discusses Detection and Recovery basedArchitecture to protect HIDS. Section 3 describes timestamp<strong>in</strong>g based protocol to check <strong>in</strong>tegrity <strong>of</strong> log files. Insection 4 and 5, we discuss implementation details.Affects <strong>of</strong> our architecture on system performance hasdescribed <strong>in</strong> section 6. In section 7, we discuss somerelated works. We present directions for future work <strong>in</strong> 6and our conclusion <strong>in</strong> section 8.II. OVERVIEW OF DETECTION AND RECOVERYBASED ARCHITECTUREIn [1], architecture has proposed to detect attacks onHIDS and recover HIDS to its previous healthy state. Thearchitecture protects HIDS from two type <strong>of</strong> attacks: firstis that it does not allow adversary to kill the HIDSprocess. And the other is it does not allow unauthorizedmodification <strong>of</strong> rule or signature database. The basic ideabeh<strong>in</strong>d the architecture is to allow the adversary toperform attack on HIDS and then recover the HIDS to itsprevious healthy state. A new process called MonitorIDShas been <strong>in</strong>troduced <strong>in</strong> the proposed architecture.MonitorIDS is a lightweight system process whichdetects the attacks that affects HIDS and takes requiredactions to recover HIDS from affects <strong>of</strong> that attack.MonitorIDS takes care <strong>of</strong> both HIDS process and<strong>in</strong>tegrity <strong>of</strong> HIDS related <strong>in</strong>formation. However, thisarchitecture does not consider underly<strong>in</strong>g technique usedby HIDS to detect <strong>in</strong>trusions. It can be used with eithersignature based or anomaly based IDS.Figure 2 depicts work<strong>in</strong>g <strong>of</strong> proposed architecture. Asshown <strong>in</strong> figure 2, a backup <strong>of</strong> HIDS related files hasbeen created immediately after the <strong>in</strong>stallation.MonitorIDS process is embedded with HIDS. Thisprocess regularly monitors the HIDS process and filesafter a small fraction <strong>of</strong> time gap. If MonitorIDS foundHIDS process dead (detect unauthorized kill <strong>of</strong> HIDS) itimmediately restarts the HIDS. It also monitors <strong>in</strong>tegrity<strong>of</strong> files related to HIDS. These files may <strong>in</strong>clude rule orsignature database. If it found any unauthorizedmodification <strong>of</strong> HIDS files it replace the modified files© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.110-114


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 111Create Backpup Directory Dur<strong>in</strong>g InstallationRun HIDS and Monitor IDS processMonitor for Attack on HIDSMonitor for Attack on MonitorIDSAttack performedAttack performedHIDS ProcessTerm<strong>in</strong>atedHIDS FilesChangedMonitorIDS ProcessTerm<strong>in</strong>atedMonitorIDS relatedFiles ChangedRestart The HIDSRestore Files FromBackup DirectoryRestart MonitorIDSProcessRestore Files FromBackup DirectoryCreate Log For Attack and <strong>in</strong>form the Adm<strong>in</strong>istartor.Figure 2 : Block Diagram <strong>of</strong> proposed architecturewith files from backup directory. It also logs the attack<strong>in</strong>formation and <strong>in</strong>forms the adm<strong>in</strong>istrator.The architecture also takes care <strong>of</strong> backup directoryand MonitorIDS process related <strong>in</strong>formation, so that thesecannot be modified by some adversary. One importantpo<strong>in</strong>t to note about MonitorIDS is that it is a Systemprocess. To run this process as system process an entrylabeled with respawn has made <strong>in</strong> /etc/<strong>in</strong>ittab file. Thatcannot be stopped. If some adversary makes attempt tokill this process, operat<strong>in</strong>g system kernel automaticallyrestarts it. MonitorIDS process also takes care <strong>of</strong>/etc/<strong>in</strong>ittab file so that entry related to it cannot beremoved.III. TIME STAMPING BASED MECHANISM TOCHECK INTEGRITY OF LOG FILESCompares Last ModificationTime <strong>of</strong> Log FileWith stored valueWrite log entry <strong>in</strong> log fileand<strong>in</strong> backup copy <strong>of</strong> log file.Encrypt Last ModificationTime <strong>of</strong> log fileandIts backup copyReplace Log File WithBackup coopyThe ma<strong>in</strong> goal is to detect and recover unauthorizedmodification <strong>of</strong> log files by any process that is not relatedto HIDS. Such detection is made based on the lastmodification time (a file attribute, changed when the filewas modified) <strong>of</strong> the log file.As shown <strong>in</strong> Figure-3, when HIDS is runn<strong>in</strong>g underthis mechanism it should follow the below givensequence <strong>of</strong> steps to write an entry <strong>in</strong> a file.1. Write log entry <strong>in</strong> log file and <strong>in</strong> backup copy <strong>of</strong>log file.2. Encrypt Last Modification Time <strong>of</strong> log file and itsbackup copy.3. Write encrypted version <strong>of</strong> last Modification time<strong>of</strong> log file and its backup copy <strong>in</strong>to a file.Save Encrypt Last ModificationTimes <strong>in</strong> a FileFigure - 3: Sequence <strong>of</strong> Steps to Write Entry <strong>in</strong> Log FileBefore writ<strong>in</strong>g any entry IDS process compares thecurrent last modification time <strong>of</strong> log file and lastmodification time that was stored <strong>in</strong> a file as specified <strong>in</strong>step 3 given above. A mismatch between these twovalues represents that any other process changed the logfile means unauthorized modification <strong>of</strong> log file. In sucha case log file is replaced with its backup copy or ifunauthorized access to the backup file is detected, it willbe replaced with log file.© 2010 ACADEMY PUBLISHER


112 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010IV. IMPLEMENTATIONThe proposed architecture has been implemented <strong>in</strong>Red Hat L<strong>in</strong>ux environment. Our architecture does notemphasis on underly<strong>in</strong>g technology used by host based<strong>in</strong>trusion detection system to detect <strong>in</strong>trusion. Rather thanconstruct a HIDS from scratch, we decided to leverage anHIDS with<strong>in</strong> current implementation <strong>of</strong> our architecture.The two hypotheses that underlie this dissertation arepractical <strong>in</strong> nature. First, they <strong>in</strong>tend to show that it isfeasible to protect HIDS us<strong>in</strong>g proposed architecture.Second, proposed architecture does not affect systemperformance adversely. Therefore, an implementationwas a center po<strong>in</strong>t for the development <strong>of</strong> this dissertationand was used both for practical verification <strong>of</strong> the<strong>in</strong>tended features <strong>of</strong> the architecture and for aid<strong>in</strong>g <strong>in</strong>reason<strong>in</strong>g about and experiment<strong>in</strong>g with itscharacteristics.V. NEW PROCESSES PROPOSED INARCHITECTUREPractically MonitorIDS process (<strong>in</strong>troduced <strong>in</strong> ourproposed architecture) has implemented with two subprocesses :1. MonitorProcesses2. MonitorFilesTo ensure that MoitorIDS processes live forever werun these processes as system processes. When theadversary tries to kill this process kernel automaticallyrestarts it. A respawn labeled entry related to theseprocesses has been written <strong>in</strong> system file ‘\etc\<strong>in</strong>ittab’ torun these processes as system processes.MonitorProcesses process ensures that all processesrelated to OSSEC are always runn<strong>in</strong>g. If it found anyprocess dead it restarts the process correspond<strong>in</strong>g HIDSprocess. MonitorProcesses also prevents modificationrelated to these entries <strong>in</strong> ‘\etc\<strong>in</strong>ittab’ file. In case <strong>of</strong>deletion or modification <strong>of</strong> these entries from‘\etc\<strong>in</strong>ittab’ file, this process writes new entries. Thepurpose <strong>of</strong> MonitorFiles sub-process is to protect HIDSfiles from unauthorized modification. If it detects anymodification or deletion, it restores the victim file withgenu<strong>in</strong>e file from backup directory.VI. AFFECTS ON PERFORMANCE OF THESYSTEMTo evaluate the affects on the performance on systemfollow<strong>in</strong>g steps are carried out :1. To evaluate the affects on execution time <strong>of</strong> basicL<strong>in</strong>ux commands, some time measurementswere carried out.2. System Monitor<strong>in</strong>g Utility was used to check thechanges <strong>in</strong> utilization <strong>of</strong> processor due toprocesses related to our proposed architecture.A. Affects on execution <strong>of</strong> L<strong>in</strong>ux commandsFor this purpose, most <strong>of</strong> the time measurements werecarried out regard<strong>in</strong>g basic L<strong>in</strong>ux commands (ps, f<strong>in</strong>d,who). Each Command was executed 100 times and allcorrespond<strong>in</strong>g 100 execution times were recorded. Theaverage <strong>of</strong> these tim<strong>in</strong>gs has been considered as theAverage Execution Time(ATE). Average Execution Time(AET) was calculated twice. In first run, we calculateexecution time (ATE1) without runn<strong>in</strong>g processes (suchas MonitorIDS process) related to our architecture. And<strong>in</strong> second run we calculate execution time (ATE2) whileprocesses related to our architecture were runn<strong>in</strong>g.Table-1 Average Execution Time <strong>in</strong> millisecondsCommand ps –ef f<strong>in</strong>d / >/dev/nullNumber <strong>of</strong> systemcalls 536 10055(a) Average Execution Time(AET 1) 25.9 63.1(time required to executeon mach<strong>in</strong>e while not runn<strong>in</strong>gprocesses related to proposedarchitecture )(b)Average Execution Time(AET 2) 30.1 65.5(time required to executeon mach<strong>in</strong>e while processesrelated to proposed architectureare runn<strong>in</strong>g )Overhead relative to (a) 0.16% 0.03%Table 1 represents average execution time (<strong>in</strong>milliseconds) and correspond<strong>in</strong>g overhead. Very smallfraction <strong>of</strong> time was observed as overhead due to theMonitorIDS process.B. Changes <strong>in</strong> processor utilization due MonitorIDSProcessMonitorIDS process is a very lightweight processthat works <strong>in</strong> iterative manner. In each iteration checksthe state (process term<strong>in</strong>ated or runn<strong>in</strong>g) <strong>of</strong> HIDSprocesses and <strong>in</strong>tegrity <strong>of</strong> HIDS related files. Oneiteration requires approximately .001 Second time forexecution.Figure 3 represents the CPU utilization graph whenMonitorIDS process was not runn<strong>in</strong>g. Because theprocessor <strong>in</strong> use is Dual Core two l<strong>in</strong>es representsutilizations <strong>of</strong> processor. As shown <strong>in</strong> the graph CPUutilization is between 0% to 20%. Most <strong>of</strong> the time theCPU utilization is below 10%.Figure 3: Graph show<strong>in</strong>g CPU utilization while MonitorIDS not runn<strong>in</strong>g© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 113But as shown <strong>in</strong> graph given <strong>in</strong> figure 4, whileMonitorIDS process has been runn<strong>in</strong>g the CPU use is<strong>in</strong>creased to some extent. Most <strong>of</strong> the time one <strong>of</strong> theCPU utilization lies between 15 to 20 % and other CPUutilization lies between 5 to 15%.even more time for execution as <strong>in</strong> comparison to time itrequires to execute on a normal mach<strong>in</strong>e.Table-2 Virtual Mach<strong>in</strong>e Overhead on execution timeCommand ps –ef f<strong>in</strong>d / >/dev/nullNumber <strong>of</strong> system calls 536 10055(a) Host Time 25 125(time required to executeOn real mach<strong>in</strong>e )(b) Guest Time 68 484(time required to executeOn real mach<strong>in</strong>e )Overhead relative to (a) 172% 287%Figure 4 Graph show<strong>in</strong>g CPU utilization while MonitorIDS runn<strong>in</strong>g.As <strong>in</strong> comparison to graph <strong>in</strong> figure3 the CPU use is<strong>in</strong>creased about approximately 8 to 10% <strong>of</strong> total CPUutilization while MonitorIDS process has been runn<strong>in</strong>g.VII. RELATED WORKTo protect the HIDS many researchers have given theproposals. In [2], Laureano and Jamhour def<strong>in</strong>e the use <strong>of</strong>virtual mach<strong>in</strong>e to protect the HIDS. Virtual mach<strong>in</strong>e isused because <strong>of</strong> its <strong>in</strong>herent properties like separation <strong>of</strong>execution space. Other benefits [3] <strong>of</strong> virtual mach<strong>in</strong>e,that are useful <strong>in</strong> system security are isolation (a processrunn<strong>in</strong>g outside the VM cannot be accessed <strong>in</strong>ternalprocess <strong>of</strong> VM), <strong>in</strong>spection (VM state can be accessed byVM Monitor), and <strong>in</strong>terposition (any operation issued byVM can be modified by VM Monitor). The idea beh<strong>in</strong>dthe architecture is to encapsulate the system activities(both user and guest activities) <strong>in</strong> virtual mach<strong>in</strong>e andplace the Intrusion Detection System outside the scope <strong>of</strong>virtual mach<strong>in</strong>e. Now any process has not been able toaccess the IDS. IDS monitors the activities performed <strong>in</strong>the virtual mach<strong>in</strong>e and identify the <strong>in</strong>trusive activities.Their approach use type II virtual mach<strong>in</strong>e. Thearchitecture protects the IDS from attacks by plac<strong>in</strong>g itout from the scope <strong>of</strong> other processes. However, thisapproach has one basic problem regard<strong>in</strong>g withtheperformance issue. The overhead due to virtualmach<strong>in</strong>e degrades the system performance to very worsestatus. As results given by them if we compare theexecution tim<strong>in</strong>gs <strong>of</strong> basic rout<strong>in</strong>es under an actualmach<strong>in</strong>e and virtual environment, there is a largevariation. The time taken by rout<strong>in</strong>es under virtualmach<strong>in</strong>e is much more than time taken on an actualmach<strong>in</strong>e.Table 2 represents a subset <strong>of</strong> results given byLaureano and Jamhour <strong>in</strong> [2]. The virtual mach<strong>in</strong>eoverhead is so high that each rout<strong>in</strong>e requires double orThe architecture also affects the networkperformance. The performance <strong>of</strong> applications such asFTP and HTML etc. is also turned down.The work <strong>in</strong> [4] represents the use <strong>of</strong> virtual mach<strong>in</strong>etype-I. The basic idea is same as to run the HIDS <strong>in</strong>execution space that cannot be accessible by otherprocesses. However, virtual mach<strong>in</strong>e overheads alsoaffect this architecture.The use <strong>of</strong> virtual mach<strong>in</strong>es for the security <strong>of</strong>systems has def<strong>in</strong>ed by G. Dunlap & et. al.[6]. Theproposal def<strong>in</strong>es an <strong>in</strong>termediate layer between themonitor and the host system, called Revirt. This layercaptures the data sent through the syslog process (thestandard UNIX logg<strong>in</strong>g daemon) <strong>of</strong> the virtual mach<strong>in</strong>eand sends it to the host system for stor<strong>in</strong>g and lateranalysis. However, if the virtual system is compromised,the guest syslog process can be term<strong>in</strong>ated and/or the logmessages can be manipulated. by the <strong>in</strong>truder, andconsequently they are no longer reliable.VIII. FUTURE WORKStill there are many issues to be addressed about howthe proposed architecture can be best implemented andused. MonitorIDS process checks HIDS cont<strong>in</strong>uously<strong>in</strong> iterative way. To check HIDS <strong>in</strong> an iterationMonitorIDS process requires .001 seconds.On an average, the adversary has .0005 (.0001/2)seconds to disable our architecture and HIDS byexecut<strong>in</strong>g follow<strong>in</strong>g steps :1. Term<strong>in</strong>ate the MonitorIDS process2. Remove the entry related to MonitorIDS processfrom /etc/<strong>in</strong>ittab file to stop the Operat<strong>in</strong>g systemto restart MonitorIDS process.3. Term<strong>in</strong>ate HIDS processes or change files relatedto HIDS.A DFA (Determ<strong>in</strong>istic F<strong>in</strong>ite Automata) shown <strong>in</strong>Figure 4, represent such sequences <strong>of</strong> steps. State q1 isthe <strong>in</strong>itial healthy state and q4 is the f<strong>in</strong>al state. Afterreach<strong>in</strong>g at q4 state attacker can tamper the HIDS. Toavoid this case, there should be some mechanism that© 2010 ACADEMY PUBLISHER


114 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010prevents transitions <strong>of</strong> system states from q1 to q4. Asdiscussed above <strong>in</strong> average case transition from q1 to q4is only possible if made <strong>in</strong> .0005 seconds. Suchmechanism can be based on detect<strong>in</strong>g system callsequence required for this transition. If any suchsequence is detected it should delay (approximately .0005execution <strong>of</strong> these system calls so that before the systemstate will change from q2 or q3 to state q4, transitionfrom q1 or q2 to state q1(<strong>in</strong>itial healthy state) took place.This mechanism can be implemented by chang<strong>in</strong>goperat<strong>in</strong>g system kernel.IX. CONCLUSIONIn this paper, we propose a new time stamp<strong>in</strong>g basedapproach to check <strong>in</strong>tegrity <strong>of</strong> log files <strong>of</strong> HIDS. Thisapproach can be comb<strong>in</strong>ed with Detection and AutoRecovery based architecture to Protect Host Based IDS.As discussed <strong>in</strong> section 4, unlike other approaches ourapproach does not use virtual mach<strong>in</strong>e and hence doesnot affect system performance adversely.Our mechanism ensures that HIDS process alwayslive (cannot be killed by adversary) and the <strong>in</strong>formationrelated to HIDS can never be updated by any adversary.This architecture also ensures the <strong>in</strong>tegrity <strong>of</strong> frequentlyupdated log files <strong>of</strong> HIDS.REFERENCESFigure-4: DFA represent<strong>in</strong>g sequence <strong>of</strong> steps to disable ourarchitecture.Issue <strong>of</strong> authorization and <strong>in</strong>tegrity <strong>of</strong> genu<strong>in</strong>eupdates <strong>of</strong> HIDS <strong>in</strong>formation is another important issueto be addressed. In this approach, we did not consider anytechnique to authorize <strong>of</strong> update. Because IDS’srules/signature database requires frequent updates,<strong>in</strong>clusion <strong>of</strong> a strong authorization mechanism would berequired.[1] A. Abraham, C. Grosan and C.M. Vide. EvolutionaryDesign <strong>of</strong> Intrusion Detection Programs. International<strong>Journal</strong> <strong>of</strong> Network Security, Vol. 4, No. 3, 2007.[2] M Laureano, C Maziero, E Jamhour, Protect<strong>in</strong>g hostbased<strong>in</strong>trusion detectors through virtual mach<strong>in</strong>es-Computer Networks- Elsevier, 2007.[3] P. Chen, B. Noble, When Virtual Is Better Than Real,Workshop on Hot Topics <strong>in</strong> Operat<strong>in</strong>g Systems, 2001.[4] T. Garf<strong>in</strong>kel, M. Rosenblum, A virtual mach<strong>in</strong>e<strong>in</strong>trospection based architecture for <strong>in</strong>trusion detection,ISOC Network and Distributed System SecuritySymposium (2003).[5] S. Axelsson. Research <strong>in</strong> <strong>in</strong>trusion detection systems: Asurvey. Technical report, Chalmers University <strong>of</strong>Technology, 1999.[6] G. Dunlap, S. K<strong>in</strong>g, S. C<strong>in</strong>ar, M. Basrai, P. Chen, ReVirt:Enabl<strong>in</strong>g Intrusion Analysis through Virtual-Mach<strong>in</strong>eLogg<strong>in</strong>g and Replay, USENIX Symposium on Operat<strong>in</strong>gSystems Design and Implementation, 2002.[7] Sur<strong>in</strong>der S<strong>in</strong>gh khurana, Ms. Divya Bansal, Pr<strong>of</strong>. SanjeevS<strong>of</strong>at “Detection and Auto Recovery Approach to ProtectHost Based IDS” 2009 IEEE International AdvanceComput<strong>in</strong>g Conference (IACC 2009)© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 115S<strong>of</strong>tware RadioVarun SharmaInfosys <strong>Technologies</strong> Limited, Chandigarh, IndiaEmail: Varun_sharma15@<strong>in</strong>fosys.comYadv<strong>in</strong>der S<strong>in</strong>gh MannInfosys <strong>Technologies</strong> Limited, Chandigarh, IndiaEmail: Yadv<strong>in</strong>derS_Mann@<strong>in</strong>fosys.comAbstract— This paper aims to provide an overview onrapidly grow<strong>in</strong>g technology <strong>in</strong> the radio doma<strong>in</strong> whichovercomes the drawbacks suffered by the conventionalanalog radio. This is the age <strong>of</strong> S<strong>of</strong>tware radio – thetechnology which tries to transform the hardware radiotransceivers <strong>in</strong>to smart programmable devices which can fit<strong>in</strong>to various devices available <strong>in</strong> today’s rapidly evolv<strong>in</strong>gwireless communication <strong>in</strong>dustry. This new technology hassome or the entire physical layer functions s<strong>of</strong>tware def<strong>in</strong>ed.All <strong>of</strong> the waveform process<strong>in</strong>g, <strong>in</strong>clud<strong>in</strong>g the physical layer,<strong>of</strong> a wireless device moves <strong>in</strong>to the s<strong>of</strong>tware. An idealS<strong>of</strong>tware Radio provides improved device flexibility,s<strong>of</strong>tware portability, and reduced development costs. Thispaper tries to get <strong>in</strong>to the details <strong>of</strong> all this. It takes onethrough a brief history <strong>of</strong> conventional radios, analyzes thedrawbacks and then focuses on the S<strong>of</strong>tware radio <strong>in</strong>overcom<strong>in</strong>g these short com<strong>in</strong>gs.I. HISTORYRadio, as anyone would perceive, is a device that canwirelessly transmit or receive signals <strong>in</strong> the radi<strong>of</strong>requency (RF) part <strong>of</strong> the electromagnetic spectrum. J.CMaxwell postulated the theory <strong>of</strong> electromagnetic wavepropagation which was confirmed by H Hertz. Theseelectromagnetic waves travel through space eitherdirectly, or have their path altered by reflection,refraction or diffraction. When EM Waves come <strong>in</strong>contact with a conductor; they get converted to anelectrical energy, radio or micro wave depend<strong>in</strong>g on itswavelength. Radio waves can carry <strong>in</strong>formation byvary<strong>in</strong>g a comb<strong>in</strong>ation <strong>of</strong> the amplitude, frequency andphase <strong>of</strong> the wave with<strong>in</strong> a frequency band. Nikola Teslaand Guglielmo Marconi <strong>in</strong>vented devices that used radiowaves for communication.Earlier, radio systems relied entirely on the energycollected by an antenna to produce signals for theoperator. Radios became more useful after the <strong>in</strong>vention<strong>of</strong> electronic devices such as the vacuum tube and laterthe transistor, which made it possible to amplify weaksignals.Today most <strong>of</strong> our gadgets conta<strong>in</strong> a radio system <strong>in</strong> it.From a cell phone to television , a walkie-talkie <strong>in</strong> a toy,space vehicles, cell phones or Satellite phones,Audio/Video broadcast<strong>in</strong>g, Navigation Systems, RADARand many other applications. Traditional Radios werebuilt only for a particular frequency range, modulationtype, and output power. “Figure 1. shows a typicaltraditional radio receiver.The RF signal is converted to Intermediate Frequency(IF) us<strong>in</strong>g a programmable local oscillator. The IF signalis a fixed frequency and the IF signal is then amplifiedand filtered before feed<strong>in</strong>g it to demodulator. Each k<strong>in</strong>d<strong>of</strong> radio will have its own type <strong>of</strong> demodulator to extractthe audio data for play<strong>in</strong>g it on speaker. These radioswould require hardware changes to modify thesefundamental characteristics like frequency range,modulation type etc. Moreover, with the advancement <strong>of</strong>technology, new communication standards keep com<strong>in</strong>gand are used to varied degree <strong>in</strong> different countries e.g.CDMA, GSM EDGE, 3G, etc. The Conventional radioscannot cope with these advances, due to compatibilityissues. Hence, there was a need for dynamicallyconfigurable radios which could be used for variousapplications by simply re-configur<strong>in</strong>g the s<strong>of</strong>twarerunn<strong>in</strong>g <strong>in</strong> them. They can also be made to comply withthe various communication standards, just by chang<strong>in</strong>gthe implemented protocol. This is the world <strong>of</strong> S<strong>of</strong>twareRadio.Figure 1. Block Diagram <strong>of</strong> a Traditional Radio Receiver© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.115-121


116 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010II. WHAT IS A SOFTWARE RADIO?Joe Mitola, who came up with the term S<strong>of</strong>tware Radiodef<strong>in</strong>es it as "A radio whose channel modulationwaveforms are def<strong>in</strong>ed <strong>in</strong> s<strong>of</strong>tware. That is, waveformsare generated as sampled digital signals, converted fromdigital to analog via a wideband DAC and then possiblyup converted from IF to RF. The receiver, similarly,employs a wideband Analog to Digital Converter (ADC)that captures all <strong>of</strong> the channels <strong>of</strong> the s<strong>of</strong>tware radionode. The receiver then extracts, down converts anddemodulates the channel waveform us<strong>in</strong>g s<strong>of</strong>tware on ageneral purpose processor." [2]The s<strong>of</strong>tware radio, by his def<strong>in</strong>ition, should have aslittle hardware as possible.A S<strong>of</strong>tware Radio consists <strong>of</strong> a receiver and atransmitter. For the reception case as shown <strong>in</strong> “Figure 2.” [1], when the Antenna receives the signal, it passes thesignal to the receiver section for filter<strong>in</strong>g and separat<strong>in</strong>gthe signal from noise and <strong>in</strong>terference. The signal is thenconverted to a desired frequency and amplitude which iscompatible with the analog to digital converter (ADC),and f<strong>in</strong>ally to digital data. The digitized data is thenprocessed us<strong>in</strong>g digital signal process<strong>in</strong>g techniques forfurther use.For the transmission process as shown <strong>in</strong> "Figure 3.[1], the s<strong>of</strong>tware programmable digital signal process<strong>in</strong>gtechniques are used for generat<strong>in</strong>g the modulatedsignal(s) <strong>in</strong> the digital doma<strong>in</strong>. The digital samples arethen converted to analog signal us<strong>in</strong>g Digital to AnalogConverter (DAC) and then amplified to the appropriatevoltage, current or power before transmission through theantenna.III. COMPONENTS OF A SOFTWARE RADIOS<strong>of</strong>tware Radio provides a flexible radio architecturethat makes it re-programmable for different usages withno or m<strong>in</strong>imal change <strong>in</strong> the hardware. This is supportedby features like <strong>in</strong>terference rejection techniques,encryption, voice recognition and compression, s<strong>of</strong>twareenabledpower m<strong>in</strong>imization and control, differentaddress<strong>in</strong>g protocols and advanced error recoveryschemes.The technology provides the flexibility to comb<strong>in</strong>edifferent grades <strong>of</strong> hardware and s<strong>of</strong>tware to strike theright balance between cost and network resilience. Thereconfigurable blocks <strong>in</strong> S<strong>of</strong>tware Radio allows easychanges to the radio’s fundamental characteristics such asmodulation types, operat<strong>in</strong>g frequencies, bandwidth,multiple access schemes, source and channelencod<strong>in</strong>g/decod<strong>in</strong>g methods, frequency spread<strong>in</strong>g/despread<strong>in</strong>gtechniques, and encryption/decryptionalgorithm.The various components <strong>of</strong> a s<strong>of</strong>tware radio are shown<strong>in</strong> “Figure 4. and described below:Figure 2. Radio Signal Reception ProcessFigure 3. Radio Signal Transmission Process© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 117Figure 4. Block diagram <strong>of</strong> S<strong>of</strong>tware RadioA. Smart AntennaAntennas are conduct<strong>in</strong>g devices which transmit orreceive electromagnetic radiations. An antenna arrayconsists <strong>of</strong> distributed antenna elements whose outputsare comb<strong>in</strong>ed and is a practical tool for enhanc<strong>in</strong>gwireless system performance. The choice <strong>of</strong> an antennafor a s<strong>of</strong>tware radio is crucial as it is expected to supportmultiple bands [1].It is an antenna array system with <strong>in</strong>-built signalprocess<strong>in</strong>g “smart” algorithms to help adapt to differentsignal environments. It can also identify the direction <strong>of</strong>arrival <strong>of</strong> the signal; add phases to the signal to create aconstructive radiation pattern to nullify <strong>in</strong>terference.Smart antennas mitigate fad<strong>in</strong>g through diversityreception and beam-form<strong>in</strong>g while m<strong>in</strong>imiz<strong>in</strong>g<strong>in</strong>terference through spatial filter<strong>in</strong>g. S<strong>of</strong>tware radiosprovide the flexibility needed for effective smart antennasand smart antennas put help <strong>in</strong> effective implementationand utilization <strong>of</strong> s<strong>of</strong>tware radio.B. RF Front EndIt appears before the Intermediate Frequency changestate and after the signal is received from the antenna. Itdoes the job <strong>of</strong> convert<strong>in</strong>g the <strong>in</strong>com<strong>in</strong>g signal to IFfrequency by us<strong>in</strong>g a tunable local oscillator.RF front end design process for a s<strong>of</strong>tware radio hasthe challenge <strong>of</strong> cater<strong>in</strong>g to a variety <strong>of</strong> waveforms withwidely chang<strong>in</strong>g parameters such as amplitude,frequency, phase etc. Due to this wide spectrum, thepresence <strong>of</strong> noise and <strong>in</strong>terference is manifold. Thismakes the process <strong>of</strong> achiev<strong>in</strong>g a dynamic range evenmore difficult. The dynamic range is the measure <strong>of</strong> thehighest and lowest level signals that can besimultaneously conta<strong>in</strong>ed <strong>in</strong> a radio. In case <strong>of</strong> mobilecommunication, <strong>in</strong>crease <strong>in</strong> dynamic range would meanmore battery consumption, which becomes a major trade<strong>of</strong>ffor mobile phones.Low level signals suffer from the problem <strong>of</strong> noise.Noise enters at the bottom <strong>of</strong> dynamic range due to thethermal effects <strong>of</strong> the components, deviation <strong>in</strong>quantization or sampl<strong>in</strong>g aperture jitter <strong>in</strong> an ADC. Highlevel signals are limited by <strong>in</strong>terference. Interference iscaused at the high end due to adjacent channel, cochannelor is self <strong>in</strong>duced by transceiver. Traditionalwireless communication receivers require s<strong>in</strong>gle RF frontend for each channel. S<strong>of</strong>tware radio, however, has onlyone wideband RF front end which can digitize desiredsignal <strong>in</strong>to separated channels via s<strong>of</strong>tware to provide alow cost solution.C. Analog to Digital ConversionBefore all the process<strong>in</strong>g can be done <strong>in</strong> the s<strong>of</strong>tware,the analog signal received at IF stage needs to beconverted to digital samples by use <strong>of</strong> Analog to Digitalconverter. Ideal S<strong>of</strong>tware Radio would require a widebandwidth and good dynamic range from the ADC. Asshown <strong>in</strong> “Figure 5. , the translation <strong>of</strong> the signal fromanalog to digital is performed via sampl<strong>in</strong>g andquantization. Sampl<strong>in</strong>g changes the signal that existscont<strong>in</strong>uously <strong>in</strong> time to a signal that is non zero only atdiscrete <strong>in</strong>tervals <strong>of</strong> time. Quantization changes thecont<strong>in</strong>uous valued signal to discrete valued signal.Figure 5. Analog to Digital Conversion© 2010 ACADEMY PUBLISHER


118 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010In an ideal s<strong>of</strong>tware radio, Analog to Digitalconversion should occur near the RF end. This wouldrequire the follow<strong>in</strong>g criteria’s to be met:• A very high or variable sampl<strong>in</strong>g rate to supportwide signals bandwidth.• Greater number <strong>of</strong> quantization bits to support ahigh dynamic range.• Operat<strong>in</strong>g bandwidth <strong>of</strong> several GHz to allowconversion <strong>of</strong> a signal over a wide range <strong>of</strong>frequencies.• Lesser distortion and wide dynamic range to allowrecovery <strong>of</strong> low level signals <strong>in</strong> the presence <strong>of</strong>strong <strong>in</strong>terferers.• Economical components to meet the abovecriteria’s without consum<strong>in</strong>g an excessive amount<strong>of</strong> power.Due to the limitations <strong>of</strong> the fabrication technology,few <strong>of</strong> the above mentioned criteria’s need to be traded<strong>of</strong>f for an acceptable design solution for the s<strong>of</strong>twareradio.D. Digital to Analog ConversionIn S<strong>of</strong>tware Radio, entire waveform and modulation isgenerated <strong>in</strong> digital doma<strong>in</strong> and is then fed to Digital toAnalog Converter before f<strong>in</strong>al transmission. As shown <strong>in</strong>“Figure 6. , the translation <strong>of</strong> the signal from digital toanalog is performed via voltage mapp<strong>in</strong>g andreconstruction, where the digital signal is changed to acont<strong>in</strong>uous valued signal. The number <strong>of</strong> bits and thefrequency range <strong>of</strong> the DAC are the important factors asthey would determ<strong>in</strong>e the reconstruction <strong>of</strong> thecont<strong>in</strong>uous signal.In a traditional analog radio, the frequency synthesis isperformed via bulky devices like quartz crystal, <strong>in</strong>ductor,capacitor, mechanical resonators etc. But differentfrequencies and waveforms can be generated <strong>in</strong> thedigital doma<strong>in</strong> by Direct Digital Synthesis (DDS)techniques and it is fast replac<strong>in</strong>g the analog devices asthey provide better accuracy, frequency can be changedwith s<strong>of</strong>tware and is simple to implement.E. Digital Down ConversionA digital down converter (DDC) provides the l<strong>in</strong>kbetween the analog RF front end and the digital baseband<strong>of</strong> a receiver. The received signal is usually sampled atmuch higher sampl<strong>in</strong>g rates than required to relax thespecifications <strong>of</strong> the anti-alias<strong>in</strong>g filter required. But toreduce the computational power required from DigitalSignal Processors (DSPs), the sampl<strong>in</strong>g rate isimmediately reduced by down converter. DSPrequirements are directly proportional to sampl<strong>in</strong>g rateand reduc<strong>in</strong>g sampl<strong>in</strong>g rates reduces CPU cycles requiredto perform the same digital signal process<strong>in</strong>g algorithmsand thus sav<strong>in</strong>g significantly on cost and DSP powerconsumption.F. Digital Up ConversionA digital up converter (DUC) provides the l<strong>in</strong>kbetween the digital base band and analog RF front endand is required on the transmitter end. The signal to betransmitted is generated by digital signal process<strong>in</strong>g atlower sampl<strong>in</strong>g rates to reduce computations <strong>of</strong> DSP. Butbefore it can be fed to DAC for convert<strong>in</strong>g to analogsignal, it is up converted to higher sampl<strong>in</strong>g rate byDigital Up Converter to relax <strong>in</strong>terpolation filterspecifications.G. Digital Signal Process<strong>in</strong>gDSP is the bra<strong>in</strong> beh<strong>in</strong>d all digital radio technology. ADSP core consists <strong>of</strong> an arithmetic logic unit (ALU),accumulator(s), multiply and accumulate MAC unit(s),data and the address buses. A DSP is designed to supporthigh performance, repetitive, numerically <strong>in</strong>tensive tasksand very high I/O performance. Large accumulators <strong>in</strong>DSPs help reduce the precision problems. The digitalsignal processor performs all the functions <strong>of</strong> filter<strong>in</strong>g,demodulat<strong>in</strong>g, generat<strong>in</strong>g the signal for transmissionus<strong>in</strong>g various modulation techniques <strong>in</strong> s<strong>of</strong>tware radio.DSPs also perform functions <strong>of</strong> data compression,encryption and special functions like speech recognition,image enhancement, neural networks for artificial<strong>in</strong>telligence etc. The three ma<strong>in</strong> categories <strong>of</strong> digitalhardware are ASICs (Application Specific IntegratedCircuit), FPGAs (Field Programmable Gate Array) andDSPs. A DSP represents the most generalized type <strong>of</strong>hardware that can be programmed repeatedly us<strong>in</strong>g highlevel programm<strong>in</strong>g language to perform variousfunctions. An ASIC is the most specialized piece <strong>of</strong>hardware and can be used only <strong>in</strong> the specific applicationfor which it has been designed. ASICs are generally usedwhen DSP has <strong>in</strong>sufficient process<strong>in</strong>g power and functionto be performed is fixed. The set-up <strong>of</strong> ASICs isimplemented on fixed silicon, which optimizes the speedand power consumption <strong>of</strong> the circuit.Figure 6. Digital to Analog Conversion© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 119FPGAs help conserve silicon area s<strong>in</strong>ce one chip canbe configured to perform more than one function hencethe configuration can be done at run time. Gate arrays<strong>of</strong>fer higher degree <strong>of</strong> parallelism <strong>in</strong> comparison to DSP.A hardware description language (HDL) is used fordesign<strong>in</strong>g highly complex circuitry. FPGAs are moreflexible than ASICs but lesser than DSPs. FPGAs arebe<strong>in</strong>g used because <strong>of</strong> their ability to perform high-speedparallel multiplication and accumulation functions andare especially well suited to handle algorithms like F<strong>in</strong>iteImpulse Response (FIR) filters (for decimation or<strong>in</strong>terpolation) and transforms like Fast FourierTransformations (FFT) and Discrete Cos<strong>in</strong>e Transforms(DCT). Also they have the advantage <strong>of</strong> provid<strong>in</strong>gflexibility to <strong>in</strong>tegrate logic design with signalprocess<strong>in</strong>g. These three hardware components constitutea design space which trades flexibility, process<strong>in</strong>g speedand power compensation.In an ideal scenario, Digital signal process<strong>in</strong>g (DSP)s<strong>of</strong>tware should help to perform most <strong>of</strong> the radi<strong>of</strong>unctions at astonish<strong>in</strong>g performance levels, enhance theperformance us<strong>in</strong>g digital filter<strong>in</strong>g and drasticallyreduc<strong>in</strong>g noise and <strong>in</strong>terferences, all <strong>of</strong> it with less bulkyequipments.IV. MODULATION AND DEMODULATIONTo understand the advantage and ease with whichmodulated signals can be generated and demodulationcan be done <strong>in</strong> digital doma<strong>in</strong> us<strong>in</strong>g digital signalprocess<strong>in</strong>g, an example <strong>of</strong> Amplitude Modulation andDemodulation is discussed below.A. Modulat<strong>in</strong>g the signalThe carrier signal as shown <strong>in</strong> “Figure 7. , can begenerated us<strong>in</strong>g either DDS technique or us<strong>in</strong>g s<strong>in</strong>e serieslibrary function. The modulat<strong>in</strong>g signal will be the output<strong>of</strong> microphone amplifier sampled at a particular rate byADC. Here for illustration purposes, carrier frequency <strong>of</strong>1000Hz and modulation signal <strong>of</strong> 20 Hz has beengenerated us<strong>in</strong>g the follow<strong>in</strong>g equations with sampl<strong>in</strong>grate <strong>of</strong> 10 KHz:for ( i = 0; i < 1000, i++){Carrier = S<strong>in</strong>(2 * PI * i * Fc / SR);ModS = 1 + S<strong>in</strong>(2 * PI * i * Fm / SR);}.In (1) above,SR is sampl<strong>in</strong>g Rate = 10KHz,Fc = 1000Hz (Carrier),Fm = 20Hz (Modulation signal).Amplitude Modulation <strong>in</strong>volves chang<strong>in</strong>g theamplitude <strong>of</strong> carrier as per the amplitude <strong>of</strong> themodulat<strong>in</strong>g signal. S<strong>in</strong>ce we have the samples <strong>of</strong> carrierand modulat<strong>in</strong>g signal <strong>in</strong> digital doma<strong>in</strong>, the amplitudemodulation <strong>in</strong> digital doma<strong>in</strong> is simply multiplication <strong>of</strong>these samples. “Error! Reference source not found.”,shows the generation <strong>of</strong> modulated signal.ModSignal = Carrier * ModS.(2)B. Demodulat<strong>in</strong>g the received signalAt the receiv<strong>in</strong>g end when this signal is received, it isfull wave rectified which <strong>in</strong> digital doma<strong>in</strong> is noth<strong>in</strong>g buttak<strong>in</strong>g the absolute value <strong>of</strong> all the samples. “Error!Reference source not found. shows the output <strong>of</strong> fullwave rectifier.RectSignal = abs(ModSignal).(1)(3)Figure 7. Generation <strong>of</strong> carrier and modulation signalsFigure 8. Amplitude modulated carrierFigure 9. Full wave rectified AM waveform© 2010 ACADEMY PUBLISHER


120 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Now the modulated signal is conta<strong>in</strong>ed <strong>in</strong> the form <strong>of</strong>envelope <strong>of</strong> full wave rectified signal and can berecovered by apply<strong>in</strong>g a low pass filter to remove thecarrier frequency. “Error! Reference source notfound.shows the output <strong>of</strong> a first order Inf<strong>in</strong>ite ImpulseResponse (IIR) filter. The equation <strong>of</strong> filter used is:Yn = 0.997*Yn-1 + 0.003*Xn.In (4) above,Xn is new <strong>in</strong>put sample (RectSignal),Yn-1 is previous output sample,Yn is new output sample (demodulated signal).Figure 10. Demodulated signal after low pass filterV. SOFTWARE RADIO AS A SOLUTION TO CONVENTIONALANALOG RADIOSA S<strong>of</strong>tware Radio <strong>in</strong> contrast to a traditional Radioruns on a generic hardware platform to perform all themodulation/demodulation, frequency selection, filter<strong>in</strong>getc <strong>in</strong> digital doma<strong>in</strong> as also expla<strong>in</strong>ed above <strong>in</strong> theexample. It can perform role <strong>of</strong> a cordless phone, cellphone, <strong>in</strong>ternet access tool, a GPS receiver etc. all <strong>in</strong> one.This is possible by chang<strong>in</strong>g the s<strong>of</strong>tware used forprocess<strong>in</strong>g. Hence, there is no limitation <strong>of</strong> any particularfrequency range, modulation type, and output power <strong>in</strong> aS<strong>of</strong>tware Radio. All these flexibilities <strong>of</strong> s<strong>of</strong>tware radio<strong>of</strong>fer advantages which can be broadly classified as:A. Frequency-AgileThe s<strong>of</strong>tware programmable process<strong>in</strong>g allows it tooperate <strong>in</strong> the entire radio waves frequency bands.B. Easy to plug n playIt is a radio <strong>in</strong>to which multiple contractors could plugparts and s<strong>of</strong>tware.C. Global MobilityIt caters to the model as it is flexible to support most <strong>of</strong>the communications standards like CDMA, GSM, IS-136etc.D. Inter-operabilityIt can be made to <strong>in</strong>ter-operate with different wirelessprotocols, <strong>in</strong>corporate new services, and upgrade to newstandards etc by simply download<strong>in</strong>g a new program (or anewer version <strong>of</strong> the s<strong>of</strong>tware) or by change <strong>of</strong> selectionfrom the user <strong>in</strong>terface.E. Compact and Power EfficientDue to reduced number <strong>of</strong> components used <strong>in</strong>S<strong>of</strong>tware Radio, its size is reduced result<strong>in</strong>g <strong>in</strong> ease <strong>of</strong>manufactur<strong>in</strong>g. Also less hardware results <strong>in</strong> less powerconsumption.(4)F. Quality <strong>of</strong> ServiceAs S<strong>of</strong>tware Radio is S<strong>of</strong>tware dependent; hence agreater quality <strong>of</strong> service is delivered consistently.VI. APPLICATIONS OF SOFTWARE RADIOThe ultimate goal <strong>of</strong> S<strong>of</strong>tware Radio is to provide as<strong>in</strong>gle radio trans-receiver which can play the roles <strong>of</strong>cordless telephone, cell phone, wireless fax, wireless e-mail system, pager, wireless videoconferenc<strong>in</strong>g unit,wireless <strong>Web</strong> browser, Global Position<strong>in</strong>g System (GPS)unit, and other functions still <strong>in</strong> the realm <strong>of</strong> sciencefiction, operable from any location on the surface <strong>of</strong> theearth, and perhaps <strong>in</strong> space as well. Few <strong>of</strong> theapplications <strong>of</strong> s<strong>of</strong>tware Radio has been coveredhenceforth and shows the variety <strong>of</strong> functionality towhich it can cater to.A. Pacemakers and Implantable Cardiac DefibrillatorsWirelessly reprogrammable and implantable medicaldevices (IMDs) such as pacemakers, implantablecardioverter defibrillators (ICDs), neurostimulators, andimplantable drug pumps use embedded computers andradios to monitor chronic disorders and treat patients withautomatic therapies. For <strong>in</strong>stance, an ICD that senses arapid heartbeat can adm<strong>in</strong>ister an electrical shock alsoknown as the s<strong>of</strong>tware radio attacks to restore a normalheart rhythm, then later reports this event to a health carepractitioner who uses a commercial device programmerwith wireless capabilities to extract data from the ICD ormodify its sett<strong>in</strong>gs without surgery. Cl<strong>in</strong>ical trials haveshown that these devices significantly improve survivalrates <strong>in</strong> certa<strong>in</strong> populations. [4]B. Smart sensorsS<strong>of</strong>tware Radios can be implemented as smart sensorsto determ<strong>in</strong>e the amount <strong>of</strong> various particles present <strong>in</strong>atmosphere, hence useful for pollution check, weatherforecast etc. When used as Bio-sensor with configurables<strong>of</strong>tware, it can be used <strong>in</strong> study <strong>of</strong> complex anatomy.C. One Cell phone for many standardsIt is highly <strong>in</strong>convenient for a regular <strong>in</strong>ter countrytraveler to change his mobile connection forcommunication due to network issues. For example,3GPP UMTS is popular <strong>in</strong> European nations, whileC/TDMA standards are widely used across North andSouth America. So, every time one travels through acountry he has to have the country specific cellularphone. But with the com<strong>in</strong>g <strong>of</strong> S<strong>of</strong>tware radio, it can be ath<strong>in</strong>g <strong>of</strong> past as the S<strong>of</strong>tware Radio can adapt to change <strong>in</strong>the local air <strong>in</strong>terface by a simple s<strong>of</strong>tware change. Allthe base stations and term<strong>in</strong>als us<strong>in</strong>g S<strong>of</strong>tware Radioarchitecture can support multiple air <strong>in</strong>terfaces dur<strong>in</strong>gperiods <strong>of</strong> transition and be easily upgraded.D. Cost Effective Up gradation <strong>of</strong> a Cellular BaseStationThe growth <strong>in</strong> radio technology is <strong>in</strong>-step with thedemand <strong>of</strong> today’s customer, but is the bus<strong>in</strong>ess ready?The customer may have asked for audio files <strong>in</strong> his© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 121cellular services yesterday, but today they look for videostreams <strong>in</strong> their phone and tomorrow they might ask forlive data feed. The cellular <strong>in</strong>dustry cannot afford to losebus<strong>in</strong>ess by not mak<strong>in</strong>g such changes. S<strong>of</strong>tware Radiohelps to save them millions by easy upgrades <strong>in</strong> s<strong>of</strong>tware.There is no need for <strong>in</strong>vestment <strong>in</strong> the hardware, sav<strong>in</strong>gthem both money and time. It is also a boon forcustomers as they don’t need to purchase newer handsetsfor newer technology. Just as any <strong>in</strong>dividual or bus<strong>in</strong>esscan update a s<strong>of</strong>tware program used on a PC, by us<strong>in</strong>gS<strong>of</strong>tware Radio technology, any cellular providers canupgrade s<strong>of</strong>tware easily and quickly to make changes ontheir systems. As a result, the cost for cellular phoneservice can cont<strong>in</strong>ue to be decreased for consumers;while the providers can see higher marg<strong>in</strong>s for the servicethey provide.E. Usability <strong>in</strong> EmergencyAs the s<strong>of</strong>tware radio is compact and easilydeployable, it can be useful for temporary coveragedur<strong>in</strong>g emergencies and special events. A s<strong>of</strong>tware radiocan be programmed and mounted onto a vehicle anddriven to the site <strong>of</strong> a natural disaster to br<strong>in</strong>g <strong>in</strong>communications where they may have been damaged andto support multiple standards.F. High Def<strong>in</strong>ition TV ApplicationsS<strong>of</strong>tware Radios are f<strong>in</strong>d<strong>in</strong>g significant applications <strong>in</strong>the conversion <strong>of</strong> both analog and digital transmissions toHDTV, an upcom<strong>in</strong>g broadcast technology.VII. CHALLENGES & LIMITATIONSS<strong>of</strong>tware radio technology alters traditional radios <strong>in</strong>three ways namely mov<strong>in</strong>g A/D closer to antenna,substitute hardware with s<strong>of</strong>tware process<strong>in</strong>g andfacilitat<strong>in</strong>g transition from dedicated to general-purposehardware. This decreases the number <strong>of</strong> hardwarecomponents result<strong>in</strong>g <strong>in</strong> high degree <strong>of</strong> extensibility for awide range <strong>of</strong> features. This will also elim<strong>in</strong>ate theredundant hardware as found <strong>in</strong> dual band phones etc.There are several technological challenges faced <strong>in</strong>S<strong>of</strong>tware Radio today, like the usage <strong>of</strong> faster A/Dconverters, requirement for less power consumption,implement<strong>in</strong>g smart antennas and mak<strong>in</strong>g the overallradio more cost effective. ADCs which can digitize thehigh range signal are very expensive. They also <strong>in</strong>creasethe level <strong>of</strong> SFDR (spurious free dynamic range). Hence,the signal received are down converted from RF signaland digitized at IF range via ADCs before send<strong>in</strong>g thedata to DSPs. To overcome this limitation, more researchand development would be required to build lessexpensive ADCs cover<strong>in</strong>g more dynamic range andsupport<strong>in</strong>g greater sampl<strong>in</strong>g rates. For FPGAs, <strong>in</strong>terval toreprogram FPGA’s limits its usability.The authenticity and security <strong>of</strong> downloaded s<strong>of</strong>twareis another area <strong>of</strong> concern. There is a need for a globallyrecognized regulatory body which can control theseprocesses. Certification from bodies like FederalCommunications Commission (FCC) is another hurdle.FCC certification process presumes that any s<strong>of</strong>tware thatis bundled with the hardware be certified as a unit. Buts<strong>of</strong>tware radio be<strong>in</strong>g programmable at any time poseschallenges <strong>in</strong> certification. A new certification procedurehas been created. S<strong>of</strong>tware changes which can affectradio frequency, power and modulation are subject tomore streaml<strong>in</strong>ed process. However, FCC does not certifyany changes by third party s<strong>of</strong>tware vendors. Allmodifications are the responsibility <strong>of</strong> the orig<strong>in</strong>almanufacturer whose orig<strong>in</strong>al hardware/s<strong>of</strong>tware radiobundle was certified. This requires that all the<strong>in</strong>dependent vendors need to work via equipmentmanufacturers. Hence, certify<strong>in</strong>g s<strong>of</strong>tware radios pose asignificant challenge because <strong>of</strong> cumbersome certificationprocesses, especially for doma<strong>in</strong>s like aerospace anddefense which require test<strong>in</strong>g for all possible scenarioswhere s<strong>of</strong>tware may misbehave.VIII. FUTURE OF SOFTWARE RADIOUltimate aim <strong>of</strong> s<strong>of</strong>tware radio would be to move ADCand DAC just next to Antenna and do<strong>in</strong>g everyth<strong>in</strong>g <strong>in</strong>s<strong>of</strong>tware. Currently, the cost <strong>of</strong> high frequency ADCs andspecialized hardware for digital signal process<strong>in</strong>g are few<strong>of</strong> the factors limit<strong>in</strong>g the application <strong>of</strong> s<strong>of</strong>tware radiosto high end use only. As the technology advances, thecosts will come down and process<strong>in</strong>g power <strong>of</strong> generalpurpose comput<strong>in</strong>g platforms will <strong>in</strong>crease. Once theprocess<strong>in</strong>g power crosses the threshold required forperform<strong>in</strong>g necessary radio functions, broaderapplications and scales <strong>of</strong> economy will come <strong>in</strong>to placeand we will see s<strong>of</strong>tware radios be<strong>in</strong>g used <strong>in</strong> our day today use gadgets. How soon it can happen is still an openquestion but s<strong>of</strong>tware radio is likely to be an importanttechnology <strong>in</strong> the years to come.REFERENCES[1] Jeffrey H. Reed, “S<strong>of</strong>tware Radio”.[2] J Mitola, "The S<strong>of</strong>tware Radio", IEEE NationalTelesystems Conference, 1992 - Digital Object Identifier10.1109/NTC.1992.267870.[3] Ulrich L. Rohde, "Digital HF Radio: A Sampl<strong>in</strong>g <strong>of</strong>Techniques”, Ham Radio Magaz<strong>in</strong>e, April, 1985.[4] http://www.secure-medic<strong>in</strong>e.org/icd-study/icd-study.pdf[5] “A S<strong>of</strong>tware-Def<strong>in</strong>ed Radio for the Masses, Part 1- 4”,Gerald Youngblood, AC5OG[6] http://www.sdrforum.org/[7] http://rfdesign.com/mag/radio_fast_hot_data/<strong>in</strong>dex.html[8] http://www.dspguide.com/© 2010 ACADEMY PUBLISHER


122 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010SDR and Error Correction us<strong>in</strong>g ConvolutionEncod<strong>in</strong>g with Viterbi Decod<strong>in</strong>gShriram K. VasudevanVIT/Embedded Systems, Vellore, IndiaEmail: shriramkv@rocketmail.comSiva Janakiraman and Subashri VasudevanSASTRA/Communication, Tanjore, IndiaSASTRA/Computer Science, Tanjore, IndiaEmail: sivajanakiraman@gmail.com,vrsuba@gmail.comAbstract— The aim <strong>of</strong> the paper is to build as<strong>of</strong>tware based radio capable <strong>of</strong> demodulat<strong>in</strong>g FrequencyModulated signals with the ability to receive upto fourstations simultaneously. In addition convolution encod<strong>in</strong>galong with Viterbi decod<strong>in</strong>g is also implemented to aid <strong>in</strong>error correction capability <strong>of</strong> digital transmissionsystems. The <strong>in</strong>itial phase is aimed at s<strong>of</strong>tware baseddemodulation <strong>of</strong> multiple channels <strong>of</strong> FrequencyModulated signals. The second phase is directed towardsthe Error correction us<strong>in</strong>g convolution encod<strong>in</strong>g withViterbi decod<strong>in</strong>g for stream<strong>in</strong>g data encountered <strong>in</strong>digital broadcast systems.S<strong>of</strong>tware Radio is a way <strong>of</strong> design<strong>in</strong>g s<strong>of</strong>twarevery close to the antenna. The basic feature <strong>of</strong> s<strong>of</strong>twareradio is that s<strong>of</strong>tware will def<strong>in</strong>e the transmittedwaveforms, and s<strong>of</strong>tware will demodulate the receivedwaveforms. This paper is developed with the help <strong>of</strong> frees<strong>of</strong>tware based radio toolkit given by a community namedGNU radio. Channel cod<strong>in</strong>g schemes need to be usedextensively <strong>in</strong> the case <strong>of</strong> transmission <strong>of</strong> digital data overthe air or through any other medium. These cod<strong>in</strong>gschemes also called FEC (Forward Error Correction)are used <strong>in</strong> cases where the re-transmission <strong>of</strong> the data isnot feasible or possible. The channel cod<strong>in</strong>g schemescomes to the rescue <strong>in</strong> such cases where redundant dataare sent over the transmission medium along with themessage. In the receiver side, this channel coded signal isdecoded to get back the orig<strong>in</strong>al data even if the channelcoded signal undergoes some <strong>in</strong>terference from the noise<strong>in</strong> the transmission medium. Though the channel cod<strong>in</strong>ghas a downside <strong>of</strong> requirement to transmit additionaldata over the transmission medium, the advantages<strong>of</strong>fered by error detection and correction mechanisms tothe receiver outweighs the disadvantage <strong>of</strong> additionaldata transfer rate and bandwidth requirements.Index Terms—SDR, Viterbi Decoder, Convolution EncoderI. INTRODUCTIONS<strong>of</strong>tware-Def<strong>in</strong>ed Radio (SDR) is an evolv<strong>in</strong>gtechnology that has received enormous recognition. In thepast few years, analog radio systems are replaced bydigital radio systems for various radio applications <strong>in</strong>civilian, military and commercial spaces. In addition tothis, programmable hardware modules are play<strong>in</strong>g a vitalrole <strong>in</strong> digital radio systems at different functional levels.SDR totally aims to take benefits <strong>of</strong> these programmablehardware modules to get open-architecture based radiosystem s<strong>of</strong>tware.SDR technology supports implementation <strong>of</strong> some <strong>of</strong>the functional modules <strong>in</strong> a radio system such asmodulation/demodulation, signal generation, cod<strong>in</strong>g andl<strong>in</strong>k-layer protocols <strong>in</strong> s<strong>of</strong>tware. This assists <strong>in</strong> gett<strong>in</strong>greconfigurable s<strong>of</strong>tware radio systems where dynamicselection <strong>of</strong> parameters for each <strong>of</strong> the above-mentionedfunctional modules is possible. A Complete hardwarebased system has many limitations.Before gett<strong>in</strong>g <strong>in</strong>to what s<strong>of</strong>tware radio does, it is goodto review the design <strong>of</strong> a traditional analog, hardwarebasedradio (Figure.1). In wireless communications,<strong>in</strong>formation is encoded <strong>in</strong>to radio waves. These arecollected (or transmitted) from (to) the air by the antenna.The received signal is then passed to a series <strong>of</strong>components that extract the useful <strong>in</strong>formation andconvert it <strong>in</strong>to the output <strong>of</strong> the radio. The basic design isthe same whether the radio signal is dest<strong>in</strong>ed for a cellphone, microwave repeater, or AM/FM car radio.Traditional radios are based on the super heterodyne(superhet) receiver circuit.Manuscript received August 2, 2009; revised August 20, 2009;© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.122-130


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 123key reasons why s<strong>of</strong>tware radios will not bedeployed first <strong>in</strong> end-user devices suchas cell phones, butrather <strong>in</strong>base stations which can take advantage <strong>of</strong>external power sources.Figure 1. Generic FM receiverIn the superhet receiver, the <strong>in</strong>com<strong>in</strong>gsignal, whichhis Radio Frequency (RF), is first down-converted to alower <strong>in</strong>termediate frequency(IF). The IF is then filteredfor noise andamplified before be<strong>in</strong>g demodulated toproduce the baseband signal that represents the desiredd<strong>in</strong>formation. This analog baseband signal may be passeddirectly to further downstage process<strong>in</strong>g, or it may firstbe digitized and subjected toadditional signal process<strong>in</strong>g.There are several important reasons for down convert<strong>in</strong>gto a lower and standardized IF:(a) It is easierand hence less expensive, to build filtersand amplifiers – especially l<strong>in</strong>ear amplifiers – for a lowerfrequency signal.(b) Use <strong>of</strong> a common IF enables standardization <strong>in</strong> thedesign <strong>of</strong> radiocomponents.Traditionaldesignsfor implement<strong>in</strong>gthe superheterodyne receiver architecture were optimized forspecific frequencies and applications and each <strong>of</strong> thestages were implemented <strong>in</strong>hardware that was closelycoupled. This was due largely to the difficulties <strong>in</strong>herent<strong>in</strong> and limitations <strong>in</strong> the state <strong>of</strong> the art <strong>in</strong>the design <strong>of</strong>analog signal process<strong>in</strong>g components. Analog process<strong>in</strong>gis much more complicated than digital process<strong>in</strong>g, whichhis one <strong>of</strong> the key reasons why the transition to digitalsignals is so important.In this paper chapter 2 deals about theperformance and power limitations, Chapter 3 talks aboutarchitecture <strong>of</strong>SDR. Chapter4 is on signalflow, Chapter5 is deal<strong>in</strong>g with how to derive <strong>in</strong>stantaneous frequency.Chapter 6 talksabout De Emphasizer. Chapter 7 expla<strong>in</strong>sabout multi channel FM reception. Chapter 8 will givedetails about the Forward Error Correction.Chapter 9 and10 speaks on implementation and results. Chapter 11 isconclud<strong>in</strong>g thepaper followed by references.II. PERFORMANCE ANDPOWER LIMITATIONSThe change from hardware to s<strong>of</strong>tware radioshas faced lot <strong>of</strong> problems. First, performance generallycomes down <strong>in</strong> the shift from dedicated to general-purpose hardware.Secondly, the transition from hardware tos<strong>of</strong>tware process<strong>in</strong>g results <strong>in</strong> a substantial <strong>in</strong>crease <strong>in</strong>computation which ultimately results <strong>in</strong> <strong>in</strong>creased powerrequirements. This reduces battery life and is one <strong>of</strong> theIII. ARCHITECTUREWe now take a view at the overview <strong>of</strong> a basicconventional digital radio system and then look athowSDR technology can be used toimplement radi<strong>of</strong>unctions <strong>in</strong> s<strong>of</strong>tware. This will be followed by thes<strong>of</strong>tware architecture <strong>of</strong> SDR. Thedef<strong>in</strong>ition <strong>of</strong> thes<strong>of</strong>tware radio system is not absolute and depends onwhere theAnalog to digital conversion is performed. Thequestion <strong>of</strong> where theA/D conversion is performeddeterm<strong>in</strong>es what radi<strong>of</strong>unctions can be moved<strong>in</strong>tos<strong>of</strong>tware and what types <strong>of</strong> hardware are required. At oneextreme, we consider call<strong>in</strong>g it s<strong>of</strong>tware radio if s<strong>of</strong>twareis used atany stage with<strong>in</strong> the radio.This case typically<strong>in</strong>volves the digitization at the baseband for signalprocess<strong>in</strong>g. In this casethe actual demodulation processis performed before theconversion todigital format. Thissetup is more <strong>of</strong> a digital radio than s<strong>of</strong>tware radio. Whatprocess can be done us<strong>in</strong>g s<strong>of</strong>tware isvery much limited.S<strong>in</strong>ce theactual demodulation itself takes placewithhardware, it cannot beused for demodulation <strong>of</strong> otherk<strong>in</strong>ds <strong>of</strong>signal and hence is very limited <strong>in</strong> itsfunctionality.At the other extreme, we might choose to use s<strong>of</strong>twareradio forcases <strong>in</strong> which A/D conversion is performedright at the antennaa with all radio functionalityimplemented <strong>in</strong> s<strong>of</strong>tware runn<strong>in</strong>g on general-purposehardware. In this case the Digitization<strong>of</strong> the signaltakesplace right at the antenna and thus gives us the completeflexibility. This setup requires the use <strong>of</strong> a veryhighspeed andwideband ADC, not economically feasible atthis po<strong>in</strong>t <strong>in</strong> time. Figure 2 shows the basic s<strong>of</strong>twareradio architecture.Figure.2 Basic S<strong>of</strong>tware Radio Architecturee© 2010 ACADEMY PUBLISHER


124 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010In this paper, we take a stance that lies <strong>in</strong>between the two cases described above. The digitization<strong>of</strong> the signal is performed <strong>in</strong>the Intermediate frequencyband, followed by the digital down conversion. Thebaseband process<strong>in</strong>g is done <strong>in</strong> a general purposecomputer. Though this setupdoes not giveus a completees<strong>of</strong>tware control over the radio spectrum, it does <strong>of</strong>fer usa great level <strong>of</strong> flexibility with the s<strong>of</strong>tware s<strong>in</strong>ce we canactually demodulate the signal us<strong>in</strong>g s<strong>of</strong>tware. Thearchitecture used <strong>in</strong> this project is <strong>in</strong>dicated <strong>in</strong> Figure 3.This helps us to explore the part <strong>of</strong> radio spectrum whichhfalls <strong>in</strong> the IF region that canbe digitized.The digital radio systemconsists <strong>of</strong> three ma<strong>in</strong>functional blocks: RF section, IF section and basebandsection. The RF section consists <strong>of</strong> essentially analoghardware modules while IF and baseband sectionssconta<strong>in</strong> digitalhardware modules. The RFsection (alsocalledas RF front-end) is responsiblefortransmitt<strong>in</strong>g/reeceiv<strong>in</strong>g the radio frequency (RF) signalfrom the antenna via a coupler and convert<strong>in</strong>g the RFsignal to an <strong>in</strong>termediate frequency (IF) signal. The RFfront-end on the receive path performs RFamplificationand analog down conversion from RF to IF. On thetransmit path, RF front-end performs analog upconversion andRF power amplification.The ADC/ /DAC blocks perform analog-to-digitaconversion (on receive path) and digital-to analogconversion (ontransmit path), respectively. DDC/DUCCblocks performdigital-downconversion (on receive path)anddigital-up-conversionrespectively. DUC/DDC blocks essentially performmodem operations, i.e., modulation <strong>of</strong> the signal ontransmit path and demodulation <strong>of</strong> the signal on receiveepath.For this paper work, the RF section andthe IF sectionare handled bythe hardware, followed bythe basebandprocess<strong>in</strong>g by Computer. The hardware used is known asthe Universal S<strong>of</strong>tware RadioPeripheral (USRP).(on transmitpath) ),III. SOFFTWARE BASEDFM RECEIVERRThe real implementation <strong>of</strong> the project starts fromhere. The hardware used is a custom built board provideddby the creators <strong>of</strong> the GNU Radio community, which isdesigned to run the free s<strong>of</strong>tware toolkit provided bythem. The ma<strong>in</strong> goal isto take the FM baseddemodulationone step further to receive up to four FMstations simultaneously.What theUSRP gives to the Computer is a Digital-Down converted, complex, quadrature signal <strong>in</strong> theBaseband. Therema<strong>in</strong><strong>in</strong>g process<strong>in</strong>g willl be taken careby the s<strong>of</strong>tware after gett<strong>in</strong>gg the signal from the USRPboard. Thus once the signal enters the computer, thedemodulation <strong>of</strong> the FMsignal consists <strong>of</strong> the follow<strong>in</strong>gsteps.(a) Signal flow from the air to the computer (from real tocomplex)(b) Gett<strong>in</strong>g the <strong>in</strong>stantaneous frequency (from complex toreal)(c) De-emphasizer(d) AudioFIR decimation filter(e) Outputo Soundcard/FileThus each stage <strong>of</strong> this signal process<strong>in</strong>g acts as a blockwith <strong>in</strong>put and outputt ports. Each block receives thesignal as<strong>in</strong>put from the previous block, performs therequired signal process<strong>in</strong>g and gives the output to thenext block <strong>in</strong> the cha<strong>in</strong>.The s<strong>of</strong>tware architecture is implemented <strong>in</strong> two layers.The bottom layer is implemented <strong>in</strong> C++, which satisfiesthe performance requirement <strong>of</strong> thedemodulationandsignal process<strong>in</strong>g. The top layer is implemented <strong>in</strong>python, which acts as a mask layer, <strong>in</strong>terconnect<strong>in</strong>g thebottom C++ layers which perform the bulk <strong>of</strong> the signalprocess<strong>in</strong>g. This two layered architecture gives us theadvantageor reus<strong>in</strong>g the signal process<strong>in</strong>g blocks andmakes it easier to customize the signal process<strong>in</strong>gflownecessary. Thus connect<strong>in</strong>g or remov<strong>in</strong>g a process<strong>in</strong>gblock from the s<strong>of</strong>tware demodulation cha<strong>in</strong> is mucheasier. The entire s<strong>of</strong>tware layer is built and run on a freeUNIX port for w<strong>in</strong>dows called cygw<strong>in</strong>. Cygw<strong>in</strong> <strong>of</strong>fers aUNIX platform on w<strong>in</strong>dows based systemIV. SIGNAL FLOW FROM THE AIR TO THE COMPUTER(FROM REAL TO COMPLEEX).Basically what the USRP does is to select the part <strong>of</strong>the spectrum we are <strong>in</strong>terested <strong>in</strong> and decimate the digitalsequence by some factor N. The result<strong>in</strong>g signal iscomplex with I/Q two channels. Thus USRP gives out a`complex' signal, witha data rate 256k samples persecond, called `quadrature rate' – or quad rate becausethe complex signal has I/Q quadrature components(Figure. 3).Figure.3 Digital down Converter© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 125V. GETTING THE INSTANTANEOUS FREQUENCY (FROMCOMPLEX TO REAL).For FM, the <strong>in</strong>stantaneousfrequency <strong>of</strong> thetransmitted waveform is varied as a function <strong>of</strong> the <strong>in</strong>putsignal. The <strong>in</strong>stantaneous frequency at anytime is givenby the follow<strong>in</strong>g formula:f(t) = k * m(t) + f cm(t) is the <strong>in</strong>put signal, k isa constant that controls thefrequency sensitivity and f c is the frequency <strong>of</strong> the carrier(for example, 100.1MHz). So to recover m(t), two stepssare needed. First we need toremove the carrier f c , thenwe're left with a baseband signal that has an<strong>in</strong>stantaneousfrequency proportional tothe orig<strong>in</strong>almessage m(t) ). The secondstep is to compute the<strong>in</strong>stantaneous frequency <strong>of</strong> the baseband signal.Remov<strong>in</strong>g the carrier is taken care by the USRP, viathe digital down converter (DDC). The result<strong>in</strong>g signalcom<strong>in</strong>g <strong>in</strong>to the Computer has already become abaseband signal and the rema<strong>in</strong><strong>in</strong>g task is to calculate its<strong>in</strong>stantaneousfrequency. If we <strong>in</strong>tegrate frequency, weget phase, or angle. Conversely, differentiat<strong>in</strong>g phasewith respect totime gives frequency. These are the key<strong>in</strong>sights we use to build the receiver. The angle betweentwosubsequentsamples can be determ<strong>in</strong>ed bymultiply<strong>in</strong>g one by the complex conjugate <strong>of</strong> the otherand then tak<strong>in</strong>gthe arc tangent <strong>of</strong> the product.Thus Arctangent <strong>of</strong> theproduct gives the phasedifference between adjacentsamples, if we divide it bythe sample <strong>in</strong>terval or multiply the data rate, we get theradian frequency, which gives the <strong>in</strong>stantaneoussfrequency (f) if further divided by 2. This process <strong>of</strong>recover<strong>in</strong>gthe<strong>in</strong>stantaneousfrequency from thequadrature signal from the USRP is called the“Quadrature Demodulation”(Figure. 4).Figure.4 Quadrature Demodulationfrequency end usually becomes unbearable. Tocircumvent this effect, `pre-emphasis' and `de-emphasis'were <strong>in</strong>troduced <strong>in</strong>to the FM system. At the transmitter,proper pre-emphasis circuits are used to manuallyamplify the high frequency components, and the converseoperations are done at the receiver to recover the orig<strong>in</strong>alpower distribution <strong>of</strong> the signal. As a result, the SNR isimprovedeffectively. Inthe analog world, a simple firstorder RLC circuit usually suffices for pre-emphasis andde-emphasis. In the case <strong>of</strong> the S<strong>of</strong>tware def<strong>in</strong>ed Radio, afirst order IIR filter is implemented to get the magnitude<strong>of</strong> amplified, high frequency signal down tothemagnitude <strong>of</strong> normal lower frequency signal, therebyimprov<strong>in</strong>g the SNR.Let us now see about Audio FIR decimation filter:After pass<strong>in</strong>g the de-emphasizer, <strong>of</strong> 256kHz.It is a baseband signal, conta<strong>in</strong><strong>in</strong>gall the frequency components <strong>of</strong> a FM station. Theitis a real signal witha data ratebandwidth <strong>of</strong> a FM station is usually around 2 * 100kHz.A sample rate <strong>of</strong> 256kHz is suitable for the 200kHzbandwidth, without los<strong>in</strong>g any spectrum <strong>in</strong>formationnFigure.5 Typical FM BandThe FMsignal band is spread out with various band <strong>of</strong><strong>in</strong>formation (Figure. 5) ). From 0 to about 16 kHz is theleft plus right (L + R) audio. The peak at 19 kHz is thestereo pilot tone. The left m<strong>in</strong>us right (L - R) stereo<strong>in</strong>formation is centeredat 2x the pilot (38kHz) and isAM-modulated on top <strong>of</strong> the FM. Additional sub carriersare sometimes found <strong>in</strong> the region <strong>of</strong> 57kHz - 96kHz.Thus for the reception <strong>of</strong> a mono FMstation, a LowpassFIR filterwith a pass band frequency <strong>of</strong> 15Khz and atransitionn band with 1Khz should suffice. Thus, once thesignal comes out <strong>of</strong> theFIR decimation filter block, it isnow ready to be played <strong>in</strong>to the soundcard.Output toSoundcard/File:VI. DE-EMPLASIZERIt has beentheoreticallyproved that, <strong>in</strong> FM detector,the power <strong>of</strong> the output noise <strong>in</strong>creases with thefrequency quadratically. However, for most practicalsignals, such as human voiceand music, the power <strong>of</strong> thesignal decreases significantlyas frequency<strong>in</strong>creases. Asa result, the “Signal to Noise Ratio” (SNR) at the highOnce the signal passes through the FIR Decimationfilter, it is ready to be played bythe soundcard oralternatively stored <strong>in</strong> a File. The signal from theFIRdecimation filter is <strong>in</strong>a raw bit format and can beconvertedto other formats us<strong>in</strong>g any suitablecompression algorithms.© 2010 ACADEMY PUBLISHER


126 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010VII. FORWARD ERROR CORRECTIONForward error correction [FEC] is a system <strong>of</strong> errorcontrol for data transmission, whereby the sender addsredundant data to its messages, which allows the receiverto detect and correct errors (with<strong>in</strong> some bound) withoutthe need to ask the sender for additional data. Theadvantage <strong>of</strong> forward error correction is thatretransmission <strong>of</strong> data can <strong>of</strong>ten be avoided, at the cost <strong>of</strong>higher bandwidth requirements on average, and istherefore applied <strong>in</strong> situations where retransmissions arerelatively costly or impossible.Such a typical situation where the receiver is not ableto make a request for the re-transmission <strong>of</strong> message isFM reception. FEC devices are <strong>of</strong>ten located close to thereceiver <strong>of</strong> an analog signal, <strong>in</strong> the first stage <strong>of</strong> digitalprocess<strong>in</strong>g after a signal has been received. That is, FECcircuits are <strong>of</strong>ten an <strong>in</strong>tegral part <strong>of</strong> the analog-to-digitalconversion process.Forward Error Correction Implemented:The Forward error correction algorithm consists <strong>of</strong>two parts namely Encod<strong>in</strong>g and Decod<strong>in</strong>g. The Encod<strong>in</strong>gis implemented us<strong>in</strong>g a Convolution algorithm and theDecod<strong>in</strong>g implemented is the Viterbi algorithm. Theconvolution encoder and the correspond<strong>in</strong>g Viterbidecoder are implemented <strong>in</strong> C programm<strong>in</strong>g language.Motivation for Forward Error CorrectionThe situation <strong>in</strong> which the receiver is not able to makea request to the sender for re-transmission <strong>of</strong> messageforms the basis for all forward error correctiontechniques. A typical radio receiver is a classic example<strong>in</strong> which the receiver has no provision to communicatewith the sender. Under such circumstances, if an erroroccurred <strong>in</strong> the signal transmitted, there will be no wayfor the receiver to detect the error unless some errorcontrol mechanisms are <strong>in</strong>corporated <strong>in</strong>to the signalbefore transmission itself. This process <strong>of</strong> add<strong>in</strong>g errorcontrol to the signal before transmission is calledForward Error Correction.A typical communication channel <strong>in</strong> which the datato be transmitted is encoded us<strong>in</strong>g some encod<strong>in</strong>galgorithm by add<strong>in</strong>g some redundant bits (Figure. 6).Thus the output <strong>of</strong> the encoder is called ChannelSymbols. These channel symbols are then transmittedover the wireless channel.Thus it can be seen that unless the error correctionmechanisms are <strong>in</strong>troduced there is no way for thereceiver to recover the orig<strong>in</strong>al <strong>in</strong>formation correctly.Hence Forward Error Correction mechanisms areessential if the receiver is to recover the orig<strong>in</strong>al<strong>in</strong>formation. There are numerous forward error correctionmechanisms each applicable to particular type <strong>of</strong>communication. The factors which govern which errorcorrection algorithm is used for a particularcommunication type are Bandwidth <strong>of</strong> the spectrumDepth <strong>of</strong> error correction requiredRate <strong>of</strong> encod<strong>in</strong>gProcess<strong>in</strong>g capacity <strong>of</strong> Sender/ReceiverIntroduction to Convolution Encod<strong>in</strong>gConvolution Encod<strong>in</strong>g typically <strong>in</strong>volves encod<strong>in</strong>g <strong>of</strong>stream <strong>of</strong> data bits by us<strong>in</strong>g previous bits to perform alogical operation, the output <strong>of</strong> which is the encodedchannel symbols. Thus depend<strong>in</strong>g upon the type <strong>of</strong>convolution encod<strong>in</strong>g, a s<strong>in</strong>gle data bit can have its<strong>in</strong>fluence on two or more adjacent bits thereby provid<strong>in</strong>gthe required redundancy to the data. This <strong>in</strong>fluence whicha bit has on other bits is what enables the receiver toidentify any bit errors that occurred dur<strong>in</strong>g the datatransmission.A convolution encoder is called so because it performsa convolution <strong>of</strong> the <strong>in</strong>put stream with encoder's impulseresponses. It can be represented mathematically aswhere x is an <strong>in</strong>put sequence, y j is a sequence from outputj and h j is an impulse response for output j. A convolutionencoder is a discrete l<strong>in</strong>ear time-<strong>in</strong>variant system. Everyoutput <strong>of</strong> an encoder can be described by its own transferfunction, which is closely related to a generatorpolynomial.Figure 6. Typical wireless communication channel© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 127C.1. Convolution Encod<strong>in</strong>g Algorithm <strong>in</strong> this paperThe convolution algorithm implemented <strong>in</strong> this projectis a Half rate,(5,7) encoder with a constra<strong>in</strong>t length <strong>of</strong>K=3, which is suitable for stream<strong>in</strong>g data. .Theconvolution encod<strong>in</strong>g typically <strong>in</strong>volves the process <strong>of</strong>encod<strong>in</strong>g data by us<strong>in</strong>g the bits <strong>of</strong> data to perform modulo2 addition, thereby add<strong>in</strong>g redundancy (Figure. 7).Then the message with errors is given as <strong>in</strong>put to theViterbi decoder and its error correction capability isanalyzed.Convolution EncoderThe length <strong>of</strong> the generated bit stream is taken as <strong>in</strong>putfrom the user. Once the bit stream is generated, theconvolution encod<strong>in</strong>g is performed and the encoded datais written to a file. The encoder simulation is shown <strong>in</strong>figure.7Figure 6. Basic convolution encod<strong>in</strong>gXIII. VITERBI ALGORITHMThe Viterbi algorithm implemented <strong>in</strong> this project issuitable for decod<strong>in</strong>g data that has been encoded with aHalf-rate,(7,5) convolution encoder with a constra<strong>in</strong>tlength <strong>of</strong> K=3.IX. IMPLEMENTATION OF ALGORITHMSThe steps <strong>in</strong>volved <strong>in</strong> simulat<strong>in</strong>g a communicationchannel us<strong>in</strong>g convolutional encod<strong>in</strong>g and Viterbidecod<strong>in</strong>g are as follows1. Generate the data to be transmitted through thechannel.2. Convolutionally encode the data.3. Introduce channel errors4. Perform Viterbi decod<strong>in</strong>g on the receivedchannel symbolsX. RESULTSThe results <strong>of</strong> the project implemented are analyzed <strong>in</strong>the sections below.S<strong>of</strong>tware Based Demodulation:Forward Error CorrectionThe simulation setup consists <strong>of</strong> a channel encoderwhich generates random bit streams consist<strong>in</strong>g <strong>of</strong> 0’s and1’s which represents the message bits. This bit stream isthen encoded. Then the encoded data is given to achannel error simulator to simulate bit errors.Figure.7 Simulation result <strong>of</strong> encoderS<strong>in</strong>ce the encod<strong>in</strong>g is typically performed on a stream<strong>of</strong> data, it must have a known length for the decoder todecode the message properly. Hence the encoder encodesthe data <strong>in</strong> frames. The frame length used <strong>in</strong> this projectis 15 message bits with 3 flush<strong>in</strong>g bits for each frame.Hence the stream <strong>of</strong> data is broken up <strong>in</strong>to frames <strong>of</strong>constant length and then encoded. Once the encod<strong>in</strong>gprocess is completed, the encoded message is then writtento a file.Channel Error SimulationIn order to verify the error correction capability <strong>of</strong> thedecoder, the encoded message must be <strong>in</strong>cluded withrandom bit errors to simulate the message transmittedthrough a noisy channel. A model <strong>in</strong> which random biterrors occurs is created.The number <strong>of</strong> bit errors to be <strong>in</strong>troduced <strong>in</strong> eachframe is taken as an <strong>in</strong>put from the user andcorrespond<strong>in</strong>gly random bits are <strong>in</strong>verted i.e. 0’s changedto 1’s and 1’s changed to 0’s which provides a reasonablemodel to simulate channel errors. The channel errorsimulation module is shown <strong>in</strong> figure 8© 2010 ACADEMY PUBLISHER


128 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010The Test case taken up consists <strong>of</strong> a 60-bit messageencoded <strong>in</strong>to four frames by the encoder. This setup isshown <strong>in</strong> FigureFigure.8 Channel error simulationIn this case, the number <strong>of</strong> bit errors <strong>in</strong>troduced is zeroand hence the encoder output and the received channelsymbols are identical. The output <strong>of</strong> the channel errorsimulator is written to a file, which will then be taken asthe <strong>in</strong>put for the decoder.Decod<strong>in</strong>g received symbolsThe <strong>in</strong>put to the Viterbi decoder is the file conta<strong>in</strong><strong>in</strong>gchannel errors, given as output by the channel errorsimulator. The decoder takes this file as <strong>in</strong>put and thenperforms decod<strong>in</strong>g and tries to recover the orig<strong>in</strong>almessage. The decod<strong>in</strong>g simulation is shown <strong>in</strong> figure 9Figure 10. An example depictionThe message is encoded <strong>in</strong>to four frames and ispassed to the channel error simulator to <strong>in</strong>troduce variousamounts <strong>of</strong> bit errors and the decoder performance isanalyzed.Figure.9 Decod<strong>in</strong>g simulation resultWhile encod<strong>in</strong>g messages are encoded <strong>in</strong> frame, so thatdecoder can start from a known state for each frame.Figure 9 shows decod<strong>in</strong>g <strong>of</strong> channel symbols conta<strong>in</strong><strong>in</strong>gonly one frame.Performance <strong>of</strong> Viterbi DecoderThe Viterbi decoder implemented <strong>in</strong> this project is aHard-decision decoder capable <strong>of</strong> decod<strong>in</strong>g the channelsymbols encoded by half-rate,(7,5) convolution encoderwith a constra<strong>in</strong>t length <strong>of</strong> 3. Various amounts <strong>of</strong> biterrors are simulated and the performance <strong>of</strong> the decoderis then analyzed.In the first case, three random bit errors are<strong>in</strong>troduced <strong>in</strong> each frame. The performance <strong>of</strong> thedecoder for this test case is shown if follow<strong>in</strong>g ScreenShot.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 129It is found that the Viterbi decoder is able to recover theorig<strong>in</strong>al message <strong>in</strong> most <strong>of</strong> the cases when 5 random biterrors are <strong>in</strong>troduced <strong>in</strong> each frame, thus <strong>of</strong>fer<strong>in</strong>g almost100% error correction when there is 33% error <strong>in</strong> thereceived channel symbols.The next test case <strong>in</strong>volves <strong>in</strong>troduc<strong>in</strong>g seven bit errorsper frame and the performance <strong>of</strong> the decoder <strong>in</strong> this caseis shown <strong>in</strong> follow<strong>in</strong>g snap.It is found that the decoder recovers the orig<strong>in</strong>almessage when three random bit errors are produced <strong>in</strong>each frame <strong>of</strong> the received channel symbols, <strong>of</strong>fer<strong>in</strong>g100% error correction capability for 3 random bit errors.In the next test case, Five bit errors are <strong>in</strong>troduced <strong>in</strong> eachframe as shown <strong>in</strong> screen shot as follows.It is found that the performance <strong>of</strong> the decoderdeteriorates as the bit error <strong>in</strong>creases to 7 errors perframe. The decoded messages differ from orig<strong>in</strong>almessage and on an average only 32% <strong>of</strong> the errors arecorrected on a trial run with 10 samples.When the number <strong>of</strong> bit errors per frame is further<strong>in</strong>creased to 9 bit errors per frame, the performance <strong>of</strong> thedecoder still goes down and the orig<strong>in</strong>al message <strong>in</strong> notrecovered by the decoder as <strong>in</strong>dicated <strong>in</strong> next screen shot.The performance <strong>of</strong> the decoder for this test case isshown <strong>in</strong> the follow<strong>in</strong>g screen shotIt is found that <strong>in</strong> case <strong>of</strong> n<strong>in</strong>e bit errors per frame, theerror recovery rate falls to as low as 8.2% on average runwith 10 samples.© 2010 ACADEMY PUBLISHER


130 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Thus overall, the performance <strong>of</strong> the Hard-decisionViterbi decoder falls with the <strong>in</strong>crease <strong>in</strong> bit error ratesand good level <strong>of</strong> error correction is available up to 5 biterrors per frame above which the message keeps gett<strong>in</strong>gdeteriorated. This is <strong>in</strong>dicated <strong>in</strong> the figure .11%Bit error correction120100806040200Bit Error Correction Rate1 2 3 4 5 6 7 8 9No <strong>of</strong> Bit errors/frameFigure 11. Analysis graphXI. CONCLUSIONThus the s<strong>of</strong>tware based multi channel FM reception<strong>of</strong>fers the capability to receive from one up to four FMstations at the same time. One station is streamed live tothe speakers while the rest are stored <strong>in</strong> the disk <strong>in</strong> rawformat. This <strong>of</strong>fers the ability to listen to the recordeddata at a later time thereby prevent<strong>in</strong>g the user frommiss<strong>in</strong>g out on some important <strong>in</strong>formation.Work<strong>in</strong>g with the FM band <strong>of</strong> the radio spectrum is theentrance to the S<strong>of</strong>tware based radio world which iscapable <strong>of</strong> handl<strong>in</strong>g many parts <strong>of</strong> the radio spectrum.This project provided a good practical exposure to theproblems <strong>in</strong>volved <strong>in</strong> replac<strong>in</strong>g a conventional radio withs<strong>of</strong>tware based one and demonstrated the power andflexibility <strong>of</strong>fered by us<strong>in</strong>g s<strong>of</strong>tware <strong>in</strong> place <strong>of</strong>conventional hardware.This project just touches the tip <strong>of</strong> the iceberg <strong>in</strong> theworld <strong>of</strong> s<strong>of</strong>tware def<strong>in</strong>ed radio, which has tremendouspotential to be unleashed. With the aid <strong>of</strong> technologyadvancement, the s<strong>of</strong>tware based radios will be able toexplore the full radio spectrum very soon <strong>in</strong>to the future.With the move towards process<strong>in</strong>g signal systems <strong>in</strong>digital format comes the problem <strong>of</strong> error detection andcorrection. Thankfully, this has been taken care bynumerous error detection and correction algorithms,which were proposed long back, but were notimplemented due to large computation requirements.The convolution encoder and the Viterbi decoderimplemented <strong>in</strong> this project <strong>of</strong>fer a reasonable amount <strong>of</strong>error correction capability to a message signal.These algorithms are the basic error correctionalgorithms on which many other complex error correctionalgorithms are built upon.REFERENCES[1] John G Proakis, Dimitris G Manolakis, “DigitalSignal Process<strong>in</strong>g: Pr<strong>in</strong>ciples, Algorithms andApplications”, 1996, Prentice Hall, ISBN: 0-13-373762-4[2] Todd K. Moon, “Error correction cod<strong>in</strong>g:Mathematical methods and algorithms”,2002, JohnWiley and sons, ISBN: 0-471-64800-0Shriram K. Vasudevan was born at TamilNadu on 29-07-1983. He holds an M.Tech <strong>in</strong> Embedded Systems and B.E., <strong>in</strong>Electronics and Instrumentation. He has done his B.E., fromAnnamalai University, Chidambaram, India. He proceeded withhis M.Tech at TIFAC-CORE <strong>of</strong> SASTRA University, Tanjore,India.He has got overall 4 years <strong>of</strong> <strong>in</strong>dustrial experience <strong>in</strong> thefield <strong>of</strong> Embedded Systems and Optical Network<strong>in</strong>g. Currentlyhe is hold<strong>in</strong>g the responsibility <strong>of</strong> Assistant Pr<strong>of</strong>essor <strong>in</strong> thefield <strong>of</strong> Embedded Systems <strong>in</strong> VIT University, Vellore, India.He was employed with Wipro <strong>Technologies</strong> for 2 years. He hasvisited USA, Dallas for his telecom tra<strong>in</strong><strong>in</strong>g.He has presented papers <strong>in</strong> National and Internationalconferences <strong>in</strong> the areas <strong>of</strong> VLSI, Embedded and Network<strong>in</strong>g.His research area focuses on Embedded Network<strong>in</strong>g.Siva Janakiraman was born at TamilNadu on 05-06-1982.He holds an M.Tech <strong>in</strong> Embedded Systems and B.E., <strong>in</strong>Electronics and Communication. He has done his B.E., fromSASTRA University, Tanjore, India. He proceeded with hisM.Tech at SASTRA University, Tanjore, India. He has gotoverall 5 years <strong>of</strong> teach<strong>in</strong>g experience <strong>in</strong> the field <strong>of</strong> EmbeddedSystems. Currently he is hold<strong>in</strong>g the responsibility <strong>of</strong> AssistantPr<strong>of</strong>essor <strong>in</strong> the school <strong>of</strong> Electrical and ElectronicsEng<strong>in</strong>eer<strong>in</strong>g <strong>in</strong> SASTRA University, Tanjore, India. Hisresearch area focuses on Embedded Systems and Cryptography.Subashri Vasudevan, born at TamilNadu on 21-01-1989.She is currently do<strong>in</strong>g her B.Tech and she is <strong>in</strong> her f<strong>in</strong>al year <strong>of</strong>her studies. She is graduat<strong>in</strong>g at SASTRA University. She hasbeen consistently work<strong>in</strong>g on many projects and she is one <strong>of</strong>the few toppers <strong>in</strong> her department. She is currently do<strong>in</strong>g projecton S<strong>of</strong>tware Radio.She has presented papers <strong>in</strong> the area <strong>of</strong> S<strong>of</strong>tware Radio andWireless communications. Her research <strong>in</strong>terest <strong>in</strong>cludesWireless communications and Embedded Systems.ACKNOWLEGDEMENTWe wish to thank all the co authors who supported thisproject for its success.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 131<strong>Web</strong><strong>in</strong>ar – Education through DigitalCollaborationAnuradha VermaInfosys <strong>Technologies</strong> Ltd, Chandigarh, IndiaEmail: anuradha_thakur@<strong>in</strong>fosys.comAnoop S<strong>in</strong>ghInfosys <strong>Technologies</strong> Ltd, Bangalore, IndiaEmail: anoop_s<strong>in</strong>gh@<strong>in</strong>fosys.comAbstract—Transition <strong>in</strong> the learn<strong>in</strong>g habits and trends <strong>of</strong>students is evident from the traditional text based to thecurrent dynamic modes like world-wide web, CAI andsimulation. <strong>Web</strong><strong>in</strong>ar as a learn<strong>in</strong>g technology <strong>of</strong>fers aplatform to overcome the gap <strong>in</strong> this digital divide and helpthe students get acqua<strong>in</strong>ted with the latest. A case describ<strong>in</strong>gthe use <strong>of</strong> web<strong>in</strong>ar by Infosys helps the reader comprehendthe digital collaboration web<strong>in</strong>ar <strong>of</strong>fers discuss<strong>in</strong>g itsshortcom<strong>in</strong>gs and benefits.Index Terms—web<strong>in</strong>ar; learn<strong>in</strong>g habits, teach<strong>in</strong>gmethodologyI. LEARNING TECHNOLOGIESAs per Gretchen Rh<strong>in</strong>es Cheney et al. (2005) [1] Indiahas the second largest education system <strong>in</strong> the world,fall<strong>in</strong>g only beh<strong>in</strong>d Ch<strong>in</strong>a. University EducationCommission (UGC) [2] set up <strong>in</strong> 1948 provides guidel<strong>in</strong>esfor coord<strong>in</strong>ation, determ<strong>in</strong>ation and ma<strong>in</strong>tenance <strong>of</strong>standards <strong>of</strong> university education <strong>in</strong> India. Study<strong>in</strong>g thevast historical background <strong>of</strong> education <strong>in</strong> India, it can beseen that though the Indian education system is powerful,yet it needs to dynamically revamp various facets toemerge strong <strong>in</strong> today’s ever chang<strong>in</strong>g scenario.In today’s fast pace world students are well <strong>in</strong>formedand require a facilitator rather than an <strong>in</strong>structor. Theyhave islands <strong>of</strong> <strong>in</strong>formation available but do not have thepatience to understand its use or consult their faculty. Thelearn<strong>in</strong>g technologies have also seen a change <strong>in</strong> thelearn<strong>in</strong>g habits <strong>of</strong> students from the past to the recenttimes. The current day students are well versed with themodern technologies and are avid <strong>in</strong>ternet userscompared to their predecessors who were morecomfortable <strong>in</strong> a text based <strong>in</strong>struction based approach.However <strong>in</strong> the current education system, there exists adigital divide – a gap <strong>in</strong> the content and method <strong>of</strong>knowledge dissipation and what value it <strong>of</strong>fers to itsstudents <strong>in</strong> today’s ever chang<strong>in</strong>g world <strong>of</strong> technologycollaboration. Study<strong>in</strong>g the trends <strong>in</strong> the past, a shift canbe ascerta<strong>in</strong>ed <strong>in</strong> learn<strong>in</strong>g habits <strong>of</strong> students from thetraditional method <strong>of</strong> lecture based to the <strong>in</strong>teractive anddescriptive based on World Wide <strong>Web</strong> (WWW) or<strong>in</strong>ternet, e-mentor<strong>in</strong>g, etc.This paper talks about the shift <strong>in</strong> the learn<strong>in</strong>g habitsand technologies and the impact web<strong>in</strong>ar can play as alearn<strong>in</strong>g technology tak<strong>in</strong>g a case study from CampusConnect team <strong>of</strong> Infosys <strong>Technologies</strong> Ltd.II. CHANGE IN LEARNING HABITS FROM TRADITIONALTO TECHNOLOGY BASEDTill late, the teach<strong>in</strong>g methodology used <strong>in</strong> most <strong>of</strong> theeducational <strong>in</strong>stitutes <strong>in</strong> India was follow<strong>in</strong>g thetraditional method <strong>of</strong> chalk and talk but <strong>in</strong> recent timesthis has seen a paradigm shift.A. Traditional MethodologyKey features <strong>of</strong> the traditional teach<strong>in</strong>g methodologycan be collated as under:• One way communication without any <strong>in</strong>teraction• No openness between the faculty and students asa forum to exchange ideas• Less focus on analytical skills and more onmemory based.• Only lecture based class room approachfollowed for knowledge deliveryThis approach faced a lot <strong>of</strong> challenges, some be<strong>in</strong>g:• Lack <strong>of</strong> Flexibility – the students were not<strong>of</strong>fered any flexibility <strong>in</strong> terms <strong>of</strong> their learn<strong>in</strong>gstyles and habits or <strong>of</strong> implement<strong>in</strong>g theirlearn<strong>in</strong>g. There was a fixed approach be<strong>in</strong>gfollowed.• Less or no access to Information - Improv<strong>in</strong>gaccess <strong>of</strong> <strong>in</strong>formation to the students is difficultas there is was no mode for <strong>in</strong>formation shar<strong>in</strong>g.• No Standardization – Quality check at all levels<strong>of</strong> education was absent <strong>of</strong>fer<strong>in</strong>g nostandardisation.B. Scientific MethodologyThe advent <strong>of</strong> multi-media revolutionised tra<strong>in</strong><strong>in</strong>gtechniques and brought <strong>in</strong> greater diversity and<strong>in</strong>teraction. The black boards have been replaced by LCDscreens. Some <strong>of</strong> the <strong>in</strong>genious methods us<strong>in</strong>g scientificor technology base are:© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.131-136


132 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010already carved a niche for itself <strong>in</strong> the arena <strong>of</strong> bus<strong>in</strong>essand has now started be<strong>in</strong>g use <strong>in</strong> education arena as well.After <strong>in</strong>creas<strong>in</strong>g the dynamism <strong>in</strong> the <strong>in</strong>dustry, web<strong>in</strong>arsare all set to br<strong>in</strong>g a revolution <strong>in</strong> the Education sector.The focal feature <strong>of</strong> a web<strong>in</strong>ar is its potential to discussand share <strong>in</strong>formation. Offer<strong>in</strong>g a one stop shop for<strong>in</strong>teract<strong>in</strong>g with an array <strong>of</strong> experts, this platformprovides a great appeal to its users.Some more characteristics <strong>of</strong> web<strong>in</strong>ars are discussedbelow:A. CharacteristicsFigure 1. Various Knowledge Dissipation Methods• Multi-media Aids – teach<strong>in</strong>g us<strong>in</strong>g medium likepower po<strong>in</strong>t presentations and slides, audiovisualclipp<strong>in</strong>g, etc enhanc<strong>in</strong>g the learn<strong>in</strong>gexperience.• Computer aided <strong>in</strong>struction (CAI) - use <strong>of</strong>computers <strong>in</strong> deliver<strong>in</strong>g tra<strong>in</strong><strong>in</strong>g, supervis<strong>in</strong>gtra<strong>in</strong>ee progress, feedback and assess<strong>in</strong>g results.A similar technique is Computer based tra<strong>in</strong><strong>in</strong>gs(CBT).• E-mentor<strong>in</strong>g and E-learn<strong>in</strong>g – as thesetechniques are not dependent on the physicalpresence <strong>of</strong> the <strong>in</strong>structor; they help students tostudy on their own comfort and speed.• Video Conferenc<strong>in</strong>g – It <strong>in</strong>corporates voice,image and data dur<strong>in</strong>g long distancetransmission <strong>of</strong>fer<strong>in</strong>g a real time and highlypr<strong>of</strong>icient means.• Bra<strong>in</strong>storm<strong>in</strong>g & Case studies – is a groupcreativity technique designed to generate a largenumber <strong>of</strong> ideas for the solution <strong>of</strong> a problem.• Simulation – reproduction <strong>of</strong> the real timeenvironment for <strong>in</strong>troduc<strong>in</strong>g students to realtime challenges.• <strong>Web</strong><strong>in</strong>ar – sem<strong>in</strong>ar or lecture over the <strong>in</strong>ternet[3] .This study attempts to establish the role <strong>of</strong> <strong>Web</strong><strong>in</strong>ars –an upcom<strong>in</strong>g technology <strong>in</strong> the field <strong>of</strong> digitalcollaboration - <strong>in</strong> bridg<strong>in</strong>g the digital divide.III. WHAT IS A WEBINAR‘<strong>Web</strong><strong>in</strong>ar’ is a union <strong>of</strong> ‘web + sem<strong>in</strong>ar’ whichsimply means a sem<strong>in</strong>ar over the <strong>in</strong>ternet. This s<strong>of</strong>twareis a remarkable <strong>in</strong>novation <strong>in</strong> the field <strong>of</strong> technologywhich <strong>of</strong>fers a platform for people to <strong>in</strong>teract andcollaborate over vast geographical boundaries throughWWW. This platform <strong>of</strong>fers a two-way communicationlead<strong>in</strong>g to higher effectiveness and <strong>in</strong>volvement by theaudience.Typically a web<strong>in</strong>ar consist <strong>of</strong> a presentation hosted bya service provider on a web server. The l<strong>in</strong>k <strong>of</strong> theweb<strong>in</strong>ar is shared with the attendees who can log on tothe site and participate <strong>in</strong> it. The <strong>Web</strong><strong>in</strong>ar platform has• Shar<strong>in</strong>g Application – It allows presenters toshare their desktops, applications, etc to help theaudience get a better understand<strong>in</strong>g <strong>of</strong> the topic.• Chat w<strong>in</strong>dow – Attendee students can ask theirqueries dur<strong>in</strong>g the session without disturb<strong>in</strong>g theflow <strong>of</strong> the session through chat w<strong>in</strong>dow. Ithelps <strong>in</strong> <strong>in</strong>teraction with the presenters privately,<strong>in</strong>teraction with the panellists privately,<strong>in</strong>teraction with other participants privately or<strong>in</strong>teraction with all the participants <strong>in</strong> one go.• Session Record<strong>in</strong>g– It may be beneficial torecord the session delivered by the presenter forre-use. This is an out-<strong>of</strong>-box feature <strong>in</strong> web<strong>in</strong>ars.The session can be recorded and shared with thestudents or participants <strong>in</strong> the form <strong>of</strong> CDs, etc.This also aids <strong>in</strong> archival <strong>of</strong> valuable<strong>in</strong>formation.• Survey – The presenter can choose to conductpolls and surveys for the audience.B. Infrastructure RequirementFor Organisers:• One dedicated personal computer (PC)• Onl<strong>in</strong>e WEBINAR monitor<strong>in</strong>g PC station(Preferred)• Dedicated phone system and l<strong>in</strong>e (high qualitypreferably Polycom)• Voice-Tap hardware for WEBINAR record<strong>in</strong>gFor Participants:• One dedicated personal computer (PC)• Installation <strong>of</strong> S<strong>of</strong>tware <strong>of</strong> the vendor be<strong>in</strong>g usedfor <strong>Web</strong><strong>in</strong>ar (For example <strong>Web</strong>Ex [4] ,GoTo<strong>Web</strong><strong>in</strong>ar [5] , etc)• Dedicated direct phone l<strong>in</strong>e• LCD projector• High quality speaker phone with amplifier (ifrequired for large audience) and mute buttonC. Steps to organise a <strong>Web</strong><strong>in</strong>ar© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 133Reach<strong>in</strong>g-out Digitally<strong>Web</strong><strong>in</strong>ar Library(Recorded)Subject & TopicsKey Questions to be Answered• Technical and S<strong>of</strong>t Skills• Faculty & ManagementSMEsPractitionersEducatorsBAsRegionEvent Center and Moderated AudioConference FacilityPodcast, Audio-Video Interviews, Internet RadioFigure 2. <strong>Web</strong><strong>in</strong>ar Event flowThe above diagram describes the event flow for aweb<strong>in</strong>ar. The host can send the <strong>in</strong>vitation <strong>of</strong> the web<strong>in</strong>arevent to <strong>in</strong>tended audience (Student, faculty, etc) throughan email, or post it on organization website or bullet<strong>in</strong>board shar<strong>in</strong>g the l<strong>in</strong>k <strong>in</strong> the <strong>in</strong>vitation mail. On the‘Land<strong>in</strong>g Page’ the logged <strong>in</strong> users can f<strong>in</strong>d detailed<strong>in</strong>formation about the web<strong>in</strong>ar like objective, speakerpr<strong>of</strong>iles, read<strong>in</strong>g materials l<strong>in</strong>ks, etc. For attend<strong>in</strong>g theevent, participants need to register on ‘Registration Page’.Once the registration is complete, participants receivean email detail<strong>in</strong>g the next set <strong>of</strong> <strong>in</strong>structions for jo<strong>in</strong><strong>in</strong>gthe web<strong>in</strong>ar. A rem<strong>in</strong>der mail can also be set for theevent. For the audio <strong>of</strong> the web<strong>in</strong>ar event, participantsneed to use their telephone and a computer for view<strong>in</strong>gthe presentation. After the event the attendee details canbe used for collat<strong>in</strong>g feedback and follow-up.IV. IMPACT OF WEBINAR ON EDUCATION – ACASE STUDY OF INFOSYS CAMPUSCONNECT INITIATVECampus Connect Initiative was launched <strong>in</strong> 2004 ByInfosys <strong>Technologies</strong> Ltd as an <strong>in</strong>dustry- academiapartnership which with the aim <strong>of</strong> enhanc<strong>in</strong>g the qualityand quantity <strong>of</strong> talent pool <strong>in</strong> India.Campus Connect team had a target to reach 500+partner colleges <strong>in</strong> an pr<strong>of</strong>icient and cost effective wayfor shar<strong>in</strong>g technical, s<strong>of</strong>t-skills, and doma<strong>in</strong> knowledge.This required reach<strong>in</strong>g the colleges across tier 2, 3 citiesand deliver sessions which required approximately 5hours <strong>of</strong> travel. Hav<strong>in</strong>g Infosys Subject Matter Experts(SMEs) from various units spend such a large amount <strong>of</strong>time on travel wasn’t a viable approach.Hence, the team decided to use a technology platformcalled <strong>Web</strong><strong>in</strong>ar. To augment the plann<strong>in</strong>g andimplementation <strong>of</strong> web<strong>in</strong>ars a process was put <strong>in</strong> place.The team decided to work with <strong>Web</strong>Ex which is aglobally acclaimed onl<strong>in</strong>e meet<strong>in</strong>g applications ands<strong>of</strong>tware services provider. Once this was zeroed <strong>in</strong>, thenext challenge was to successfully deploy it across all 9Development Centres (DCs) <strong>of</strong> Infosys <strong>in</strong> India. It alsorequired each DC be equipped with the knowledge <strong>of</strong><strong>Web</strong><strong>in</strong>ar – understand<strong>in</strong>g the concept, its set up andconduction.Figure 3. <strong>Web</strong><strong>in</strong>ar PlatformTo provide clarification for all <strong>of</strong> this and to def<strong>in</strong>e aformal process, the team came up with a Field Guide [6]for web<strong>in</strong>ars which served as a s<strong>in</strong>gle po<strong>in</strong>t <strong>of</strong> referencefor the above.The follow<strong>in</strong>g give an idea on the effectiveness and use<strong>of</strong> web<strong>in</strong>ar by the team. [7]A. Stakeholder Feedback1. Faculty feedbackThe web<strong>in</strong>ar efficacy was calculated as part <strong>of</strong> theCampus Connect Perception Measurement survey <strong>in</strong> 306colleges with 521 faculty member responses. The averagerat<strong>in</strong>g turned out to be 3.53 on a scale <strong>of</strong> 1 to 4 (Scale: 1.Strongly disagree 2. Disagree 3. Agree 4. Strongly agree).2. Student feedback –Comprehensive feedback was collected for eachweb<strong>in</strong>ar from the students. It covered feedback forcontent, flow, effective delivery, <strong>in</strong>teraction throughQ&A sessions, etc. Average feedback scores for majorcategories are given <strong>in</strong> the table below. (Scale: 1–Poor, 2-Satisfactory, 3- Good, 4-Very good, 5-Excellent). Overall<strong>Web</strong><strong>in</strong>ar Effectiveness was rated as 4.29 out <strong>of</strong> 5, above'Very Good'.TABLE I.CONSOLIDATED WEBINAR FEEDBACKArea <strong>of</strong> Feedback<strong>Web</strong><strong>in</strong>ar Content 3.93<strong>Web</strong><strong>in</strong>ar Design 3.90Presenter Effectiveness 4.05Plann<strong>in</strong>g & Delivery 3.95Overall <strong>Web</strong><strong>in</strong>ar Effectiveness 4.29B. <strong>Web</strong><strong>in</strong>ar MetricsAverage Rat<strong>in</strong>g (ona scale <strong>of</strong> 1-5)Some consolidated metrics for the web<strong>in</strong>ars conductedso far across the DCs are mentioned below. Table 2 givesthe number <strong>of</strong> web<strong>in</strong>ars conducted till date and theirimpact.© 2010 ACADEMY PUBLISHER


134 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010TABLE II.WEBINAR COVERAGE DATA PERIOD - FEB 2006 - MAY 2009, 9 DCSNo. Item Number1 Total number <strong>of</strong> <strong>Web</strong><strong>in</strong>ars conducted 592Number <strong>of</strong> Colleges impacted acrossIndia 5093 Number <strong>of</strong> Faculty impacted 11474 Number <strong>of</strong> Students impacted 22527C. Rationalization <strong>of</strong> Travel Cost and ProductivityTotal cost <strong>of</strong> 1 hour web<strong>in</strong>ar session cover<strong>in</strong>g 10partner colleges is approximately Rs. 12,000/-(TwelveThousand) and to conduct similar sem<strong>in</strong>ar session <strong>in</strong> 1partner college by SME through physical travel cost Rs.39500 (Thirty N<strong>in</strong>e Thousand). So each web<strong>in</strong>ar sessionresults <strong>in</strong> sav<strong>in</strong>g <strong>of</strong> Rs. 383000/- (Three Lack EightyThree Thousand).No.12TABLE III.COST BREAKUP TO CONDUCT 1 SEMINAR SESSIONCost Sav<strong>in</strong>g Per <strong>Web</strong><strong>in</strong>arSessionRs.Cost <strong>of</strong> <strong>Web</strong><strong>in</strong>ar cover<strong>in</strong>g10 colleges 12000Cost <strong>of</strong> Sem<strong>in</strong>ar cover<strong>in</strong>g10 colleges395000 ( 39500 * 10Colleges)Total Sav<strong>in</strong>gs per web<strong>in</strong>arsession 383000TABLE IVCOST SAVING PER WEBINAR SESSIONNo. Cost Breakup to conduct 1 Sem<strong>in</strong>ar Rs.1 Flight Tickets / Taxi Charges 120002 Accommodation – 2 Days 50003 Food /Misc. Expense 25004 Productivity loss due to travell<strong>in</strong>g 100005 Banner / Market<strong>in</strong>g Material etc 10000Total 39500Sav<strong>in</strong>gs <strong>in</strong> terms <strong>of</strong> the SME travel time is anothersignificant benefit. Tak<strong>in</strong>g a conservative estimate <strong>of</strong> twobus<strong>in</strong>ess days the SME would have spent <strong>in</strong> travell<strong>in</strong>g tothe college and deliver<strong>in</strong>g the sem<strong>in</strong>ar, a sav<strong>in</strong>g <strong>of</strong> 1018bus<strong>in</strong>ess days has resulted because <strong>of</strong> us<strong>in</strong>g web<strong>in</strong>ars.D. Capability improvement – Scalability and ReachBefore the advent <strong>of</strong> <strong>Web</strong><strong>in</strong>ars <strong>in</strong> campus connectknowledge dissipation, SMEs were required to travel tothe colleges pos<strong>in</strong>g a restra<strong>in</strong>t on the number <strong>of</strong> collegesthat can be covered. The reach to the colleges before andafter <strong>in</strong>troduc<strong>in</strong>g web<strong>in</strong>ars gives a clear picture <strong>of</strong> theextent <strong>of</strong> change brought about. Table 5 shows thenumber <strong>of</strong> colleges the team was able to reach before andafter <strong>in</strong>troduc<strong>in</strong>g web<strong>in</strong>ars.Without <strong>Web</strong><strong>in</strong>ars, the coverage percentage wouldhave come down from 22.18% to 18.53%. Because <strong>of</strong> thewide reach <strong>of</strong> <strong>Web</strong><strong>in</strong>ars, the coverage percentage has<strong>in</strong>creased from 22.18% to 57.22%, an <strong>in</strong>crease <strong>of</strong> 35.04%<strong>in</strong> coverage <strong>of</strong> colleges. This coverage has further<strong>in</strong>creased to 40% cover<strong>in</strong>g almost each Campus ConnectPartner Colleges.No.1234TABLE VIMPROVEMENT IN COLLEGE COVERAGEPeriod# PartnerColleges#CollegesCovered%CoverageNov 2005 - Oct2006 (Without<strong>Web</strong><strong>in</strong>ars) 275 61 22.18Nov 2006 - Oct2007 (Without<strong>Web</strong><strong>in</strong>ars) 367 68 18.53Nov 2006 - Oct2007 (With<strong>Web</strong><strong>in</strong>ars) 367Nov 2007 – TillDate (With210(142+68) 57.22<strong>Web</strong><strong>in</strong>ars) 520 509 97.8E. Reusability and ReproductionThese web<strong>in</strong>ars covered a wide range <strong>of</strong> topics fromTechnical, S<strong>of</strong>t-Skills, Effective English, Quality andDoma<strong>in</strong> areas. These web<strong>in</strong>ar sessions delivered by SMEare recorded and re-use later. These web<strong>in</strong>ar sessions arereproduced and edited <strong>in</strong> such a manner that they can beused later on by partner colleges. Record<strong>in</strong>g <strong>of</strong> thesesessions are shared with participants <strong>in</strong> the form <strong>of</strong> CDsor by upload<strong>in</strong>g the content on <strong>Web</strong>Ex portal. This alsoaid <strong>in</strong> archival <strong>of</strong> Digital library.V. BENEFITS WEBINAR PLATFORM USAGE IN INFOSYSCAMPUS CONNECTSome benefits the team achieved were:• Collaboration – It <strong>of</strong>fered the presenters to share<strong>in</strong>formation, data, applications, desktops, etcalong with allow<strong>in</strong>g participants and presentersto <strong>in</strong>teract amongst themselves publically orprivately thus serv<strong>in</strong>g as a successfulcollaborative medium.• Multiple speakers – The team could employ theadvantage <strong>of</strong> multiple speakers for a s<strong>in</strong>glesession without bear<strong>in</strong>g the travell<strong>in</strong>g cost foreach. It has been seen that a panel <strong>of</strong> speakerscreates more impact than an <strong>in</strong>dividual,especially for longer presentations.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 135• Greater target access – <strong>Web</strong><strong>in</strong>ar has an edge <strong>in</strong>terms <strong>of</strong> its greater reach to audience andovercome geographical boundaries. It is easy toaccess and use through WWW and is availableanywhere anytime.• No location dependency – As web<strong>in</strong>ar arelocation <strong>in</strong>dependent, it can <strong>in</strong>volve SubjectMatter Experts (SME) from a variety <strong>of</strong>locations to talk about their respective areas <strong>of</strong>expertise. This helped the students leverage theknowledge base <strong>of</strong> these SMEs which may nothave been possible otherwise.• Interactive platform – It <strong>of</strong>fered an <strong>in</strong>teractiveplatform to the session audience (students,faculty or college management) to communicatewith the facilitator hence mak<strong>in</strong>g it an effectivemeans <strong>of</strong> communication. Hav<strong>in</strong>g a questionanswer round with all the participants <strong>in</strong> a setorder like alphabetical helps solve the commonqueries <strong>of</strong> the participants and record them.• Learn<strong>in</strong>g <strong>of</strong>fl<strong>in</strong>e – Record<strong>in</strong>g allows participantsto re-run the session and learn the concepts <strong>in</strong>detail.• Engage senior speakers– as the presenters <strong>of</strong> thesessions were practitioners and seniorInfoscions, physical travel was not possiblegenerally. <strong>Web</strong><strong>in</strong>ars helped the team overcomethe issues and <strong>in</strong>crease the SME base.• Download Material – Participants coulddownload the material <strong>of</strong> the web<strong>in</strong>ar and read it<strong>of</strong>fl<strong>in</strong>e. This <strong>in</strong>creased the learn<strong>in</strong>g w<strong>in</strong>dow forthem. The SMEs could share applications dur<strong>in</strong>gtheir sessions as well.• Feedback –Instructor feedback could berecorded through web<strong>in</strong>ars. It helped to analyseand improve further.VI. HURDLES FOR THE TEAM IN WEBINARS• Need for high end Infrastructure- requiresquality <strong>of</strong> service and has dependency <strong>of</strong>electricity connection especially for the VOIP(Voice over <strong>in</strong>ternet protocol). Call drop-<strong>of</strong>frates dur<strong>in</strong>g web<strong>in</strong>ar session is typically 10percent so live helpdesk support through phoneand onl<strong>in</strong>e chat is required <strong>in</strong> case <strong>of</strong> anytechnical issue.• Cost <strong>of</strong> host<strong>in</strong>g – As a medium <strong>of</strong> <strong>in</strong>struction,web<strong>in</strong>ar proves to be costly as compared to theothers. Institutions or students may f<strong>in</strong>d itdifficult to purchase licenses for web<strong>in</strong>ars<strong>of</strong>tware and susta<strong>in</strong> the same.• Restricted Audience Involvement–The two-waycommunication channel has a limited usagehere. Hence, this may prove to a hurdle at times.It may not be able to live up to the same level asa physical <strong>in</strong>teraction with the expert.• Limited modes <strong>of</strong> multi-media usage –PowerPo<strong>in</strong>t Presentation Animation along with videocannot be played smoothly if a participantdoesn’t have the required bandwidth. <strong>Web</strong><strong>in</strong>ardoesn’t allow the <strong>in</strong>structor to use audio andvideo mode simultaneously.VII.CONCLUSIONThe traditional methods <strong>of</strong> tra<strong>in</strong><strong>in</strong>g <strong>in</strong> educationalsystem may have been <strong>in</strong> practice s<strong>in</strong>ce a long time, thecurrent time throws a challenge for students to updatethemselves on the technologies and their usage. With theadvent <strong>of</strong> IT era, the learn<strong>in</strong>g habits <strong>of</strong> students haveundergone a transformation from referr<strong>in</strong>g the text booksto brows<strong>in</strong>g the <strong>in</strong>ternet, hav<strong>in</strong>g 3D images andanimations as aids.<strong>Web</strong><strong>in</strong>ar today has ga<strong>in</strong>ed significant popularity. Moreand more <strong>in</strong>stitutions want to leverage technology <strong>in</strong> thefield <strong>of</strong> education and percolate its maximum advantageto their students. It has helped overcome the issues <strong>of</strong>bandwidth and leverage expertise but has still to developits potential as an <strong>in</strong>teractive forum and costeffectiveness.Go<strong>in</strong>g ahead, this technology can be deployed toharness a formal mechanism <strong>of</strong> measurement and anevaluation framework. Its usage can be extended to otherareas <strong>of</strong> learn<strong>in</strong>g and its target audience base <strong>in</strong>creased.While the current study talks about the web<strong>in</strong>arsconducted through <strong>Web</strong>Ex, some common vendors that<strong>of</strong>fer this platform can be listed as below:• InterCall [8]• GoToMeet<strong>in</strong>g [9]• IBM Lotus Sametime [10]• Meet<strong>in</strong>gBridge [11]• ReadyTalk [12]• <strong>Web</strong>MeetLive [13]ACKNOWLEDGMENTWe would like to thank Dr Ramesh Babu, Mr. R.N.Prasad, Mr. Mukundh Nagarajan and Mr. Sarfaraz AbdulAziz Jaitapkar from Infosys <strong>Technologies</strong> Ltd. forshar<strong>in</strong>g their <strong>in</strong>puts and experiences for this paper.REFERENCES[1] Gretchen Rh<strong>in</strong>es Cheney, Betsy Brown Ruzzi and KarthicMuralidharan, “A Pr<strong>of</strong>ile <strong>of</strong> Indian Education System,National Center on Education and the Economy,”November 2005[2] Home Page, http://www.ugc.ac.<strong>in</strong>/[3] <strong>Web</strong><strong>in</strong>ar Def<strong>in</strong>ition,http://www.pcmag.com/encyclopedia_term/0,2542,t=<strong>Web</strong><strong>in</strong>ar&i=54380,00.asp[4] Home Page, http://www.webex.com/[5] Home Page, http://www.gotoweb<strong>in</strong>ar.com/[6] <strong>Web</strong><strong>in</strong>ar Field Guide V1.0, Infosys <strong>Technologies</strong> Ltd.,2006[7] Anuradha Verma, Anoop S<strong>in</strong>gh, “Leverag<strong>in</strong>g <strong>Web</strong><strong>in</strong>ar forStudent Learn<strong>in</strong>g”, International Workshop on Technologyfor Education, 2009[8] http://www.<strong>in</strong>tercall.com/© 2010 ACADEMY PUBLISHER


136 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010[9] https://www1.gotomeet<strong>in</strong>g.com/?Portal=www.gotomeet<strong>in</strong>g.com[10] http://www.ibm.com/lotus/sametime[11] http://www.meet<strong>in</strong>gbridge.com/[12] http://www.readytalk.com/[13] http://www.webmeetlive.com/Anuradha Verma is currently work<strong>in</strong>g as TechnicalEvangelist <strong>in</strong> the Education & Research Department at Infosys<strong>Technologies</strong> Ltd. She has over 6 years <strong>of</strong> IT Industryexperience cover<strong>in</strong>g areas like Tra<strong>in</strong><strong>in</strong>g & Development,Test<strong>in</strong>g, S<strong>of</strong>tware Development and Industry-AcademiaPartnership.She has Masters <strong>in</strong> Bus<strong>in</strong>ess Adm<strong>in</strong>istration along with aMasters <strong>in</strong> <strong>Journal</strong>ism and Mass Communication. She iscurrently pursu<strong>in</strong>g her Doctor <strong>of</strong> Philosophy <strong>in</strong> Managementwith Human Resource Specialization. She has authoredpublications <strong>in</strong> International Conferences and <strong>Journal</strong>.Anoop S<strong>in</strong>gh. At Infosys, Anoop S<strong>in</strong>gh is currently work<strong>in</strong>gas GROUP LEADER <strong>in</strong> the E&R Department. He has over 12years <strong>of</strong> IT Industry experience <strong>in</strong>clud<strong>in</strong>g 4 years <strong>of</strong> exposure <strong>in</strong>global market, work<strong>in</strong>g <strong>in</strong> various counties <strong>of</strong> South East Asiaregion like S<strong>in</strong>gapore, Hong Kong and Ch<strong>in</strong>a. Anoop hasextensive IT Industry experience cover<strong>in</strong>g areas like Tra<strong>in</strong><strong>in</strong>g &Development, Bus<strong>in</strong>ess Partner Development, Product L<strong>in</strong>emanagement and Industry-Academia Partnership.Anoop has earlier worked with IT organizations like NIIT,NIIT Shanghai Ltd. and have server large global customer likeMicros<strong>of</strong>t, S<strong>in</strong>gapore Airl<strong>in</strong>e, Beij<strong>in</strong>g International Airport andvarious Ch<strong>in</strong>ese universities. He has worked on technologiesareas like Database, Network Design and various programm<strong>in</strong>glanguages. Anoop also holds a Master’s Degree <strong>in</strong> InformationScience.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 137Efficient Visual CryptographyEr. Supriya K<strong>in</strong>gerCSE Department, Chitkara Institute <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g and Technology,Rajpura, Punjab, IndiaEmail: ahujasupriya@gmail.comAbstract – Visual cryptography scheme (VCS) is a secretshar<strong>in</strong>gscheme which allows the encryption <strong>of</strong> a secretimage <strong>in</strong>to n shares that are distributed to n participants.The beauty <strong>of</strong> such a scheme is that, the decryption <strong>of</strong> thesecret image requires neither the knowledge <strong>of</strong>cryptography nor complex computation. Colour visualcryptography becomes an <strong>in</strong>terest<strong>in</strong>g research topic afterthe formal <strong>in</strong>troduction <strong>of</strong> visual cryptography by Naor andShamir <strong>in</strong> 1995. It is a powerful technique which comb<strong>in</strong>esthe notions <strong>of</strong> perfect ciphers and secret shar<strong>in</strong>g <strong>in</strong>cryptography with that <strong>of</strong> raster graphics. A b<strong>in</strong>ary imagecan be divided <strong>in</strong>to shares which can be stacked together toapproximately recover the orig<strong>in</strong>al image. Unfortunately, ithas not been used much primarily because the decryptionprocess entails a severe degradation <strong>in</strong> image quality <strong>in</strong>terms <strong>of</strong> loss <strong>of</strong> resolution and contrast. Its usage is alsohampered by the lack <strong>of</strong> proper techniques for handl<strong>in</strong>ggrayscale and color images. In this paper, I have developeda novel technique which enables visual cryptography <strong>of</strong>color as well as grayscale images. The physical transparencystack<strong>in</strong>g type <strong>of</strong> decryption allows for the recovery <strong>of</strong> thetraditional visual cryptography quality image. An enhancedstack<strong>in</strong>g technique allows for the decryption <strong>in</strong>to a halftonequality image. And f<strong>in</strong>ally, a computation based decryptionscheme makes the perfect recovery <strong>of</strong> the orig<strong>in</strong>al imagepossible. Based on this basic scheme, I have then establisheda progressive mechanism to share color images at multipleresolutions. I extracted shares from each resolution layer toconstruct a hierarchical structure; the images <strong>of</strong> differentresolutions can then be restored by stack<strong>in</strong>g the differentshared images together. I have implemented our techniqueand present results.Index Terms – Secret shar<strong>in</strong>g, Color halfton<strong>in</strong>g, imageshar<strong>in</strong>g, multiple resolutions, secret shar<strong>in</strong>g, and visualcryptographyI. INTRODUCTIONVisual cryptography was orig<strong>in</strong>ally proposed for theproblem <strong>of</strong> secret shar<strong>in</strong>g. Secret shar<strong>in</strong>g is one <strong>of</strong> theearly problems to be considered <strong>in</strong> cryptography. Theidea <strong>of</strong> the visual cryptography model proposed <strong>in</strong> [1] isto split an image <strong>in</strong>to two random shares (pr<strong>in</strong>ted ontransparencies) which separately reveal no <strong>in</strong>formationabout the orig<strong>in</strong>al secret image other than the size <strong>of</strong> thesecret image. The image is composed <strong>of</strong> black and whitepixels. The orig<strong>in</strong>al image can be recovered bysuperimpos<strong>in</strong>g the two shares. The underly<strong>in</strong>g operation<strong>of</strong> this visual cryptography model is OR.Visual cryptography is a unique technique <strong>in</strong> thesense that the encrypted messages can be decrypteddirectly by the human visual system. Therefore, a systememploy<strong>in</strong>g visual cryptography can be used by anyonewithout any knowledge <strong>of</strong> cryptography. Another<strong>in</strong>terest<strong>in</strong>g th<strong>in</strong>g about visual cryptography is that it is aperfectly secure cipher. There is a simple analogy <strong>of</strong> theone time-pad cipher to visual cryptography.II. BACKGROUND ON VISUAL CRYPTOGRAPHYBesides <strong>in</strong>troduc<strong>in</strong>g the new paradigm, Naor andShamir also provided their constructions <strong>of</strong> visualcryptographic solutions for the general k out <strong>of</strong> n secretshar<strong>in</strong>g problem. One can assume that every secretmessage can be represented as an image, and furthermorethat the image is just a collection <strong>of</strong> black and whitepixels i.e. it is assumed to be a b<strong>in</strong>ary image. Eachorig<strong>in</strong>al pixel appears <strong>in</strong> n modified versions (calledshares) <strong>of</strong> the image, one for each transparency. Eachshare consists <strong>of</strong> m black and white sub-pixels. Eachshare <strong>of</strong> sub-pixels is pr<strong>in</strong>ted on the transparency <strong>in</strong> closeproximity (to best aid the human perception, they aretypically arranged together to form a square with mselected as a square number). The result<strong>in</strong>g structure canbe described by a Boolean matrix M = (m i j ) n*m where m i j= 1 if and only if the j-th sub-pixel <strong>of</strong> the i-th share(transparency) is black. The important parameters <strong>of</strong> thescheme are:1. m, the number <strong>of</strong> pixels <strong>in</strong> a share. Thisparameter represents the loss <strong>in</strong> resolution fromthe orig<strong>in</strong>al image to the recovered one.2. α, the relative difference <strong>in</strong> the weight betweenthe comb<strong>in</strong>ed shares that come from a whitepixel and a black pixel <strong>in</strong> the orig<strong>in</strong>al image.This parameter represents the loss <strong>in</strong> contrast.3. γ, the size <strong>of</strong> the collection <strong>of</strong> C 0 and C 1 . C 0refers to the sub-pixel patterns <strong>in</strong> the shares fora white pixel and black refers to the sub-pixelpatterns <strong>in</strong> the shares for the 1 pixel.The constructions can be clearly illustrated by a 2 out<strong>of</strong> 2 visual cryptographic scheme. Here we def<strong>in</strong>e thefollow<strong>in</strong>g collections <strong>of</strong> 2*4 matrices:C 0 = all the matrices obta<strong>in</strong>ed by permut<strong>in</strong>g thecolumns <strong>of</strong>1 1 0 01 1 0 0C 1 = all the matrices obta<strong>in</strong>ed by permut<strong>in</strong>g thecolumns <strong>of</strong>1 1 0 00 0 1 1© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.137-141


138 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010The six patterns <strong>of</strong> shares created based on the abovematrices are shown <strong>in</strong> figure 1. Note that one pixel <strong>of</strong> theorig<strong>in</strong>al image now corresponds to four pixels <strong>in</strong> eachshare.(c) The second shareFig 1: The six patterns <strong>of</strong> 4 pixel shares: vertical,horizontal and diagonalA visual cryptography scheme can then beconstructed by pick<strong>in</strong>g shares <strong>in</strong> the follow<strong>in</strong>g manner:a) If the pixel <strong>of</strong> the orig<strong>in</strong>al b<strong>in</strong>ary image iswhite, randomly pick the same pattern 0 <strong>of</strong> f ourpixels for both shares. It is important to pick thepatterns randomly <strong>in</strong> order to make the patternrandom.b) If the pixel <strong>of</strong> the orig<strong>in</strong>al image is black, pick acomplementary pair <strong>of</strong> patterns, i.e., the patternsfrom the same column <strong>in</strong> figure 1.It can be easily verified that the resultant scheme hasthe parameters [m = 4; α= 12 ; γ= 6]: any two shares <strong>of</strong>C 0 cover two out f our <strong>of</strong> the pixels, while any pair <strong>of</strong>shares from C 1 covers all the f our pixels. An example <strong>of</strong>the above scheme is shown <strong>in</strong> figure 2. The first image isthe orig<strong>in</strong>al image, the next two are the shares and the lastimage is the recovered orig<strong>in</strong>al image obta<strong>in</strong>ed byperform<strong>in</strong>g the equivalent <strong>of</strong> physically stack<strong>in</strong>g twoimage shares on top <strong>of</strong> each other (assum<strong>in</strong>g that they arepr<strong>in</strong>ted on transparencies). It should be noted that the lastthree images <strong>in</strong> figure 2 are four times as large as the firstone but I have scaled them to the same size as the orig<strong>in</strong>alimage.(a) Sample <strong>of</strong> monochrome image(d) The stacked ImageFig 2. Implementation <strong>of</strong> exist<strong>in</strong>g methodologyIII. RELATED WORKThere has been a steadily grow<strong>in</strong>g <strong>in</strong>terest <strong>in</strong> visualcryptography. Despite its appearance <strong>of</strong> be<strong>in</strong>g a simpletechnique, visual cryptography is a secure and effectivecryptographic scheme. S<strong>in</strong>ce the orig<strong>in</strong> <strong>of</strong> this newparadigm, various extensions to the basic scheme havebeen developed to improve the contrast and the areas <strong>of</strong>application have also been greatly expanded.In [1], the construction <strong>of</strong> (n,n)-VCS was extended for(k,n)-VCS. In 1996, the same authors <strong>in</strong>troduced the idea<strong>of</strong> cover based semi-group to further improve the contrast[3]. Ateniese et al. [4] provided the first construction <strong>of</strong>(2, n)-VCS hav<strong>in</strong>g the best possible contrast for any n·2.Blundo et al. [5] provided a contrast optimal (3,n)-VCSand gave a pro<strong>of</strong> on the upper bound on the contrast <strong>of</strong>any (3,n)-VCS. [1] first considered the problem <strong>of</strong>conceal<strong>in</strong>g the existence <strong>of</strong> the secret image. [6] provideda general solution for that problem.The random nature <strong>of</strong> secret shares makes sharesunsuitable for transmission over an open channel. [6]used a modified scheme to embed some mean<strong>in</strong>gfulimages <strong>in</strong>to the shares. [7] used different moiré patternsto visualize the secret <strong>in</strong>stead <strong>of</strong> different gray levels. Asfar as extend<strong>in</strong>g to color images goes, [8] provided aprimitive scheme for images <strong>of</strong> 24 colors. Hou [9] thenproposed a novel approach to share color images basedon halfton<strong>in</strong>g. Other <strong>in</strong>terest<strong>in</strong>g topics <strong>in</strong>clude visualauthentication [10] and watermark<strong>in</strong>g based on visualcryptography [11]. Recently, there has been an attempt tobuild a physical visual cryptographic system based onoptical <strong>in</strong>terferometry [12]. However, all <strong>of</strong> these earlierworks result <strong>in</strong> a decrypted image <strong>of</strong> reduced quality.(b) The first Share© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 139IV. OUR CONTRIBUTIONThe state <strong>of</strong> the art <strong>in</strong> visual cryptography leads to thedegradation <strong>in</strong> the quality <strong>of</strong> the decoded images, whichmakes it unsuitable for digital media (image, video)shar<strong>in</strong>g and protection. This is quite obvious <strong>in</strong> figure 2where the white background <strong>of</strong> the orig<strong>in</strong>al imagebecomes gray <strong>in</strong> the decrypted image.Through this paper, I propose a visual cryptographicschemes that not only can support grayscale and colorimages, but also allow high quality images <strong>in</strong>clud<strong>in</strong>g that<strong>of</strong> perfect (orig<strong>in</strong>al) quality to be reconstructed.The nagg<strong>in</strong>g presence <strong>of</strong> the loss <strong>of</strong> contrast makestraditional visual cryptography scheme practical onlywhen quality is not an issue which is quite rare. I havetherefore focused our attention on specificallyovercom<strong>in</strong>g this problem by primarily devot<strong>in</strong>g ourefforts towards improv<strong>in</strong>g the quality <strong>of</strong> the reconstructedimages. I first extend the basic scheme from [1] to allowvisual cryptography to be directly applied on grayscaleand color images. Image halfton<strong>in</strong>g is employed <strong>in</strong> orderto transform the orig<strong>in</strong>al image from the grayscale/colorspace <strong>in</strong>to the monochrome space which has proved to bequite effective.It is a well known fact that the digital halfton<strong>in</strong>g isalways a lossy process [2], which means that whenever ahalfton<strong>in</strong>g is used for the transformation, it is impossibleto fully reconstruct the orig<strong>in</strong>al secret image. A newencod<strong>in</strong>g scheme has therefore been developed whichallows for perfectly lossless transformation betweenmonochrome, grayscale and color spaces. This newencod<strong>in</strong>g scheme can be seamlessly <strong>in</strong>corporated <strong>in</strong>to theproposed scheme for visual cryptography and it allowsthe orig<strong>in</strong>al secret image to be perfectly restored. Ibelieve this advancement <strong>in</strong> visual cryptography can beuseful <strong>in</strong> secret shar<strong>in</strong>g <strong>of</strong> images, <strong>in</strong> transmission <strong>of</strong>secret images over multiple untrustworthy channels, <strong>in</strong> e-commerce <strong>of</strong> digital media and <strong>in</strong> digital rightsmanagement <strong>of</strong> digital media..(a) Sample <strong>of</strong> monochrome image(b) The first Share(c) The second shareV. OUR APPROACHA. For Monochrome ImagesUs<strong>in</strong>g XOR to Fully Restore Monochrome SecretImages :-I, first made the crucial observation that withjust one additional computational operation; eventraditional visual cryptography can allow full recovery <strong>of</strong>the secret b<strong>in</strong>ary image. Normally, when we superimposethe two shares pr<strong>in</strong>ted on transparencies, this stack<strong>in</strong>goperation is computationally modeled as the b<strong>in</strong>ary ORoperation which causes the contrast level to be lowered.By simply substitut<strong>in</strong>g this OR operation with the XORoperation, the orig<strong>in</strong>al b<strong>in</strong>ary image can be recoveredwithout any loss <strong>in</strong> contrast. Thus, the produced imagecould have a more visually pleasant appearance with lessstorage space requirement. However, the XOR operationneeds computation - the physical stack<strong>in</strong>g process canonly simulate the OR operation. Figure 3 recovers thesame secret image as <strong>in</strong> figure 2 us<strong>in</strong>g the XOR operationand thus it is clearly evident that the contrast <strong>of</strong> theorig<strong>in</strong>al image is restored.(d) The stacked Image with XORFig 3. Implementation <strong>of</strong> proposed methodologyAs we have seen earlier, the application <strong>of</strong> digitalhalfton<strong>in</strong>g techniques results <strong>in</strong> some downgrad<strong>in</strong>g <strong>of</strong> theorig<strong>in</strong>al image quality due to its <strong>in</strong>herently lossy natureand it is not possible to recover the orig<strong>in</strong>al image fromits halftone version. We will refer to this proposedscheme as EVCS (Efficient Visual CryptographicScheme).The novelty <strong>of</strong> my approach is that it not only allowsthe secret image to be just seen but allows the secretimage to be reconstructed with perfect quality. Theadvantage <strong>of</strong> this approach is that it still reta<strong>in</strong>s thecrucial advantages <strong>of</strong> traditional visual cryptography likesimplicity, visual decod<strong>in</strong>g and perfect security. Theextra feature is that depend<strong>in</strong>g on whether additionalcomput<strong>in</strong>g resources are provided, images <strong>of</strong> different© 2010 ACADEMY PUBLISHER


140 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010quality can be decoded from the same set <strong>of</strong> shares. Ifonly the stack<strong>in</strong>g operation is allowed (i.e. nocomputations), then our scheme recovers the orig<strong>in</strong>alvisual cryptographic quality. If the XOR operation isprovided (<strong>in</strong>stead <strong>of</strong> the OR operation <strong>of</strong> stack<strong>in</strong>g), thenwe can fully restore the orig<strong>in</strong>al quality image.B. For Colored Images (Halftone-based Grayscale andColor Visual Cryptography)Digital halfton<strong>in</strong>g has been extensively used <strong>in</strong>pr<strong>in</strong>t<strong>in</strong>g applications where it has been proved to be veryeffective. For visual cryptography, the use <strong>of</strong> digital halfton<strong>in</strong>g is for the purpose <strong>of</strong> convert<strong>in</strong>g the grayscaleimage <strong>in</strong>to a monochrome image. Once we have a b<strong>in</strong>aryimage, then the orig<strong>in</strong>al visual cryptography techniquecan be applied. However, the concomitant loss <strong>in</strong> qualityis unavoidable <strong>in</strong> this case.For color images, there are two alternatives forapply<strong>in</strong>g digital halfton<strong>in</strong>g. One is to split the color image<strong>in</strong>to channels <strong>of</strong> cyan, magenta and yellow. Then eachchannel is treated as a grayscale image to whichhalfton<strong>in</strong>g and visual cryptography are applied<strong>in</strong>dependently. After the monochrome shares aregenerated for each channel, channels are comb<strong>in</strong>edseparately to create the color shares. This is the approachpresented <strong>in</strong> [9]. The alternative approach would be todirectly apply color halfton<strong>in</strong>g, then perform theseparation <strong>in</strong>to color channels followed by the application<strong>of</strong> visual cryptography to each channel <strong>in</strong>dependently.Actually, these two approaches lead to the same resultsf<strong>in</strong>ally. There are many mature halfton<strong>in</strong>g techniquesavailable for selection like dispersed-dot dither<strong>in</strong>g,clustered-dot dither<strong>in</strong>g and error diffusion techniques.Halfton<strong>in</strong>g based visual cryptographic scheme can besummarized as follows:a) Encryption: This stage is for the creation <strong>of</strong>shares. This can be further divided <strong>in</strong>to the follow<strong>in</strong>gsteps:i. Color halfton<strong>in</strong>g: Standard algorithms such as theones described <strong>in</strong> [2], [13] and [14] can be usedfor this step. One could do the color channelsplitt<strong>in</strong>g first and then do the grayscale halfton<strong>in</strong>gfor each channel:ii.Or one could do color halfton<strong>in</strong>g first followed bythe splitt<strong>in</strong>g:Creation <strong>of</strong> shares: Consider<strong>in</strong>g the case <strong>of</strong>(2,2)-VCS, the steps areb) Decryption: This stage is for the reconstruction<strong>of</strong> the orig<strong>in</strong>al secret image. This can be further divided<strong>in</strong>to the follow<strong>in</strong>g steps:i. Stack<strong>in</strong>g <strong>of</strong> shares: The follow<strong>in</strong>g stack<strong>in</strong>g (OR)operation needs to be performed:ii. Subsampl<strong>in</strong>g for reconstruction: Theseoperations need to be performed where everyblock <strong>of</strong> f our pixels is sub-sampled <strong>in</strong>to onepixel <strong>of</strong> the f<strong>in</strong>al image. This step is optional andshould be used only with the XOR recoverydescribed <strong>in</strong> Section III-B.1 to achieve betterquality.Then, for every 2*2 block B(i; j) <strong>of</strong> I, whereIt is clear that our technique, though <strong>in</strong>dependentlydeveloped, is quite similar <strong>in</strong> spirit to the one described <strong>in</strong>[9]. So both share the same drawback that digitalhalfton<strong>in</strong>g always leads to permanent loss <strong>of</strong> <strong>in</strong>formationwhich means that the orig<strong>in</strong>al image can never beperfectly restored. Inverse halfton<strong>in</strong>g is a possiblesolution that can attempt to recover the image. The bestresults can obta<strong>in</strong> a restoration quality <strong>of</strong> 30 dB measured<strong>in</strong> PSNR, which is quite good. But this is not sufficientfor applications which require that the orig<strong>in</strong>al image befaithfully recovered. In fact, <strong>in</strong> all other cryptographictechniques, it is taken for granted that the decryption <strong>of</strong> aciphertext perfectly recovers the pla<strong>in</strong>text. But visualcryptography has been a glar<strong>in</strong>g exception so far.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 141VI. CONCLUSIONIn this paper, I have extended traditional visualcryptography by employ<strong>in</strong>g new schemes whichovercome its limitations. I propose a technique forgrayscale and color visual cryptography. Our <strong>in</strong>sight isthat the OR operation <strong>in</strong> the traditional visualcryptography can be replaced by the XOR operation <strong>in</strong>order to allow for lossless decryption. However, there aresome practical issues that need careful consideration.First, the transparencies should be precisely aligned <strong>in</strong>order to obta<strong>in</strong> a clear reconstruction. Secondly, there isusually some unavoidable noise <strong>in</strong>troduced dur<strong>in</strong>g thepr<strong>in</strong>t<strong>in</strong>g process. Thirdly, the stack<strong>in</strong>g method can onlysimulate the OR operation which always leads to a loss <strong>in</strong>contrast. Proper alignment is absolutely essential whensuperimpos<strong>in</strong>g the shares. In real experiments, we havefound that obta<strong>in</strong><strong>in</strong>g perfect alignment is alwaystroublesome. As visual cryptographic schemes operate atthe pixel levels, each pixel on one share must be matchedcorrectly with the correspond<strong>in</strong>g pixel on the other share.Superimpos<strong>in</strong>g the shares with even a slight shift <strong>in</strong>alignment results <strong>in</strong> a drastic degradation <strong>in</strong> the quality <strong>of</strong>the reconstructed image. In the worst case, even a s<strong>in</strong>glepixel shift can render the secret image totally <strong>in</strong>visible.This alignment problem can be resolved if the boundary<strong>of</strong> each share is clearly marked which can act as guidesfor the alignment.REFERENCES[1] M. Naor and A. Shamir, “Visual cryptography,” <strong>in</strong> Advances<strong>in</strong> Cryptology -EUROCRYPT’94, A. D. Santis., Ed., vol.950. Spr<strong>in</strong>ger-Verlag, 1995, pp. 1–12.[2] H. R. Kang, Digital Color Halfton<strong>in</strong>g, ser. SPIE/IEE Serieson Imag<strong>in</strong>g Science and Eng<strong>in</strong>eer<strong>in</strong>g, E. R. Dougherty,Ed.Bell<strong>in</strong>gham, Wash<strong>in</strong>gton USA and New York:Copublished by SPIE Optical Eng<strong>in</strong>eer<strong>in</strong>g Press and IEEEPress, 1999.[3] M. Naor and A. Shamir, “Visual cryptography 2: Improv<strong>in</strong>gthe contrast via the cover base,” 1996, a prelim<strong>in</strong>aryversionappears <strong>in</strong> “Security Protocols”, M. Lomas ed. Vol.1189 <strong>of</strong> Lecture Notes <strong>in</strong> Compute Science, Spr<strong>in</strong>ger-Verlag, Berl<strong>in</strong>,pp.197-202, 1997.[4] A. D. S. G. Ateniese, C. Blundo and D. R. St<strong>in</strong>son,“Constructions and bounds for visual cryptography,” <strong>in</strong> 23 rdInternational Colloquium on Automata, Languages andProgramm<strong>in</strong>g, ser. Lecture Notes <strong>in</strong> Computer Science, F.M. auf der Heide and B. Monien, Eds., vol. 1099. Berl<strong>in</strong>:Spr<strong>in</strong>ger-Verlag, 1996, pp. 416–428.[5] C. Blundo, P. D’Arco, A. D. Snatis, and D. R. St<strong>in</strong>son,“Contrast optimal threshold visual cryptography schemes,”SIAM <strong>Journal</strong> on Discrete Mathematics, available at:http://citeseer.nj.nec.com/blundo98contrast.html, vol. 16,no. 2, pp. 224–261, April 1998.[6] G. Ateniese, C. Blundo, A. D. Santis, and D. St<strong>in</strong>son,“Extended schemes for visual cryptography,” TheoreticalComputerScience, vol. 250, pp. 143–161, 2001.[7] Y. Desmedt and T. V. Le, “Moire cryptography,” <strong>in</strong> the 7thACM Conference on Computer and CommunicationsSecurity’00, Athens, Greece, 2000.[8] V. Rijmen and B. Preneel, “Efficient color visual encryptionfor shared colors <strong>of</strong> benetton,” 1996, EUCRYPTO’96RumpSession. Availabe athttp://www.iacr/org/conferences/ec96/rump/preneel.ps.[9] Y. C. Hou, C. Y. Chang, and S. F. Tu, “Visual cryptographyfor color images based on halftone technology,”<strong>in</strong>International Conference on Information Systems,Analysis and Synthesis. World Multiconference onSystemics, Cyberneticsand Informatics. Image, Acoustic,Speech And Signal Process<strong>in</strong>g: Part II, 2001.[10] M. Naor and B. P<strong>in</strong>kas, “Visual authentication andidentification,” Lecture Notes <strong>in</strong> Computer Science, vol.1294, pp. 322–336, 1997. [Onl<strong>in</strong>e]. Available:citeseer.nj.nec.com/67294.html[11] Q. B. Sun, P. R. Feng, and R. Deng, <strong>in</strong> InternationalConference on Information Technology: Cod<strong>in</strong>g andComput<strong>in</strong>g (ITCC ’01), available at:http://dlib.computer.org/conferen/itcc/1062/pdf/10620065.pdf, Las Vegas, April 2001.[12] S.-S. Lee, J.-C. Na, S.-W. Sohn, C. Park, D.-H. Seo, andS.-J. Kim, “Visual cryptography based on an <strong>in</strong>terferometricencryption technique,” ETRI <strong>Journal</strong>, vol. 24, pp. 373–380,2002, available at http://etrij.etri.re.kr/etrij/pdfdata/24-05-05.pdf.Supriya A. K<strong>in</strong>ger was born <strong>in</strong> Haryana,India on 15 th july 1982. She did herMaster’s <strong>in</strong> technology <strong>in</strong> field <strong>of</strong>computer science from YMCA, Haryana<strong>in</strong> year 2005, India and Bachelor’s <strong>in</strong>technology <strong>in</strong> Computer Science fromKU, Haryana, India. In year2003.Currently she is do<strong>in</strong>g research <strong>in</strong>field <strong>of</strong> S<strong>of</strong>tware Eng<strong>in</strong>eer<strong>in</strong>g(Component Based S<strong>of</strong>twareEng<strong>in</strong>eer<strong>in</strong>g).She has more than 5 Years <strong>of</strong> experience <strong>in</strong> teach<strong>in</strong>g andresearch. She has attended and organized a number <strong>of</strong>workshops and conferences. She hosted a conference ASET-2006 at CIET and acted as convener <strong>in</strong> it. She has presentednumber <strong>of</strong> papers <strong>in</strong> national and <strong>in</strong>ternational conferences <strong>of</strong>repute on the topics <strong>of</strong> web crawlers, Component baseds<strong>of</strong>tware Eng<strong>in</strong>eer<strong>in</strong>g, Information Security and Networks.Currently she is Work<strong>in</strong>g with Chitkara Institute <strong>of</strong> Eng<strong>in</strong>ner<strong>in</strong>gand Technology, Punjab, India as Senior Lecturer. Earlier shehas worked at Institute <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g and Technology. She islife member <strong>of</strong> ISTE© 2010 ACADEMY PUBLISHER


142 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Multistage Interconnection Networks: ATransition from Electronic to OpticalR<strong>in</strong>kle Rani AggarwalDepartment <strong>of</strong> Computer Science & Eng<strong>in</strong>eer<strong>in</strong>g,Thapar University, Patiala –147004 (India)raggarwal@thapar.eduDr. Lakhw<strong>in</strong>der Kaur, Dr. Himanshu AggarwalDepartment <strong>of</strong> Computer Eng<strong>in</strong>eer<strong>in</strong>g,Punjabi University, Patiala–147002 (India)mahal2k8@yahoo.com, himanshu@pbi.ac.<strong>in</strong>Abstract—Optical communication are necessary forachiev<strong>in</strong>g reliable, fast and flexible communication.Advances <strong>in</strong> electro-optic technologies have made opticalcommunication a reliable network<strong>in</strong>g choice to meet the<strong>in</strong>creas<strong>in</strong>g demands for high bandwidth and lowcommunication latency <strong>of</strong> high-performancecomput<strong>in</strong>g/communication applications. So optical networksgives high performance as well as low latency. Althoughoptical MINs hold great promise and have advantages overtheir electronic networks, they also hold their ownchallenges. This paper compares electronic and OpticalMINs. The design issues and solution approaches availablefor optical MINs are also expla<strong>in</strong>ed and analyzed.Index Terms— Multistage Interconnection Networks (MIN),Optical networks, Crosstalk, W<strong>in</strong>dow methods.I. INTRODUCTIONTo meet the <strong>in</strong>creas<strong>in</strong>g demands <strong>of</strong> high performancecomput<strong>in</strong>g applications for high channel bandwidth andlow communication latency, traditional metal-basedcommunication technology used <strong>in</strong> parallel comput<strong>in</strong>gsystems is becom<strong>in</strong>g a potential bottleneck. Now, theneed arise either for some significant progress <strong>in</strong> thetraditional <strong>in</strong>terconnects or for some new <strong>in</strong>terconnecttechnology be <strong>in</strong>troduced <strong>in</strong> parallel comput<strong>in</strong>g systems.Electro-optic technologies have made opticalcommunication a promis<strong>in</strong>g network choice to meet the<strong>in</strong>creas<strong>in</strong>g demands with its advancement <strong>in</strong> thetechnology. Fiber optic communications <strong>of</strong>fer acomb<strong>in</strong>ation <strong>of</strong> high bandwidth, low error probability andgigabit transmission capacity.Multistage <strong>in</strong>terconnection networks have beenextensively accepted as an <strong>in</strong>terconnect<strong>in</strong>g scheme forparallel comput<strong>in</strong>g systems. As optical technologyadvances, there is considerable <strong>in</strong>terest <strong>in</strong> us<strong>in</strong>g opticaltechnology to implement <strong>in</strong>terconnection network andswitches. A multistage <strong>in</strong>terconnection network iscomposed <strong>of</strong> several stages <strong>of</strong> switch elements by whichany <strong>in</strong>put port can be connected to any output port <strong>in</strong> thenetwork. Optical MIN represents a very important class<strong>of</strong> <strong>in</strong>terconnect<strong>in</strong>g schemes used for construct<strong>in</strong>g Optical<strong>in</strong>terconnections for communication networks andmultiprocessor systems. This network consists <strong>of</strong> N<strong>in</strong>puts, N outputs and n stages (n=log 2 N). Each stage hasN/2 switch<strong>in</strong>g elements each SE has two <strong>in</strong>puts and twooutputs connected <strong>in</strong> a certa<strong>in</strong> pattern. The most widelyused MINs are the electronic MINs. In electronic MINs,electricity is used, s<strong>in</strong>ce <strong>in</strong> optical MINs, light is used totransmit the messages. Although electronic MINs andoptical MINs have many similarities but there are somefundamental differences between them. Available opticalMINs were built ma<strong>in</strong>ly on banyan or its equivalent (e.g.basel<strong>in</strong>e, omega) networks because they are fast <strong>in</strong> switchsett<strong>in</strong>g (self-rout<strong>in</strong>g) and also have a small number <strong>of</strong>switches between an <strong>in</strong>put-output pair. Banyan networkshave a unique path between an <strong>in</strong>put-output pair, and thismakes them block<strong>in</strong>g networks. Non-block<strong>in</strong>g networkscan be constructed by either append<strong>in</strong>g some extra stagesto the back <strong>of</strong> a regular banyan network. Crosstalk <strong>in</strong>optical networks is one <strong>of</strong> the major shortcom<strong>in</strong>gs <strong>in</strong>optical switch<strong>in</strong>g networks, and avoid<strong>in</strong>g crosstalk is animportant for mak<strong>in</strong>g optical communication properly. Toavoid a crosstalk, many approaches have been used suchas time doma<strong>in</strong> and space doma<strong>in</strong> approaches. Becausethe messages should be partitioned <strong>in</strong>to several groups tosend to the network, some methods are used to f<strong>in</strong>dconflicts between the messages.II. MULTISTAGE INTERCONNECTIONNETWORKSMultistage <strong>in</strong>terconnection networks (MINs) consist<strong>of</strong> more than one stage <strong>of</strong> small <strong>in</strong>terconnection elementscalled switch<strong>in</strong>g elements and l<strong>in</strong>ks <strong>in</strong>terconnect<strong>in</strong>g them.Multistage <strong>in</strong>terconnection networks (MINs) are used <strong>in</strong>multiprocess<strong>in</strong>g systems to provide cost-effective, highbandwidthcommunication between processors and/ormemory modules. A MIN normally connects N <strong>in</strong>puts toN outputs and is referred as an N × N MIN [9,10]. Theparameter N is called the size <strong>of</strong> the network. There areseveral different multistage <strong>in</strong>terconnection networks© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.142-147


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 143proposed and studied <strong>in</strong> the literature. Figure 1 illustratesa structure <strong>of</strong> multistage <strong>in</strong>terconnection network, whichare representatives <strong>of</strong> a general class <strong>of</strong> networks. Thisfigure shows the connection between p <strong>in</strong>puts and boutputs, and connection between these is via number <strong>of</strong>stages. Multistage <strong>in</strong>terconnection network is actually acompromise between crossbar and shared bus networks<strong>of</strong> various types <strong>of</strong> multiprocessor <strong>in</strong>terconnectionsnetworks [1]. Multistage <strong>in</strong>terconnection networksattempt to reduce cost and decrease the path lengthspeed mismatch occur due to the high speed <strong>of</strong> opticalsignals. The second approach is all-optical switch<strong>in</strong>g.This has removed the problem that occurred with thehybrid approach but, such systems will not becomepractical <strong>in</strong> the future and hence only hybrid opticalMINs are considered. In hybrid optical MINs, theelectronically controlled optical switches, such as lithiumniobate directional couplers, can have switch<strong>in</strong>g speedsfrom hundreds <strong>of</strong> picoseconds to tens <strong>of</strong> nanoseconds.A. Switch<strong>in</strong>g <strong>in</strong> optical networksIn optical networks, circuit switch<strong>in</strong>g is used. Packetswitch<strong>in</strong>g is not possible with Optical MultistageInterconnection Networks. If packet switch<strong>in</strong>g is used,the address <strong>in</strong>formation <strong>in</strong> each packet must be decoded<strong>in</strong> order to determ<strong>in</strong>e the switch state. In a hybrid MIN, itmeans it require conversions from optical signals toelectronic ones, which could be very costly [4]. For thisreason, circuit switch<strong>in</strong>g is usually preferred <strong>in</strong> opticalMINs.Figure 1: A MultistageNetworkMINsTABLE IPROPERTIES OF DIFFERENT INTERCONNECTIONTECHNIQUESOPTICALELECTRONICProperty Bus Crossbar MultistageSpeed Low High HighCost Low High ModerateReliability Low High HighConfigurability High Low ModerateComplexity Low High ModerateHYBRIDGUIDEDWAVEALL OPTICSSPACEOPTICSIII. OPTICAL MULTISTAGE INTERCONNECTIONNETWORKSAn optical MIN can be implemented with either freespaceoptics or guided wave technology. It uses the TimeDivision Multiplex<strong>in</strong>g. To exploit the huge opticalbandwidth <strong>of</strong> fiber, the Wavelength DivisionMultiplex<strong>in</strong>g (WDM) technique can also be used. WithWDM, the optical spectrum is divided <strong>in</strong>to manydifferent logical channels, and each channel correspondsto a unique wavelength. Optical switch<strong>in</strong>g, <strong>in</strong>volves theswitch<strong>in</strong>g <strong>of</strong> optical signals, rather than electronic signalsas <strong>in</strong> conventional electronic systems. Two types <strong>of</strong>guided wave optical switch<strong>in</strong>g systems can be used [5].The first is a hybrid approach <strong>in</strong> which optical signals areswitched, but the switches are electronically controlled.With this approach, the use <strong>of</strong> electronic control signalsmeans that the rout<strong>in</strong>g will be carried out electronically.As such, the speed <strong>of</strong> the electronic switch control signalscan be much less than the bit rate <strong>of</strong> the optical signalsbe<strong>in</strong>g switched. So, with this approach there is a bigFigure 2: Types <strong>of</strong> Multistage NetworksB. Comparison <strong>of</strong> Electronic and Optical NetworksThere are lots <strong>of</strong> benefits <strong>of</strong> optical networks overthe electronic ones. The ma<strong>in</strong> benefit <strong>of</strong> the opticalnetworks over the electronic network is the high speed <strong>of</strong>the Optical signals. In the optical networks light istransmitted which has a very good speed but <strong>in</strong> theelectronic Multistage <strong>in</strong>terconnection networks electricityis used which has very slow speed. The second advantageis the Bandwidth. Now a day’s applications <strong>in</strong>communication require high bandwidth, the opticalnetworks gives comb<strong>in</strong>ation <strong>of</strong> very high bandwidth andlow latency. Therefore, they have been used <strong>in</strong> theparallel process<strong>in</strong>g applications. Optical MINs are alsoused <strong>in</strong> wide area networks, which require less errorprobability and very high bandwidth. Fiber optic© 2010 ACADEMY PUBLISHER


144 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010transmission distance is significantly greater than theelectronic ones, signal need not to be regenerated <strong>in</strong>optical networks. Optical fiber has very less weight <strong>in</strong>comparison to electronic MINs. Thus Optical networksgive the comb<strong>in</strong>ation <strong>of</strong> high bandwidth and low latency.TABLE IICOMARISON OF ELECTRONIC AND OPTICAL NETWORKSCharacteristicsElectronicMultistageNetwotksOpticalMultistageNetworksSpeed Less HighEnergyElectricity LightTransmittedBandwidth Used for lessbandwidthapplicationsUsed for highbandwidthapplicationsLatency High LessError Probability High LessWeight More LessCost Less MoreSwitch<strong>in</strong>g Packet Switch<strong>in</strong>g CircuitSwitch<strong>in</strong>gPathProvide Multi path Provide s<strong>in</strong>glefrom source to path fromdest<strong>in</strong>ation. source todest<strong>in</strong>ationComplexity More Complex Less ComplexStructureconsidered2-dimensional 3-dimensionalIV. PROBLEMS IN OPTICAL NETWORKSDue to the difference <strong>in</strong> speeds <strong>of</strong> the electronic andoptical switch<strong>in</strong>g elements and the nature <strong>of</strong> opticalsignals, optical MINs also hold their own challenges.A. Path Dependent LossPath dependent loss means that optical signalsbecome weak after pass<strong>in</strong>g through an optical path. In alarge MIN, a big part <strong>of</strong> the path-dependent loss isdirectly proportional to the number <strong>of</strong> couplers that theoptical path passes through [16]. Hence, it depends on thearchitecture used and its network size. Hence, if theoptical signal has to pass through more no <strong>of</strong> stages orswitches the path dependent loss will be more.B. Optical CrosstalkOptical crosstalk occurs when two signal channels<strong>in</strong>teract with each other. There are two ways <strong>in</strong> whichoptical paths can <strong>in</strong>teract <strong>in</strong> a switch<strong>in</strong>g network. Thechannels carry<strong>in</strong>g the signals could cross each other.Alternatively; two paths shar<strong>in</strong>g a switch couldexperience some undesired coupl<strong>in</strong>g from one path toanother with<strong>in</strong> a switch. For example, assume that thetwo <strong>in</strong>puts are y and z, respectively, the two outputs willhave ly+lxz and lz+lxy, respectively, where l is path lossand x is signal crosstalk <strong>in</strong> a switch. Us<strong>in</strong>g the best devicex=35 dB and l=0.25 dB. For more practically availabledevices, it is more likely that x=20 dB and l=1 dB [5].Hence, when a signal passes many switches, the <strong>in</strong>putsignal will be distorted at the output due to the loss andcrosstalk <strong>in</strong>troduced on the path.Crosstalk problem is more dangerous than the pathdependentloss problem with current optical technology.Thus, switch crosstalk is the most significant factor thatreduces the signal-to-noise ratio and limits the size <strong>of</strong> anetwork. Luckily, ensur<strong>in</strong>g that a switch is not used bytwo <strong>in</strong>put signals simultaneously can elim<strong>in</strong>ate first-ordercrosstalk. Once the major source <strong>of</strong> crosstalk disappears,crosstalk <strong>in</strong> an optical MIN will have a very small effecton the signal-to-noise ratio and thus a large optical MINcan be built and effectively used <strong>in</strong> parallel comput<strong>in</strong>gsystems.V. APPROACHES TO SOLVE CROSSTALKA. Space Doma<strong>in</strong> ApproachOne way to solve crosstalk problem is a spacedoma<strong>in</strong> approach, where a MIN is duplicated andcomb<strong>in</strong>ed to avoid crosstalk [8]. The number <strong>of</strong> switchesrequired for the same connectivity <strong>in</strong> networks with spacedoma<strong>in</strong> approach is slightly larger than twice that for theregular network. This approach uses more than doublethe orig<strong>in</strong>al network hardware to achieve the same. Thusfor the same permutation the hardware or we can say theno <strong>of</strong> switches will be double. Thus cost will be morewith the networks us<strong>in</strong>g space doma<strong>in</strong> approach. In allthe four cases only one <strong>in</strong>put and only one output isactive at a given time so that no cross talk occurs. Withthe space doma<strong>in</strong> approach, extra switch<strong>in</strong>g elements(SEs) and l<strong>in</strong>ks are used to ensure that at most one <strong>in</strong>putand one output <strong>of</strong> every SE will be used at any giventime.Figure 3. Crosstalk avoidance us<strong>in</strong>g space doma<strong>in</strong> approachB. Time Doma<strong>in</strong> ApproachAnother way to solve the problem <strong>of</strong> crosstalk is thetime doma<strong>in</strong> approach [3]. With the time doma<strong>in</strong>approach, the same objective is achieved by treat<strong>in</strong>gcrosstalk as a conflict; that is, two connections will beestablished at different times if they use the same SE.Whereas we want to distribute the messages to be sent tothe network <strong>in</strong>to several groups, a method is used to f<strong>in</strong>d© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 145out which messages should not be <strong>in</strong> the same groupbecause they will cause crosstalk <strong>in</strong> the network. A set <strong>of</strong>connections is partitioned <strong>in</strong>to several subsets such thatthe connections <strong>in</strong> each subset can be establishedsimultaneously <strong>in</strong> a network. There is no crosstalk <strong>in</strong>these subsections. This approach makes importance <strong>in</strong>optical MINs for various reasons. First, most <strong>of</strong> themultiprocessors use electronic processors and opticalMINs. There is a big mismatch between the slowprocess<strong>in</strong>g speed <strong>in</strong> processors and the highcommunication speed <strong>in</strong> networks carry<strong>in</strong>g opticalsignals [15]. Second, there is a mismatch between therout<strong>in</strong>g control and the fast signal transmission speed. Toavoid crosstalk, the TDM approach is used, where the set<strong>of</strong> messages are partitioned <strong>in</strong>to several groups such thatthe messages <strong>in</strong> each group can be sent simultaneouslythrough the network without any crosstalk.VI. METHODS FOR MESSAGE PARTITIONING INTDM APPROACHA. W<strong>in</strong>dow methodW<strong>in</strong>dow method is the method that is used to f<strong>in</strong>d themessages that are not <strong>in</strong> the same group because it causescrosstalk <strong>in</strong> the network. If we consider the network <strong>of</strong>size N x N, there are N source and N dest<strong>in</strong>ation address.Comb<strong>in</strong><strong>in</strong>g source and its dest<strong>in</strong>ation address formscomb<strong>in</strong>ation matrix. From this, optical w<strong>in</strong>dow size is M-1 where M = log 2 N and N is size <strong>of</strong> network. In w<strong>in</strong>dowmethod, the number <strong>of</strong> w<strong>in</strong>dows is equal to the number <strong>of</strong>stages [11].After f<strong>in</strong>d<strong>in</strong>g conflicts us<strong>in</strong>g w<strong>in</strong>dow method,conflict graph is generated shown <strong>in</strong> figure. The number<strong>of</strong> nodes is the size <strong>of</strong> the network. The nodes that arehav<strong>in</strong>g conflict are connected through edge. Degree <strong>of</strong>each message is the number <strong>of</strong> conflicts to the othermessage. Conflict graph is shown <strong>in</strong> figure 4.Figure 4. Conflict graphThe conflict matrix is a square matrix with N x Nentry, it consists <strong>of</strong> the output <strong>of</strong> the w<strong>in</strong>dow method, asshown <strong>in</strong> figure 5. The def<strong>in</strong>ition <strong>of</strong> Conflict Matrix is thematrix M ij with size N x N. N is the size <strong>of</strong> the network.B. Improved w<strong>in</strong>dow methodIn this method the first w<strong>in</strong>dow is elim<strong>in</strong>ated for thiswe make the conflict matrix <strong>in</strong>itialized to 0, here Number<strong>of</strong> w<strong>in</strong>dows is M-1. It takes less time to f<strong>in</strong>d conflictsthan the w<strong>in</strong>dows method. Therefore, it is calledimproved w<strong>in</strong>dows method [11,12].Figure 5. Conflict matrix© 2010 ACADEMY PUBLISHER


146 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Figure 7. Bitwise w<strong>in</strong>dow methodC. Bitwise comb<strong>in</strong>ation matrixFigure 6. Improved w<strong>in</strong>dow methodFor Bitwise comb<strong>in</strong>ation matrix, all b<strong>in</strong>ary bits <strong>of</strong>s<strong>in</strong>gle rows is each w<strong>in</strong>dows are converted to decimal,no. <strong>of</strong> w<strong>in</strong>dow is reduced to n. By this method, time isreduced approximately by ten times. It is very effectivemethod even when the network is very large.For example the bitwise comb<strong>in</strong>ation matrix for 8 8network size is demonstrated <strong>in</strong> Fig. 5. The number <strong>of</strong>columns <strong>in</strong> WM is 6 (Ci, i = 2n) and for bitwise WM is 2(Ci, i = n) [11,12].VII. CONCLUSIONIn this paper properties <strong>of</strong> electronic and opticalMINs have been expla<strong>in</strong>ed and compared. It isconcluded that for today’s applications such as <strong>in</strong> widearea networks (WANs) optical networks is the promis<strong>in</strong>gchoice to meet the high demand <strong>of</strong> Speed and Bandwidth.The paper also describes the problems and solutions <strong>of</strong>optical MINs. Various methods available <strong>in</strong> literature,which are used for crosstalk avoidance <strong>in</strong> TDM approach,are described <strong>in</strong> detail. It has been observed that theimproved w<strong>in</strong>dow method takes lesser time to f<strong>in</strong>dconflicts as compared to w<strong>in</strong>dow method. The bitwisew<strong>in</strong>dow method reduces the execution time ten timesthan the other algorithms even when the network size islarge.REFERENCESComb<strong>in</strong>ation MatrixD. Bitwise w<strong>in</strong>dow methodBitwise Comb<strong>in</strong>ation MatrixIn this method, source and dest<strong>in</strong>ation address is <strong>in</strong>decimal format. Number <strong>of</strong> w<strong>in</strong>dows is log 2 N. Thus, fromcomb<strong>in</strong>ation matrix, the optical w<strong>in</strong>dow size is only onefor a different network size and the number <strong>of</strong> w<strong>in</strong>dow islog 2 N. In other words, there are only one decimal number<strong>in</strong> each row and each w<strong>in</strong>dow for comparison and f<strong>in</strong>d<strong>in</strong>ga conflict [11,12].[1] A. Verma and C.S. Raghvendra, “InterconnectionNetworks for Multiprocessors and Mul-ticomputers:Theory and Practice”, IEEE Computer Society Press,Los Alamitos, California, 1994.[2] A.K. Katangur, Y. Pan and M.D Fraser, “MessageRout<strong>in</strong>g and Schedul<strong>in</strong>g <strong>in</strong> Optical Mul-tistageNetworks Us<strong>in</strong>g Simulated Anneal<strong>in</strong>g”, InternationalProceed<strong>in</strong>gs <strong>of</strong> the Parallel and Distributed Process<strong>in</strong>gSymposium (IPDPS), 2002.[3] C. Qiao, and R. Melhem, “A Time Doma<strong>in</strong> ApproachFor Avoid<strong>in</strong>g Crosstalk In Optical Block<strong>in</strong>g Multi-stageInterconnection Networks”, <strong>Journal</strong> <strong>of</strong> LightwaveTechnology, vol. 12 no. 10, October 1994, pp. 1854-1862.[4] C. Siu and X. Tiehong , “New Algorithm for MessageRout<strong>in</strong>g and Schedul<strong>in</strong>g <strong>in</strong> Optical MultistageInterconnection Network”, Proceed<strong>in</strong>gs <strong>of</strong> InternationalConferwnce on Optical Communications Systems andNetworks, 2004.[5] D. K. Hunter and I. Andonovic, “Guided wave opticalswitch architectures,” International <strong>Journal</strong> <strong>of</strong>Optoelectronics, vol. 9, no. 6, 1994, pp. 477-487.[6] Hasan, “Rearrangeability <strong>of</strong> (2n − 1)-Stage Shuffle-Exchange Networks”, Society for Industrial and AppliedMathematics, vol. 32, no. 3, 2003, pp. 557-585.[7] J. T. Blaket and K.S. Trivedi, “Reliabilities <strong>of</strong> TwoFault-Tolerant Interconnection Networks”, Proceed<strong>in</strong>g<strong>of</strong> IEEE, 1988, pp. 300-305.[8] K. Padmanabhan and A. Netravali, “Dilated Networksfor Photonic Switch<strong>in</strong>g”, IEEE Transactions onCommunication, vol. 35, no. 12, 1987, pp. 1357-1365.[9] L. N. Bhuyan and D.P. Aggarwal, “Design andperformance <strong>of</strong> generalized <strong>in</strong>terconnection networks”,© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 147IEEE Transactions on computers, vol. C-32, no. 2,1983, pp. 1081–1090.[10] L. N. Bhuyan, Q. Yang Q<strong>in</strong>g and D.P. Aggarwal,“Performance <strong>of</strong> Multiprocessor InterconnectionNetworks”, IEEE Computers, vol. 22, 1989, pp. 25-37.[11] M. A, M. Othman and R. Johari, “An efficient approachto avoid crosstalk <strong>in</strong> optical Omega Network”,International <strong>Journal</strong> <strong>of</strong> Computer, Internet andManagement, vol. 14, no. 1, 2005, pp. 50-60.[12] M. Ali, M. Othman, R. Johari and S. Subramaniam,“New Algorithm to Avoid Cros- stalk <strong>in</strong> OpticalMultistage Interconnection Networks”, Proceed<strong>in</strong>gs <strong>of</strong>IEEE International Conference on Network (MICC-ICON), 2005, pp. 501-504.[13] M. Fang, Layout Optimization for Po<strong>in</strong>t to Multi Po<strong>in</strong>t,Wireless Optical Networks via Simulated Anneal<strong>in</strong>g &Genetic Algorithm”, Master Project, University <strong>of</strong>Bridgeport, 2000.[14] Regis Bates, “Optical Switch<strong>in</strong>g and Network<strong>in</strong>gHandbook”, McGraw-Hill, New York, 2001.[15] X. Shen, F. Yang and Y. Pan, “Equivalent permutationcapabilities between time division optical omeganetworks and non-optical extra-stage omega networks”,IEEE Transactions on Network<strong>in</strong>g, vol.9, no. 4, 2001,pp. 518-524.[16] Y. Pan , X. L<strong>in</strong>, and X. Jia, Evolutionary Approach ForMessage Schedul<strong>in</strong>g In Optical Omega Networks, FifthIntern. Conf. on Algorithms and Architectures forParallel Process<strong>in</strong>g (ICA3PP), 2002.Himanshu Aggarwal, Ph.D., isReader <strong>in</strong> Computer Eng<strong>in</strong>eer<strong>in</strong>g atUniversity College <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g,Punjabi University, Patiala. He hasmore than 16 years <strong>of</strong> teach<strong>in</strong>gexperience and served academic<strong>in</strong>stitutions such as Thapar Institute<strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g & Technology,Patiala, Guru Nanak DevEng<strong>in</strong>eer<strong>in</strong>g College, Ludhiana and Technical Teacher'sTra<strong>in</strong><strong>in</strong>g Institute, Chandigarh. He is an active researcher whohas supervised many M.Tech. Dissertations and contributed 32articles <strong>in</strong> Conferences and 13 papers <strong>in</strong> research <strong>Journal</strong>s. Hisareas <strong>of</strong> <strong>in</strong>terest are Information Systems, ERP and ParallelComput<strong>in</strong>g.BiographiesR<strong>in</strong>kle Rani Aggarwal,B.Tech (Computer Science &Engg.), M.S. (S<strong>of</strong>twareSystems), is Senior Lecturer <strong>in</strong>Computer Science &Eng<strong>in</strong>eer<strong>in</strong>g Department atThapar University, Patiala. Shehas more than 12 years <strong>of</strong>teach<strong>in</strong>g experience and servedacademic <strong>in</strong>stitutions such as Guru Nanak DevEng<strong>in</strong>eer<strong>in</strong>g College, Ludhiana and S.S.I.E.T 'Derabassi.She has supervised many M.Tech. Dissertations andcontributed 23 articles <strong>in</strong> Conferences and 11 papers <strong>in</strong>research <strong>Journal</strong>s. Her areas <strong>of</strong> <strong>in</strong>terest are ParallelComput<strong>in</strong>g and Algorithms.Lakhw<strong>in</strong>der Kaur, Ph.D. isReader <strong>in</strong> Computer Eng<strong>in</strong>eer<strong>in</strong>g atUniversity College <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>gPunjabi University, Patiala. Shehas 17 years <strong>of</strong> teach<strong>in</strong>gexperience. She has published 12research papers <strong>in</strong> International<strong>Journal</strong>s. Her areas <strong>of</strong> <strong>in</strong>terest areImage process<strong>in</strong>g, ParallelComput<strong>in</strong>g and ComputerGraphics.© 2010 ACADEMY PUBLISHER


148 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010<strong>Web</strong> Based H<strong>in</strong>di to PunjabiMach<strong>in</strong>e Translation SystemVishal Goyal and Gurpreet S<strong>in</strong>gh LehalDepartment <strong>of</strong> Computer Science, Punjabi University, Patiala, Punjab, India{vishal.pup,gslehal}@gmail.comAbstract - H<strong>in</strong>di and Punjabi are closely related languageswith lots <strong>of</strong> similarities <strong>in</strong> syntax and vocabulary BothPunjabi and H<strong>in</strong>di languages have orig<strong>in</strong>ated from Sanskritwhich is one <strong>of</strong> the oldest language. In terms <strong>of</strong> speakers,H<strong>in</strong>di is third most widely spoken language and Punjabi istwelfth most widely spoken language. Punjabi language ismostly used <strong>in</strong> the Northern India and <strong>in</strong> some areas <strong>of</strong>Pakistan as well as <strong>in</strong> UK, Canada and USA. H<strong>in</strong>di is thenational language <strong>of</strong> India and is spoken and used by thepeople all over the country. In the present research, BasicH<strong>in</strong>di to Punjabi mach<strong>in</strong>e translation system us<strong>in</strong>g directtranslation approach has been developed. The results <strong>of</strong>this translation system are surpris<strong>in</strong>gly good. The system<strong>in</strong>cludes lexicon based translation, transliteration andcont<strong>in</strong>uously improv<strong>in</strong>g the system through mach<strong>in</strong>elearn<strong>in</strong>g module. It also takes care <strong>of</strong> basic word sensedisambiguation.Index Terms - Mach<strong>in</strong>e Translation System, Closely relatedLanguages, H<strong>in</strong>di, Punjabi, Natural Language Process<strong>in</strong>g,Computational L<strong>in</strong>guistics, Transliteration.I. INTRODUCTIONMT is a field <strong>of</strong> research that has been around s<strong>in</strong>cethe birth <strong>of</strong> electronic computers. Warren Weaver, adirector <strong>of</strong> the Rockefeller Foundation received muchcredit for br<strong>in</strong>g<strong>in</strong>g the concept <strong>of</strong> MT to the publicwhen he published an <strong>in</strong>fluential paper on us<strong>in</strong>gcomputers for translation <strong>in</strong> 1949. MT is the name forcomputerized methods that automate all or part <strong>of</strong> theprocess <strong>of</strong> translat<strong>in</strong>g from one human language toanother. Fully-automatic general purpose high qualitymach<strong>in</strong>e translation system (FGH-MT) is extremelydifficult to build. In fact, there is no system <strong>in</strong> theworld <strong>of</strong> any pair <strong>of</strong> languages which qualifies to becalled FGH-MT. This paper expla<strong>in</strong>s the methodologyfollowed for develop<strong>in</strong>g the mach<strong>in</strong>e translationsystem between closely related languages – H<strong>in</strong>di andPunjabi. Closely related languages have lots <strong>of</strong>similarities <strong>in</strong> syntax and vocabulary. Mach<strong>in</strong>eTranslation between closely related languages is easierthan between language pairs that are not related witheach other. Hav<strong>in</strong>g many parts <strong>of</strong> their grammars andvocabularies <strong>in</strong> common reduces the amount <strong>of</strong> effortneeded to develop a translation system between relatedlanguages. Closely related languages are the languages <strong>of</strong>people who have similar cultures and common historicalroots.II. HISTORYThe first attempt to verify the hypothesis that relatedlanguages are easier to translate started <strong>in</strong> mid 80s atCharles University <strong>in</strong> Prague [FEMTI; Hajic et al. 2000].The project was called RUSLAN and aimed at thetranslation <strong>of</strong> documentation <strong>in</strong> the doma<strong>in</strong> <strong>of</strong> operat<strong>in</strong>gsystems for ma<strong>in</strong>frame computers. From that date to tilldate so many examples are there <strong>in</strong> history which supportthe argument that with close languages, the quality <strong>of</strong>MT system, with simple techniques, is better. To name afew one are CESILKO (a system for translat<strong>in</strong>g Czechand Slovak), MT system for translat<strong>in</strong>g Turkish ToCrimean Tatar etc. We are also try<strong>in</strong>g to strengthen thesame concept by experiment<strong>in</strong>g with a word for worddirect translation system for H<strong>in</strong>di to Punjabi. Theselanguages are very closely related and have manyfeatures <strong>in</strong> common.III. SYSTEM DESCRIPTIONThe major task beh<strong>in</strong>d direct Mach<strong>in</strong>e translationsystem is develop<strong>in</strong>g an exhaustive lexicon consist<strong>in</strong>g <strong>of</strong>source language words along with its correspond<strong>in</strong>gtranslated version <strong>of</strong> the target language. There is nomach<strong>in</strong>e readable dictionary available for H<strong>in</strong>di toPunjabi language. Two traditional dictionaries – onefrom Bhasha Vibhag, Patiala and another from NationalBook Trust has been published. We got it digitized andmoulded required for mach<strong>in</strong>e translation purpose whichis itself a big job. Now lexicon consists <strong>of</strong> approx.1,00,000 words. This lexicon is used for word for wordtranslation. Extend<strong>in</strong>g the lexicon demands large h<strong>in</strong>dicorpus. Sometimes it is available <strong>in</strong> Unicode format andsometimes it is available <strong>in</strong> number <strong>of</strong> other non standardfonts like Susha, Agra, Krutidev etc. which needs to beconverted <strong>in</strong>to Unicode first. Conversion is be<strong>in</strong>g donethrough Font Converter that converts non standard fonts<strong>in</strong>to Unicode Format. The beauty <strong>of</strong> the developed Fontconverter is that it is able to convert MS-Access files, MSWord files, HTML files and Text Files. Because thecorpus can be <strong>in</strong> any file type, so it handles all thepossible file types. Besides translation it performs thetask <strong>of</strong> transliteration as well. Transliteration means toreplace character by character <strong>of</strong> word from sourcelanguage character to target language character likeेमचंद <strong>in</strong>to ਪੇਮਚਂਦ. This system is basically an extension© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.148-151


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 149<strong>of</strong> previous system that does not handle any word sensedisambiguation. The above said system just checks thewords to be translated <strong>in</strong> the dictionary, if found it isreplaced with the translated version stored <strong>in</strong> thedictionary, otherwise it is transliterated. But now <strong>in</strong> theextended system, the lexicon is divided <strong>in</strong>to two parts –one table consists <strong>of</strong> words with no disambiguation andsecond consists <strong>of</strong> words that have multiple mean<strong>in</strong>gsdepend<strong>in</strong>g upon the context <strong>of</strong> the word <strong>in</strong> which it hasbeen used <strong>in</strong> the sentence.IV. SYSTEM ARCHITECTUREThe architecture for the HPMTS (H<strong>in</strong>di to PunjabiMach<strong>in</strong>e Translation System) consists <strong>of</strong> number <strong>of</strong>modules that are listed below:a. Tra<strong>in</strong><strong>in</strong>g the system with tra<strong>in</strong><strong>in</strong>g corpusb. Input Text Font Conversion <strong>in</strong>to UnicodeFormatc. H<strong>in</strong>di Text Normalizationd. F<strong>in</strong>d<strong>in</strong>g and Replac<strong>in</strong>g Collocationse. F<strong>in</strong>d<strong>in</strong>g and replac<strong>in</strong>g named entitiesf. Word to word translation us<strong>in</strong>g lexiconsg. Resolv<strong>in</strong>g Ambiguity among wordsh. Transliteration <strong>of</strong> wordsi. Post Process<strong>in</strong>gj. Improv<strong>in</strong>g the accuracy <strong>of</strong> the system throughmach<strong>in</strong>e learn<strong>in</strong>g dur<strong>in</strong>g every translation job.k. Test<strong>in</strong>g the system us<strong>in</strong>g test corpus other thantra<strong>in</strong> corpusIn the above architecture, the most important part andstart<strong>in</strong>g po<strong>in</strong>t is to tra<strong>in</strong> the system. Tra<strong>in</strong> the systemmeans generat<strong>in</strong>g the lexicon us<strong>in</strong>g the already exist<strong>in</strong>gcorpus. The second module is optional and is skipped ifthe <strong>in</strong>putted text is already <strong>in</strong> Unicode format. UnicodeFont requirement arises due to <strong>in</strong>ternalization <strong>of</strong> thesystem and mak<strong>in</strong>g the system free from specific fontdependency. This font converter can be also used forconvert<strong>in</strong>g the non-Unicode corpus <strong>in</strong>to Unicode formatcorpus. Indian language words face spell<strong>in</strong>gstandardization issues, thereby result<strong>in</strong>g <strong>in</strong> multiplespell<strong>in</strong>g variants for the same word. The ma<strong>in</strong> reason forthis phenomenon can be attributed to the phonetic nature<strong>of</strong> Indian Languages and multiple dialects. To give anidea <strong>of</strong> this data problem, these words were found –मंिजल, मिजल, मंिज़ल Third module is H<strong>in</strong>di TextNormalization that solves this spell<strong>in</strong>g variant problem.H<strong>in</strong>di text is normalized <strong>in</strong>to standard spell<strong>in</strong>gs before itgoes for translation. Next Module <strong>of</strong> the system f<strong>in</strong>d andreplaces all the collocations us<strong>in</strong>g the lexicon enteries. ACollocation is an expression consist<strong>in</strong>g <strong>of</strong> two or morewords that correspond to some conventional way <strong>of</strong>say<strong>in</strong>g th<strong>in</strong>gs. Or <strong>in</strong> the other words <strong>of</strong> Firth (1957:181) :“Collocations <strong>of</strong> a given word are statements <strong>of</strong> thehabitual or customary places <strong>of</strong> that word”. This modulehelps <strong>in</strong> <strong>in</strong>creas<strong>in</strong>g the accuracy <strong>of</strong> the translation.Generat<strong>in</strong>g Lexicon for Collocations is itself achalleng<strong>in</strong>g task. Then comes the turn <strong>of</strong> the heart <strong>of</strong> thesystem – word for word translation uses the lexicon. Thissearch for the H<strong>in</strong>di word <strong>in</strong> the lexicon and replaces itwith the correspond<strong>in</strong>g Punjabi translated version present<strong>in</strong> the lexicon. If this H<strong>in</strong>di word is not found <strong>in</strong> thelexicon it searches that word <strong>in</strong> the database <strong>of</strong>ambiguous words, if found us<strong>in</strong>g tri-gram approach itresolves the ambiguity <strong>of</strong> word and replaces it withcorrect Punjabi mean<strong>in</strong>g among multiple Punjabimean<strong>in</strong>gs. For Example, the h<strong>in</strong>di word सरूप can betranslated <strong>in</strong>to either <strong>of</strong> the two Punjabi words - ਸਮਾਨ,ਸੁ ੰ ਦਰ. But how will the system decide which word tochoose is basically to know the context <strong>in</strong> which theH<strong>in</strong>di word सरूप has been used <strong>in</strong> the sentence. If theword is not found <strong>in</strong> both the tables it means it is notavailable <strong>in</strong> the database and need to be transliterated.For improv<strong>in</strong>g the accuracy <strong>of</strong> the system, this is must toknow the system about which new words have beencome across and if they have been transliteratedaccurately or not. If they were not present <strong>in</strong> the databaseand need to be present, it is added to lexicon for futuretranslations. If it has been translated wrongly butrequired one, it is corrected first before add<strong>in</strong>g to thelexicon. In this way this is the ongo<strong>in</strong>g improvement <strong>of</strong>the system performance dur<strong>in</strong>g every translation exercisethrough mach<strong>in</strong>e learn<strong>in</strong>g module. Post Process<strong>in</strong>gModule takes <strong>in</strong>to consideration some commongrammatical mistakes that has been done dur<strong>in</strong>gtranslation phases and based on the rules framed, itremoves those mistakes and <strong>in</strong>creases the accuracy to thesystem. Now system has been tra<strong>in</strong>ed a lot by number <strong>of</strong>translation exercises, it is time to check the accuracy <strong>of</strong>the system by test<strong>in</strong>g the system through test data otherthan the data used for tra<strong>in</strong><strong>in</strong>g. Test<strong>in</strong>g the system is alsovery tedious task. First step <strong>in</strong> it is to prepare the testcases that covers all the possibilities.V. WEB BASED TOOLResearch must not be restricted to papers, It must bepropagated to public for use and test. Tak<strong>in</strong>g this aim, thewhole system has been developed as a web tool and isonl<strong>in</strong>e for use fre <strong>of</strong> cost. The website address ishttp://h2p.learnpunjabi.org/ . Follow<strong>in</strong>g are the features<strong>of</strong> this web tool:a. H<strong>in</strong>di Text can be written <strong>in</strong> Unicode encod<strong>in</strong>gby us<strong>in</strong>g the most popular H<strong>in</strong>di Font Krutidev.This concept is very useful for those who are <strong>in</strong>habit <strong>of</strong> typ<strong>in</strong>g the text <strong>in</strong> Krutidev and laterthey f<strong>in</strong>d some source for convert<strong>in</strong>g them <strong>in</strong>toUnicode encod<strong>in</strong>g. Thus, this feature has solvedtheir purpose <strong>in</strong> very easy manner. Now, theywill type <strong>in</strong> their style and the typed matter willalso be <strong>in</strong> Unicode.b. The text can also be <strong>in</strong>put to the system fortranslation through text file. File can be readus<strong>in</strong>g the Browse button provided.c. Input text can be translated <strong>in</strong>to Punjabi text byjust click<strong>in</strong>g the Translate button. With<strong>in</strong>seconds, the text is translated <strong>in</strong>to Punjabi.© 2010 ACADEMY PUBLISHER


150 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010d. Input Text can be transliterated also, if there isneed by click<strong>in</strong>g on the Transliterate button.e. Email facility has also been provided. Text canbe typed <strong>in</strong> H<strong>in</strong>di and English both. Subject canbe written <strong>in</strong> both the languages. Then whilesend<strong>in</strong>g email there is an option <strong>of</strong> send<strong>in</strong>g theemail <strong>in</strong> orig<strong>in</strong>al or after translat<strong>in</strong>g <strong>in</strong> Punjabi.This is also very powerful feature.f. The ma<strong>in</strong> feature <strong>of</strong> the webtool is user cantranslate the full H<strong>in</strong>di website <strong>in</strong>to Punjabiwebsite by just provid<strong>in</strong>g the l<strong>in</strong>k <strong>of</strong> h<strong>in</strong>diwebsite and press Translate. The h<strong>in</strong>di websiteis translated <strong>in</strong>to Punjabi with<strong>in</strong> seconds andPunjabi version <strong>of</strong> the website is displayed <strong>in</strong>the same format as it was orig<strong>in</strong>ally <strong>in</strong> h<strong>in</strong>diwebsite.VI. SCREEN SHOTSFollow<strong>in</strong>g is the screen shot <strong>of</strong> web based mach<strong>in</strong>etranslation system:A. Input Text:VII. SAMPLE OUTPUTभारत और पड़ोसगुवार, 01 नवंबर, 2007 को 08:02 GMT तक के समाचारकनाटक को लेकर राजनीितक सरगम बढ़कु मारःवामी ने राजनीितक चाल बदलते हुए येदयुरपा कोमुयमंऽी के प म समथन देने का फ़ै सला कया हैकनाटक को लेकर राजनीितक गहमागहमी तेज़ हो गई है औरअब यह मामला दली आ गया है.संभावना है क जद ह कनाटक के राजनीितक भवंय काकोई फ़ै सला हो जाएगा.बुधवार को जहाँ भाजपा के उच ःतरय ूितिनिध मंडल नेूधानमंऽी मनमोहन िसंह से मुलाक़ात क है ूधानमंऽी औरसोिनया गाँधी ने कांमेस कोरमुप क बैठक म कनाटक केराजनीितक हालात पर चचा क है.उधर भाजपा ने धमक द है क यद भाजपा-जनतादल (एस)को सरकार बनाने के िलए आमंऽत नहं कया गया तो दोनदल के 129 वधायक रापित के सामने परेड करगे.उलेखनीय है क जनता दल (एस) और भाजपा का गठबंधनसात अू बर तक सा म था. लेकन समझौते के अनुसारमुयमंऽी बदले जाने के ववाद के चलते गठबंधन टूट गयाऔर भाजपा ने सरकार से समथन वापस ले िलया.B. Translated Output Text:ਭਾਰਤ ਅਤੇ ਗੁਆੰ ਢਵੀਰਵਾਰ , 01 ਨਵੰ ਬਰ , 2007 ਨੂ ੰ 08 : 02 GMT ਤੱਕ ਦੀਆਂਖ਼ਬਰਕਰਨਾਟਕ ਨੂ ੰ ਲੈਕੇ ਰਾਜਨੀਤਕ ਜੋਸ਼ ਵਿਧਆਕੁਮਾਰਸਵਾਮੀ ਨ ਰਾਜਨੀਤਕ ਚਾਲ ਬਦਲਦੇ ਹੋਏ ਯੇਿਦਉਰੱਪਾ ਨੂ ੰਮੁੱਖਮੰ ਤਰੀ ਦੇ ਰੁਪ ਿਵੱਚ ਸਮਰਥਨ ਦੇਣ ਦਾ ਫੈਸਲਾ ਕੀਤਾ ਹੈਕਰਨਾਟਕ ਨੂ ੰ ਲੈਕੇ ਰਾਜਨੀਤਕ ਗਿਹਮਾਗਿਹਮੀ ਤੇਜ਼ ਹੋ ਗਈ ਹੈ ਅਤੇਹੁਣ ਇਹ ਮਾਮਲਾ ਿਦੱਲੀ ਆ ਿਗਆ ਹੈ .ਸੰ ਭਾਵਨਾ ਹੈ ਿਕ ਜੱਲਦੀ ਹੀ ਕਰਨਾਟਕ ਦੇ ਰਾਜਨੀਤਕ ਭਿਵੱਖ ਦਾਕੋਈ ਫੈਸਲਾ ਹੋ ਜਾਵੇਗਾ .ਬੁੱਧਵਾਰ ਨੂ ੰ ਿਜੱਥੇ ਭਾਜਪਾ ਦੇ ਚ ਪੱਧਰ ਪਿਤਿਨੱਧੀ ਮੰ ਡਲ ਨਪਧਾਨਮੰ ਤਰੀ ਮਨਮੋਿਹਨ ਿਸੰ ਘਨਾਲ ਮੁਲਾਾਤ ਕੀਤੀ ਹੈਪਧਾਨਮੰ ਤਰੀ ਅਤੇ ਸੋਿਨਆ ਗਧੀ ਨ ਕਗਰਸ ਕੋਰਗਰੁਪ ਦੀ ਬੈਠਕਿਵੱਚ ਕਰਨਾਟਕ ਦੇ ਰਾਜਨੀਤਕ ਹਾਲਾਤ ਤੇ ਚਰਚਾ ਕੀਤੀ ਹੈ .ਓਧਰ ਭਾਜਪਾ ਨ ਧਮਕੀ ਿਦੱਤੀ ਹੈ ਿਕ ਜੇਕਰ ਭਾਜਪਾ - ਜਨਤਾਦਲ (ਏਸ ) ਨੂ ੰ ਸਰਕਾਰ ਬਣਾਉਣ ਲਈ ਸੱਿਦਆ ਨਹ ਕੀਤਾ ਿਗਆ ਤ ਦੋਨਦਲ ਦੇ 129 ਿਵਧਾਇਕ ਰਾਸ਼ਟਰਪਤੀ ਦੇ ਸਾਹਮਣੇ ਪਰੇਡ ਕਰਣਗੇ .ਿਲਖਣ ਯੋਗ ਹੈ ਿਕ ਜਨਤਾ ਦਲ ( ਏਸ ) ਅਤੇ ਭਾਜਪਾ ਦਾ ਗੰ ਢ-ਜੋੜਾਸੱਤ ਅਕਤੂਬਰ ਤੱਕ ਸੱਤਾ ਿਵੱਚ ਸੀ . ਪਰ ਸਮੱਝੌਤੇ ਦੇ ਅਨੁਸਾਰਮੁੱਖਮੰ ਤਰੀ ਬਦਲੇ ਜਾਣ ਦੇ ਝੱਗੜਾ ਦੇ ਚੱਲ ਦੇ ਗੰ ਢ-ਜੋੜਾ ਟੁੱਟ ਿਗਆਅਤੇ ਭਾਜਪਾ ਨ ਸਰਕਾਰ ਨਾਲ ਸਮਰਥਨ ਵਾਪਸ ਲੈ ਿਲਆ .The accuracy <strong>of</strong> the translation comes out be approx.95%.VIII. CONCLUSIONThe present system is translat<strong>in</strong>g any complexsentence. The System accuracy is measured up to 95%.This web tool has number <strong>of</strong> applications <strong>in</strong> real world.This web tool can be used by Newspaper agencies, anywebsite owner, us<strong>in</strong>g email facilty by community <strong>of</strong>different countries or regions i.e. Writ<strong>in</strong>g the email <strong>in</strong>H<strong>in</strong>di and recipient will receive the email <strong>in</strong> Punjabi.Thus remov<strong>in</strong>g the language bars, communicationbecomes easy <strong>in</strong> one’s owm language.© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 151REFERENCES1. Kemal Alt<strong>in</strong>tas, Dept. <strong>of</strong> Computer Eng<strong>in</strong>eer<strong>in</strong>g, BilkentUniversity, Ankara, Turkey, “A Mach<strong>in</strong>e TranslationSystem Between a Pair <strong>of</strong> Closely Related Languages”.Internet:http://www.cs.bilkent.edu.tr/~ilyas/PDF/iscis2002.pdf2. Bharati A., Chaitanya V and Sangal R, "Natural Languageprocess<strong>in</strong>g: A Pan<strong>in</strong>ian Perspective", Prentice Hall <strong>of</strong> India,New Delhi, 1995.3. Joseph Seasly, “Mach<strong>in</strong>e Translation: A Survey <strong>of</strong>Approaches”, University <strong>of</strong> Michigan, Ann Arbor, 2003.4. Durgesh Rao, “Mach<strong>in</strong>e Translation <strong>in</strong> India: A briefsurvey”, National Centre for S<strong>of</strong>tware Technology,Mumbai, 2001. Internet:http://www.eldra.fr/en/rproj/scalla/SCALLA2001Rao.pdf5. R.M.K. S<strong>in</strong>ha, R. Ja<strong>in</strong> and A. Ja<strong>in</strong> "Translation from Englishto Indian Languages: ANGLABHARTI Approach",Proceed<strong>in</strong>g <strong>of</strong> STRANS-2002, pp. 69-85, 2002.6. Christopher D. Mann<strong>in</strong>g and H<strong>in</strong>rich Schutze, “Foundations<strong>of</strong> Statistical Natural Language Process<strong>in</strong>g”, MITPress,1999.7. Manish S<strong>in</strong>ha, Mahesh Kumar Reddy, PushpakBhattacharya, “H<strong>in</strong>di Word Sense Disambiguation”.Internet:http://www.cse.iiitb.ac.<strong>in</strong>/Pb/papers/H<strong>in</strong>diWSD.pdf8. R. Canals-Marote, A. Esteve-Guillén, A. Garrido-Alenda,M.I. Guardiola-Savall, A. Iturraspe-Bellver, S. Montserrat-Buendia, S. Ortiz-Rojas, H. Pastor-P<strong>in</strong>a, P.M. Pérez-Antón,and M.L. Forcada, “The Spanish_ Catalan mach<strong>in</strong>etranslation system <strong>in</strong>terNOSTRUM”, Internet:http://<strong>in</strong>ternostrum.com/docum/iN-MTS.pdf9. Kemal Alt<strong>in</strong>tas, Ilyas Cicekli,”A Mach<strong>in</strong>e TranslationSystem Between a Pair <strong>of</strong> Closely Related Languages”,Internet:http://www.cs.bilkent.edu.tr/~ilyas/PDF/iscis2002.pdf10. Kev<strong>in</strong> P. Scannell ,”Mach<strong>in</strong>e translation for closely relatedlanguage pairs” Internet: http://borel.slu.edu/pub/ga2gd.pdf11. Jan AJIC, Jan HRIC, Vladislav KUBON, “CESILKO – anMT system for closely related languages”, Internet:http://www.cs.ust.hk/acl2000/Demo/03_kubon.pdf© 2010 ACADEMY PUBLISHER


152 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010Protect<strong>in</strong>g Data From the Cyber Theft – AVirulent Disease1 Dr. S.N. Panda and 2 Vikram Mangla1 Pr<strong>of</strong>essor & Pr<strong>in</strong>cipal, 2 Assistant Pr<strong>of</strong>essor1 RIMT-IMCT, Mandi Gob<strong>in</strong>d Garh, Punjab.2 Chitkara Institue <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g & Technology, Rajpura, Punjab.1 panda.<strong>in</strong>dia@gmail.com, 2 mangla.vikram@gmail.comAbstract - Network security policies are essential elements <strong>in</strong>Internet security. Network security perimeter devices suchas firewalls, IPSec, and IDS/IPS devices operate based onlocally configured policies. Malware-related data breacheshave reached pandemic proportions as crim<strong>in</strong>als discoverthat Internet crime is easy to commit, highly lucrative, andlargely under-policed. With a few hundred dollars, a cybercrim<strong>in</strong>al can beg<strong>in</strong> a career <strong>of</strong> break<strong>in</strong>g <strong>in</strong>to computers tosteal identity and confidential data for sale to the highestbidder. This paper will cover current and emerg<strong>in</strong>g trends <strong>of</strong>stealth malware, such as mov<strong>in</strong>g primarily to the <strong>Web</strong> s<strong>in</strong>cemost organizations allow <strong>Web</strong> traffic <strong>in</strong>to the network. Itwill also cover new advances <strong>in</strong> network securitytechnologies that use multi-phase heuristic and virtualmach<strong>in</strong>e analysis to detect and mitigate the damages thatresult from malware-related data thefts.Index Terms - Network Security, <strong>Web</strong> Threats, Malware,Phish<strong>in</strong>gI. INTRODUCTIONWith the global connectivity provided by the Internet,network security has ga<strong>in</strong>ed significant attention <strong>in</strong>research and Industrial communities. Due to the<strong>in</strong>creas<strong>in</strong>g threats <strong>of</strong> network attacks, network securitydevices such like firewalls and IPSec gatewaye havebecome important <strong>in</strong>tegrated elements not only <strong>in</strong>enterprise networks but also <strong>in</strong> small size and homenetworks. Motivated by the lure <strong>of</strong> pr<strong>of</strong>its from the sale <strong>of</strong>stolen confidential <strong>in</strong>formation, cyber crim<strong>in</strong>als today areshift<strong>in</strong>g to the <strong>Web</strong> as their chosen attack vector, whichprovides an ideal environment for cyber crime. Malwarerelateddata breaches have reached pandemic proportionsas crim<strong>in</strong>als discover that Internet crime is easy tocommit, highly lucrative, and largely under-policed. Witha few hundred dollars, a cyber crim<strong>in</strong>al can beg<strong>in</strong> a career<strong>of</strong> break<strong>in</strong>g <strong>in</strong>to computers to steal identity andconfidential data for sale to the highest bidder. Fraudsterswho purchase the data have developed a variety <strong>of</strong>schemes to monetize that <strong>in</strong>formation rang<strong>in</strong>g fromtransact<strong>in</strong>g unauthorized stock trades to transferr<strong>in</strong>g fundsto <strong>of</strong>fshore bank accounts. The cyber crime economy is sorobust that there is a vibrant market for pr<strong>of</strong>essionalmalware toolkits available for $500 to $1,000 and comepre-configured with a range <strong>of</strong> attack modules, exploit‘ma<strong>in</strong>tenance’ updates, and 24 x 7 onl<strong>in</strong>e technicalsupport.Many <strong>Web</strong> threats can be deployed unbeknownst to theuser, requir<strong>in</strong>g no additional action than merely open<strong>in</strong>g a<strong>Web</strong> page. Large numbers <strong>of</strong> users, an assortment <strong>of</strong>technologies, and a complex network structure providecrim<strong>in</strong>als with the targets, exploitable weaknesses, andanonymity required for large-scale fraud. <strong>Web</strong> threatspose a broad range <strong>of</strong> risks, <strong>in</strong>clud<strong>in</strong>g f<strong>in</strong>ancial damages,identity theft, and loss <strong>of</strong> confidential bus<strong>in</strong>ess<strong>in</strong>formation, theft <strong>of</strong> network resources, damaged brand orpersonal reputation, and erosion <strong>of</strong> consumer confidence<strong>in</strong> e-commerce. These high stakes, the pervasive use <strong>of</strong>the <strong>Web</strong>, and the complexity <strong>of</strong> protect<strong>in</strong>g aga<strong>in</strong>st <strong>Web</strong>threats comb<strong>in</strong>e to form perhaps the greatest challenge toprotect<strong>in</strong>g personal and bus<strong>in</strong>ess <strong>in</strong>formation <strong>in</strong> a decade.In August 2007, a scene played out as cyber crim<strong>in</strong>als<strong>in</strong>filtrated the monster.com job site through “Monster forEmployers” accounts, compromis<strong>in</strong>g the personal<strong>in</strong>formation <strong>of</strong> 1.6 million users. Many <strong>of</strong> these users thenreceived <strong>of</strong>ficial-look<strong>in</strong>g emails, claim<strong>in</strong>g to be frommonster.com and encourag<strong>in</strong>g them to download a “helperapplication” that turned out to be yet more malware.These attacks were well-researched, us<strong>in</strong>g familiarlanguage and brand<strong>in</strong>g, and coded to transfer data slowly,under the radar <strong>of</strong> IT adm<strong>in</strong>istrators look<strong>in</strong>g for suspiciousnetwork traffic.[1] <strong>Web</strong> threats also <strong>in</strong>clude malware thatis downloaded from an email attachment, but accesses the<strong>Web</strong> to convey <strong>in</strong>formation to the hacker. In 2007,fraudulent emails were sent purport<strong>in</strong>g to be from theFederal Trade Commission. These emails claimed that acompla<strong>in</strong>t had been filed aga<strong>in</strong>st the company andconta<strong>in</strong>ed an attachment. If the recipient opened theattachment, a keylogg<strong>in</strong>g Trojan was deployed thatattempted to steal log<strong>in</strong> <strong>in</strong>formation from the user’scomputer and send it back to the hacker. [2].Phish<strong>in</strong>g is a prevalent <strong>Web</strong> threat, spo<strong>of</strong><strong>in</strong>g legitimatecompanies to trick people <strong>in</strong>to provid<strong>in</strong>g confidential<strong>in</strong>formation. Consumer phish<strong>in</strong>g is wide-spread, send<strong>in</strong>gemails that spo<strong>of</strong> organizations like banks and on-l<strong>in</strong>eretailers. These phish<strong>in</strong>g emails <strong>of</strong>ten use l<strong>in</strong>ks to takerecipients to <strong>Web</strong> sites where confidential <strong>in</strong>formation isgathered. Employees can fall victim to these consumerthreats, but phish<strong>in</strong>g can also affect corporations moredirectly. In 2005, phish<strong>in</strong>g emails targeted CEOs andother high-level executives <strong>of</strong> US credit unions <strong>in</strong> anattempt to ga<strong>in</strong> control <strong>of</strong> millions <strong>of</strong> personal f<strong>in</strong>ancialrecords. The email messages conta<strong>in</strong>ed a l<strong>in</strong>k to a <strong>Web</strong>site where a Trojan was downloaded. Even one successful© 2010 ACADEMY PUBLISHERdoi:10.4304/jetwi.2.2.152-155


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 153<strong>in</strong>fection could have caused millions <strong>of</strong> dollars <strong>of</strong> damageand caused irreparable harm to hundreds <strong>of</strong> thousands <strong>of</strong>users through identity and asset theft. [3]But <strong>Web</strong> threats don’t just steal confidential<strong>in</strong>formation; they can also steal network resources.Variations <strong>of</strong> e-greet<strong>in</strong>g card spam were sent throughout2007. These simple spam messages told recipients that afriend had sent them an e-greet<strong>in</strong>g card and to follow thel<strong>in</strong>k <strong>in</strong> the email to view the card. If recipients followedthe l<strong>in</strong>k, it took them to a <strong>Web</strong> site that downloadedmalicious code.This code hijacked the computer, turn<strong>in</strong>g it <strong>in</strong>to a “bot”and allow<strong>in</strong>g the hackers to use the mach<strong>in</strong>e for their ownpurposes—send<strong>in</strong>g spam, host<strong>in</strong>g malicious <strong>Web</strong> sites,and much more. Consumer and corporate computers were<strong>in</strong>fected by the millions. Hackers network these <strong>in</strong>fectedcomputers to create botnets, steal<strong>in</strong>g resources and furtherperpetuat<strong>in</strong>g their fraudulent activities.II. WEB THREATS DEFINED<strong>Web</strong> threats are any threat that uses the <strong>Web</strong> t<strong>of</strong>acilitate cyber crime. They are sophisticated <strong>in</strong> theirmethods, us<strong>in</strong>g multiple types <strong>of</strong> malware and fraud, all <strong>of</strong>which utilize HTTP or HTTPS protocols, but can alsoemploy other protocols as components <strong>of</strong> the attack, suchas l<strong>in</strong>ks <strong>in</strong> email or IM, or malware <strong>in</strong> attachments or onservers that access the <strong>Web</strong>. The creators <strong>of</strong> such threatsfrequently update <strong>Web</strong> site content, variants, and malwaretypes <strong>in</strong> order to evade detection and achieve greatersuccess.<strong>Web</strong> threats based on malware are hidden with<strong>in</strong> <strong>Web</strong>pages and victims are <strong>in</strong>fected when they visit the page.Fraudulent sites mimic legitimate bus<strong>in</strong>ess <strong>Web</strong> sites anduse social eng<strong>in</strong>eer<strong>in</strong>g to request visitors to discloseconfidential <strong>in</strong>formation. Individuals once characterizedas hackers, virus writers, spammers, and spy ware makersare now simply known as cyber crim<strong>in</strong>als with f<strong>in</strong>ancialpr<strong>of</strong>it their primary aim.Over the last 15 years, <strong>in</strong>formation security threatshave evolved through a series <strong>of</strong> <strong>in</strong>carnations. In eachcase, malware writers and fraudsters sought out themedium that was most used and least protected (forexample email). Today, a new wave <strong>of</strong> threats is emerg<strong>in</strong>gthat uses the <strong>Web</strong> as a delivery vehicle. These <strong>Web</strong> threatsare ga<strong>in</strong><strong>in</strong>g traction at a time when the <strong>Web</strong> has become amajor commerce eng<strong>in</strong>e as well as social network<strong>in</strong>gvehicle, with usage cont<strong>in</strong>u<strong>in</strong>g to grow.At the same time, the <strong>Web</strong> is relatively unprotected,compared to messag<strong>in</strong>g for example, as a medium todeliver malware and conduct fraud. Accord<strong>in</strong>g to IDC,“Up to 30% <strong>of</strong> companies with 500 or more staff havebeen <strong>in</strong>fected as a result <strong>of</strong> Internet surf<strong>in</strong>g, while only20%-25% <strong>of</strong> the same companies experienced viruses andworms from emails.” [4]III. WEB THREAT DELIVERY MECHANISMS<strong>Web</strong> threats can be divided <strong>in</strong>to two primarycategories, based on delivery method – push and pull.Push based threats use spam, phish<strong>in</strong>g, or other fraudulentmeans to lure a user to a malicious (<strong>of</strong>ten spo<strong>of</strong>ed) <strong>Web</strong>site, which then collects <strong>in</strong>formation and/or <strong>in</strong>jectsmalware. Push attacks use phish<strong>in</strong>g, DNS poison<strong>in</strong>g (orpharm<strong>in</strong>g), and other means to appear to orig<strong>in</strong>ate from atrusted source. Their creators have researched their targetwell enough to spo<strong>of</strong> corporate logos, <strong>of</strong>ficial <strong>Web</strong> sitecopy, and other conv<strong>in</strong>c<strong>in</strong>g evidence to <strong>in</strong>crease theappearance <strong>of</strong> authenticity. Precisely-targeted push-basedthreats are <strong>of</strong>ten called “spear phish<strong>in</strong>g” to reflect thefocus <strong>of</strong> their data gather<strong>in</strong>g (“phish<strong>in</strong>g”) attack.Spear phish<strong>in</strong>g typically targets specific <strong>in</strong>dividualsand groups for f<strong>in</strong>ancial ga<strong>in</strong>. In November 2006, amedical center fell victim to a spear phish<strong>in</strong>g attack.Employees <strong>of</strong> the medical center received an email tell<strong>in</strong>gthem they had been laid <strong>of</strong>f. The email also conta<strong>in</strong>ed al<strong>in</strong>k that claimed to take the recipient to a careercounsel<strong>in</strong>g site. Recipients that followed the l<strong>in</strong>k were<strong>in</strong>fected by a keylogg<strong>in</strong>g Trojan. [5] In other push-basedthreats, malware authors use social eng<strong>in</strong>eer<strong>in</strong>g such asentic<strong>in</strong>g email subject l<strong>in</strong>es that reference holidays,popular personalities, sports, pornography, world events,and other popular topics to persuade recipients to open theemail and follow l<strong>in</strong>ks to malicious sites or openattachments with malware that accesses the <strong>Web</strong>.Pull-based threats are <strong>of</strong>ten referred to as “drive-by”threats, s<strong>in</strong>ce they can affect any visitor, regardless <strong>of</strong>precautions. Pull threat developers <strong>in</strong>fect legitimate <strong>Web</strong>sites, which unknow<strong>in</strong>gly transmit malware to visitors oralter search results to take users to malicious sites. Uponload<strong>in</strong>g the page, the user’s browser passively runs amalware downloader <strong>in</strong> a hidden HTML frame (IFRAME)without any user <strong>in</strong>teraction. Both push- and pull-based<strong>Web</strong> threat variants target <strong>in</strong>fection at a regional or locallevel (for example, via local language sites aimed atparticular demographics), rather than us<strong>in</strong>g the mass<strong>in</strong>fection technique <strong>of</strong> many earlier malware approaches.These threats typically take advantage <strong>of</strong> Internet port 80,which is almost always open to permit access to the<strong>in</strong>formation, communication, and productivity that the<strong>Web</strong> affords to employees.IV. TODAY’S INSIDER - THREAT IS STEALTH MALWARELaw enforcement, computer crime experts, and eventhe military are play<strong>in</strong>g catch up to the threat posed toconsumers, bus<strong>in</strong>esses, and national security as cybercrim<strong>in</strong>als cash <strong>in</strong> on stolen identity data, fraudulent onl<strong>in</strong>etransactions, and cyber espionage. It is no surprise that therise <strong>in</strong> cyber crime has co<strong>in</strong>cided with the <strong>in</strong>creased use <strong>of</strong>the Internet and especially “<strong>Web</strong> 2.0” technologies.<strong>Web</strong> sites and applications now support usercontributedcontent, syndicated content, iframes, thirdpartywidgets (or applets), and convoluted advertis<strong>in</strong>gdistribution networks <strong>in</strong>to which ‘stealth’ malware caneasily be <strong>in</strong>jected somewhere along the l<strong>in</strong>e. In a 2007USENIX paper, Google researchers determ<strong>in</strong>ed thatapproximately 9% <strong>of</strong> all suspicious web sites launched“drive-by” downloads <strong>of</strong> stealth malware b<strong>in</strong>aries[12].Government studies[13] estimate that 65% <strong>of</strong> all exploits© 2010 ACADEMY PUBLISHER


154 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010now enter via the <strong>Web</strong> and IBM Internet Security Systems(ISS) estimates that nearly 100% <strong>of</strong> <strong>Web</strong> attacks nowutilize obfuscated JavaScript as a very effective techniqueto bypass antivirus and <strong>in</strong>trusion prevention.Today, once a PC is <strong>in</strong>fected with stealth malware, ittypically opens two-way communications to a “commandand control” (C&C) server to establish a channel back tothe cyber crim<strong>in</strong>al. This allows the “bot” (as <strong>in</strong> “robotcomputer”) to report status as well as any valuable<strong>in</strong>formation that is immediately accessible. Groups <strong>of</strong>these remotely controlled, malware-<strong>in</strong>fected computersare commonly called botnets, and serve as the foundation<strong>of</strong> most cybercrime on the Internet.How do victims get <strong>in</strong>fected? A user may be drawn bya phish<strong>in</strong>g e-mail to a <strong>Web</strong> site hosted on a hijackedserver, which serves up a browser exploit; this downloadsand <strong>in</strong>stalls a bot on the user’s PC. The bot thendownloads more malware like “keyloggers” that silentlyrecord keyboard and mouse activities to execute furthercrim<strong>in</strong>al activities, such as steal<strong>in</strong>g user credentials andcaptur<strong>in</strong>g other sensitive <strong>in</strong>formation. All <strong>of</strong> this takesplace without the knowledge <strong>of</strong> the user or adm<strong>in</strong>istrator.As their prevalence has <strong>in</strong>creased, remote-controlmalware/botnets have become serious concerns forsecurity adm<strong>in</strong>istrators.The recent January, 2009 malware-related data thefts atHeartland Payment Systems and earlier malwareRecent Research[14] Has Found:11 % <strong>of</strong> the world’s computers are enmeshed <strong>in</strong> at leastone botnet23 % <strong>of</strong> home computers become <strong>in</strong>fected despite hav<strong>in</strong>gsecurity enabled72 % <strong>of</strong> corporate networks larger than 100 PC’s have an<strong>in</strong>fection<strong>in</strong>filtrations at Hannaford Supermarkets, University <strong>of</strong>Florida Medical Center, and NASA underscore theescalat<strong>in</strong>g threat <strong>of</strong> malware-related data breaches. TheIdentity Theft Resource Center, a nonpr<strong>of</strong>it group focusedon understand<strong>in</strong>g and prevent<strong>in</strong>g identity theft, reportedthat 656 known security breaches had taken place <strong>in</strong> 2008,reflect<strong>in</strong>g a 47 percent <strong>in</strong>crease over 2007’s total. As <strong>of</strong>March 17, 2009 the resource center had already reported110 breaches <strong>in</strong> 2009.V. STEALTH MALWARE ATTACKS ARE OUTMANEUVERINGCONVENTIONAL DEFENSESDefend<strong>in</strong>g corporate networks from today’s malwarerelateddata thefts requires modern protection that goesbeyond current signature- and heuristic-based detectiontechniques. Modern threats exploit the <strong>in</strong>ability <strong>of</strong>conventional network protection to provide a unifieddefense aga<strong>in</strong>st a crim<strong>in</strong>al who attacks on multiple fronts,from OS and browser vulnerabilities to social eng<strong>in</strong>eer<strong>in</strong>g.The anachronistic concept <strong>of</strong> detect<strong>in</strong>g <strong>in</strong>fections with as<strong>in</strong>gle technique, such as signatures, has left manybus<strong>in</strong>esses and consumers open to attack, despite theirdeployment <strong>of</strong> antivirus and IPS (<strong>in</strong>trusion preventionsystems). The sheer volume and escalat<strong>in</strong>g danger <strong>of</strong>modern attacks are overwhelm<strong>in</strong>g limited IT resourcesand outmaneuver<strong>in</strong>g conventional defenses that mayalready be <strong>in</strong> place. To enable a more efficient IT securityprocess, accurate and timely identification <strong>of</strong> <strong>in</strong>fectedmach<strong>in</strong>es is the first step <strong>in</strong> prevent<strong>in</strong>g malware-relateddata breaches. And, the only viable solutions are thosethat provide thorough coverage across the many vectorsthat are used <strong>in</strong> attacks.VI. CONVENTIONAL APPROACHES FAIL TO PROTECTAGAINST WEB THREATS<strong>Web</strong> threat scann<strong>in</strong>g has specific requirements that arenot met by the traditional approach to virus scann<strong>in</strong>g.Conventional antivirus s<strong>of</strong>tware <strong>in</strong>stalled on clientmach<strong>in</strong>es, for example, while crucial to the protection <strong>of</strong>these mach<strong>in</strong>es from a variety <strong>of</strong> threats, does notadequately protect aga<strong>in</strong>st the evolv<strong>in</strong>g set <strong>of</strong> <strong>Web</strong> threats.One reason is that the conventional approach to virusprotection <strong>in</strong>volves collect<strong>in</strong>g samples <strong>of</strong> viruses,develop<strong>in</strong>g patterns, and quickly distribut<strong>in</strong>g thesepatterns to users. Because many <strong>Web</strong> threats are targetedattacks and span many variants, collect<strong>in</strong>g samples isalmost impossible.The large numbers <strong>of</strong> variants use multiple deliveryvehicles (for example, spam, <strong>in</strong>stant messag<strong>in</strong>g, and <strong>Web</strong>sites), render<strong>in</strong>g the conventional sample collection,pattern creation, and deployment process <strong>in</strong>sufficient.Another reason that conventional virus detectionprocesses fall short <strong>in</strong>volves a fundamental differencebetween these viruses and evolv<strong>in</strong>g <strong>Web</strong> threats.Conventional viruses were fundamentally designed tospread as quickly as possible, and were therefore <strong>of</strong>teneasy to spot. With the advent <strong>of</strong> <strong>Web</strong> threats, malware hasevolved from this outbreak model to stealthy “sleeper”<strong>in</strong>fections that are therefore difficult to detect viaconventional antivirus techniques.Recover<strong>in</strong>g from <strong>in</strong>fections also presents newchallenges. In some cases, <strong>Web</strong> threats may result <strong>in</strong> asystem <strong>in</strong>fection that is so extensive (for example, via arootkit <strong>in</strong> which the system file is replaced) thatconventional un<strong>in</strong>stall or system clean<strong>in</strong>g approachesbecome useless. Infected systems <strong>of</strong>ten require a completesystem recovery, <strong>in</strong> which the hard drive is wiped and theoperat<strong>in</strong>g system, applications, and user data arere<strong>in</strong>stalled.VII. FUTURE WORKA New Approach Is Needed: Integrated, Multi-Layered Protection - Clearly, users need a newapproach to address<strong>in</strong>g <strong>Web</strong> threats that complementsexist<strong>in</strong>g techniques.The most effective approach willemploy multiple layers <strong>of</strong> protection and <strong>in</strong>corporate arange <strong>of</strong> protective measures. In addition, the evolv<strong>in</strong>gnature <strong>of</strong> the threat necessitates some form <strong>of</strong> <strong>in</strong>formationfeedback and <strong>in</strong>tegration, <strong>in</strong> which <strong>in</strong>formation gathered<strong>in</strong> one portion <strong>of</strong> the protection network is used to update<strong>in</strong>formation <strong>in</strong> other layers. Any effective approach© 2010 ACADEMY PUBLISHER


JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 155should also address all relevant protocols, because <strong>Web</strong>threats leverage multiple protocols <strong>in</strong> their attacks, <strong>in</strong>particular email as the <strong>in</strong>itial delivery mechanism and the<strong>Web</strong> as the threat host. However, other mechanisms canalso help perpetrate attacks such as l<strong>in</strong>ks <strong>in</strong> IM and<strong>in</strong>fected files.Coord<strong>in</strong>at<strong>in</strong>g measures requires efficient, centralizedmanagement <strong>of</strong> region-specific expertise to help addressthe regional, and even localized nature <strong>of</strong> many <strong>of</strong> thethreats. The key to effectively address<strong>in</strong>g <strong>Web</strong> threats is amulti-layered approach. The network po<strong>in</strong>ts arecategorized <strong>in</strong> four different layers (see Figure 2): 1) “<strong>in</strong>the-cloud”(i.e. before the traffic reaches the Internetgateway), 2) at the Internet gateway, 3) across the networkservers, 4) and at the endpo<strong>in</strong>t (for example, the client). Inthe below example, the description uses the po<strong>in</strong>ts <strong>in</strong> thenetwork for high level organization and describes theprotocol protection and security technologies that can bedeployed at these po<strong>in</strong>ts. The subsections on protocolprotection and security technologies describe emailsolutions first, which is <strong>of</strong>ten the first step <strong>in</strong> a <strong>Web</strong> threatattack, followed by <strong>Web</strong> solutions that directly protect<strong>Web</strong> usage.A multi-layered approach is needed to protect aga<strong>in</strong>stthe broad range <strong>of</strong> <strong>Web</strong> threatsDNA <strong>of</strong> an Ideal Solution:Dynamic, real-time detection <strong>of</strong> threat: F<strong>in</strong>ds thelatest stealth, 0-day attacksAccurate detection: No false positives, and no falsenegativesReturn on security <strong>in</strong>vestment: Easy to <strong>in</strong>stall,manage, support and scaleVIII. CONCLUSION<strong>Web</strong> threats are prevalent today and are grow<strong>in</strong>g <strong>in</strong>numbers and impact. Their complexity, large number <strong>of</strong>variants, and use <strong>of</strong> multiple vectors, comb<strong>in</strong>ed with theirexploitation <strong>of</strong> the most commonly used medium today -the <strong>Web</strong> - make <strong>Web</strong> threats the most challeng<strong>in</strong>g threatthat consumers, bus<strong>in</strong>esses, and services providers, havefaced <strong>in</strong> a long time.Potential costs associated with these threats <strong>in</strong>cludeconfidential <strong>in</strong>formation leakage and theft <strong>of</strong> networkresources, with the adverse impact <strong>of</strong> erosion <strong>of</strong>customers, trust, and brand reputation; regulatory andlegal implications; negative public relations; and loss <strong>of</strong>competitive advantage. Because conventional approachesfail to protect aga<strong>in</strong>st <strong>Web</strong> threats, the <strong>in</strong>formationsecurity <strong>in</strong>dustry is at a crossroads. Bus<strong>in</strong>esses <strong>of</strong> all sizes,as well as service providers, need to deploy solutions viaan <strong>in</strong>tegrated, multi-layered approach to provide real-time,comprehensive protection aga<strong>in</strong>st these threats.REFERENCES1. Gregg Keizer, Computerworld, August 19, 2007, “Identityattack spreads; 1.6M records stolen from Monster.com,”http://computerworld.com/action/article.do?command=viewArticleBasic&articleId=9031418&pageNumber=1.2. Dan Kaplan, SC Magaz<strong>in</strong>e, October 30, 2007, “FTC SpamConta<strong>in</strong>s Keylogg<strong>in</strong>g Trojan”,http://www.scmagaz<strong>in</strong>eus.com/FTC-spam-conta<strong>in</strong>skeylogg<strong>in</strong>g-trojan/article/58273/3. Paul F. Roberts, eWeek.com, December 16, 2005, “SpearPhish<strong>in</strong>g Attack Targets Credit Unions,”http://www.eweek.com/article2/0,1895,1902896,00.asp.4. IDC, press release, July 18, 2006, “Private Internet Use byStaff Threatens IT Security <strong>in</strong> Danish Companies, SaysIDC,”http://www.idc.com/getdoc.jsp?conta<strong>in</strong>erId=pr2006_07_14_125434.5. Cara Garretson, NetworkWorld.com, January 11, 2006,“Spam that Delivers a P<strong>in</strong>k Slip”http://www.networkworld.com/news/2006/110106-spamspear-phish<strong>in</strong>g.html6. Gregg Keizer, Tech<strong>Web</strong> Technology News, January 24, 2006,“Botnet Creator Pleads Guilty, Faces 25 Years,”http://www.techweb.com/wire/security/177103378.7. Marius Oiaga, S<strong>of</strong>tpedia, October 4, 2006, “Hack<strong>in</strong>g RussianTrio Gets 24 Years <strong>in</strong> Prison,”http://news.s<strong>of</strong>tpedia.com/news/Hack<strong>in</strong>g-Russian-Trio-Gets-24-Years-<strong>in</strong>-Prison-37149.shtml.8. Byron Acohido and Jon Swartz, USA TODAY “Cybercrimeflourishes <strong>in</strong> onl<strong>in</strong>e hacker forums,” October 11, 2006,http://www.usatoday.com/tech/news/computersecurity/<strong>in</strong>fotheft/2006-10-11-cybercrime-hackerforums_x.htm.9. Police <strong>of</strong> the City <strong>of</strong> Munich, August 25, 2006,http://www.sueddeutsche.de/,tt3m3/muenchen/artikel/612/83529.10. Avivah Litan, “Phish<strong>in</strong>g Attacks Escalate, Morph, and CauseConsiderable Damage,” Gartner, December 12, 2007.11. Tom Krazit, Cnet, “Two <strong>in</strong> three retail PCs are notebooks,”December 20, 2006,http://news.com.com/Two+<strong>in</strong>+three+retail+PCs+are+notebooks/2100-1044_3-6144921.html.12. Niels Provos, Dean McNamee, Panayiotis Mavrommatis, KeWang, and Nagendra Modadugu: The Ghost <strong>in</strong> the BrowserAnalysis <strong>of</strong> <strong>Web</strong>-based Malware, May 2007.13 David Barroso, ENISA Position Paper No. 3: Botnets – TheSilent Threat, November 2007,http://www.enisa.europa.eu/doc/pdf/deliverables/enisa_pp_botnets.pdf.14 Panda Security,http://www.pandasecurity.com/homeusers/media/pressreleases/viewnews?noticia=9077© 2010 ACADEMY PUBLISHER


Aims and ScopeCall for Papers and Special Issues<strong>Journal</strong> <strong>of</strong> <strong>Emerg<strong>in</strong>g</strong> <strong>Technologies</strong> <strong>in</strong> <strong>Web</strong> <strong>Intelligence</strong> (JETWI, ISSN 1798-0461) is a peer reviewed and <strong>in</strong>dexed <strong>in</strong>ternational journal, aims atgather<strong>in</strong>g the latest advances <strong>of</strong> various topics <strong>in</strong> web <strong>in</strong>telligence and report<strong>in</strong>g how organizations can ga<strong>in</strong> competitive advantages by apply<strong>in</strong>g thedifferent emergent techniques <strong>in</strong> the real-world scenarios. Papers and studies which couple the <strong>in</strong>telligence techniques and theories with specific webtechnology problems are ma<strong>in</strong>ly targeted. Survey and tutorial articles that emphasize the research and application <strong>of</strong> web <strong>in</strong>telligence <strong>in</strong> a particulardoma<strong>in</strong> are also welcomed. These areas <strong>in</strong>clude, but are not limited to, the follow<strong>in</strong>g:• <strong>Web</strong> 3.0• Enterprise Mashup• Ambient <strong>Intelligence</strong> (AmI)• Situational Applications• <strong>Emerg<strong>in</strong>g</strong> <strong>Web</strong>-based Systems• Ambient Awareness• Ambient and Ubiquitous Learn<strong>in</strong>g• Ambient Assisted Liv<strong>in</strong>g• Telepresence• Lifelong Integrated Learn<strong>in</strong>g• Smart Environments• <strong>Web</strong> 2.0 and Social <strong>in</strong>telligence• Context Aware Ubiquitous Comput<strong>in</strong>g• Intelligent Brokers and Mediators• <strong>Web</strong> M<strong>in</strong><strong>in</strong>g and Farm<strong>in</strong>g• Wisdom <strong>Web</strong>• <strong>Web</strong> Security• <strong>Web</strong> Information Filter<strong>in</strong>g and Access Control Models• <strong>Web</strong> Services and Semantic <strong>Web</strong>• Human-<strong>Web</strong> Interaction• <strong>Web</strong> <strong>Technologies</strong> and Protocols• <strong>Web</strong> Agents and Agent-based Systems• Agent Self-organization, Learn<strong>in</strong>g, and AdaptationSpecial Issue Guidel<strong>in</strong>es• Agent-based Knowledge Discovery• Agent-mediated Markets• Knowledge Grid and Grid <strong>in</strong>telligence• Knowledge Management, Networks, and Communities• Agent Infrastructure and Architecture• Agent-mediated Markets• Cooperative Problem Solv<strong>in</strong>g• Distributed <strong>Intelligence</strong> and Emergent Behavior• Information Ecology• Mediators and Middlewares• Granular Comput<strong>in</strong>g for the <strong>Web</strong>• Ontology Eng<strong>in</strong>eer<strong>in</strong>g• Personalization Techniques• Semantic <strong>Web</strong>• <strong>Web</strong> based Support Systems• <strong>Web</strong> based Information Retrieval Support Systems• <strong>Web</strong> Services, Services Discovery & Composition• Ubiquitous Imag<strong>in</strong>g and Multimedia• Wearable, Wireless and Mobile e-<strong>in</strong>terfac<strong>in</strong>g• E-Applications• Cloud Comput<strong>in</strong>g• <strong>Web</strong>-Oriented ArchitectruesSpecial issues feature specifically aimed and targeted topics <strong>of</strong> <strong>in</strong>terest contributed by authors respond<strong>in</strong>g to a particular Call for Papers or by<strong>in</strong>vitation, edited by guest editor(s). We encourage you to submit proposals for creat<strong>in</strong>g special issues <strong>in</strong> areas that are <strong>of</strong> <strong>in</strong>terest to the <strong>Journal</strong>.Preference will be given to proposals that cover some unique aspect <strong>of</strong> the technology and ones that <strong>in</strong>clude subjects that are timely and useful to thereaders <strong>of</strong> the <strong>Journal</strong>. A Special Issue is typically made <strong>of</strong> 10 to 15 papers, with each paper 8 to 12 pages <strong>of</strong> length.The follow<strong>in</strong>g <strong>in</strong>formation should be <strong>in</strong>cluded as part <strong>of</strong> the proposal:• Proposed title for the Special Issue• Description <strong>of</strong> the topic area to be focused upon and justification• Review process for the selection and rejection <strong>of</strong> papers.• Name, contact, position, affiliation, and biography <strong>of</strong> the Guest Editor(s)• List <strong>of</strong> potential reviewers• Potential authors to the issue• Tentative time-table for the call for papers and reviewsIf a proposal is accepted, the guest editor will be responsible for:• Prepar<strong>in</strong>g the “Call for Papers” to be <strong>in</strong>cluded on the <strong>Journal</strong>’s <strong>Web</strong> site.• Distribution <strong>of</strong> the Call for Papers broadly to various mail<strong>in</strong>g lists and sites.• Gett<strong>in</strong>g submissions, arrang<strong>in</strong>g review process, mak<strong>in</strong>g decisions, and carry<strong>in</strong>g out all correspondence with the authors. Authors should be<strong>in</strong>formed the Instructions for Authors.• Provid<strong>in</strong>g us the completed and approved f<strong>in</strong>al versions <strong>of</strong> the papers formatted <strong>in</strong> the <strong>Journal</strong>’s style, together with all authors’ contact<strong>in</strong>formation.• Writ<strong>in</strong>g a one- or two-page <strong>in</strong>troductory editorial to be published <strong>in</strong> the Special Issue.Special Issue for a Conference/WorkshopA special issue for a Conference/Workshop is usually released <strong>in</strong> association with the committee members <strong>of</strong> the Conference/Workshop like generalchairs and/or program chairs who are appo<strong>in</strong>ted as the Guest Editors <strong>of</strong> the Special Issue. Special Issue for a Conference/Workshop is typically made <strong>of</strong>10 to 15 papers, with each paper 8 to 12 pages <strong>of</strong> length.Guest Editors are <strong>in</strong>volved <strong>in</strong> the follow<strong>in</strong>g steps <strong>in</strong> guest-edit<strong>in</strong>g a Special Issue based on a Conference/Workshop:• Select<strong>in</strong>g a Title for the Special Issue, e.g. “Special Issue: Selected Best Papers <strong>of</strong> XYZ Conference”.• Send<strong>in</strong>g us a formal “Letter <strong>of</strong> Intent” for the Special Issue.• Creat<strong>in</strong>g a “Call for Papers” for the Special Issue, post<strong>in</strong>g it on the conference web site, and publiciz<strong>in</strong>g it to the conference attendees.Information about the <strong>Journal</strong> and Academy Publisher can be <strong>in</strong>cluded <strong>in</strong> the Call for Papers.• Establish<strong>in</strong>g criteria for paper selection/rejections. The papers can be nom<strong>in</strong>ated based on multiple criteria, e.g. rank <strong>in</strong> review process plus theevaluation from the Session Chairs and the feedback from the Conference attendees.• Select<strong>in</strong>g and <strong>in</strong>vit<strong>in</strong>g submissions, arrang<strong>in</strong>g review process, mak<strong>in</strong>g decisions, and carry<strong>in</strong>g out all correspondence with the authors. Authorsshould be <strong>in</strong>formed the Author Instructions. Usually, the Proceed<strong>in</strong>gs manuscripts should be expanded and enhanced.• Provid<strong>in</strong>g us the completed and approved f<strong>in</strong>al versions <strong>of</strong> the papers formatted <strong>in</strong> the <strong>Journal</strong>’s style, together with all authors’ contact<strong>in</strong>formation.• Writ<strong>in</strong>g a one- or two-page <strong>in</strong>troductory editorial to be published <strong>in</strong> the Special Issue.More <strong>in</strong>formation is available on the web site at http://www.academypublisher.com/jetwi/.


(<strong>Contents</strong> Cont<strong>in</strong>ued from Back Cover)<strong>Web</strong><strong>in</strong>ar – Education through Digital CollaborationAnuradha Verma and Anoop S<strong>in</strong>ghEfficient Visual CryptographySupriya A. K<strong>in</strong>gerMultistage Interconnection Networks: a Transition from Electronic to OpticalR<strong>in</strong>kle Rani Aggarwal, Lakhw<strong>in</strong>der Kaur, and Himanshu Aggarwal<strong>Web</strong> Based H<strong>in</strong>di to Punjabi Mach<strong>in</strong>e Translation SystemVishal Goyal and Gurpreet S<strong>in</strong>gh LehalProtect<strong>in</strong>g Data from the Cyber Theft – a Virulent DiseaseS. N. Panda and Vikram Mangla131137142148152

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!