knowledge · information · learning - Forschungszentrum L3S

Knowledge · InformatIon · learnIng 

annual report 2008

2 

PREFACE 

Shaping the Future of the Web 

Providing, processing and using information of all 

kind has dramatically changed during the last 15 

years. Mosaic, one of the first Web browsers, pro- 

vided access to about 200 Web servers in Septem- 

ber 1993. Today, about 160 million Web servers pub- 

lish about 40 billion of Web pages, and most of the 

world’s knowledge is available through the Web and 

its many connected databases and digital libraries. 

Furthermore, the Web has become a highly inter- 

active medium, where users can not only consume, 

but also produce new information, connecting more 

than 2 billion people all over the world. 

FORSCHUNGSZENTRUM L3S L3S RESEARCH CENTER 

Despite or maybe even because of this enormous 

progress, the Web provides more challenges than 15 

years ago. How can I select the most relevant infor- 

mation out of millions of documents, which sources 

are reliable, and how can I combine and aggregate 

information from various sources? More Web 2.0 

user generated content is provided each day than 

traditional content made available through compa-

nies, news agencies and other institutions, making 

author reputation more important but also more 

challenging to check. 

Diversity – implied by the ever increasing multitude 

of information providers – is the reason for diverg- 

ing viewpoints and conflicts, yet is barely recognized 

and not at all supported by the current Web and 

Web Search infrastructure. Clearly, we want to move 

from a Web Search infrastructure which focuses on 

the most popular results for a query to an infrastruc- 

ture which takes bias, opinions and diversity into 

account, to provide a balanced view on all informa- 

tion available on the World Wide Web. 

Such a diversity-aware Web Search infrastructure is 

the goal of the LivingKnowledge project, which we 

are starting in February 2009, together with excel- 

lent partners from academia and industry, includ- 

ing the Yahoo! Barcelona Research Lab. Our Living- 

Knowledge Future Predictor will be able to answer 

factual queries regarding future events and state- 

PREFACE 

ments, based on information available already on 

the Web. Our Media Research Analyser will address 

questions about the public image of a company, pos- 

sibly changing over time, or the effectiveness of a 

PR campaign as reflected through user generated 

content in blogs and other public forums. 

In this as well as in many other projects, L3S research- 

ers are busy in shaping the future of the Internet and 

the future of the huge information space building on 

top of it, the World Wide Web. If you are interested, 

contact us for further information and collaboration 

possibilities or join – there are a lot of interesting 

challenges still waiting to be explored! 

Hannover, February 2009 

Prof. Dr. Wolfgang Nejdl, L3S Executive Director 

FORSCHUNGSZENTRUM L3S L3S RESEARCH CENTER 3

4 

CONTENTS 

Shaping the Future of the Web ………………………………………………………………………………………………………………2 

Mission Statement ……………………………………………………………………………………………………………………………6 

2008: Another Successful Year! ………………………………………………………………………………………………………………8 

L3S Members & Advisory Board ………………………………………………………………………………………………………… 10 

L3S Staff ……………………………………………………………………………………………………………………………………… 12 

NEW PROjECTS 

LivingKnowledge – Fact, Opinions and Bias in Time …………………………………………………………………………………… 16 

STELLAR – Sustaining Technology Enhanced Learning Large-scale Multidisciplinary Research …………………………………… 17 

SYNC3 – Synergetic Content Creation and Communication ………………………………………………………………………… 18 

IT – Ecosystems: Autonomy and Controllability for Software-intensive Systems …………………………………………………… 19 

KNOWLEDgE 

OKKAM – Enabling the Web of Entities ………………………………………………………………………………………………… 22 

NEPOMUK – the Social Semantic Desktop ……………………………………………………………………………………………… 24 

REWERSE – Reasoning on the Web with Rules and Semantics ………………………………………………………………………… 26 

SemWeb – Semantic Web Technologies to Improve Customer Service ……………………………………………………………… 28 

APIS – Advanced Personalization in Information Services ……………………………………………………………………………… 30 

PSW – Personalization in the Semantic Web …………………………………………………………………………………………… 32 

RTS-STILL – the Autonomous Forklift Truck ……………………………………………………………………………………………… 34 

Trobot – Tactical Robot …………………………………………………………………………………………………………………… 36 

INFORMATION 

PHAROS – Platform for Search of Audiovisual Resources across Online Spaces ……………………………………………………… 40 

iSearch – Advanced Search Technology ………………………………………………………………………………………………… 42 

LinSearch – Indexing and Natural-language Search for Technical and Scientific Documents ……………………………………… 44 

LiWA – Living Web Archives ……………………………………………………………………………………………………………… 46 

IRIS – Interdisciplinary Research Initiative on Security ………………………………………………………………………………… 48 

PUMA – Personalized Universal Multimedia Access …………………………………………………………………………………… 50 

ViFaChem II – Personalized Information Spaces for Chemical Documents …………………………………………………………… 52 

D-Grid Integration Project Phase 2 ……………………………………………………………………………………………………… 54 

GDI-Grid – Geospatial infrastructure Grid ……………………………………………………………………………………………… 56 

RRZN – Computing Center for Science and Service …………………………………………………………………………………… 58 

UKoloS – Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications ……………………… 60 

FORSCHUNGSZENTRUM L3S L3S RESEARCH CENTER

CONTENTS 

C3World – Connected Cars in a Connected World …………………………………………………………………………………… 62 

WiMAX – Wireless Broadband Access in Rural Areas …………………………………………………………………………………… 64 

EUWB – Coexisting Short Range Radio by AdvancEd Ultra-WideBand Radio Technology ………………………………………… 66 

RoboLoc – Infrastructure-Aided Localization with UWB Antenna Arrays ……………………………………………………………… 68 

PULSERS II – Pervasive Ultra-Wideband Low Spectral Energy Radio Systems Phase II ……………………………………………… 70 

Prototype for Linux/Xenomai and Java …………………………………………………………………………………………………… 72 

LEARNINg 

GRAPPLE – Generic Responsive Adaptive Personalized Learning Environment ……………………………………………………… 76 

PROLIX – Aligning learning and business processes in enterprises …………………………………………………………………… 78 

TENCompetence – Building the European Network for Lifelong Competence Development …………………………………… 80 

HELCA – Hannover eLearning Campus …………………………………………………………………………………………………… 82 

L3SCPD – L3S Center for Professional Development …………………………………………………………………………………… 84 

NEWS & EvENTS 

L3S Presents Innovations in Digital Libraries at CeBIT 2009 …………………………………………………………………………… 87 

KDUbiq – Knowledge Discovery in Ubiquitous Environments ………………………………………………………………………… 88 

L3S organized Adaptive Hypermedia 2008 ……………………………………………………………………………………………… 88 

New Managing Director at L3S …………………………………………………………………………………………………………… 89 

L3S Student Sukriti Ramesh Awarded …………………………………………………………………………………………………… 89 

ICUWB 2008 ………………………………………………………………………………………………………………………………… 89 

L3S and Opera Software Organized Seminar about the Future of the Internet and Web Standards ……………………………… 90 

European Land Robot Trial (ELROB) 2008 ……………………………………………………………………………………………… 91 

L3S launches Future Internet Research Seminar Series ………………………………………………………………………………… 91 

L3S PARTNERS 

International and Industrial Partners …………………………………………………………………………………………………… 92 

PuBLICATIONS & COMMITTEES 

Publications 2008 …………………………………………………………………………………………………………………………… 94 

Programm Committees ………………………………………………………………………………………………………………… 100 

Organization Committees & Boards …………………………………………………………………………………………………… 102 

Imprint …………………………………………………………………………………………………………………………………… 104 


6 

NEW PROJECTS 

Mission Statement 

Vision 2009 – 2013 

L3S is leading in the development of innovative methods and technologies with a focus 

on providing access to and supplying personalized information as well as intelligent 

processing and preparation of knowledge for the European knowledge society. 

Since its launching in 2001, the research center L3S has established itself in the area of 

information, knowledge and learning technologies on an international level. L3S research 

focuses on “knowledge – information – learning” and combines knowledge-based research in the 

field of innovative information and cutting-edge communication technologies with applicationbased 

requirements of the European knowledge society. 

L3S projects in the research area “knowledge” focus on utilizing and converting information 

found on the Internet or in companies, existing as a result of social interaction on the Internet or 

supplied by sensors as images of the real world. The challenge here is to use semantic procedures 

to enrich and evaluate existing data. New approaches for creating, joint utilizing, finding and 

combining information allow for new perspectives on existing data inventories and new ways 

to process information. 


NEW PROJECTS 

The development of innovative technologies for efficient distribution and safe utilization of 

information are the objectives of the “information” area. Optimal utilization of information 

usually means searching and/or filtering partial amounts of relevant information from a large 

inventory of potentially available information. Digital libraries play an important role in the 

structuring of large information space, which makes information suitably accessible for the 

user. L3S activities range from searching for information in texts, multimedia documents and 

personal data collections up to secure distributed infrastructures, which allow the processing of 

large amounts of data in grids at a high performance rate. 

Finally, the objective of L3S in the “learning” area is to combine information and learning 

technologies in innovative environments and services for life-long learning in order to offer 

universities and companies efficient and sustainable learning environments tailored to the 

user’s needs. The key aspects here are to integrate learning technologies as a component of a 

homogenous knowledge management system in companies and to link learning platforms to 

existing administration systems in universities. 


8 

L3S RESEARCH CENTER 

2008: Another Successful Year! 

Again, our L3S Research Center not only excelled 

in research, but also managed to further increase 

the amount of third party funding. Our total bud- 

get in 2008 amounted to 6 million Euros, third 

party funding comes from projects funded by the 

European Commission, german Research Founda- 

tion (DFg), german federal state governments or 

governmental institutions as well as from indus- 

try. Our third party funding rate remains very high 

with over 70%, a further increase compared to 

our 2007 figures. 

In the past year the project portfolio of L3S was 

extended with new projects working on web enti- 

ties, web archiving, libraries for chemistry, person- 

alized learning or applications for ultra-wideband 

radio technologies. under the knowledge theme 

an important aspect is the extraction and use of 

entities like persons, events or other resources 

from Web documents. The realization of an inno- 

vative and comprehensive management solution 

for Web entities is the goal of our European Inte- 

grated Project OKKAM. 

L3S started three major projects under the theme 

information in 2008. The aim of the European Liv- 

ing Web Archives project is to improve the qual- 

ity of web archives and to enable the long term 

access and interpretation of its content. The devel- 

opment of enhanced personalized search function- 

alities to better serve the needs of chemists is the 

focus of the DFg funded viFaChem II project. The 

application of wireless high-speed networks of up 

to 10 gBit/s high quality video streaming and high 

speed data exchange between mobile devices is 

the focus of the European project EuWB. 


In the field of technology-enhanced learning, the 

European project gRAPPLE will develop a learn- 

ing environment that allows automatic adaptation 

to user’s personal preferences, prior knowledge, 

skills competences, learning goals and personal 

or social context. 

L3S Budget 2004 – 2008 

Our success in the acquisition of third party fund- 

ing is also reflected in an increased number of 

employees and publications. About 72 research- 

ers published more than 130 conference papers, 

journal articles or books. L3S researchers pre- 

sented their results on major conferences like the 

World Wide Web conference, SIgIR, CIKM, AAAI 

or ICuWB, and the 18th International World Wide 

Web Conference, taking place this year in Madrid, 

will be chaired by Prof. Nejdl from L3S, together 

with Yoelle Maarek from google 

L3S RESEARCH CENTER 

Overall, 2008 has been a very successful year, and 

we look forward to an exciting year 2009, and 

to many fruitful collaborations and interesting 

projects! 

Hannover, February 2009 

Dr. Thomas Risse, Deputy Managing Director 


10 

L3S MEMBERS 

Directors 

Prof. Dr. techn. Wolfgang Nejdl Executive Director 

Prof. Dr.-Ing. gabriele von voigt Deputy Director 

Prof. Dr. Wolf-Tilo Balke Deputy Director 

Dr. uwe Thaden Managing Director 

Dr. Thomas Risse Deputy Managing Director 

Members 

Prof. Dr. techn. Wolfgang Nejdl Leibniz University of Hannover 

Prof. Dr.-Ing. gabriele von voigt Leibniz University of Hannover / RRZN 

Prof. Dr. Wolf-Tilo Balke Carolo-Wilhelmina Technical University of Braunschweig 

Prof. Dr.-Ing. Klaus jobmann Leibniz University of Hannover 

Dir. uwe Rosemann TIB / UB Hannover 

Prof. Dr. gerd Stumme University of Kassel 

Prof. Dr.-Ing. Bernardo Wagner Leibniz University of Hannover 

Associated Members 

Prof. Dr.-Ing. Christian grimm Leibniz University of Hannover/ RRZN 

Prof. Dr. Nicola Henze Leibniz University of Hannover 

Prof. Dr.-Ing. Thomas Kaiser Leibniz University of Hannover 


Advisory Board 

ADVISORY BOARD 

Prof. Marc Eisenstadt Knowledge Media Institute / Open University, United Kingdom 

Prof. Dr. Matthias jarke Fraunhofer Institute for Applied Information Technology, Bonn 

Dept. of Computer Science V, Aachen University of Technology, Germany 

Prof. Dr. Hermann Maurer Institute for Information Systems and Computer Media, Graz 

University of Technology, Austria 

Prof. Dr. Erich j. Neuhold Faculty of Computer Science, University of Vienna, Austria 

Prof. Dr. Thomas Ottmann Institute for Computer Science, 

Albert-Ludwigs-University of Freiburg, Germany 

Prof. Dr. Dr. h.c. mult. A.-W. Scheer Institute for Information Systems, 

University of Saarbrücken, Germany 

Prof. em. gio Wiederhold, Ph.D. Computer Science Department, Stanford University, USA 


12 

L3S STAFF 

L3S Staff 

M.Sc. Fabian Abel 

M.Sc. Mohammed Alrifai 

Dipl.-Ing. Sondos Alaa El Din Ibrahim 

Dipl.-Wirtsch.-Ing. Kim Bartke 

M.A. Kerstin Bischoff 

Dr. Stephan Braune 

M.Sc. Michael Brenner 

B.Sc. Marko Brosowski 

Dipl.-Ing. Ingo Brunkhorst 

Dipl.-Ing. Sergiu Chelaru 

Dr. Ling Chen 

M.Sc. Sergey Chernov 

Dipl.-Ing. Stefania Costache 

Dipl.-Ing. Souhir Daoud 

Dipl.-Ing. juri Luca De Coi 

Dipl.-Inf. gianluca Demartini 

M.Sc. Elena Demidova 

Dr. Kerstin Denecke 

Dr. Fan Deng 

Dipl.-Dok. FH Elena Derr 

Carola Diaz Oceguera 

M.Sc. Emil Dimitrov 

Dipl. oec. Susanne Elsner 

Dr. Peter Fankhauser 

Dipl.-Ing. Claudiu-Sergiu Firan 

Dipl.-Ing. Marco Fisichella 

Dipl.-Ing. Stefan galler 

Dipl.-Ing. julien gaugaz 

M.Sc. Ralf gröper 

M.Sc. Benjamin Henne 

M.Sc. Patrick Hennig 

Dr. Eelco Herder 

M.Sc. Ekaterini Ioannou 

Dipl.-Ing. Tereza Iofciu 

Dipl.-Inf. Olaf jansen-Olliges 

Dipl.-Math. Robert jäschke 

Dipl.-Inf. Philipp Kärger 

M.Sc. Ricardo Kawase 

Dipl.-Math. Christian Knopf 

M.Sc. Benjamin Köhncke 

Dipl.-Wirtsch.-Ing. Christoph König 

Dipl.-Inf. Arne Kösling 

Dipl.-Inf. FH Christian Kohlschütter 

M.Sc. Daniel Krause 


Dipl.-Inf. Ralf Krestel 

M.Sc. Christopher Kunz 

Dr. Claus Kupferschmidt 

M.Sc. Marco Langerwisch 

Dipl.-Ing. Daniel Lecking 

Dipl.-Inf. Enrico Minack 

M.Sc. Sanam Moghaddamnia 

Dr. Yassene Mohammed 

Dr. Thanh Hieu Nguyen 

Dr. Claudia Niederée 

Dipl.-Ing. jorge Nieto Madrid 

Dr. Daniel Olmedilla 

Dipl.-Ing. Raluca Paiu 

Dipl.-Ing. georgios Papadakis 

M.Sc. Odysseas Papapetrou 

Dipl.-Ing. Dolores Perez guirao 

Dipl.-Inf. FH Sybille Peters 

Dr. Stefan Piger 

Dipl.-Ing. golaleh Rahmatolahi 

Dr. Thomas Risse 

Dipl.-Ing. Simon-Frederik Rüsche 

Dipl.-Wirtsch.-Inf. Stephan Rüttgers 

Dipl.-Ing. Harald Schwier 

M.Sc. joachim Selke 

Dr. Wolf Siberski 

Dipl.-Inf. Rodolfo Stecher 

M.Sc. Avaré Stewart 

Dipl.-Ing. Sebastian Sczyslo 

M.Sc. Nina Tahmasebi 

M.Sc. Sascha Tönnies 

Dr. uwe Thaden 

M.Sc. Leonid Tomaschpolski 

Dipl.-Inf. gian Luca volpato 

jana Westendorff 

Marion Wicht 

Dipl.-Ing. jan Wiebelitz 

Dipl.-Inf. Andreas Wodrich 

M.Sc. gideon Zenz 

M.Sc. Zhao Zhao 

Dr. Feng Zheng 

Iris Zieseniß 

L3S STAFF 


14 

NEW PROJECTS 

NEW PROJECTS 


NEW PROJECTS 

viFaChem 2 aims at providing a digital library 

infrastructure for the purpose of creating personalized 

information spaces. The value added 

services and Scientific Web 2.0 techniques not 

only actively support scientists and researchers 

in their retrieval tasks, but also offers valueadded 

services by deriving new knowledge 

from the collected information. 

Over the years L3S has established itself as a well renowned partner in national and international 

research projects. Four new projects (LivingKnowledge, Stellar, Sync3, IT-Ecosystems) in all 

research areas of L3S have already been started in 2009. 


16 

NEW PROJECTS 

LivingKnowledge – Fact, Opinions and Bias in Time 

Diversity Matters 

The Web lives from the multitude of actors 

that are involved in content creation. It thus 

has managed to achieve a democratization of 

content production that gives a voice to everybody. 

However, today’s search technologies fail 

to reflect this variety in an explicit and struc- 

Motivation 

For controversially discussed topics such as “global warming” 

the content available in the Web reflects the variety of 

positions. However, it is difficult to get a structured diversity 

overview, due to the way content is ranked by current 

search technology (mainly based on popularity), and due 

to content, which is partly strongly biased without making 

the underlying intention explicit. 

If users get a good overview over existing opinions, and are 

supported in discovering bias and analysing the underlying 

diversity (driven by differences in cultural backgrounds, 

schools of thoughts, temporal context etc.), this clearly 

helps them in building an own opinion in a well-informed 

way and in reflecting and contextualizing own positions. It 

is the goal of the LivingKnowledge project to explore and 

build technology that serves this purpose. LivingKnowledge 

aims to make diversity a real and tangible asset of 

the Web. 

The LivingKnowledge project will develop innovative 

technology for bias-aware, diversity-aware 

and evolution-aware information management 

and access. The resulting search technology is 

expected to provide the user with a high-level 

overview on the variety of opinions on a topic 

with the option for stepwise refinement and for 

learning about the underlying diversity and the 

temporal dimension. 

Challenges & First Steps 


tured way. It is the goal of the LivingKnowledge 

project to develop innovative methods 

for bias-aware, diversity-aware and evolutionaware 

information management and access 

technology to overcome this restriction. 

For achieving its goal, demanding research and technology 

development is required. Challenges have to be faced 

in the area of fact and opinion extraction; opinion-based 

and evolution-aware information clustering and aggregation. 

End users play a key role and innovative search technology 

which leverages bias, diversity and evolution and 

makes them tangible to the user is necessary. Furthermore, 

a thorough understanding of diversity and its impact is 

required as a sound foundation for the methods developed 

in the project. For establishing this foundation an interdisciplinary 

team of researchers will contribute. 

The LivingKnowledgde project will start in February 

2009. 

Applications 

The main focus of the LivingKnowledge project will be on 

foundational research and the establishment of a related 

research community. As part of this activity a testbed will 

be created, which fosters the experimentation of the developed 

methods within and beyond the consortium. Furthermore, 

it is planned to develop two exemplary applications, 

which showcase the LivingKnowledge technology. 

One of these applications will be coupled with Yahoo! 

Search technology and will explore future predictions in 

Web content. 

Contact: Dr. Claudia Niederée, niederee@L3S.de 

URL: http://www.L3S.de/livingknowledge

NEW PROJECTS 

STELLAR – Sustaining Technology Enhanced Learning Large-scale Multidisciplinary Research 

It Takes Two to Tango 

STELLAR represents the effort of the leading 

institutions and projects in European Technology-Enhanced 

Learning (TEL) to unify the 

diverse TEL community. This Network of Excel- 

Motivation 

STELLAR builds upon the results of the previous Networks 

of Excellence (NoE) in TEL: PROLEARN and Kaleidoscope. 

Both the PROLEARN network – coordinated by the L3S 

– and Kaleidoscope have set the TEL agenda for the last 

four years, albeit from different perspectives. The multidisciplinary 

STELLAR consortium will integrate and move 

beyond the earlier networks via an annually reviewed Grand 

Challenge program. 

Challenges 

STELLAR research activities concentrate on three major 

challenges. First, it is our aim to conciliate the current, centralized 

approach to e-learning with the self-directed, selfmanaged 

and self-maintained manner that is shown to be 

successful in Web-based communities. Second, collaborative 

learning demands a new approach to pedagogy, didactics 

and assessment. Third, the co-design of technology and 

pedagogy should consider the various technological and 

physical contexts in which learning takes place. 

Highlights 

The network will reach out to a wider community of stakeholders 

including: researchers, industry, policy makers, 

developers and end users. A variety of events will serve 

as vehicles of communication such as: the strategic Meeting 

of the Minds events; or academic events such as the 

Research Rendez-Vous; STELLAR Summer School and the 

ECTEL conference series. 

lence is motivated by the need for European TEL 

research to, synergize and extend the valuable 

work we have started by significantly building 

capacity in TEL research within Europe. 

STELLAR represents the effort of the leading institutions 

and projects in European TEL to unify our 

diverse the TEL community. The Network will 

be executed via a series of venues designed to 

increase the research capacity of European TEL at 

all levels. These venues will act as the backbone 

of an interlocking three-theme grand Research 

Challenge initiative: Connecting People, Orchestration 

and Contextualization. 

Potential Applications & Future Issues 

The STELLAR consortium will integrate European research 

in technology-enhanced learning. Cooperation and joint 

initiatives projects springing from the network will continue 

to change the TEL scene in Europe past 2012. 

Contact: Dr. Eelco Herder, herder@L3S.de 

URL: http://www.stellarnet.eu 


18 

NEW PROJECTS 

SYNC3 – Synergetic Content Creation and Communication 

People Discuss 

about News! 

Internet users choose mainstream media for 

their structured presentation of news, blogs 

for expressing their own opinion, and Wikipedia 

for the power of collaborative editing. 

In essence, the vast user-created content that 

refers to running news stories is almost totally 

Motivation 

While browsing the news search results in a news augmentation 

portal (e.g. Google News), one soon realizes that the 

thousands of news articles on a single issue tend to repeat 

the same information with little differentiation. On the contrary, 

a user blog entry on the same issue could provide 

much richer information and, most importantly, a different 

point of view. In 2002, blog evangelist Dave Winer made 

a long bet that a blog post on the top five news stories 

of 2007 will rank higher in Google search than the associated 

New York Times article. Winer won the bet, but it 

is a fact that most internet users still choose mainstream 

media for news coverage. 

Internet users strongly want to participate in the formation 

of public opinion but lack the tools to achieve wider coverage. 

The “fifteen minutes of fame” for our era is when a 

blog post ranks among the first in user ratings and is read 

by millions of people world-wide. The Present-day blogosphere 

lacks the structure and framework to routinely 

achieve this. Famous blog posts rarely surface through the 

ineffective and slow path of search engine ranking which 

is definitely not built for that specific purpose. 

Challenges 

Identify the news entities in the running news stories 

It is clear that a single news entity is associated with many 

news articles, e.g. articles from various newspapers, TV 

spots, etc. At first, rules are defined that detect news entities. 

For each news entity, additional rules will be defined 

that: a) assign news articles to a news entity and b) can 

be subsequently used to search user generated content for 

comments that refer to this entity. 

Attach news entities to user blog content 


unconnected and certainly unexploited. The 

goal of SYNC3 is to create a framework for 

enabling collaborative creation and collection 

of the extensive user-provided content that is 

produced in personal blogs and refers to running 

news issues. 

SYNC3 combines news related information 

from the Blogshpere with classic news Portals. 

Hence, news is enriched with personal opinions, 

extended discussions, and different facets while 

blogs become a fundamental part of shaping the 

public opinion. 

Blog entries that comment on the associated news entities 

will be discovered. These entries will be linked from a 

news portal, which will be created in the SYNC3 project, 

and vice versa. 


Bloggers routinely view and comment on other users posts, 

which reveals the current need for blogger interaction based 

on common interests. SYNC3 provides a new, high resolution 

connection dimension in the form of news themes 

and news entities allowing users to find others who comment 

on the same issue. Users that routinely comment on 

the same news theme could spontaneously form a group. 

With collaborative functions inside the group (co-editing 

rights, news entity assignment to specific user, etc), the 

group could fully cover a news theme and on the long 

run create a broadly accepted news source for the specific 

theme inside and outside the blog community. We envision 

groups of dedicated users to attain world-wide status as 

significant news source on their specific issues of interest! 

Contact: Prof. Dr. Nicola Henze, henze@L3S.de 

URL: http://www.L3S.de/sync3

IT – Ecosystems: Autonomy and Controllability for Software-intensive Systems 

Towards Complex 

Software Systems: 

Borrowing from Nature 

As technical systems grow more flexible and 

more autonomous, they become more and 

more similar to living organisms in their construction 

and behaviour. When putting many 

Motivation 

Software is used throughout all areas of the working environment 

and our society. It is a fact, however, that most 

software-systems continuously grow larger and more complex. 

Exchanging information and reaction to this information 

shows an even higher rate of growth. 

Contradicting, today’s classical methods in computer science 

software maintenance are limited and do not support 

such growth and complexity. 

Challenges 

An IT-Ecosystem is an ever-changing community of independent, 

cooperating and competing individual systems. 

These systems may be actuators, such as autonomous 

systems, robots, or smaller physical devices. Additionally, 

all kinds of sensors are necessary to perceive many 

parts of the environment. Humans play an integral part, as 

does the communication and interaction between all systems. 

The core issues for any IT-Ecosystem are its autonomy 

and its controllability, and the balance between those 

properties. 

It is impossible to plan and develop such an IT-Ecosystem 

in advance. Instead, new challenges arise for specification, 

design and validation. Such topics as self-organization, selfoptimization, 

self-monitoring, and self-healing have to be 

closely inspected and examined. 

Potential Applications & Future Issuess 

NEW PROJECTS 

such systems together, a system of systems 

evolves with analogous properties, but far more 

complex. It is a key objective to master the complexities 

of these entities. 

In contrast to engineering, where a single building 

can be planned, explained, and implemented; 

building a city requires a completely different set 

of models, mechanisms and patterns. Towards 

this end, computer science faces a radical paradigm 

shift. 

Much work has to be done on algorithms for cooperation 

in large distributed networks. Scalable and flexible architectures 

and procedures are needed. 

However, we are a long way from bringing the dream of 

the smart city to life: where all sensors and actuators are 

networked and able to communicate with each other to 

to enhance our lives. 

Contact: Prof. Bernardo Wagner, wagner@L3S.de 

URL: http://www.L3S.de/ecosystems 


20 

KNOWLEDGE 

KNOWLEDGE 


KNOWLEDGE 

The aim of the L3S research in the area of „Knowledge“ is to transform data found on the 

web or within companies into valuable assets by taking their semantic means into account. 

L3S advances the state-of-the-art in the field by developing new approaches for the creation, 

sharing, finding and combination of knowledge artefacts that enable end user to get more 

insights about their data or to process and integrate low level sensor data for autonomous 

navigation of intelligent robot vehicels. 


22 

KNOWLEDGE 

OKKAM – Enabling the Web of Entities 

I Know Whom You are Talking About 

Imagine that you want to build a celebrity information 

service using multiple, existing information 

sources in such a way that information 

about an individual person, organization, or 

event from different sources would magically 

be integrated, without additional effort. An 

Motivation 

Today new identifiers are created whenever structured 

information about entities such as persons, organizations 

and products is stored in a new repository. Identifiers are 

typically only kept locally unique and are not globally reused. 

Global identifier re-use would, however, ease information 

integration, since it would become much easier to 

merge information about entities together in ways not foreseen 

at the time of information creation. It is the goal of 

the OKKAM project to create what is called an Entity Name 

Server (ENS), a service which manages entity identifiers and 

makes them retrievable via entity descriptions. 

Challenges 

The main challenge in building the OKKAM ENS is to provide 

methods that are able to find the respective entity 

ID (OKKAM ID) already in use given a description of the 

respective entity. The complexity of such a goal stems 

from the fact that the description might come from many 

different sources (extraction results, user inputs, etc.) and 

exist in many different forms. In addition, the entity repository 

itself is expected to become very large over time. 

Further R&D challenges arise from the fact that information 

in the repository has to be automatically kept up-todate 

and streamlined to support an efficient discrimination 

between entities. 


elegant way of achieving this is the global reuse 

of entity identifiers. The OKKAM project 

aims to build an Entity Name Server (ENS), by 

providing the infrastructure for enabling such 

global entity identifier re-use – considerably 

easing information integration. 

The OKKAM project will realize an innovative 

and comprehensive entity identifier management 

solution fostering entity identifier reuse. 

It will cover effective entity matching and ranking, 

“OKKAMization” of content and entity-centric 

search applications exploiting the potential 

of the entity-centric approach. 

User “buy-in” is another important challenge of the project. 

The ENS can only achieve its full potential, if there is a 

considerable amount of OKKAMized content (i.e. content 

enriched with OKKAM IDs - available.) as well as a broad 

base adoption of the OKKAM idea. 

Highlights 

In this first year of the project, the focus has been on laying 

the foundations for the OKKAM ENS and on getting 

a first version of the ENS operational, while building on a 

flexible and extensible architecture. A first integrated prototype 

has been successfully implemented within the first 

ten month of the project. The main contribution of the 

L3S team toward this prototype is an extensible matching 

framework, which allows the integration and run-time 

selection of matching modules. Furthermore, the L3S team

– in collaboration with the other project partners – designed 

a request language and a comprehensive,two-phase matching 

process. With respect to entity lifecycle management, 

the L3S team implemented and evaluated an innovative 

approach for an identification scheme, which preserves 

the lineage with ancestors when entity decisions have to 

be revised. If, for example, two entities have to be merged 

in the entity repository the identifier of the new merged 

entity is designed in a way that it is still compatible with 

the identifiers of its two ancestors. 


An entire portfolio of entity-centric services is envisioned by 

the OKKAM consortium – enabled by the entity identifier 

re-use as it is fostered by the OKKAM ENS. Three exemplary 

entity-centric applications are already addressed during 

the OKKAM project: entity-centric organizational knowledge 

management, entity-centric search, and entity-centric 

content authoring. Next steps in the OKKAM project 

are the improvement of the ENS e.g. with respect to types 

of entities supported and the implementation of the aforementioned 

entity-centric applications. 

KNOWLEDGE 

Project Type: Integrated Project Eu/ICT FP7 

Project duration: january 2008 – june 2010 

Project Research Areas: Entity matching, semantic and 

entity-centric search, entity ranking, entity extraction 

uRL of the project: http://www.okkam.org 

Project managers: 

Prof. Dr. techn. Wolfgang Nejdl, nejdl@L3S.de 

Dr. Claudia Niederée, niederee@L3S.de 

Publications: 

1. Ekaterini Ioannou, Claudia Niederée, Wolfgang 

Nejdl. Probabilistic Entity Linkage for Heterogeneous 

Information Spaces. In: Advanced Information 

Systems Engineering, 20th International Conference 

(CAiSE), Montpellier, France, june 16-20, Proceedings, 

pp. 556-570, 2008, Springer, 978-3-540-69533-2. 

2. Paolo Bouquet, Heiko Stoermer, Claudia Niederée, 

and Antonio Mana. Entity Name System: The 

Backbone of an Open and Scalable Web of Data. In 

Proceedings of the IEEE International Conference on 

Semantic Computing, ICSC 2008, number CSS-ICSC 

2008-4-28-25. IEEE, August 2008 

3. julien gaugaz, gianluca Demartini. Entity 

Identifiers for Lineage Preservation. In 1st 

international workshop on Identity and Reference on 

the Semantic Web (IRSW2008) hosted by the 5th 

European Semantic Web Conference ESWC-08, 

Tenerife, Spain, june, 2008. 


24 

KNOWLEDGE 

NEPOMUK – the Social Semantic Desktop 

Tuning Your Desktop 

The ability to interlink desktop items clearly 

helps in performing tasks. In the NEPOMuK 

project an – automatically populated – semantic 

layer manages knowledge and relationships 

for notes, persons, emails, images and other 

objects on your desktop. One level higher, interlinking 

is also useful across individual desktops, 

Effective organization, management and access of the 

information on the personal desktop are crucial building 

blocks in every day working processes. Things can be done 

faster and better, if you quickly find the resources on your 

PC you need and also see the interconnection. However, 

on today’s desktops data is fragmented between applications 

and many connections stay implicit in the data. Even 

more recent desktop search tools rely on retrieval technology 

only, and do not reflect the rich knowledge and interlinking 

implicitly available on the desktop. It is the goal 

of the NEPOMUK project to create a semantic interlinked 

layer on top of desktop resources in order to overcome 

these restrictions. 

Challenges 

In the first two years, a variety of semantic desktop tools 

and services have been built. Besides improving stability, 

integration and usability of these components, additional 

challenges had been identified for this third year of 

the project: 

• Considering personal content such as photos, videos, 

etc. as part of personal information management (PIM) 

in Web 2.0 applications such as Flickr 

• Improving knowledge sharing capabilities with respect 

to ease of sharing and with respect to handling heterogeneity 

in information sources 

• Easing access to the rich information in the semantic 

layer 


e.g. for enabling search and controlled knowledge 

exchange between the desktops of coworkers. 

Enabled by NEPOMuK you might learn 

from such an exchange, that your colleague has 

created a report that saves you 40% of the time 

for creating your own material. 

The PIM project NEPOMuK develops technologies 

for easing the management and retrieval of 

relevant resources on the own PC desktop as well 

as for benefitting from the overlap and (implicit) 

links that exist between the own desktop and the 

desktop content of coworkers. 

Highlights 

Addressing the identified challenges, the R&D Highlights 

of the work of the L3S team in 2008 were in the following 

areas: 

• User friendly query construction support – In many 

cases complex structured queries are required to find 

the desired results when searching the desktop. For this 

purpose, a user friendly tool has been developed for 

constructing complex queries in an innovative graphical, 

system-assisted way. Using this tool the user neither 

needs to know the syntax of a query language nor the 

details of the underlying ontology, which describes the 

information structure. 

• Intelligent query rewriting – A solution has been developed 

for dealing with data sources that rely on different 

ontologies (schema heterogeneity). This solution applies 

query rewriting and relaxation based on partial mappings 

between ontologies. It enables the user to query 

resources in a uniform way in spite of the differences 

between the underlying ontologies.

• Towards the Virtual Personal Desktop –The extension 

of the NEPOMUK functionality towards the 

Virtual Personal Desktop reacts to the trend to manage 

personal content in Web 2.0 applications. It reintegrates 

all the personal content under a joint virtual 

hood with respect to search and information 

management and at the same time leveraging of 

added values such as tags created by the community. 


The three year project NEPOMUK ends in December 2008. 

The developed components have reached a high level of 

stability and integration, which even goes beyond original 

expectation. NEPOMUK technology provides a flexible 

platform for implementing tools for knowledge workers on 

top of it. Within the project this has already been done in 

an exemplary fashion for three application domains. For 

example – in collaboration with SAP – the NEPOMUK technology 

has been combined with task pattern, in order to 

better support re-occurring work processes and tasks. Various 

take up activities of NEPOMUK know how and technology 

are planned or already in progress (e.g. as part of 

KDE) and are encouraged by making the developed software 

available to the community. 

KNOWLEDGE 

Project Type: Integrated Project Eu/IST FP6 

Project duration: january 2006 – December 2008 

Project Research Areas: personal information 

management, search and ranking, desktop search 

uRL of the project: 

http://nepomuk.semanticdesktop.org 



Dr. Claudia Niederée, niederee@L3S.de 

Publications: 

1. Rodolfo Stecher, Claudia Niederée, Wolfgang Nejdl. 

Wildcards for Lightweight Information Integration 

in virtual Desktops. In Proceeding of the 17th ACM 

Conference on information and Knowledge Mining 

(Napa valley, California, uSA, October 26 - 30, 2008). 

CIKM ‘08. ACM, New York, NY, 797-806. 

Rodolfo Stecher, gianluca Demartini, Claudia 

2. 

Niederée. Social Recommendations of Content and 

Metadata. In Proceeding of the 10th International 

Conference Information Integration and Web-based 

Applications & Services (Linz, Austria, November 

24 - 26, 2008). 


26 

KNOWLEDGE 

REWERSE – Reasoning on the Web with Rules and Semantics 

Making the Web Think 

The World Wide Web consists of a huge 

amount of documents provided by humans 

and made for humans. The Semantic Web 

strives for a revolution by advocating the 

need for content which can be understood 

by both humans and machines. In this way, 

a huge amount of information can be auto- 

Motivation 

The Semantic Web envisions technologies and tools that 

are able to autonomously process the huge and increasing 

amount of information available on the Web. Such 

tools would be able to extract implicit information from 

data – similarly the way a human infers from a wet street 

that it rained. This knowledge provided to humans or to 

other tools would bring the Web to its full potential. Current 

limitations can be viewed from two different perspectives. 

On the one hand, user interfaces are needed which 

provide the Web’s knowledge in a human understandable 

way. On the other hand, methodologies are required that 

help humans to organize and provide their knowledge in 

a machine understandable way. 

Highlights 

In 2008 the successful work of REWERSE was continued 

at L3S despite the project’s end, examples include the 

following: 

• L3S as a member of the European Association for Semantic 

Web Education maintains the EASE Repository, a persistent 

repository of semantically annotated didactic online 

material. Today more than 200 learning resources, 

like video recordings, presentations, and description of 

Semantic Web applications can be accessed online. 

• The Personal Reader’s central semantic repository of user 

profile information enables application to share user data 

in order to tailor their functionality to users. In 2008 an 


matically processed, yielding a Web that 

knows what is in it, or a “Web that thinks”. 

REWERSE’s focus is to provide models and techniques 

supporting automated reasoning on the 

Web. Although successfully finished in February 

2008, REWERSE’s outcomes are being extended 

and further developed. 

REWERSE aims at establishing Europe as a leader 

in Semantic Web technologies. L3S focused on 

exploiting the Semantic Web’s reasoning capabilities 

in order to enable advanced personalization 

of web information systems. L3S also developed 

methodologies and tools for privacy policy 

definition, enforcement, and handling aiming to 

foster user awareness in security and trust. 

Access Control Layer for RDF stores was integrated into 

the Personal Reader Framework. Now users can specify 

who is allowed access their user profile information on a 

fine-grained level by means of an easy-to-use graphical 

user policy editor. 

• L3S further developed the Protune policy framework. 

The use of policies for personalization purposes, the 

creation of a front-end which allows to define policies 

in (controlled) natural language and the integration 

of Protune into reactive scenarios are among the most 

important contribution of L3S to the REWERSE’s policy 

working group. 

• L3S also participated in this year’s edition of the REW- 

ERSE summer school. Its first edition was held in 2005 

in Malta. Since that time, each summer the Reasoning 

Web Summer School attracted the best European Students 

and Researchers providing coherent introduction 

into Semantic Web methods with a particular focus on

easoning. The Summer School 2008 was held in Venice, 

Italy showing the importance of REWERSE’s research field 

also after the actual end of the project. 


Research in the area of policy reasoning and representation 

remains an important research issue at L3S. Questions such 

as “How can a non-technical user specify a complex policy?” 

or “How can the result of a policy evaluation be communicated?” 

will drive our research in this area. Together 

with REWERSE partners in Naples and Zurich, we will exploit 

Natural language processing techniques to provide useroriented 

solutions. L3S is extending the notion of policies 

towards an advanced Policy-based behavior control of 

complex software systems. A policy such as “A call during 

business hours has to be passed to the secretary.” which 

may be implemented in a company’s communication system 

requires events (e.g., incoming calls), time (e.g., business 

hours), and reactions (e.g., pass the call to the secretary) 

to be incorporated in the policy language. Together 

with our partners in Lisbon we develop an extended policy 

framework for such reactive policies. 

KNOWLEDGE 

Project Type: Network of Excellence Eu/FP6 

Duration: March 2004 - February 2008 

Research Areas: Semantic-based knowledge systems 

uRL of the project: http://rewerse.net 



Prof. Dr. Nicola Henze, henze@L3S.de 

Selected publications: 

1. juri L. De Coi and Daniel Olmedilla. A review 

of trust management, security and privacy policy 

languages. In International Conference on Security 

and Cryptography (SECRYPT 2008). INSTICC Press, 

july 2008. 

2. juri L. De Coi, Daniel Olmedilla, Sergej 

Zerr, Piero A. Bonatti, and Luigi Sauro. A trust 

management package for policy-driven protection & 

personalization of web content. In IEEE International 

Policies for Distributed Systems and Networks 

(POLICY 2008), Palisades, NY, uSA, june 2008. IEEE 

Computer Society. 

3. josé júlio Alferes, Ricardo Amador, Philipp Kärger, 

and Daniel Olmedilla. Towards Reactive Semantic Web 

Policies: Advanced Agent Control for the Semantic 

Web. 7th International Semantic Web conference 

(ISWC 2008), Poster and Demo Track, Karlsruhe, 

germany, October 2008. 


28 

KNOWLEDGE 

SemWeb – Semantic Web Technologies to Improve Customer Service 

Managing Customer Requests Efficiently 

A huge amount of service calls and mails reaches 

enterprises every day. Reacting appropriately to 

them and managing customers’ service needs 

efficiently is a problem, especially in small and 

medium-sized enterprises. The relevant knowledge 

is often not stored in a retrievable form, 

or only a few employees are capable of handling 

the issues. It is often difficult for other 

employees to discover this tacit knowledge and 

Motivation 

Customer care is a critical success factor in small and 

medium-sized mechanical engineering companies. The 

consumer’s preference for a particular producer is often 

influenced by the level of customer services offered. People 

working within the service department devote a significant 

amount of time in searching for relevant information. 

Even with existing retrieval systems, posing the “best” 

request and receiving relevant results is still a challenge. 

This is due to the numerous ways in which a question may 

be posed when using natural language. The consequence 

is repeated search for solutions to the same or similar problems 

without the benefit of relevant, prior knowledge. 

Furthermore, knowledge transfer among interdependent 

departments is often a tedious process. An integrated solution, 

such as the one proposed in the SemWeb project, fosters 

an integrated service pipeline and seamlessly allows 

the rapid propagation of product-specific knowledge and 

an enhanced quality of service. 

Challenges 

Service messages are documented in natural language 

and are therefore stored in an unstandardized, unstructured 

manner. To allow efficient access and reuse of this 

data, service messages have to be stored in a standardized 

way and the underlying semantics have to be extracted. 

Different expressions and synonyms need to be mapped 

to the same semantic concepts, and concepts need to be 


to overcome the learning curve associated with 

acquiring such knowledge. Within the SemWeb 

project, solutions are being developed to manage 

service calls using Semantic Web technologies. 

The objective is to allow employees to 

effectively find similar requests, allow efficient 

access to the database of service data and store 

all the knowledge they create. 

The objective of the SemWeb project is the implementation 

of a system to improve the quality of 

technical support that is suitable in particular for 

small and medium-sized enterprises. Terms that 

are relevant for this particular domain are identified 

in service messages based on a thesaurus 

describing the engineering domain. In this way, 

similar messages can be discovered even if different 

terms were used to describe similar issues. 

Based on dependency information between single 

terms (hypernomy, hyponymy), we create hierarchical 

facets representing the content of ex-isting 

service messages in a database. This allows 

for browsing the message data-base in an intuitive 

manner. 

mapped to super-concepts to connect all service messages 

to a semantic network. This leads to vastly improved 

search mechanisms as well as improved maintainability of 

data and knowledge. 

Highlights 

The current work in the SemWeb project exploits a thesaurus 

of terms describing the domain of engineering. We 

map service messages from enterprises to concepts of this 

thesaurus. In this way, the service requests become compa-

able and automatically interpretable. Within the thesaurus, 

synonyms, hypernyms and hyponyms are indicated. In 

this way, for single terms, more general concepts or more 

specific concepts can be derived. 

We exploit these relations to improve the search of service 

messages and to create a more intuitive representation of 

search results. To improve access to search results and provide 

facilities to explore and navigate them, a hierarchical 

faceted interface is created. This is in contrast to current 

flat, fixed result lists. 

Since Semantic Web Technologies exploit domain specific 

knowledge, domain experts can more easily extend the 

underlying knowledge base. 


Even though the current scenarios target enterprises in the 

field of mechanical engineering, the methodologies developed 

are transferable to other domains by substituting an 

appropriate knowledge base. 

In the future, we plan to focus on identifying relations 

between terms and concepts in request messages and 

to exploit the knowledge with data and text mining 

facilities. 

KNOWLEDGE 

Project Type: Funded by Arbeitsgemeinschaft 

industrieller Forschungsvereinigungen e.v. (AiF) 

Project Duration: December 2007-November 2009 

Project Research Areas: Semantic Web Technologies 

uRL of the project: www.service-wzm.de 

Project Managers: 


Dr. Kerstin Denecke, denecke@L3S.de 


30 

KNOWLEDGE 

APIS – Advanced Personalization in Information Services 

The Personal Essence of Queries 

Human choices are guided by individual preferences. 

In initiating the decision process, we usually 

have no idea about the optimal choice or its 

potential impact. Nevertheless, we often have 

an intuitive understanding of relative desirability. 

By repeated comparisons between alternatives 

we get a clear picture of what we are 

actually looking for. Since more and more information 

is stored digitally, support for preferen- 

Motivation 

Today many e-commerce companies assist their customers 

with digital shopping aids. A very successful type of shopping 

aid are recommender systems. Typically, these systems 

evaluate product ratings given by a large set of customers. 

Shopping recommendations are then generated 

by finding users that are similar to the target customer who 

is requesting a recommendation. Well-known examples of 

such systems are: Amazon “Customers Who Bought This 

Item Also Bought” feature; and the movie recommendations 

given by the DVD rental service Netflix. 

Although predictions made by recommender systems are 

often quite impressive, they have limitations. Since these 

systems rely on implicit similarities between customers 

and items, they are the tool of choice, whenever no other 

explicit preferential information is available. This can be 

clearly seen in the case of movies and books, where describing 

items apriori within a fixed attribute scheme (e.g. by 

quantifying the amount of humor, action, and suspense) is 

difficult and pointless for inherently subjective tasks. In contrast, 

when comparative choices are desired, recommendations 

should take into account preferential statements such 

as: “I like Audi better than Volkswagen”. Unfortunately, current 

recommender systems cannot do that, and there are 

no convincing alternatives available. 

The APIS project investigates the design of recommendation 

algorithms based on explicit preference statements. 

A major goal is to integrate this functionality into standard 

database technology, since product databases or catalogs 


tial choice processes in database technology is 

essential for supporting sound decision-making. 

unfortunately, current database systems 

force users to provide a precise description of 

information needs, which they often are unable 

to provide. The goal of the APIS project is to 

equip databases with features and tools for 

closing this “preference gap”. 

The APIS group at L3S Research Center investigates 

how the handling of human preferences 

can be integrated into current database systems. 

The goal of APIS is to equip databases with the 

capabilities to answer the user’s queries in a personalized 

fashion. Currently, research within APIS 

focuses on efficient query processing, preferences 

regarding compromises, and intuitive methods of 

user interaction. 

provide the main area of application. Furthermore, database 

integration is the only way to make explicit preference 

handling easily available to a broad range of users. 

Challenges 

The most important challenges within APIS are performance, 

effectiveness, and usability. These factors translate 

into strict requirements when it comes to building a successful 

preference-based database system: 

• The system must be fast and able to process large 

amounts of data, since more and more digital information 

is available every day and users want to have their 

queries answered immediately. 

• The system must produce reasonable and comprehensible 

results, since users will only trust a system that is

• 

able to explain why the given recommendation is considered 

optimal. 

The system must be intuitive to use, since users are not 

willing to accept technical burdens on a task that is already 

cognitively demanding. 

Highlights 

In previous years, APIS concentrated on developing formal 

models suitable for capturing real-life user preferences. This 

resulted in applying the well-known skyline query paradigm 

and extending it by support for tradeoffs across attributes. 

Skylining proved to be a very successful approach 

for practical applications. 

Current research and development within APIS focuses on 

intuitive user interfaces as well as statistically evaluating the 

quality of the results. As mentioned above, communication 

between the users and the system must be as effortless as 

possible; simultaneously however, the system must also 

be as informative as possible. What is the “right” form of 

user interaction? In recent international publications, several 

answers to this question have been proposed. The APIS 

Group developed efficient and effective elicitation strategies 

both for traditional skyline queries as well as skyline 

queries supporting tradeoffs and a prototype system is 

currently under development. This system will be used to 

collect preference data from real users, and allow statistical 

tests for the proposed methods. Since no data sets are 

publicly available, there is a compelling need for introducing 

the prototype it into the research community. 


The results of APIS will soon be ready for practical user tests. 

Currently, test scenarios are investigated; good candidates 

seem to be e-shopping sites offering technical equipment 

such as notebooks or used cars. Such data sets offer the 

advantage of detailed product descriptions in terms of technical 

facts, which can be exploited by customers to specify 

their preferences. When the working prototype is complete, 

the APIS Group will seek to engage e-shopping companies 

in its use for the purpose of experimental testing. 

KNOWLEDGE 

Project Type: DFg-Project within the Emmy Noether 

Program of Excellence 

Project duration: November 2004 – October 2008 

Project Research Areas: Databases and Information 

Systems, Service Provisioning, Personalization 

uRL of the project: http://www.L3S.de/apis/ 

Project manager: 

Prof. Dr. Wolf-Tilo Balke, balke@L3S.de 

Publications: 

1. C. Lofi, u. güntzer, W. Balke, “Consistency Check 

Algorithms for Multi-Dimensional Preference Trade- 

Offs”, International journal of Computer Science & 

Applications (IjCSA), 2008. 

2. W. Balke, j. Selke, “Exploiting Conceptual 

Knowledge for Querying Information Systems”, 

International Conference on Philosophy’s Relevance 

in Information Science (PRIS), Paderborn, germany, 

2008. 

j. Lee, g. You, S. Hwang, j. Selke, W. Balke, “Optimal 

3. 

Preference Elicitation for Skyline Queries over 

Categorical Domains”, 19th International Conference 

on Database and Expert Systems Applications (DEXA), 

Turin, Italy, 2008. 


32 

KNOWLEDGE 

PSW – Personalization in the Semantic Web 

Coloring Your Web Experience 

The rise of the Web 2.0 era made applications 

popular that are based on machine-machine 

communication: users enjoy the so called Mashups 

as they combine already known functionality 

from different services. However, they have 

two drawbacks: (1) They are created manually 

and need regular updates if the used ser- 

Motivation 

The Web develops faster than ever before. Applications 

that use other Web applications via RESTful interfaces or 

SOAP-based services need regular maintenance whenever 

an interface is updated or the entry point changes. Large 

Mashups become hardly maintainable resulting into a need 

for an automatic composition and semantic description 

of services. However, not only does service discovery and 

invocation need to be flexible, but the services themselves 

also need to be adapted to specific user needs. Due to legal 

issues and personal requirements it is not possible to pass 

user profile information directly to the invoked services. 

An infrastructure is required that integrates the user as an 

authoritative instance to control and restrict the exchange 

of user profile information between services. 

Challenges 

To achieve a Semantic Web based personalization framework 

as described in the motivation, the following challenges 

have to be tackled: 

• How to discover and personalize appropriate services? 

To discover services, a semantic registry is needed that 

describes the technical interface, available functionality, 

the parameters that can be applied for user-adaptivity. 

While WSDL and WSMO cover the first two descriptions, 

this project developed an ontology, which allows 

developers to describe formally how a service can be 

personalized. 


vices change and (2) it is most often not possible 

to adapt the services to a specific user. The 

PSW project aims at providing a framework to 

enable services to discover, use and personalize 

other services in an automatic way while 

preserving privacy and usability. 

The PSW project aims at creating a Framework 

to enable applications to discover and configure 

appropriate services to deliver personalized content 

and functionality. This challenge has been 

tackled by the Personal Reader Framework which 

enables applications to access personalized functionality 

encapsulated into services while preserving 

confidential user profile information. 

• How to exchange user profile data securely? 

For a secure exchange of user profiles, the user must be 

aware of the exchanged data and be able to control the 

data exchange. Hence, the user profiles should not be 

stored on a third party service side. Furthermore, different 

services should be able to access the user profile and 

update it. For this purpose we developed a user modeling 

service, which stores user profiles in RDF stores. A 

rule-based access control layer, AC4RDF, enables nontechnical 

users to adjust access rights to their profiles via 

an easy-to-use interface. 

Highlights 

In collaboration with the University of Saskatchewan and 

the Federal University of Campina Grande we proved that 

the Personal Reader Framework, which was developed in the 

PSW project, can improve recommender systems by applying 

personalization to the recommendation process.


The Personal Reader Framework and its unique idea of 

encapsulating personalization functionality gathered great 

attention at the authoritative conference in this field (Adaptive 

Hypermedia Conference 2008). Cooperation with Brusilovsky’s 

ADAPT2 system and Vasileva`s Comtella system 

showed that the Personal Reader is useful and promising 

to simplify the process of creating personalized Semantic 

Web applications massively. 

KNOWLEDGE 

Project type: Research project funded by the DFg 

Project duration: May 2006 – April 2008 

Project research areas: Information discovery, 

Semantic Web, Personalization, Rules 

uRL of the project: http://personal-reader.de/psw/ 




1. Fabian Abel, Ig Ibert Bittencourt, Nicola Henze, 

Daniel Krause, julita vassileva: A Rule-Based 

Recommender System for Online Discussion 

Forums. 5th International Conference on Adaptive 

Hypermedia and Adaptive Web-Based Systems, july 

28-August 1, 2008, Hannover, germany 

Fabian Abel, Nicola Henze, Daniel Krause, Daniel 

2. 

Plappert: user Modeling and user Profile Exchange 

for Semantic Web Applications, 16th Workshop on 

Adaptivity and user Modeling in Interactive Systems. 

LWA 2008 – Workshop-Woche: Lernen-Wissen- 

Adaption, October 6-8, 2008, Würzburg, germany 


34 

KNOWLEDGE 

RTS-STILL – the Autonomous Forklift Truck 

“FM-X Autonom” – a Revolution on the Factory Floor 

The vision of a fully automated factory has been 

in existence for some time. However, the vision 

is becoming a tangible reality with the evolution 

of autonomous systems – such as the 

“FM-X autonom”. The L3S Institute for Systems 

Engineering of the Leibniz university of Han- 

Motivation 

The L3S Institute for Systems Engineering of the Leibniz 

Universität Hannover works in cooperation with the STILL 

GmbH towards developing an autonomous forklift truck 

to facilitate flexible navigation and materials handling. An 

overriding aim of the project is to reduce costs, by using 

flexible automated materials handling vehicles – both in 

the warehouse, and in production. Economic gains can be 

expected, for example, by considerably reducing the risk 

of accidentally dropping material or misplaced goods. Furthermore, 

little or no infrastructure changes (such as track 

guides) are necessary. The possibilities for an autonomous 

forklift truck are enormous since the transition between 

manual and automated operation can be optimised. As well, 

the transport processes can be reproduced – even those in 

which a high degree of care is needed when positioning. 

Project Approach 

The autonomous forklift truck has been designed and realized 

using the conventional fork lift carrier. For autonomous 

navigation of the forklift truck, robust self-localization is a 

main requirement. Therefore, we introduced a self-localization 

system based on ceiling structures, with the assistance 

of a 3D laser scanner specially developed for navigational 

tasks. The 3D laser scanner perceives the ceiling 

structure as three dimensional; the actual position of the 

forklift truck is determined by comparing it with a previously 

prepared ceiling map. The localization system enables 


nover has developed an autonomous forklift 

truck, in co-operation with STILL gmbH, to 

facilitate flexible navigation and material handling. 

The forklift truck is able to recognize 

pallets, to lift these up and to move them to 

another location autonomously. 

The essential innovation of the autonomous forklift 

truck can be found in the localization equipment: 

A 3D ceiling localization system enables 

navigation in highly dynamic environments. Further 

important achievements of our project have 

been the interoperability of the system with the 

human driver and its flexibility to perform pallet 

handling also when the pallet position is not 

precisely known in advance. 

self-localization even with curved, sloped or stepped ceilings. 

The benefit of using ceiling landmarks is that ceiling 

structures don’t vary over time compared with those on 

the ground. 

Experimental results show that the localization system 

works robustly and with high precision in industrial environments. 

A long term test has been carried out in an 

industrial hall with a stepped and curved ceiling. In this 

test, the autonomous fork lift truck covers a distance of 

100 meters through different halls, with ceilings of various 

heights and curvatures. 

To enable pallet handling, the autonomous forklift truck is 

able to identify pallets, picking them up and automatically

setting them down in a new location. The pallets, as with 

the usual systems, need not be placed at a pre-defined hand 

over point. Instead, they are recognized by using laser scanners 

and can be automatically lifted from varying positions 

and heights. The autonomous forklift truck can manipulate 

pallets up to heights of 7-8 meters. 

Presentations & Future Issues 

The functional efficiency of the fork lift truck was demonstrated 

during the fair HANNOVER MESSE 2008 and the 

CeMAT 2008. To date, three autonomous forklift trucks 

are in full operation on the factory floor of an automotive 

supplier. 

KNOWLEDGE 

Project Type: Industrial Project 

Project Research Areas: Autonomous mobile robots, 

3D-Perception, Industrial Automation 


Prof. Dr.-Ing. Bernardo Wagner, wagner@L3S.de 

Dipl.-Ing. Daniel Lecking, lecking@L3S.de 

uRL of the Project: http://www.rts.uni-hannover.de/ 

index.php/Autonomer_gabelstapler 

Selected Publications 

1. Lecking, D.; Wulf, O.; Wagner, B.: ”Localization 

in a wide range of industrial environments using 

relative 3D ceiling features”, 13th IEEE International 

Conference on Emerging Technologies and Factory 

Automation, September 15-18, 2008, Hamburg. 

2. Hentschel, M.; Lecking, D.; Wagner, B.: 

“Deterministic Path Planning and Navigation for an 

Autonomous Fork Lift Truck”, 6th IFAC Symposium on 

Intelligent Autonomous vehicles (IAv), September 

3 – 5, 2007, Toulouse, France. 

Lecking, D.; Wulf, O.; Wagner, B.: “variable Pallet 

3. 

Pick-up for Automatic guided vehicles in Industrial 

Environments”, 11th IEEE International Conference 

on Emerging Technologies and Factory Automation, 

September 20-22, 2006, Prague, Czech Republic. 


36 

KNOWLEDGE 

Trobot – Tactical Robot 

Robotic Technology 

on the Way to Security Applications 

The Rheinmetall Landsysteme gmbH, a german 

system developer of defense and security technology 

and the L3S Institute for Systems Engineering 

at the Leibniz universität Hannover, 

are jointly working to build a research proto- 

Motivation 

In today’s society, global conflicts remain a fact of life. 

Modern personnel forces operate in poorly known regions 

and unclear urban areas. These challenges require significantly 

improved protection, reconnaissance, mobility and 

effectiveness. Helping to reduce the endangerment of soldiers, 

robotic vehicles can intelligently substitute personnel 

in these missions. 

In joint cooperation with the company Rheinmetall Landsysteme 

GmbH and the L3S Institute for Systems Engineering 

the Trobot (Tactical Robot), a research prototype for an 

autonomous land robot, has been developed. 

Project Approach 

The Trobot is based on an off-the-shelf amphibious 8x8 allterrain 

vehicle. For remote-controlled and autonomous operation, 

the vehicle is equipped with a custom-made driveby-wire 

retrofit kit. Designed by Rheinmetall Landsysteme, 

the system consists of electronics and actuators for steering, 

throttle, breaks and gear-shifting. As the drive-by-wire 

kit does not affect regular driving, the Trobot can either be 

operated manned or unmanned by selecting the desired 

operating mode just with the turn of a switch. 

For unmanned operation, a 3D laser scanner is used as the 

main sensor for environmental perception [1]. This 3D sensor 

enables a robust detection of stationary landmarks, as 

well as positive and negative obstacles such as trees and 

ditches. Based on this sensor, the Institute for Systems Engi- 


type for a robotically retrofitted land vehicle. 

Functioning both as a manned and unmanned 

vehicle, this prototype can be applied to multiple 

missions. 

The Trobot is a research prototype for a robotically 

retrofitted land vehicle with a wide range of 

applications. It can be operated as a manned as 

well as unmanned vehicle. Equipped with numerous 

sensors, including a 3D laser scanner for environmental 

perception, autonomous driving in 

unstructured environment is achieved. Based 

on the autonomous driving capabilities, new 

approaches for tele-operation and semi-autonomous 

operation over medium and long range distances 

are realized within this project, enhancing 

the situational awareness of the operator. 

neering developed new approaches for localization [3], 

tele-operation and autonomous driving in unstructured 

environments. 

A precise localization in urban as well as in non-urban environment 

is achieved by a combination of GPS and laser-based 

localization [2]. In non-urban environments, the position of 

the robot is based on the GPS measurements, filtered with 

wheel odometry and inertial data. Due to the multipath error 

propagation and limited satellite visibility, the accuracy of 

GPS is limited in urban areas. In these areas, the localization 

is based on the landmark information perceived with the 3D 

laser scanner and a given reference map of the environment. 

For a continuous transition between GPS and laser-based 

localization, robust probabilistic methods are applied.

For vehicle control, semi-autonomous driving techniques 

are used. With the aid of an aerial map, global waypoints 

are defined by the operator and transmitted to the vehicle. 

The vehicle follows these waypoints fully autonomously 

performing obstacle avoidance. In this way, , the operator 

is removed from the high frequent position control and 

obstacle avoidance loop. Also, given the fact that transmission 

latencies have no effect on the vehicle control, these 

waypoints can be transmitted via almost any radio channel 

of limited bandwidth. 

To enhance the operator’s situation-awareness, 3D visual 

feedback is used for tele-operating the vehicle. The 3D point 

cloud taken by the 3D laser scanner and the actual vehicle 

position is displayed in the graphical user interface at the 

operator station in a 3D virtual world model. By moving the 

virtual camera freely to any position within the virtual world, 

a 3D impression of the surrounding of the robot is displayed 

in real-time. For tele-operation at long-distances, a slow radio 

channel of limited bandwidth can be applied. With a maximum 

transfer rate of only 19.2 Kilobit a compressed laser 

scan and a camera image are transmitted from the vehicle 

to the operator for situational awareness. 

Facing the user 

In the beginning of 2008, the Trobot was assigned to the 

Bundeswehr Technical Center for Automotive and Armored 

Vehicles (WTD41) in Trier. In extensive field tests, the functionality 

of the vehicle and the robotic extension were 

approved in its typical application areas. 

The Trobot participated at the European Land Robot Trial 

(ELROB) in Hammelburg, Germany from June 30th through 

July 3rd, 2008. In this trial, more than 20 international teams 

KNOWLEDGE 

from industry and academia had the opportunity to showcase 

their capabilities in the fied of autonomous mobile land 

robots in four realistic and challenging scenarios. 

Project Type: Industrial project 

Project Research Areas: Autonomous mobile robots, 

tele-operation, 3D perception, localization, object 

recognition 

Contact: 


Dipl.-Ing. Matthias Hentschel, hentschel@L3S.de 

Selected Publications: 

1. Oliver Wulf, Kai O. Arras, Henrik I. Christensen 

and Bernardo Wagner: 2D Mapping of Cluttered 

Indoor Environments by Means of 3D Perception. In: 

Proceedings of the IEEE/RAS International Conference 

on Robotics and Automation (ICRA), April 26-May 1, 

2004, New Orleans, uSA. 

2. Matthias Hentschel, Oliver Wulf and Bernardo 

Wagner: A gPS and Laser-based Localization for 

urban and Non-urban Outdoor Environments. 

In: Proceedings of the IEEE/RSj International 

Conference on Intelligent Robots and Systems (IROS), 

September22-26, 2008, Nice, France. 

3. Oliver Wulf, Andreas Nüchter, joachim Hertzberg 

and Bernardo Wagner: ground Truth Evaluation 

of Large urban 6D SLAM. In: Proceedings of the 

International Conference on Intelligent Robots and 

Systems (IROS), October 29-November 2007, San 

Diego, uSA. 


38 

NEW PROJECTS 

INFORMATION 


NEW PROJECTS 

Developing innovative technologies for the efficient distribution of information and their reliable 

and secured usage is the aim of the L3S research area “Information”. The projects range from 

efficient retrieval of information and multimedia content and personal desktops to secured 

distributed infrastructures that enable the reliable and high performance processing of huge 

and complex information. 


40 

INFORMATION 

PHAROS – Platform for Search of Audiovisual Resources across Online Spaces 

got Lost in the Sea of Audio-visual Objects? 

Let PHAROS guide Your Way! 

With the spread of Web2.0, more and more 

individual users start uploading audiovisual 

objects to the Web. The enormous – and still 

continuously growing – amount of audiovisual 

content, provided both by users and content 

Motivation 

Worldwide, the volume of stored information is growing 

exponentially, and an increasing share is audiovisual content. 

This content drives the demand for new services, 

making audiovisual search one of the major challenges for 

organizations and businesses today. Confronted with the 

growing variety of audiovisual formats, standards and tools, 

a coherent approach to the search for audiovisual objects 

is desired. Furthermore, the sheer volume of online audiovisual 

objects leads to scalability, as well as user intent and 

satisfaction issues in multimedia retrieval. 

Challenges 

There are many challenges in efficiently and effectively 

searching of audiovisual objects. The aspects addressed by 

the PHAROS platform include, but are not limited to: 

• Intelligent content publishing mechanisms – making 

data collection of audiovisual resources more scalable. 

• Automatic semantic annotation of audiovisual content – 

making retrieval of audiovisual content easier. 

• Advanced schema-agnostic search – exploiting metadata 

of different formats for enriching search and search 

results. 

• Context-awareness and personalization – providing appropriate 

results for a specific user and a specific task. 

• Innovative user interfaces – going beyond simple keyword 

search boxes. 

PHAROS 


providers, poses huge challenges for multimedia 

search. PHAROS aims to improve users’ 

multimedia experiences by collectively taking 

into account content characteristics, metadata 

and user-supplied knowledge. 

The Pharos Project is present at the European ICT 

2008 Exhibit, “Europe’s biggest research event for 

information and communication technologies”. 

The Pharos Team displays a demonstration of the 

current technical achievements of the Project and 

promotes the Pharos Federation to potentially 

interested partners, both in the industry and in 

academia. A further showcase will be conducted 

in january 2009 to gather user feedback and validate 

functions. 

• Content protection – allowing for appropriate business 

models for content providers. 

• Spam detection – getting relevant and reliable search 

results and recommendations. 

Highlights 

During the second 12 months of PHAROS project, sophisticated 

algorithms, as well as engineering issues are addressed 

to fulfill the goals of this platform. Particularly, Prof. Nejdl, 

from L3S, acts as scientific director and coordinates the 

research in the areas of Social Media and Search, Advanced 

Personalization and Ranking. A prototype called “Social 

Media Beta” has been successfully released in June 2008. 

This prototype consists of several offline modules focusing 

on social media analysis, including user and community

profiling (UCP), social networks- and blogspace analysis 

(SNBA), and personalization based on user profiles (PM). 

Moreover, a very important component of this prototype 

is represented by the User and Social Information Storage 

(USIS), where all dimensions of the user and community 

profiles reside. The analysis results of the other offline 

components building the Social Media Beta prototype are 

stored in USIS as well and are later made available for personalized 

search and recommendation methods. 

In June 2008 PHAROS was selected ‘Project of the Month’ of 

the Directorate General for Information Society and Media 

of the European Commission and in October 2008, the first 

version of PHAROS platform has been successfully released 

and demonstrated in a live-demo at the ICT 2008 event in 

Lyon. In December 2008, a prototype of spam detection, 

trust and reputation is released. This prototype implements 

algorithms developed by L3S to combat spam using social 

media data. The Reference Reconciliation module, also the 

responsibility of L3S, has been as well released in December 

2008 and provides several advanced methods for identifying 

near-duplicates inside PHAROS content. 

INFORMATION 


Project Duration: january 2007 – December 2009 

Project Research Areas: Audiovisual Search, 

Multimedia Information Retrieval, Context and user 

Technologies 

uRL: http://www.pharos-audiovisual-search.eu/ 



Dr. Ling Chen, lchen@L3S.de 

Dipl.-Ing. Raluca Paiu, paiu@L3S.de 


1. “Can all tags be used for search?” Kerstin 

Bischoff, Claudiu Firan, Wolfgang Nejdl, Raluca Paiu. 

Proceedings of the 17th Conference on Information 

and Knowledge Management. 2008, uSA. 

2. “The art of tag: Measuring the quality of tags”. 

Ralf Krestel, Ling Chen. Proceedings of the 3rd Asian 

Semantic Web Conference. 2008, Thailand. 

3. “using Co-occurrence of Tags and Resources to 

Identify Spammers”. Ralf Krestel, Ling Chen. ECML 

PKDD Discovery Challenge. 2008. Belgium. 


42 

INFORMATION 

iSearch – Advanced Search Technology 

The Search Engine Designed Exclusively for You! 

Nowadays, search engines have become the 

de facto entry point to large volume information 

resources, such as the WWW, enterprise 

web, and individual data storage. Search tech- 

Motivation 

With the increasing importance of search engines as the 

primary methods for accessing all types of content, L3S 

Research Center is dedicated to developing innovative 

search technologies. Advanced search technologies involve 

issues from multiple areas: such as ranking, personalization, 

text mining and spam combating etc. Therefore, the 

iSearch project focuses on developing intelligent search 

technologies by collectively considering different dimensions 

related to the search service. 

Challenges 

Several important challenges, such as how to enable personalized 

information access, how to exploit novel social 

media data, and how to search semi-structured and structured 

data, have been considered in iSearch in the past 

years. In this year, new challenges have been targeted by 

iSearch and include: 

• Extracting true web content and filtering noise from web 

pages are beneficial for optimized web search. Effective 

approaches, which include heuristic models as well as 

statistics models, should be examined. 

• Compared with text based spam, image-based spam is 

even more difficult to combat. New characteristics of 

image spam should be studied. 

• The presence of noise can violate the modeling assumptions 

of recommendation systems. Collaborative 

filtering techniques should be attack resistant. 


nologies are critical to the success of search 

engines. The iSearch project aims to develop 

novel search algorithms to optimize existing 

search engines from multiple dimensions 

The iSearch project will continue its work on 

creating innovative search algorithms and solutions, 

by building upon its existing core competence 

and maintaining L3S Research Center’s 

competitiveness. 

Highlights 

Work in iSearch has led to various innovative solutions and 

subsequently to various high quality publications at top 

rated international conferences. Highlights for the year 

2008 are as follows: 

• A new approach to segment HTML pages, building on 

methods from Quantitative Linguistics and strategies 

borrowed from the area of Computer Vision. The notion 

of text-density is used as a measure to identify the 

individual text segments of a web page, reducing the 

problem to solving a 1D-partitioning task. 

• A new collaborative algorithm based on SVD which is accurate 

as well as highly stable to shilling. This algorithm 

exploits previously established SVD based shilling detection 

algorithms, and combines it with SVD based-CF. 

• Two methods for detecting image-based spam have 

been developed. The first solution, which uses the visual

features for classification, offers an accuracy of about 

98%, i.e. an improvement of at least 6% compared to 

existing solutions. SVMs (Support Vector Machines) are 

used to train classifiers using judiciously decided color, 

texture and shape features. The second solution offers a 

novel approach for near duplication detection in images. 

It involves clustering of image GMMs (Gaussian Mixture 

Models) based on the Agglomerative Information Bottleneck 

(AIB) principle, using Jensen-Shannon divergence 

(JS) as the distance measure. 

INFORMATION 

Project Type: Local government funding 

Project Duration: 2004 – 2009 

Project Research Areas: Web/Desktop/Enterprise 

Search, Personalization, Text and data mining 

uRL: http://www.L3S.de/web/iSearch 



Dr. Claudia Niederée, niederée@L3S.de 


1. “A Densitometric Approach to Web Page 

Segmentation” Christian Kohlschütter,Wolfgang 

Nejdl . CIKM 2008: Proceedings of the 17th ACM 

Conference on Information and Knowledge 

Management. 

2. “Attack Resistant Collaborative Filtering”. Bhaskar 

Mehta,Wolfgang Nejdl. Proceedings of the 31st ACM 

SIgIR Conference, 2008. 

“Detecting image spam using visual features and 

3. 

near duplicate detection”. Bhaskar Mehta,Manish 

gupta, Saurabh Nangia,Wolfgang Nejdl. Proceedings 

of the 17th International Conference on World Wide 

Web, 2008. 


44 

INFORMATION 

LinSearch – Indexing and Natural-Language Search for Technical and Scientific Documents 

Search for Professionals Made Easy 

Knowledge workers with a high demand on 

information are using specialized and commercial 

information providers to easily access 

high quality publications. Classification is an 

important method to narrow the information 

space and index terms are essential for describ- 

Motivation 

Commercial information providers, such as FIZ Technik and 

TIB Hannover libraries, are a natural information source for 

knowledge workers. Knowledge workers typically require 

high quality information and therefore do not completely 

rely on the internet as an information source. The reasons 

are not only the time consuming process to retrieve relevant 

information, but also the low quality results and unavailability 

of certain publications. Commercial information providers 

reduce the complexity of information providing barrierfree 

access and facilitate interaction with the information 

system by incorporating user-oriented forms of visualization 

for tasks such as complex retrieval queries. 

The requirements of professional users are demanding, 

as they request high quality and up-to-date information, 

quickly. Before users are able to pose their queries, it is necessary 

to prepare the content by indexing and classifying it. 

Classifications are an important method to narrow the information 

space and index terms are used to provide detailed 

content descriptions that help search engines find relevant 

items, faster. Due to the quality requirements, indexing 

and classification in these libraries have been done manually. 

In a manual classification process, an expert reads 

the document and assigns the appropriate classifications 

and index terms. 

The aim of the LinSearch project is the development, evaluation 

and usage of an integrated and efficient system for 

indexing and searching technical and scientific documents 

within FIZ Technik and TIB Hannover libraries. The system 


ing the content in more detail. Therefore, the 

aim of LinSearch is the development, evaluation 

and usage of an integrated automated 

system for indexing and searching technical 

and scientific documents for FIZ Technik and 

TIB Hannover. 

The daily business of a technical information services 

(FIZ) and libraries is to provide professional 

users with high quality information in a certain 

domain. The aim of the LinSearch project is the 

development, evaluation and usage of an efficient 

integrated system for the indexing and searching 

of technical and scientific documents for FIZ 

Technik and TIB Hannover. 

should be able to allocate the content into clusters, support 

the automated processing of metadata and the intellectual 

process of subject indexing. An automated flow of 

content into special databases further improves the workflow. 

The project results should easily fit into the existing 

business processes. 

Challenges & Highlights 

The challenge of the project is to support the human 

indexers in their job by advance existing indexing and 

classification approaches in order to provide a reliable 

semi-automatic and automatic indexing and classification 

methods. 

Within LinSearch, machine learning techniques and combinations 

of features have been analyzed to select the 

best approach for the classification problem. The selected

approach has been complemented by using explicit knowledge 

already available in metadata records, e.g. the name 

of a journal. The resulting classification process is a combination 

of rule based and statistical methods. 

Another aim of the project is to improve the user satisfaction 

especially by avoiding empty result sets. Several 

complementing approach are currently under evaluation. 

Linguistic processing can be used to not only correct the 

spelling of terms, but also identify the language, as well as 

provide an automatic thesaurus-based translation of domain 

specific terms into other languages. Semantic technologies 

complement the linguistic processing by automatically 

enhancing the query with related terms in case the 

result is too small or empty. 

Potential Applications & Future issues 

By the end of the project, FIZ Technik and TIB Hannover 

will be able to index new documents much more efficiently 

and with a higher quality than is possible today. This will 

strengthen their position in the global information market, 

since with less overhead, their customers will ultimately 

have higher quality and recent information. Moreover, 

since the results are of a generic nature, they are usable 

by publishers or for company’s internal information management 

as well. 

INFORMATION 

Project Type: Funded by BMWi 


Project Research Areas: Digital Libraries, 

Classification, Information Retrieval 

uRL of the project: http://www.linsearch.de/ 



Dr. Thomas Risse, risse@L3S.de 


1. Thomas Bähr, Kerstin Denecke; LINSearch – 

Linguistisches Indexieren und Suchen Chancen und 

Risiken im grenzbereich zwischen intellektueller 

Erschließung und automatisch gesteuerter 

Klassifikation; In: Ockenfeld M (Hrsg): verfügbarkeit 

von Informationen. 30.Online-Tagung der DgI, 2008 

Paul Schmidt, Thomas Risse, Kerstin Denecke, 

2. 

Claudiu-S Firan, jens Biesterfeld, Thomas Bähr; 

LINSearch – Aufbereitung von Fachwissen für die 

Informationsversorgung; KnowTech, 10.Kongress zum 

Wissensmanagement, 2008 


46 

INFORMATION 

LiWA – Living Web Archives 

Preserving the Web for Future generations 

The Web today plays a crucial role in our information 

society: it provides information and services 

for virtually all domains, reflects all types 

of events, opinions, and general development 

within society, science, politics, environment, 

Motivation 

Web preservation is a very challenging task. In addition 

to the “usual” challenges of digital preservation (media 

decay, technological obsolescence, authenticity and integrity 

issues, etc.), web preservation has its own unique 

difficulties: 

• distribution and temporal properties of online content, 

with unpredictable aspects such as transient unavailability, 

• rapidly evolving publishing and encoding technologies, 

which challenge the ability to capture web content in 

an authentic and meaningful way that guarantees longterm 

preservation and interpretability, 

• the huge number of actors (organizations and individuals) 

contributing to the web, and the wide variety 

of needs that web content preservation will have to 

serve. 

The intention of the LiWA project is to turn Web archives 

from mere Web page storages into “living Web archives”. 

Such living archives will be capable of: handling a variety 

of content types; improving the quality of their content 

by detecting capturing traps and filtering out irrelevant 

content such as Web spam; dealing with issues of temporal 

Web archive coherence as well as improving long-term 

content usability. 


business, etc. Due to the central role the World 

Wide Web plays in today’s life, its continuous 

growth, and its change rate, an adequate way 

of Web archiving has become a cultural necessity 

for preserving knowledge. 

It is the goal of the LiWA project is to turn classic 

web page stores into “living Web archives”. 

The LiWA project will build next-generation 

Web archiving technology for high-quality Web 

archives by improving archive fidelity, archive 

coherence and integrity as well as archive 

interpretability. 

Challenges 

Ensuring archival content is just the first step toward “full” 

content preservation. It also important that, in the long 

term, content can be found and interpreted. This type of 

semantic accessibility of content suffers due to changes in 

language over time, especially if we consider time frames 

beyond ten years. Language changes are triggered by various 

factors including new insights, political and cultural 

trends, new legal requirements, or high-impact events. 

As an example, consider the name of the city Saint Petersburg: 

This Russian city was founded in 1703 as “Sankt- 

Piter-Burh” and soon after renamed to “Saint Petersburg”. 

From 1914-1924 it was named “Petrograd” and afterwards 

“Leningrad”. Since 1991 the name changed back to “Saint 

Petersburg”. Evolution of terms is of course not restricted 

to location names and the terminology change rate clearly 

depends on the domain of discourse.

Highlights 

In the past year the work in LiWA focused on the problem 

statement and detailed specification of requirements, 

as well as defining a framework which will allow seamless 

integration of LiWA components with the Heritrix and 

Hanzo crawlers. On our way to an unsupervised method 

for detecting terminology evolution, our approach is to 

mine long time archives and examine changes in patterns. 

In LIWA, we draw conclusions about term evolution when 

the surroundings of a term change over time. We set up a 

model for approximating the sense of a term when looking 

at only one collection. Our initial results show that it 

will be possible to use these snapshots to detect evolution 

over time. Throughout the project our approach will be 

extended and refined to automatically derive mappings of 

terminologies between different times. 


Over the next years, it is the goal of the L3S Research Center 

to develop a complete framework that automatically 

detects the evolution of terminologies in Web archives 

and makes it usable for retrieval of web pages and documents. 

The approach will not be limited to web archives, 

but will also be useful for all types of archive and document 

repositories. 

INFORMATION 

Project Type: 

Specific Targeted Research Project Eu/IST FP7 

Project duration: February 2008 – january 2011 

Project Research Areas: Web archiving, preservation 

uRL of the project: http://www.liwa-project.eu 



Dr. Thomas Risse, risse@L3S.de 


Nina Tahmasebi, Tereza Iofciu, Thomas Risse, 

1. 

Claudia Niederée, and Wolf Siberski; Terminology 

Evolution in Web Archiving: Open Issues; In Proc. of 

the 8th International Web Archiving Workshop in 

conjunction with ECDL 2008, Aarhus, Denmark 


48 

INFORMATION 

IRIS – Interdisciplinary Research Initiative on Security 

Do You Trust Your Online Pharmacy? 

Security covers aspects from quite a few different 

disciplines including security in information 

processing, online marketing, financial credit 

management and meteorology. The IRIS initia- 

Motivation 

IRIS spawns novel ideas for addressing security problems in 

various research fields; encompassing safety, reliability, risk, 

privacy and trust. It also covers a heterogeneous spectrum 

of issues from the risk minimization of the credit decisions 

to e-trust. In all these areas, L3S contributes its expertise 

in secure information processing; social networks; policies 

and trust negotiations: providing the solid technical core 

for the new research activities initiated by IRIS. 

Challenges 

In many cases, ensuring the proper levels of security is not 

possible within a single discipline. One of the most important 

challenges in the interdisciplinary environment of IRIS, 

is creating a common understanding of the security related 

issues among researchers from different disciplines. The IRIS 

forum brings researchers together to identify cross-disciplinary 

problems, which cannot be solved within a single 

discipline, and initiate research toward their solutions. 

Highlights 

Companies offering credence goods, such as those appearing 

in a new online pharmacy, face cold start problems due 

to the lack of customers’ trust. Together with the Institut 

für Marketing und Management, IRIS will create the technical 

means for trust-building in electronic environments. 

Trust negotiation technology, as well as research in social 

Interdisciplinary Research 

IRIS 

Initiative on Security 

Interdisciplinary Research 

IRIS 

Initiative on Security 


tive brings together researchers from different 

fields to recognize open issues, which cannot 

be solved within a single discipline, and initiate 

joint research work in these areas. 

Within the IRIS project, researchers from the natural, 

computer science human and social sciences 

have united to create an interdisciplinary forum 

to address open issues in the area of security. The 

scope of such work requires the cooperation of 

scientists in various research fields. IRIS creates 

clusters of organizations working together on 

heterogeneous security problems and coordinates 

security projects and initiatives at the Leibniz 

universität Hannover. L3S is actively involvement 

within the IRIS initiative and in the first 

year of the project, put forth a number of challenging 

research proposals which currently under 

development. 

networks currently developed at L3S, will play a central 

role in the upcoming studies. 

Small companies offering services and goods do not have 

competences to access credit rating of a customer. They 

rely on a financial partner, who can provide the actual 

investment. This introduces overhead and increases the 

cost of the service. Together with the Institut für Banken 

und Finanzierung we plan to build up a novel policy-based 

credit rating system based on the policy engine developed 

at L3S to enable service providers make their credit decisions 

independently.

IRIS is further engaged in an interdisciplinary security project 

to analyze video monitoring data for automatically identifying 

critical situations, such as the suspicious behavior 

of an airport visitor. In this context, it is crucial to preserve 

the privacy of those being monitored. L3S, in partnership 

with the Institut für Informationsverarbeitung, Institut für 

Soziologie und Sozialpsychologie and Regionales Rechenzentrum 

für Niedersachsen, will address these and related 

research challenges. 

Security becomes especially important in the sky; where 

potentially hazardous weather conditions increase flight 

risks. Current flight planning systems do not include weather 

information, and manual plan adaptation is required in 

adjusting to changing weather situations. Together with 

the Institut für Meteorologie, we will investigate using 

L3S’ policy engine to extend flight planning systems with 

appropriate safety rules. 

Potential Applications 

Trust negotiation technology developed at L3S, as well 

as current L3S research in the area of social networks can 

improve trust establishment in the e-commerce applications. 

Moreover, the policy engine developed at L3S can 

simplify decision making processes in many real world 

security related applications, such as credit ratings or flight 

planning. 

INFORMATION 

Project Type: Research Initiative of the Leibniz 

universität Hannover 

Project duration: 01.01.2008 – 31.12.2009 

Project Research Areas: policies, trust and security 

uRL of the project: http://www.fis.uni-hannover.de/ 

Projects managers: 


M.Sc. Sergej Zerr, zerr@L3S.de 


1. Sergej Zerr, Elena Demidova, Daniel Olmedilla, 

Wolfgang Nejdl, Marianne Winslett, Soumyadeb 

Mitra. Zerber: r-Confidential Indexing for Distributed 

Documents. 11th International Conference on 

Extending Database Technology (EDBT 2008), March 

25-30 2008, Nantes, France. 

Sergej Zerr, Wolfgang Nejdl, Daniel Olmedilla, 

2. 

Wolf Siberski. Zerber+R: Top-k Retrieval from a 

Confidential Index. 12th International Conference on 

Extending Database Technology (EDBT 2009), March 

23-26 2009, Saint-Petersburg, Russia 


50 

INFORMATION 

PUMA – Personalized Universal Multimedia Access 

Personalized video Streams: 

Whenever and Wherever You Want 

Nowadays, the variety of client devices is dramatically 

increasing. To enable universal media 

access from each kind of client device, personalization 

and adaptation aspects have to be considered. 

Although, Web service architectures 

are a common task in today’s business applications 

the area of multimedia applications is 

Motivation 

A benefit of service-oriented systems is the possibility of 

easily integrating value-adding services from third party 

providers into delivery workflows. Let us imagine a user 

who wants additional subtitles, in a rarely used language, 

added to his video stream. His content provider does not 

provide the required subtitles but can obtain them easily 

from a third party provider by integrating the corresponding 

service into the delivery workflow. An important 

issue regarding this feature is a clear interface description 

to enable interoperability between services from different 

services providers. 

Challenges 

Delivering multimedia content over a plethora of devices 

in a personalized fashion puts great demands on the selection 

of suitable services. Services can only be used interchangeably, 

if their descriptions allow an adequate distinction 

for the tasks they perform. Therefore, extensive service 

descriptions are necessary. These descriptions are evaluated 

and a suitable service orchestration is created. 

After the delivery workflow is successfully initialized, monitoring 

is needed to immediately react to possible service 

failures or QoS constraint violations. In such a case, the 

appropriate service has to be replaced, on-the-fly, without 

an interruption in the media processing. 


still dominated by complex, monolithic systems. 

Within the PuMA project, we were able to overcome 

this limitation by building a service-oriented 

streaming architecture, where multimedia 

content is adapted by different services as 

it travels through the network. 

Although Web service architectures are a common 

task nowadays for business applications, the area 

of multimedia applications is still dominated by 

complex monolithic systems. However, without 

the usage of service-oriented approaches the personalization 

of multimedia applications remains 

a difficult, costly, and time-consuming problem. 

Within PuMA, we overcome the limited support 

for continuous media data in current Web service 

frameworks and built a service-oriented streaming 

architecture, where multimedia content is 

adapted to the individual user’s needs. 

Highlights 

The on-the-fly adaptation of the content is driven by the 

MPEG-21 standard for Digital Item Adaptation, of which 

only very few adaptation tasks are actually used in realtime 

delivery systems, to reduce the complexity. On the 

other hand, planning approaches, which take all adaptation 

possibilities into account, are too complex to provide 

the fast workflow creation and verification required for 

our envisioned delivery system. Additionally, maintaining 

a domain ontology, containing all the rules necessary to 

reason about the adaptation workflows, is hard to create 

and hard to maintain. Therefore, we use a hybrid approach 

of providing exemplary workflows for a large set of adap-

tation “scenarios”, e.g. content delivery with changing size 

and coding format. 

Furthermore, in an open system it is important that all 

the participants are able to communicate with each other. 

Instead of implementing a strict protocol which has to be 

implemented by all participants, we devised a role-based 

conformance check which ensures that as long as a service 

is compatible with the role it has to play in the workflow, 

e.g. scaling the video, it will be able to interoperate 

with the other parties in the system. Semantic Web 

technology, such as OWL-S, is necessary for expressively 

describing an adaptation service’s capabilities and protocol 

implementation. 


Since the number of mobile devices is steadily increasing 

we plan to determine the behaviour of our service-oriented 

approach in a mobile scenario. In future work we 

will focus on the distribution of mobile client devices to different 

adaptation services to assure an appropriate overall 

performance. Furthermore, also QoS and scalability issues 

will be considered. 

INFORMATION 


Project duration: August 2006 – September 2009 

Project Research Areas: Service Oriented Multimedia, 

Media Streaming, Personalized Content Selection and 

Digital Item Adaptation 

uRL of the project: http://www.L3S.de/puma/ 




1. “Multimedia Content Provisioning using Service 

Oriented Architectures”. Ingo Brunkhorst, Sascha 

Tönnies and Wolf-Tilo Balke. In Proceedings of the 

6th International Conference on Web Services (ICWS 

2008), Beijing, China, 2008 

“Preference-Driven Personalization for Flexible 

2. 

Digital Item Adaptation”. Benjamin Köhncke and 

Wolf-Tilo Balke. In Multimedia Systems journal 

(MMSj), vol. 13(2), Springer, 2007 


52 

INFORMATION 

ViFaChem II – Personalized Information Spaces for Chemical Documents 

Chemical Information at Your Fingertips 

The interdisciplinary viFaChem II project investigates 

and deploys innovative value-adding 

services and scientific Web 2.0 techniques for 

Information access in the area of chemistry. 

The project’s vision is the creation of personal 

information spaces that offer a variety of rele- 

Motivation 

The rapid changes in information technology have heavily 

influenced the scientific way of working. Global communication 

technologies, such as email, enable a fast and ubiquitous 

information exchange and the time spans between 

the generation of new results and the subsequent publication 

and dissemination (innovation cycles) are becoming 

shorter. This results in a flood of available scientific 

information that cannot be handled manually by the individual 

reader. 

Today digital libraries play a major part in providing information 

services. Many information providers have extended 

their services from the traditional catalog-based search for 

literature to comprehensive digital portals searching for 

information over heterogeneous document collections and 

databases. Generally users can conveniently access both 

printed and electronic resources either directly or by document 

delivery services. 

However, different scientific disciplines have their own 

demands and the respective community has different workflows 

and expectations when it comes to searching for literature. 

Hence, libraries have branched out into topically 

centered virtual libraries for several disciplines closely focusing 

on the needs of each individual science. 

Challenges 

In the domain of chemical information it is not sufficient 

just to provide keyword-based access. Chemical informa- 


vant resources, tailored to the individual user’s 

view of the topic and actively support chemical 

scientists and researchers in retrieval tasks 

as well as in deriving new knowledge from the 

collected information. 

viFaChem II aims at providing a digital library 

infrastructure for creating personalized information 

spaces. The value added services and Scientific 

Web 2.0 techniques actively support scientists 

and researchers in retrieval tasks, as well as 

in deriving new knowledge from the collected 

information. 

tion deals with information about molecules, their properties, 

their biological and pharmaceutical activities, their 

industrial use, and their reactions. To a large degree chemical 

information is communicated by graphical representations 

of chemical structures and reaction schemes instead 

of verbal descriptions. Such representations, allow practitioners 

to efficiently discriminate between substances 

based on their visual representations or superclasses. For 

a high quality information retrieval it is therefore necessary 

incorporate information about chemical entities based on 

actual chemical workflows. In order to do so, strong interdisciplinary 

work is mandatory. 

Building on the experiences gained from successful designs 

within the chemical information platform, “chem.de” 

(http://www.chem.de), the ViFaChem II project focuses 

on using knowledge about chemical workflows as a basis 

for expanding the digital library portal. The project aims 

at a personalized knowledge space for the individual prac

titioner in the field. Building on (automatically derived) 

ontologies and taxonomies structuring the domain, openly 

accessible topical databases, and specialized indexes of substances 

derived from a set of user-selected documents, a 

personalized knowledge space is created that promises to 

help users combating the information flood. 

Highlights 

Scientific libraries provide an information infrastructure 

that collects processes and connects heterogeneous document 

collections with respect to the information needs 

of each individual user. Due to the editorial process, the 

quality of information is guaranteed throughout the process. 

Using advanced information extraction and entity 

recognition techniques on chemical literature the information 

(e.g. full texts, chemical reactions, images of molecular 

structures) is collected. Moreover, using document 

information, structural properties of the domain can be 

derived and subsequently used for structuring novel personal 

information spaces enriched by metadata with a 

controlled quality. Example structures include taxonomies 

of tags and annotations, or domain ontologies over controlled 

vocabularies. 


The value added services will be integrated in the chemical 

information platform “chem.de”, which is hosted by 

the TIB, the Chemistry Information Centre Germany (FIZ 

Chemie), and the German Chemical Society (GDCh). The 

platform provides a pervasive information infrastructure 

for universities as well as industry to support the genera- 

INFORMATION 

tion of new knowledge and a personalized way of literature 

search in the field of chemical information. 

Project Type: Funded by DFg 


Project Research Areas: Digital Libraries, Scientific 

Web 2.0, Information Spaces, Personalization and 

user Modeling Technologies 

uRL of the project: http://www.L3S.de/vifachem 



Dr. Irina Sens, sens@L3S.de 

Dr. Oliver Koepler, koepler@L3S.de 


1. “Personalised Information Spaces for Chemical 

Digital Libraries “. Oliver Koepler, Sascha Tönnies, 

Benjamin Köhncke and Wolf-Tilo Balke. In Proceedings 

of the 4th german Conference on Chemoinformatics, 

goslar, germany, 2008 

2. FacetedDBLP - Navigational Access for Digital 

Libraries. jörg Diederich and Wolf-Tilo Balke, In: 

Bulletin of IEEE Technical Committee on Digital 

Libraries, volume 4 Issue 1, Spring 2008, ISSN 1937- 

7266. 

Automatically Created Concept graphs using 

3. 

Descriptive Keywords in the Medical Domain. jörg 

Diederich and Wolf-Tilo Balke, In: Methods of 

Information in Medicine (METHODS), vol. 47(3), 

Schattauer, 2008. 


54 

INFORMATION 

D-Grid Integration Project Phase 2 

Toward a Reliable grid 

Infrastructure in germany 

The first D-grid Integration Project (DgI-1) 

established a core grid infrastructure in germany. 

The follow-up project, DgI-2, will establish 

this infrastructure for long-term use and 

sustainability. Towards these goals, the main 

objectives of DgI-2 (in close collaboration with 

existing e-science communities in germany) 

Challenges 

D-Grid allows many different communities to access distributed 

high performance computing and storages resources. 

The challenge of DGI-2 is to create feasible accessibility 

and sound business models by ensuring suitable levels of 

security and performance; in conjunction with commercial 

and legal support. 

Highlights 

Security Management in D-Grid: The objective of security 

management is to coordinate all security related activities 

in D-Grid. One task is the definition of appropriate criteria 

for evaluating existing and potential security levels for the 

D-Grid communities. Another important task is the creation 

of suitable policies for supporting the sustainable operation 

of the D-Grid infrastructure. Additionally, L3S delivers 

pertinent recommendations and supports enforcing each 

security level while taking into account the specific applications 

of each grid community. 

In D-Grid, authorization is currently based solely on user 

identities as represented by public key certificates. This rudimentary 

approach will be replaced by a more fine-grained 

one, which extends the authentication and authorization 

infrastructure to additionally rely on user attributes. Authorization 

decisions shall be based upon attributes managed 

by the users’ Virtual Organizations (groups, roles), as well 

as the so-called campus attributes which are managed by 

their respective home organizations (nationality, affilia- 


were precisely outlined. In phase two, emphasis 

will be placed on the support and operation 

of the grid infrastructure, its data management, 

and security. The L3S Research Center 

is responsible for security management and 

development activities within DgI-2. 

L3S coordinates the security and development 

activities in DgI-2 with a strong focus on the sustainable 

implementation of services for e-science. 

For this purpose, L3S defines suitable 

levels of security in D-grid, implements the 

required authentication and fine-grained authorization 

together with concepts for using firewalls, 

and provides a comprehensive accounting 

infrastructure. 

tion). Further, the use of a Short-Lived Certificate Service 

shall simplify the access to D-Grid for entire communities 

by mapping users of existing identity management systems 

to short-lived public key certificates. 

The vast majority of resources in D-Grid are operated within 

networks that are protected by firewalls. Firewalls need to 

be correctly configured, so that unauthorized accesses are 

blocked, while seamlessly allowing legitimate communications 

to take place. To simplify this process, L3S delivers 

a set of profiles for firewall configuration characterized 

by different levels of security. Resource providers and user 

communities are able to choose the configuration that best 

meets their requirements. In order to verify that a given 

profile is correctly implemented, a tool automatically performs 

periodic checks to verify that the firewall is in compliance 

with expected behavior.

Development Activities in D-Grid: Although DGI-2 is a consolidation 

oriented project, small development activities in 

the area of accounting, monitoring and the user portal Grid- 

Sphere take place in order to close identified gaps. Based 

on the results of DGI-1, existing prototypes are extended 

to deliver stable and user-friendly services. The coordination 

has to ensure the quality of the results and the adherence 

to milestones. 

To provide a sustainable and long-term operation of the 

D-Grid infrastructure, comprehensive accounting is imperative. 

Due to a current lack of accounting facilities, L3S is 

developing a system to account for storage of distributed 

resources, cost-sensitive data and licensed software. 


DGI-2 is designed as a nucleus of the national grid infrastructure 

in Germany. Together with similar international 

grid providers, the National Grid Initiatives (NGIs) will 

introduce a new era in distributed high performance 

computing. 

INFORMATION 

Project Type: Funded by BMBF 


Research Areas: grid Computing 

uRL of the project: http://www.d-grid.de/ 


Prof. Dr.-Ing. gabriele von voigt, vonvoigt@L3S.de 

Prof. Dr.-Ing. Christian grimm, grimm@L3S.de 

Selected publications 

1. S. Piger, C. grimm, R. groeper, C. Kunz. A 

Comprehensive Approach to Self-Restricted 

Delegation of Rights in grids. 8th IEEE International 

Symposium on Cluster Computing and the grid 

(CCgrid2008), Lyon, May 2008 

2. j. Wiebelitz, S. Dal Pra, W. Müller, g. von voigt. 

The german grid Initiative: A uniform Accounting 

Service in Multiple Middleware Environments. 5th 

International Workshop on grid Economics and 

Business Models (gECON 2008), Las Palmas, August 

2008 

g.L. volpato, T. Metsch et al. (2008), Requirements 

3. 

on operating grids in Firewalled Environments, Open 

grid Forum document gFD-I.142 


56 

INFORMATION 

GDI-Grid – Geospatial infrastructure Grid 

using the grid for Flood Risk Assessment 

Spatial data has become a major asset for science 

and industry in the past decades. With 

the advent of widespread mainstream applications 

for spatial data infrastructures, demand 

for spatial information is on a sharp rise. Technological 

advance in data acquisition provides 

Motivation 

Using established standards and middleware solution, the 

Grid offers highly-scalable, secure and comprehensive storage 

and computing capabilities by interconnecting distributed 

resources. It seems natural to connect SDIs and the 

Grid and thus bring resource consumers and resource providers 

together. The main goal of “GDI Grid” is to close 

this gap between spatial data infrastructures (SDI) based 

on OGC web services and the Grid. For this, it is necessary 

to combine the current base technologies of SDI and 

Grid middleware to enable seamless processing of spatial 

data in Grids. 

Challenges 

Current SDI applications and the Globus Grid middleware 

both make heavy use of Web Service technologies. While 

Globus employs the Web Service Resource Framework 

(WSRF) standard and deploys additional security mechanism, 

conventional SDI applications normally adhere to one 

of the numerous OGC Web Service (OWS) standards. 

Coupling these standards and finding common security 

mechanisms is one of the major challenges in GDI-Grid. 

The project is working on an extension to the OGC standards, 

which implements an authentication mechanism 

for Web Service clients. With this solution, Grid-compatible 

authentication is possible for OGC Web Services, while 

backwards compatibility is preserved. 


researchers and companies with much more 

detailed raw data, but also greatly increases 

storage and processing demands. vast amounts 

of information from the spatial domain must 

be stored and processed into more meaningful 

representations. 

The gDI-grid project strives towards interoperation 

between spatial data infrastructure, geo 

information systems and grid computing by creating 

an interface for high-performance computing 

of geospatial data. using the infrastructure 

provided by the D-grid and grid-enabled workflows, 

geospatial simulation and data analysis will 

be dramatically accelerated. 

The implementation will be validated using the following 

three example scenarios: 

• spatial simulation of flood disasters 

• noise dispersion simulation 

• real-time route optimization for disaster management 

In current development, a focus is set on a scenario for flood 

simulation. In response to the frequent flooding hazards 

in Europe, the European Union has released a set of laws 

requiring that the probability and foreseen consequences 

of flooding to be determined. By the year 2013, all states 

of the EU have to provide flood risk maps for all river basins 

and stretches of coastal line. For this purpose, flow models 

such as two-dimensional hydrodynamic simulations, are 

applied to estimate the flood inundation areas. With storage 

resources and processing power, the Grid will help in 

realizing these simulations.

Highlights 

By relying on Web Services for GDI-Grid, a standard compliant 

proof of concept has been developed to test the 

interoperation of SDI and Grid. The GDI-Grid project partners 

– who belong to the cutting edge of the national SDI 

community – can leverage Grid resources for data storage 

and computation, improving simulation quality and 

speeding up calculations by a large degree. GDI-Grid services 

for hydrodynamic modelling can greatly enhance a 

spatial data infrastructure by tools that support the process 

of building a flow model and by reducing the necessary 

processing times. 


A wide array of possible applications for the GDI-Grid exists 

in the SDI world. In addition to the example scenarios 

denoted above, data management and processing methods 

developed during the GDI-Grid project will help the 

SDI community cope with increasingly complex workflows 

involving large amounts of input data. 

In the future, additional OGC standards will be adapted to 

the appropriate Grid equivalents to enable more different 

application types to make use of the Grid. 

INFORMATION 


Project duration: july 2007 – june 2010 

Project Research Areas: Spatial Data Infrastructures, 

grid infrastructure, Workflow development 

uRL of the project: http://www.gdi-grid.de/ 


Prof. Dr. gabriele von voigt, vonvoigt@L3S.de 

Prof. Dr. Christian grimm, grimm@L3S.de 


58 

INFORMATION 

RRZN – Computing Center for Science and Service 

Fundamental Research in High Performance 

Computing and grid Computing 

In the year 2008, fundamental research was 

performed in the areas of High Performance 

and grid Computing, with special attention to 

High Performance and grid Computing 

The work done in the areas of High Performance Computing 

(HPC) and Grid Computing centred on formulating the 

set of requirements for scheduling compute-intensive batch 

jobs. Based on this work, special emphasis was placed on 

evaluating various Linux multi-core systems for HPC and 

Grid Computing. One challenge in using multi-core systems 

is the implementation of highly scalable computational 

fluid dynamics (CFD) simulations. With this challenge 

in mind, a BMBF project proposal was initiated, together 

with 12 other researchers from universities, research institutions 

and industries. In the field of Grid Computing, special 

research was given to evaluating high throughput interconnections 

between the Grid Cluster and a Storage Area 

Network (SAN). With10 Gigabit Ethernet and Fibre Channel, 

two different approaches were investigated within a 

dedicated network environment. This work will be continued 

in 2009, by combining both technologies into a Fibre 

Channel over Ethernet and protecting the entire infrastructure 

with high speed firewalls. 

Research was also carried out to formulate benchmarks as 

a precursor for evaluating new HPC technologies at RRZN. 

Further work in 2008 concentrated on the integration of 

the new, high performance platform from SGI and the 

transfer of programs and data from the IBM Power 6 series 

platform to the SGI ICE 8200 Plus “Carlsbad+”. The system 

contains a Massively Parallel Processing system (MPP) 

and a Symmetrical Multi Processor system (SMP) providing 

about 35 Tflops/s. In 2009, this will be expanded to 


the technology of distributed systems, as well 

as IT security and search algorithms. 

The research focuses on the long-term goal of 

building the necessary foundation to sustain complex 

computing environments. Support rules for 

the operations of a high quality computing service 

center are developed with special regards to 

the Leibniz universität Hannover. 

24,832 cores delivering 312 Tflop/s peak performance. 

These larger numbers of cores require adequate implementations 

of CFD simulations in order to utilize the available 

computing power on the SGI. 

The internal project on accounting and billing in Grid environments 

is very closely linked with the two grid computing 

projects at RRZN, namely DGI-2 and GDI-Grid. The research 

in this project continued the development of the accounting 

and billing infrastructures started in 2005. 

IT Security within Distributed and High Performance 

Computing 

The work in the area of IT-Security in 2007 resulted in running 

systems now available at the Leibniz Universität Hannover. 

In 2008, the research dealt with the application areas 

of high performance and grid computing. The challenge 

we faced was to deliver high throughput and easy access,

while ensuring the required level of data protection and 

complying with strict security regulations for hardware. 

Search Algorithms in Distributed Systems 

The objective of the research is to build the prototype 

search engine for harvesting relevant documents and to 

define suitable indicators for information retrieval on the 

aggregated content base. In the later phases of the project, 

query engine modules will be developed for the purposes 

of analysis, text mining and the evaluation of adequate 

indicators and methodologies. The search engine 

will be designed to fulfil two main tasks within this project: 

1) dynamically finding new documents in the field of educational 

research (crawler), and 2) making the content of 

all of the documents available for searching, text mining 

and analysis (query engine). 

INFORMATION 

Project Type: 

Internal Project, funded by local government MWK 

Project duration: jan 2008 – Dec 2008 

Project Research Areas: High Performance and grid 

Computing, IT security, Search algorithms 



Prof. Dr. Christian grimm, grimm@L3S.de 


60 

INFORMATION 

UKoloS – Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications 

Best Practice for Industrial Wireless Applications 

Wireless connectivity has the potential to provide 

substantial benefits in industrial environments; 

for example, with an increase in mobility 

or a reduction in cabling costs. However, 

it imposes tight challenges on reliability and 

energy supply. In order to accomplish these 

challenges protocol and hardware design must 

Motivation 

The demand for self-configuring wireless networks for 

industrial control and sensing is experiencing a surge. 

For widespread market success, low cost and low power 

is also of major importance. Impulse Radio Ultra Wideband 

(IR-UWB) is a particularly suitable technique for the 

development of such networks. Its inherent high temporal 

resolution reinforces its robustness against fading and 

multiple access interference, making uncoordinated access 

to the channel possible. Further, low cost and low complexity 

implementation possibilities arise from its baseband 

nature. 

Challenges 

Advantageously, the inherent high temporal resolution of 

IR-UWB, allows low data rate scenarios to be realized with 

ALOHA, a physical-layer independent and low complexity 

approach. Provided that the system’s load is low, compared 

to the system bandwidth, recent work has proven 

the successful performance of the ALOHA principle. However, 

in self-configuring network scenarios, one can think 

of situations for which this approach may lead to inefficient 

and undesirable performance. For instance, if applications 

requesting higher QoS or increases load are involved. 

Sensor nodes are predominantly battery-operated, and in 

many cases not rechargeable, thus energy conservation is 

another important issue for protocol design in these networks. 

Power control and activity management are two 


offer a unified solution. The uKoLoS project 

aims at developing a medium access control 

(MAC) scheme that enables efficient and lowpower 

communications using Impulse Radio 

ultra Wideband (IR-uWB) radio technology in 

industrial applications. 

The main research effort of the uKoLoS project 

consists of the design of a novel, cross-layer, 

cognitive, MAC approach for low data rate, low 

power communications using IR-uWB radio. The 

approach consists of a rate adaptation function, 

which handles impulsive interference by autonomously 

adapting the links’s pulse rate (transmitted 

pulses per second), and a power saving 

function, which controls the sensors sleep/active 

cycles. 

main schemes for minimizing the energy consumption in 

wireless sensor networks. Since IR-UWB technology is characterized 

by the power efficiency of transmitter as well as 

the short-time data transmission, trying to save energy by 

means of activity management scheme is much more purposeful 

in this framework. 

UKoLoS addresses these two major challenges by means of : 

• a rate adaptation function which allows IR-UWB links to 

share the spectrum in a way that it is fair, efficient and 

compatible with individual QoS requirements 

• an activity management function to regulate the devices 

sleep/active cycles

Highlights 

The rate adaptation function is motivated by the fact that in 

IR-UWB systems, the limiting resource is the cumulative pulse 

load - as measured in pulses per second. Thus, it allows each 

source node to independently adapt its pulse rate (transmitted 

pulses per second). Nodes’ adaptations are driven by 

the goal of maximizing the aggregated network throughput, 

while achieving a fair resource allocation among users 

and guaranteeing a certain QoS at the bit level (expressed 

in terms of an optimal BER). Game theory has been used to 

develop and study this approach. 

The activity management function enhances the power saving 

scheme used in the IEEE 802.15.4a standard with mobility 

state and battery charge level information. Including mobility 

awareness, for nodes with low mobility, it results in great 

energy saving, whereas for fast moving nodes, the energy saving 

has to be traded off with the localization accuracy. When 

the energy efficiency is a priority, taking the rest battery state 

into the computation of the sleep interval, provides additional 

energy saving. UKoLoS has proven a beneficial integration of 

mobility and battery charge level awareness. 


The UWB radio technology offers a complementary 

approach to existing wireless technologies enabling additional 

features (accurate ranging) and applications, especially 

in the fields of communications, localization and sensor 

measurements. 

INFORMATION 


Project duration: june 2006 – june 2008 

Project Research Areas: ultra-Wideband radio 

technology, medium access control, interference 

mitigation, energy efficiency 


http://www.emt.tu-ilmenau.de/ukolos/ 


Prof. Dr. Klaus jobmann, jobmann@L3S.de 

Dipl. –Ing. M. Dolores Pérez guirao, lola@L3S.de 


“Pulse Rate Adaptive Multiple-Access Scheme for 

1. 

Cognitive Autonomous IR-uWB Networks “, M.-D. 

Pérez guirao, R. Luebbe, T. Kaiser, IEEE International 

Conference on ultra-Wideband – ICuWB 2008, 

Hannover, 10-12 September, 2008. 


62 

INFORMATION 

C3World – Connected Cars in a Connected World 

The Car’s World of Wireless Connectivity 

Imagine you’re stuck in a traffic jam while you’re 

on your way to an important appointment. 

Wouldn’t it be a good idea if cars encountering 

a traffic jam could disseminate this information 

to other cars, enabling them to choose 

a different route? If your car is equipped with 

Car-to-X communication, wouldn’t it be great 

In-Car Communication 

Motivation 

The connectivity of devices as well as people’s usage of it 

has increased immensely during the last couple of years 

and it is envisioned that this will grow in the future. Since 

people rely heavily upon their cars, they might like to use 

their portable devices within the cars as well. It is the goal 

of the In-Car-Communication project to create a seamless 

wireless handover from the portable device to an integrated 

communication system. 

Challenges 

The in-car environment is a challenging area for a wireless 

system. This is due, in part to the combination of metal 

and fabric inherently used in the construction of cars. This 

physical environment makes the prediction of the wireless 

signal’s behaviour very difficult. Furthermore, the electronic 

systems which are used in the car pose significant 

challenges to the adoption of a wireless system. Electronic 

sensitivity is twofold: the car’s system should, in no way, be 

disturbed by a wireless transmission, and the UWB [Ultra- 

Wideband] should not affect the normal operation of the 

car (e.g. starting the engine). 

Highlights 

The first step in this project is to study the feasibility of 

using UWB for in-car applications. To get a clearer insight 

into the situation, channel measurements have been per- 


if you were able to wirelessly connect your PDA 

to your car, integrating it into the car’s communication 

system and enable it to download 

your E-Mail and other data? The C3World project 

seeks to make this vision a reality through 

the development of the wireless Car-to-X- and 

In-Car Communication systems. 

C3World is a collaboration of the Niccimon (Competence 

Centre of Lower Saxony for information 

systems for mobile usage) and the volkswagen 

Ag. It aims at the provision of the technological 

prerequisites in order to connect cars with their 

environment. In this project, L3S is in charge of 

the adaptation of protocols for the Car-2-X scenarios 

as well as for the developments in the area 

of in-car communication both resulting in prototypical 

realisations. 

formed. The results are to be checked against the measurements 

that were done using “real” UWB hardware. Further 

measurements with products of different vendors are taken 

in order to compare them with each other for deriving an 

independent conclusion about the nature of propagation 

effects within a car. 


Future issues concern the combination of simulations with 

a hardware testbed environment. The testbed will consist 

of a UWB development kit for the actual transmission, 

which can be accessed and configured by a PC. The PC 

hosts a simulator which is in charge of the data link layer 

and other upper layers. This allows for adaptations of algorithms, 

testing them in a real setup and so comparing them 

with purely simulative results.

Car-2-X Communication 

Motivation 

Can we connect cars to the Internet while providing data 

rates high enough to sufficiently support multimedia applications? 

– This is but one of the questions which will be 

answered by developing highly-efficient and robust communication 

protocols within wireless Car-to-X communication 

scenarios. While the provision of internet access predominantly 

serves the infotainment domain, other important 

applications aim to improve roadway traffic efficiency and 

safety. Electronic brake lights which can increase the driver’s 

visual range and electronic merging assistance systems 

that avoid traffic jams are just two examples which motivate 

car manufacturers, suppliers and researchers all over 

the world towards developing Car-to-X communication. 

Challenges 

IEEE 802.11 wireless LANs have turned out to the technology 

of choice for enabling communication between 

cars and their environment. Possible network topologies 

include infrastructure networks (Car-to-Infrastructure) as 

well as Ad-Hoc networks (Car-to-Car). In contrast to conventional 

wireless LANs, these topologies are extremely 

dynamic with relative velocities of up to 400 kilometres 

per hour. These factors, in combination with application 

requirements concerning delay and reliability, pose major 

protocol design challenges. 

Highlights: 

INFORMATION 

Project Type: Funded by the Ministry for Science and 

Culture of Lower Saxony 

Project duration: April 2007 – March 2012 

Project Research Areas: Protocols for Car-to-X- 

Communication, uWB for In-Car Communication, 

georeferenced Search, Channel Modelling, Hybrid 

Networks, Integration of Mobile Devices 

uRL of the project: http://www.c3world.de 

Prof. Dr.-Ing. Klaus jobmann, jobmann@L3S.de 

Dipl.-Wirtsch.-Ing. Kim Bartke, bartke@L3S.de 

Dipl.-Wirtsch.-Ing. Henrik Schumacher, schumacher@L3S.de 

A simulation environment has been established to acquire insight 

into the behaviour of Car-to-X networks as well as the performance 

and tunability of the customized protocols. The environment 

is based on the OMNeT++ network simulator and forms 

the basis for the development of optimized protocols and subsequent 

tests with real equipment. In addition to this, the effects 

of certain Car-to-X applications on traffic efficiency have been 

evaluated by simulations with very encouraging results. 


Future work will mainly consist of enhancing the network simulation 

environment. This includes the improvement of the radio 

propagation modelling as well as the integration of realistic traffic 

mobility patterns. To achieve this, a coupling between network 

protocol, road traffic and radio channel simulations is planned. 


64 

INFORMATION 

WiMAX – Wireless broadband access in rural areas 

Future Internet for All! 

Today broadband internet access is often 

regarded as a social and strategic factor for 

enterprises and private households, as well 

as for the medical and the educational sector. 

However, there still is a digital divide between 

urban and rural areas regarding a basic availability 

of broadband internet access. The impli- 

Motivation 

At present, only urban areas of the European Union have 

guaranteed access and a comprehensive coverage of broadband. 

In most rural areas, where more than 25 percent of 

all European citizens live, broadband coverage is disproportionately 

inadequate. Consequently, 40 million private 

households and enterprise users do not have a satisfying 

access regarding modern internet-based applications. 

Challenges 

The digital divide between urban and rural areas is mainly 

caused by economic constraints, due to the fact that the 

development and implementation of wired broadband 

networks in rural areas is very cost intensive and often 

cannot be amortized in an acceptable period of time. The 

solution to this problem is the implementation of hybrid 

broadband access networks, a combination of wired and 

wireless broadband access technologies by one network 

carrier. The limiting factors are the cost for both the investment 

and the network operations. 

Research Highlights 

Today, the most promising wireless broadband access technology 

is IEEE 802.16, also known as WiMAX (Worldwide 

Interoperability for Microwave Access). Within this project 

the mobile enhancement of WiMAX (IEEE 802.16e) were 

analyzed with respect to its technological capacity and 


cation is that more than a quarter of all Europeans 

do not have a satisfying access to current 

and future internet-based applications. Driven 

by this disparity, the project focuses on the 

usage of Mobile WiMAX as a wireless enhancement 

in order to form economic hybrid broadband 

networks. 

The main results of this project have shown 

that there are efficient approaches available to 

establish economic, broadband access for future 

internet applications in rural areas. The recommended 

solution is the implementation of hybrid 

broadband networks, which contain both wired 

and wireless access networks for the last mile 

delivery. The project was managed by the L3S 

Research Center and executed with researches 

of the Leibniz universität Hannover and the Tu 

Braunschweig. 

investment requirements and operation. 

The project emphasizes the following tasks: 

• Performance analysis 

• Network dimensioning and simulation 

• Profitability analysis 

The media applications and the user behavior define the 

basic requirements for a wireless broadband access network. 

Taking this into account, several factors were evaluated: 

first, the Quality of Service (QoS) requirements of 

classical internet applications such as e-mail or file transfer; 

second, future internet real-time applications, such as 

Unified Communications, were also evaluated. Following, 

this theoretical performance analysis, the distribution of 

different user groups within the target area were statis-

tically determined. The resulting demand of bandwidth, 

depending also on the distribution of land use (Fig.1), was 

calculated and furthermore simulated (Fig. 2). Finally, the 

project was completed with a comprehensive profitability 

analysis to evaluate the so-called Total Cost of Ownership 

(TCO). 


The initial work in future internet applications establishes 

a strong foundation for the planning and implementation 

of hybrid access networks. Future work will focus on studying 

additional technical and social parameters in real-world 

scenarios. This will result in an improvement of the wireless 

approach regarding the needs of future internet applications 

and will provide a holistic “tool box” for the implementation 

of hybrid access networks in rural areas. 

Based on the results of this project the government of 

Lower Saxony, Germany, decided to fund a further twoyear 

pilot project to evaluate the results of this initial project 

in a real world scenario from 2008 until 2010. Within 

this pilot project two WiMAX-based access networks will be 

implemented and 300 users will be connected in two different 

rural areas. The radio systems based on IEEE 802.16 

will operate in the regulated 3.5 GHz band, but the project 

team will also be allowed to operate in the promising 700 

MHz band to analyze the possible interference between 

OFDM-based wireless communications solutions and digital 

broadcast solutions. 

INFORMATION 

Project Type: Local government Funding and PROFIL 

of the European union 


Project Research Areas: Future Internet, Network 

Simulation, Performance Analysis 


Prof. Dr.-Ing. Thomas Kaiser, kaiser@L3S.de 

Dipl.-Ing. Simon F. Rüsche, ruesche@L3S.de 


1. Rial, v.A. et al: Empirical propagation model 

for WiMAX at 3.5 gHz in an urban environment, 

Microwave and Optical Technology Letters, vol. 50, 

Issue 2, 2007 

Belghith, A., Nuaymi, L.: WiMAX Capacity 

2. 

Estimations and Simulation Results, vehicular 

Technology Conference, 2008. IEEE-vTC Spring 2008 


66 

INFORMATION 

EUWB – Coexisting Short Range Radio by AdvancEd Ultra-WideBand Radio Technology 

Need for More Data Speed! 

The EuWB-project has a three-fold aim, namely 

to: i) explore the enormous economic potential 

of the innovative and disruptive radio technology 

embodied in ultra-wideband (uWB); 

ii) combine the innovative uWB concept with 

advanced methods of wireless technology 

such as cognitive signaling, intelligent multi- 

Motivation 

Edholm’s law of bandwidth confirms an almost exponential 

increase of data rates in the last two decades for wireless 

and wired communication systems. Assuming this 

development holds true also for the future evolution of 

short range communication systems, we can expect peak 

data rates of up to 10 GBit/s over a distance of a very few 

meters by 2015. Such high data rates are the underpinning 

for high-quality multimedia streaming and high-speed 

data exchange between mobile devices. One can envision 

mobile phones offering storage capacities in excess of 100 

GB after 2010. Therefore, add-on technologies not only for 

boosting data-rates, but also for enhancing coverage and 

for improving link quality are required to fulfill the demand 

of future wireless short-range communications. The combination 

of Multiband-Orthogonal-Frequency-Division-Multiplexing 

(MB-OFDM) based UWB and multiple antenna systems 

at the transmitter and the receiver side, also known as 

Multiple-Input-Multiple-Output-systems (MIMO), enables 

very high data rates with a maximum of spectral efficiency 

and reliability. In the EUWB-project the combination of 

MIMO and UWB will be investigated for different complex 

scenarios such as public transportation, automotive environment, 

and home entertainment. 

Challenges 

Based on the complex scenarios, new system concepts and 

practical requirements will be identified. Measurements of 

radio channels shall reflect the identified generic measure- 


ple antenna and multiband/multimode uWB 

system concepts; and finally iii) enable the 

introduction of advanced services and competitive 

applications using the radio spectrum 

in a highly sophisticated manner by applying 

devices based on next generation uWB. 

The EuWB-project is focused on the application 

of MIMO-uWB technology in complex environments. 

From this technology, peak data rates of 

up to 10 gBit/s can be expected, which will enable 

multimedia applications such as very high quality 

video streaming and high speed data exchange 

between mobile devices. New add-on technologies 

especially for boosting data-rates or for 

enhancing coverage and improving link quality 

will be developed to fulfill the demand of future 

wireless short-range communications. 

ment scenarios and will be performed with a MIMO-UWB 

real-time sounder. Consequently, a succeeding part of this 

task is the research on and definition of a set of (time-variant) 

channel models describing the spatial and temporal 

behavior and correlation in MIMO-UWB for the different 

scenarios. Further research areas are: 

• The ultimate range extension obtainable with MIMO- 

UWB for the applications of interest 

• The role of channel state information on the MIMO- 

UWB capacity, including information on positions and 

angle of arrivals 

• The ultimate increase in interference rejection via spatial 

separation/beam forming techniques obtainable with 

MIMO-UWB in the multi-user scenario

In the next step, a MIMO-UWB test-bed for research and 

algorithm evaluation will be built to provide an important 

tool for access to the real MIMO-UWB channel and for verifying 

model-based algorithms and system design. 


The research highlights of the working area “MIMO-UWB” 

within the EUWB-project are the following: 

• Identification and provision of system concepts, requirements 

and measurement set-ups for 

• MIMO-UWB in different complex scenarios 

• Provision of a MIMO-UWB test-bed for evaluation and 

verification of specific multiple antenna algorithms, system 

designs and studying of multi-user and interfering 

scenarios by providing access to the real MIMO channel 

• Development of application-aware algorithms to enable 

link quality improvement, range extension and multiuser 

enhancements 

• Development of implementation-aware algorithms and 

system design to solve the challenges arising from various 

application-oriented solutions 

• Resource evaluation and validation of certain multiple 

antenna solutions via prototyping approaches 


Within the work area of the EUWB-project the MIMO-UWB 

technology will be applied to complex applications such as 

public transportation, automotive environment and home 

entertainment. Further, the localization of tags in the urban 

INFORMATION 

Project Type: Integrated Project Eu/ICT FP7 

Project duration: Apr 2008 – Mar 2011 

Project Research Areas: MIMO-uWB, Channel 

measurements and modeling, Test-bed 


Prof. Dr.-Ing. Thomas Kaiser, kaiser@L3S.de 

Dr.-Ing. Claus Kupferschmidt, kupferschmidt@L3S.de 


1. Emil Dimitrov and Thomas Kaiser: Advanced MIMO 

vHDR MB-OFDM Approaches, The 2008 IEEE Int. 

Conf. on ultra-Wideband, ICuWB 2008, Hannover, 

September 10-12, 2008 

2. Claus Kupferschmidt, Emil Dimitrov and Thomas 

Kaiser: Multiple Antenna uWB Systems - WP3 of the 

EuWB Project, Invited Session, The 2008 IEEE Int. 

Conf. on ultra-Wideband, ICuWB 2008, Hannover, 

September 10-12, 2008 

F. Berens, E. Dimitrov, T. Kaiser, A. Anttonen, A. 

3. 

Krause and A. Weir: An enhanced very high data rate 

uWB air interface based on the WIMEDIA standard - 

An European view, IEEE Int. Conf. on ultra-Wideband, 

ICuWB 2007, Singapore, 24-26 Sept 2007 

traffic transport has been identified as a future application 

of MIMO-UWB. Considerable industrial partners within the 

EUWB-project will push the implementation of MIMO-UWB 

technology in future industrial products. 


68 

INFORMATION 

RoboLoc – Infrastructure-Aided Localization with UWB Antenna Arrays 

“Where am I?” 

Localization in Indoor Scenarios 

As everyone knows cleaning your home can 

be a bothersome activity and it is probably 

not what you like to do most with your free 

time. Having a household robot is not a new 

idea and has recently been depicted in popular 

movies such as “I, Robot” or “The Bicentennial 

Motivation 

Wireless Ultra-Wideband (UWB) systems are characterized 

by an enormous bandwidth, ranging up to several GHz. It 

is therefore a promising candidate for high data rate indoor 

communications and, in parallel, for the precise localization 

of UWB signal-emitting objects. The reason is that the 

huge bandwidth results in very short pulses in the order 

of 100 picoseconds and below. These short pulses lead to 

a very high resolution of 10cm and even less. 

Challenges 

Though having all these benefits, the Ultra wideband Technology 

suffers from the fact that only a very small transmit 

power (approx.0.5mW) is allowed for the transmission 

when compared to a GSM cellular with a transmit power of 

2W. Hence, signal processing, as well as RF technology, are 

the biggest challenges for this technology since the perspective 

is absolutely contrary to present technology. 

When compared to a sparse-path radar scenario, the dense 

UWB multi-path environment makes the reliable detection 

of the direct path between transmitter and receiver an 

ambitious challenge. For instance, the channel of a typical 

indoor environment consists of a few hundred paths, 

whereas the direct path only carries the relevant location 

information since the indoor environment is generally 

unknown. 

Nevertheless, the first testbed has been successfully built 

and objects have been located at distances of 1cm - in the 


man”. In order to realize the ideal of a household 

robot, the challenge of robot localization 

must be addressed; namely, the robot should 

know its exact position at any time. RoboLoc 

tries to solve this problem. 

The RoboLoc project deals with the development 

of a new localization system. The primary target 

for this system is a household robot. The basic 

technology used for this project is ultrawideband 

which is seen as a perfect candidate for high resolution 

radar, due to its very short pulses in the 

order of 100 picoseconds and less. The project is 

based on a novel approach - phased arrays - to 

overcome the challenge of robot localization. 

so called “Line of Sight” scenarios. Such scenarios imply 

that the mobile unit can “see” all of the receiving units. 

Hence, there is a direct path between the mobile and the 

receiving unit. For the household robot scenario, many situations 

arise where the direct path is either obstructed or 

even blocked, for instance by a wall, a closet or a person 

stepping in the way. 

R&D Highlights 

One potential solution to these Non-Line of Sight situations 

is the BeamLoc algorithm, which forms the basis of 

this project. Very narrow antenna beams, derived from a 

phased array, rotate around the mobile unit, as well as the 

receiver, to detect the direct path. By using triangulation, 

the object’s position can be derived.

The aforementioned phased arrays are a hot topic in the 

commercial market, and will potentially find their application 

also in automotive radars. Their popularity is due to 

the fact that instead of using a single mechanically rotating 

antenna, multiple antennas are used, which are excited 

at different times, leading to an additive superposition in 

one direction. Hence the transmit unit’s direction can be 

steered electronically. The concept has been used successfully 

in military settings, as well as civil aviation; but has 

neither been adapted to Ultrawideband technology nor to 

the broader commercial market. 


Beside the household robot, many more application fields 

can be found for localization technology, e.g. an actor or 

musical star can be located on the stage so that the spotlight 

can easily be directed on him. Moreover, the technical 

equipment of a hospital can be tracked, so that in urgent 

cases, it can be found directly. Firemen can be located during 

their rescue mission, or a car can be lead directly to a 

free parking lot in a garage. 

INFORMATION 


Project duration: 3 years 

Project Research Areas: ultrawideband Technology, 

Localization, Signal Processing, RF engineering 


http://www-emt.tu-ilmenau.de/ukolos/sub_RoboLoc.php 


Prof Dr.Ing. Thomas Kaiser, kaiser@L3S.de 


1. “Hybrid Localization using uWB and Inertial 

Sensors”, S. Sczyslo, j. Schroeder,S. galler, T. Kaiser, 

Leibniz universität Hannover, ICuWB 2008 

2. “Dual-orthogonal polarized vivaldi antenna for 

ultra wideband applications,”g. Adamiuk, T. Zwick, 

and W. Wiesbeck, International Conference on 

Microwaves,Radar and Wireless Communications 

2008. 

“FIR filter based equalization of ultra wideband 

3. 

mutual coupling on linear antenna arrays“, Neinhüs, 

M.; Held, S.; Solbach, K., 2nd International ITg 

Conference on Antennas 2007 


70 

INFORMATION 

PULSERS II – Pervasive Ultra-Wideband Low Spectral Energy Radio Systems Phase II 

The Train is Leaving Now... Can You Stream 

Those Five DvDs to My Pocket PC Please!? 

PuLSERS Phase II, an industry-led initiative of 

39 major industrial and academic organisations, 

will continue and extend the successful 

work carried out in Phase I. The first phase, the 

Integrated Project PuLSERS, started in january 

2004 within the IST Programme (FP6) of the 

6th Eu Framework Programme, and was successfully 

completed year end 2005. The suc- 

Motivation 

The almost exponential increase of data rates experienced 

over the last two decades has invoked a wide spectrum of 

novel applications in existing Wireless Personal Area Networks. 

The ever increasing demand for high speed wireless 

indoor communications paved the way for the development 

of numerous wireless schemes capable of delivering 

peak data rates of up to 480 Mbps over the airway. Very 

High Data Rate (VHDR) applications such as high definition 

video streaming or multimedia exchange between handheld 

devices call for advanced technologies not only able 

to boost the data rates well beyond 1 Gbps, but also capable 

of improving the coverage and link reliability of future 

short range communications. 

Multiple-Input Multiple-Output (MIMO) systems have been 

widely considered such as viable solution to overcome the 

current limits in wireless communication. The application 

of Ultra-wideband to indoor environments, with the rich 

energy scattering and large angular spreads of the multipath 

channel present there, provides an ideal scenario for MIMO. 

By including the spatial dimension, multiple antennas can 

effectively turn multi-path propagation, considered initially 

a drawback in wireless communications, into an advantage 

so as to linearly increase the capacity and data rate of the 

system, and/or improve the quality of the wireless link. 

Challenges 

However, the benefits of MIMO often come at the price of a 

manifold increase in complexity, and consequently, the total 


cessor PuLSERS Phase II builds on the results 

of the first phase and aims to research ultra- 

Wideband (uWB) innovative devices and system 

concepts starting with proof of concept 

and obtaining fully working experimental prototypes 

enabling verification of the objectives 

and specific technical approaches. 

The main objective of PuLSERS II is to explore the 

enormous potential of ultra-Wideband technology 

by means of research, concept development 

and integrated system definition including verification 

platform implementation. The project 

members actively contribute to regulation and 

standardisation targeting to set preconditions 

for harmonised and viable technical framework 

enabling the use of uWB in Europe. 

area and power consumption of the system. While the application 

of MIMO to UWB has received considerable interest 

in the academic world in the last few years, the field of real 

implementation and verification of MIMO UWB is still in its 

early stages. It is therefore our task to explore the major challenges 

of the future employment of multiple-antennas to 

VHDR UWB systems, propose viable solutions for efficient 

MIMO architectures and verify the achievable gains under 

real-world constraints. 

Although MIMO UWB offers an additional degree of freedom, 

namely the bandwidth, MIMO UWB research is still in 

its infancy in comparison with the work in narrowband MIMO 

systems, implying that many questions are still open: 

• Due to the huge bandwidth of 7.5 GHz, UWB antenna 

parameters and electrical properties become strongly 

dependent on frequency. Further, the inclusion of UWB 

antennas into the whole effective UWB Channel Model

has to be considered 

• Effects of mutual coupling among neighbouring antennas 

upon the overall performance of the MIMO UWB system 

• MIMO UWB signalling trade-off’s (e.g. diversity gain vs. 

multiplexing gain) 

• Suitable MIMO architectures and implementation complexity 

• Energy efficiency of MIMO UWB systems 


Throughout PULSRES II, we are concerned with MIMO signaling 

schemes to realize the performance gains promised, 

while taking into account real-world constraints such as 

channel uncertainty, low transmit power, and delay limitations. 

This work provides a firm basis and guidelines for 

the design of UWB multiple antenna systems for both lowand 

very high data rate applications. A further benefit of 

MIMO is the improved, and so far virtually unused, capability 

for positioning, location tracking, and imaging. For 

certain applications, only rough localization information is 

required, but devices have to be of very low complexity, 

while for other applications, accuracy has to be high. We 

are working on algorithms and techniques covering both 

cases, improving the performance and lowering the complexity 

of rough regioning and high-precision locationing 

and imaging algorithms. 

All the above MIMO approaches are supported by activities 

characterizing, modeling, and measuring the dynamic 

UWB channel. A novel time-varying MIMO UWB channel 

model has been developed, taking into account spatial cor- 

INFORMATION 



Project Research Areas: ultra-Wideband Technologies, 

Services and Applications 

uRL of the project: http://www.pulsers.eu/ 


Prof. Thomas Kaiser, kaiser@L3S.de 

Dipl.-Ing. M. Dolores Pérez guirao, lola@L3S.de 


1. Mohamed El-Hadidy, Taleb Ould Mohamed, Feng 

Zheng and Thomas Kaiser: 3D Hybrid EM Ray-tracing 

Deterministic uWB Channel Model, Simulations and 

Measurements, 2008 IEEE International Conference 

on ultra-Wideband, ICuWB 2008, September 10-12, 

2008. 

2. Emil Dimitrov and Thomas Kaiser: Advanced MIMO 

vHDR MB-OFDM Approaches, 2008 IEEE International 

Conference on ultra-Wideband, ICuWB 2008, Sept 

10-12, 2008. 

Mohamed El-Hadidy and Thomas Kaiser: An uWB 

3. 

Channel Model Considering Angular Antenna Impulse 

Response and Polarization, The Second European 

Conference on Antennas and Propagation (EuCAP 

2007), Edinburgh, uK , Nov 11-16, 2007 

relation and the impact of real-world UWB antenna arrays, 

to provide a realistic model for communication and localization 

applications. 


72 

INFORMATION 

Prototype for Linux/Xenomai and Java 

Open Source Software for vehicles and 

Equipment of Armed Forces 

The armed forces are interested in new IT 

trends like open source real time operating 

systems and embedded systems development 

with high level programming languages. Thus 

Motivation 

The number of electronic control units (ECUs) installed on 

armed forces vehicles and equipment is growing continuously. 

Analogous to factory and automotive industry automation, 

functionality is increasingly being implemented 

in software. But unlike desktop or business applications, 

embedded applications at present depend strongly on the 

embedded hardware and specialized operating systems. 

These heterogeneous conditions increase the cost of future 

developments. Another limiting factor is underutilization 

of high level programming languages, modern operating 

systems and software tools that can be useful in coping 

with the high complexity of large software projects. Thus 

this project aims to exemplify how armed forces can use 

modern, real time operating systems and high level programming 

languages for future developments. 

Challenges 

The prototype that was built featured two mobile surveillance 

robots and one operator station. The two robots are 

based on the MoRob-Kit (Modular Robotic Toolkit) and 

are equipped with a number of sensors for autonomous 

navigation. In addition to basic mobility functions such as 

localization and teleoperation, the robots are able to collect 

3D environment data. This data is transmitted via WLAN 

to the operator station. The function of the operator station 

is to fuse the data of the two surveillance robots and 

to display a 3D situation picture. 


the L3S was commissioned to demonstrate the 

capabilities of Linux/Xenomai and java in a prototype 

application with mobile, radio linked, 

surveillance robots. 

The amount of embedded software that is integrated 

into new equipment and vehicles for the 

armed forces is continuously growing. Thus this 

project aims to examine whether Linux/Xenomai, 

a modern real time operating system, in 

combination with the high level programming 

languages such as C++ and java can be used for 

efficient development in the future. 

This demo application includes a number of tasks with 

hard real time and soft real time requirements. Tasks with 

hard real time requirements are implemented in C++ on 

the open source real time operating system Linux/Xenomai. 

These tasks include: 

• Real time 3D data acquisition 

• Localization of mobile robots in urban outdoor environments 

• Synchronization between 3D laser data and robot position 

data.

The components with soft real time requirements are implemented 

in Java/Java3D, and include: 

• Wireless data communication between the mobile robots 

and an operator station 

• Fusion of the sensor data from different robots 

• Displaying a combined 3D situation picture at the operator 

station 

An important issue considered is the data transmission over 

WLAN and its capability to handle real-time data between 

the robots and the operator station reliably. It was demonstrated 

that this challenging task can be achieved under 

optimal WLAN conditions i.e. fast and unhindered radio 

communication. 


The aim of this project was to implement a first prototype 

which was successfully presented in February 2008. 

The presentation covered a reconnaissance scenario with 

two robots examining an unknown vehicle. This vehicle 

was scanned from two sides. The robots transmitted their 

view of the unknown vehicle to the operator station where 

both 3D situation pictures were continuously combined 

into one view. 

The evaluated software products and techniques can be 

integrated into new vehicles and equipment for the armed 

forces. In doing so, the development process can be made 

more flexible an efficient. 

INFORMATION 

Project Type: governmental funded 

Project duration: October 2007 – February 2008 

Project Research Areas: real-time systems, 3D 

perception and data fusion, cooperative robotics 



Dipl.-Ing. Sebastian Smolorz, smolorz@L3S.de 


Oliver Wulf, Andreas Nüchter, joachim Hertzberg 

1. 

and Bernardo Wagner; “Benchmarking urban 6D 

SLAM”, in journal of Field Robotics, vol. 25, Issue 3, 

March 2008. 


74 

NEW PROJECTS 

LEARNING 


NEW PROJECTS 

As learning technologies are becoming an integrated and critical component of corporate 

knowledge management, the objective of the L3S research area “Learning” is to combine 

information and knowledge technologies in innovative environments and services for life long 

learning. Personalized learning environments developed at L3S enable more efficient and sustainable 

learning of students and employees. 


76 

LEARNING 

GRAPPLE – Generic Responsive Adaptive Personalized Learning Environment 

We Are All Individuals, We Are All Different 

With the growing diversity of learner needs, 

goals and usage contexts, personalization 

will be a key factor for the success and acceptance 

of learning technologies. Two decades 

of research in adaptive educational hypermedia 

has produced many prototypical systems. 

Motivation 

Learning management systems (LMS) are widely used in 

higher education as well as in lifelong learning. Most of 

these systems use a one-size-fits-all approach in catering 

to its learners. Since learners have different needs, goals, 

interests and backgrounds, the learning process would 

be greatly improved if the system would take these differences 

into account while selecting, ordering and presenting 

the learning material. A large body of knowledge 

and techniques is available from the fields of adaptive educational 

hypermedia and technology-enhanced learning. 

The main objective of GRAPPLE is to support life-long 

learning by means of a personalized and adaptive, technology-enhanced 

learning environment that is seamlessly 

integrated with major learning management systems in a 

service-oriented web-based approach. 

Challenges 

Most adaptive learning systems have been developed in 

a research context. They are typically prototypes that are 

built for one specific usage context, with specific learner 

models and personalization techniques that are tightly 

linked with the underlying domain. The framework needs 

to take this heterogeneity into account and to allow LMSs 

to use their own models and techniques, while at the same 

time centralization and the sharing of user models needs 

to be stimulated. 


Most learning management systems, however, 

do not yet include many adaptation functionalities. 

gRAPPLE will provide a generic personalized 

learning environment, which connects 

and extends existing systems. 

The gRAPPLE project aims to deliver a technology-enhanced 

learning environment which guides 

users through a life-long learning experience. A 

key underpinning of the gRAPPLE system design 

is its automatic adaptation to a user’s personal 

preferences, prior knowledge, skills competences, 

learning goals and personal or social context. 

Highlights 

The L3S Research Center is mainly involved in the work 

on distributed user modeling methods and techniques. In 

cooperation with DFKI, the Technical University of Eindhoven, 

and Delft University of Technology we are designing 

a platform and storage architecture that is open for both 

internal and external user-adaptive systems. Rather than 

adopting a monolithic approach, as was common in the 

1990s, the core system will provide basic functionality for 

connected parties to share and reason about each others’ 

refined and contextualized user profiles via standardized 

interfaces. In theory, this could mean that one will have to 

choose between several competing parties that offer their 

own versions of a ‘user interest model’. A provenance mechanism, 

which enables tracing back all reasoning steps to the 

original observation, allows parties to verify the trustworthiness 

and applicability of the inferences. We expect that

this competitive, evolving, and demand-driven approach 

will answer the needs of adaptive learning environments 

far better than a predefined, centralized user model. 


Experimentation and user evaluation play a central role in 

the GRAPPLE research and development process. In the 

first year of the project, emphasis was placed on requirements 

elicitation, both in academia and in industry. The 

framework will incorporate state-of-the-art techniques and 

will support major open-source and commercial learning 

management systems. This provides a great opportunity for 

researchers for investigating the effects of adaptive technologies 

in real-world contexts on a larger scale. 

LEARNING 

Project Type: 

Specific Targeted Research Project Eu/IST FP7 

Project duration: February 2008 – january 2011 

Project Research Areas: Adaptive Educational 

Hypermedia, user Modeling, Semantic Web 

uRL of the project: http://www.grapple-project.org/ 




78 

LEARNING 

PROLIX – Aligning Learning and Business Processes in Enterprises 

Lifelong Learning at the Workplace 

In many enterprises, learning processes are still 

decoupled from business processes. As a result, 

employees are acquiring competencies they 

can’t apply to their daily work, and are missing 

knowledge they would need to perform 

their tasks effectively. As enterprises change 

Motivation 

Today enterprises adapt their processes continuously to 

changing business needs. As a consequence, employees 

need to acquire new skills on a regular basis, making ‘lifelong 

learning’ a normal part of life. However, deciding 

which competencies are needed in the near or mid-term 

future and planning the corresponding learning activities 

has become a challenge for enterprises, because learningprocesses 

and business-process changes are often disjointed. 

The aim of PROLIX is to provide an integrated management 

environment for business and learning processes. 

To achieve this goal existing and newly developed applications 

are integrated into a service-oriented architecture. 

Challenges 

The integration of professional learning into the enterprise 

change management raises conceptual as well as technical 

issues. The main conceptual challenge is the design 

of a competency model which allows organizations to 

track the actual and desired skills of individuals, as well 

as required competency profiles for organizational roles. 

From a technical point of view, the major challenge is to 

integrate existing, largely monolithic applications, such 

as business process management systems and integrated 

learning platforms. 


their business processes at an ever faster pace, 

this problem is exacerbated. PROLIX realizes 

an integrated support system to align learning 

processes with business needs. This allows 

the individual, as well as the organization, to 

optimize their learning plans. 

For agile enterprises, business process changes 

and professional learning processes need to be 

highly coordinated. PROLIX provides the tools and 

methods to cope with this challenge. 

Highlights 

As usual in service-oriented architectures, PROLIX uses an 

Enterprise Service Bus (ESB) to interconnect components. 

The main technical contribution is a novel combination of 

service technology and workflow support, facilitated by 

the event-condition-action (ECA) pattern. Each component 

publishes relevant events on an event channel provided 

by the ESB. Workflows can be associated with these 

events, and specified to perform actions when the corresponding 

event occurs. Using this approach, the PROLIX 

architecture realizes tight integration while at the same time 

keeps components decoupled. The declarative workflow 

specification allows easy customization of processes to an 

individual enterprise context. 

In the past, the development of a comprehensive competency 

model has been the core effort. Now, the design and 

specification of processes supported by PROLIX is being targeted. 

The introduction of competency plans captures all 

learning information related to a specific business change. 

A competency plan’s lifetime starts with change-planning,

and continues with the selection of appropriate courses to 

realize existing competency plans, and additionally, methods 

for actually conducting the selected courses. In this 

way, the entire lifecycle of learning activities associated 

with business process improvements is covered. 

Further Work 

In the next year, the project plans to generalize its approach 

to a SOA for learning architecture. This architecture will 

significantly extend to existing proposals for standardized 

learning services and will provide the means for integration 

of non-partner third party applications as components. 

Evaluation in different application areas (telecommunications, 

publishing, government) will be continued and the 

results taken into account for further improvement. 

LEARNING 


Project duration: December 2005 – December 2009 

Project Research Areas: Service-oriented architecture, 

Competency management 

uRL of the project: http://www.prolix-project.eu/ 



Dr. Wolf Siberski, siberski@L3S.de 


Philipp Kärger, Daniel Olmedilla, Fabian Abel, Eelco 

1. 

Herder, Wolf Siberski: What Do You Prefer? using 

Preferences to Enhance Learning Technology. IEEE 

Transactions on Learning Technologies 1(1): 20-33 

(2008) 


80 

LEARNING 

TENCompetence – Building the European Network for Lifelong Competence Development 

Learn Because You Can – Can Because You Learn! 

Learning does not end once you have finished 

school or university. If you want to be successful 

in your current job, or if you have aspirations 

for a new job, you ensure that your skills 

and competences are up-to-date. There are 

Motivation 

In the past, one learned the essential skills for a lifelong 

job. Currently, virtually everyone is confronted with the 

need to develop themselves within today’s demanding, 

knowledge-based society. Most electronic learning platforms 

are based on formal curricula that typically do not 

meet the highly specific needs of a lifelong learner, who has 

to combine the learning activities with the demands of a 

regular job. A more informal, competence-based approach 

ensures that the learning process is tightly integrated into 

the knowledge worker’s everyday life. 

Challenges 

Learning and the acquisition and exchange of knowledge 

takes place on different levels. On the most informal level, 

people share and make use of knowledge resources via 

a large variety of tools: local intranets, email, collaborative 

working environments, blogs and bulletin boards, as 

well as popular sites such as YouTube and Flickr. To date, 

there is no unifying framework for these various knowledge 

sources and a more integrated search and browsing 

approach is needed. 

In a more formal type of learning - explicit learning - makes 

use of one or more units of learning. New pedagogical 

models should ensure self-directed and self-paced learning, 

with new types of assessment to provide evidence that 

a competence has indeed been acquired. 


many learning opportunities to choose from, 

but which ones do you need? And who can 

help you to become adept at with new software-skills 

requirements? 

TENCompetence provides a flexible and costeffective 

solution for learners that require lifelong 

competence development. Its infrastructure 

helps users to develop their competences (or 

acquire new ones) in a very flexible way: allowing 

users to build life-altering skills, in a convenient 

manner. 

A more conceptual problem is the planning of these learning 

activities. If there are several alternative options, which 

ones are the best options? And is there an optimal order 

in which to plan these activities? 

Finally, people do not learn in isolation. In lifelong learning, 

networks and communities play an important role. However, 

it is challenging to identify networks to join which 

can foster a mutual exchange of expertise. 

Highlights 

In the first years of the project many tools have been developed 

to address the challenges. Experimental evaluation 

has increased our knowledge on how to better support the 

process of lifelong learning. 

The Personal Development Planning Tool is an interactive, 

Web-based application that helps learners in generating, 

inspecting and revising their development plans. A Graph-

ical Planning Tool provides comprehensive drag-and-drop 

planning options. Personal advice is provided by the Hybrid 

Personalizer, which combines complementary techniques 

such as course sequencing, collaborative filtering, community 

rating and preference-based search. 

The LearnWeb 2.0 Environment provides one-stop access to 

learning opportunities in traditional learning management 

systems as well as in popular Web 2.0 repositories and communities, 

including Flickr, YouTube and FaceBook. 

Other tools include the ReCourse editor, a powerful tool for 

teachers to organize their courses, and the TenTube platform 

for educational video content. 


The tools and approaches developed within TENCompetence 

provide many insights in how to stimulate and support 

lifelong learning. A variety of tools is developed that 

together serve as a basic technological infrastructure. The 

challenge of the final year of the project is to integrate the 

bits and pieces, and to apply them in business settings. 


LEARNING 

Project duration: December 2005 – November 2009 

Project Research Areas: E-Learning, Adaptive 

Hypermedia, Social Networks, Context and user 

Technologies 

uRL of the project: http://www.tencompetence.org/ 



Dr. Eelco Herder, herder@L3S.de 


1. Philipp Kärger, Daniel Olmedilla, Fabian Abel, Eelco 

Herder, and Wolf Siberski. What do you prefer? using 

Preferences to Enhance Learning Technology. IEEE 

journal for Transactions on Learning Technologies, 

1(1), 2008. 

2. Ivana Marenzi, Elena Demidova, Wolfgang 

Nejdl: LearnWeb 2.0: Integrating Social Software 

for Lifelong Learning. Proc. World Conference 

on Educational Multimedia, Hypermedia and 

Telecommunications (ED-Media 2008), 2008 

Arne Wolf Kösling, Eelco Herder, juri Luca De 

3. 

Coi, Fabian Abel: Making Legacy LMS adaptable 

using Policy and Policy templates 16th Workshop on 

Adaptivity and user Modeling in Interactive Systems, 

2008. 


82 

LEARNING 

HELCA – Hannover eLearning Campus 

eLearning Services for 20 000 Students 

The project HELCA was successfully finished in 

2008 and achieved all major goals. As a consequence, 

the eLearning Service Department, 

ELSA - which was founded during the project 

runtime - was transformed into a permanent 

Motivation 

The use of digital media is quite common for students. It 

was therefore an imperative for the Leibniz University to 

focus on the significant potential , that digital media can 

offer for enhancing lectures. ELSA is exploring and realizing 

e-Learning solutions to benefit both students and teachers. 

The ELSA services include individual care, via telephone 

hotline and electronic mail. Additionally, ELSA offers system 

training for students and employees so they can so they 

can become efficient users; thus enhancing their experience 

with eLearning lectures. Currently, ELSA is initiating 

talks with its faculty to increase the synergy of e-Learning 

throughout the university. 

Highlights 

In 2005, HELCA established the student information system 

and learning management platform Stud.IP. Currently, this 

system provides online access to information and relevant 

learning material for lectures to all students. It is a valuable 

means for communication and collaboration; offering 

digital library access, and modules for assessment, surveys 

and multimedia support for eLearning. Stud.IP has 

become the mail portal for all eLearning related activity 

in the university. 

To publicize this development, in October 2008 the ELSA 

team organized a central event for all freshmen students. 

This two-day event “Erstsemestertage” seeks to welcome 

all new students to university life and introduce them to the 


department of the university. The new department 

ELSA aims at providing and maintaining 

essential eLearning services and has also set 

up support services for all 20,000 students and 

the university staff. 

The HELCA project focused on establishing central 

services for eLearning at the Leibniz university 

Hannover. As a result, ELSA, the eLearning 

Service Department, is now operational, helping 

20,000 students with lecturers in an eLearning 

environment. 

Leibniz University online services. It was the first time, the 

Leibniz University set ELSA in charge of both single events 

and the result was convincing. The first day attracted 3000 

students out of 3800. Over 1200 students visited the event 

on the second day. 


In 2009, ELSA will start new services in the Leibniz University. 

The first service, named “Flowcast”, will cover the 

end-to-end production of lecture video recordings; fully 

automating the workflow and emphasizing simplicity of 

use. The outcome of the ELSA project, has allowed us to 

identify the main technical bottlenecks: specifically, the 

labor-intensive stages in recording and post processing 

lectures. Also teachers with little technical knowledge will 

only need to start and stop the video recording of their 

lectures with a click on a button and the recording will be

published on the Stud.IP system within minutes after the 

lecture has finished. 

As a second main project, ELSA together with the Leibniz 

University will set up a first help desk for students, addressing 

questions related eLearning and the digital media services 

of ELSA. Therefore, it will complement ELSA’s existing 

support services with face-to-face communication. 

LEARNING 


Project duration: july 2005 – june 2008 

Project Research Areas: eLearning, learning 

management systems, IT and media services 

uRLs of the project: 

http://www.elsa.uni-hannover.de 

http://elearning.uni-hannover.de 




Dipl.-Sozw. Cornelis Kater, kater@L3S.de 


84 

LEARNING 

L3SCPD – L3S Center for Professional Development 

How to Develop 

eLearning Scenarios Scientifically 

The L3SCPD project focuses on a central 

research question: How can innovative information, 

learning and knowledge technologies 

be used in education with an added value? For 

this purpose, eLearning experts are working 

Motivation 

Current research on media didactics falls shorts on elucidating 

the results which are applicable for every day education. 

They are either too general or too detailed to give 

useful recommendations for the design of eLearning scenarios. 

From a practical point of view, there are many open 

questions to be considered. Specifically: How can new 

media be used for education? What is the added value? 

What do lecturers have to consider when designing an 

eLearning scenario? 

The solution is a recently developed research approach 

founded on a sound scientific methods that are applied to 

the eLearning domain. The so-called design-based research. 

As this research approach is rather new, we are testing it by 

developing a new eLearning scenario. For this reason, our 

current research work has the following goals: 

a) Development of a new eLearning scenario using the 

design-based research approach. 

b) Further development and refinement of the research 

approach based on the pending research outcomes. 

Challenges 

Current work deals with an innovative eLearning scenario 

that is based on lecture recording [1]. Our goal is to reduce 

the teacher-centered character of the media by creating 

learner-centered eLearning scenarios. Thus, we created a 

new eLearning scenario called VideoLearn [2]. Students 


on didactical and methodological issues. The 

main goal is to ground eLearning scenarios on 

empirical findings by using the design-based 

research approach. 

L3SCPD stands for L3S Center for Professional 

Development. The goal of L3SCPD is to develop 

eLearning scenarios based on the design-based 

research approach. 

learn in groups of two or three using a text guide, the normal 

lecture materials and the recorded lectures. Based on 

the available media, each group of students should be able 

to answer the questions in the text guide. Some challenging 

questions within this setting are: Does the design-based 

research approach work in this study? What will the students 

do during the lecture? What are the design aspects 

of VideoLearn? Will there be empirically based recommendations 

for lecturers? 

Highlights 

VideoLearn was tested in a vocational school and at the 

Leibniz University of Hannover and the experience as well 

as the evaluation results were proven to be very successful. 

Students experienced great satisfaction with this kind of 

learning, as they can work independently. Teachers appreciated 

the advantage of not having to deliver content during 

classes; instead they can use this time for direct student 

supervision. The empirical investigation was carried 

out this year. The aspects of self-directed learning and the

communication process between teacher and students as 

well as students with students were measured. The analysis 

of the research results and the evaluation of the research 

approach were very successful. Current work will focus on 

the publication of the results. 


The project finished at the end of 2008. Further research 

works will be done by the eLearning Service Department 

(www.elsa.uni-hannover.de) of the Leibniz Universität 

Hannover. 

LEARNING 


Project duration: juli 1999 – December 2008 

Project Research Areas: Technology enhanced 

Learning 

uRL of the project: http://www.L3S.de/L3SCPD 


Prof. Dr. Klaus jobmann, jobmann@L3S.de 

Dipl.-Berufspäd. Marc Krüger, krueger@L3S.de 


1. Marc Krüger „vortragsaufzeichnungen in 

Hochtechnologieberufen: Darstellungsformen, 

Aktionsformen und Lernszenarien“ In: Annelies 

Bruhne, Inga Herbold, Andreas Weiner, Christine 

Wichmann (Hrsg.): Aus- und Weiterbildung in 

Hochtechnologieberufen. Tagungsband des 

niedersächsischen Ausbildungsnetzwerks mstBildung 

2007. Aachen 2007 

Marc Krüger “Selbstgesteuertes und kooperatives 

2. 

Lernen mit vortragsaufzeichnungen im 

Lernarrangement videoLern“ In: Marc Krüger, ulrike 

von Holdt: (Hrsg.) “Neue Medien in vorlesungen, 

Seminaren & Projekten an der Leibniz universität 

Hannover” Tagungsband zur eTeaching und eScience 

Tagung 2007. Aachen 2007 


86 

NEWS & EVENTS 

NEWS 


L3S Presents Innovations 

in Digital Libraries at CeBIT 2009 

L3S Research Center will present the newest insights 

from the area of digital libraries at the research booth 

of the state of Lower Saxony at CeBIT 2009 in Hanover. 

In cooperation with the german National Library of Science 

and Technology (TIB) the management of chemical 

information is presented in viFaChem – the virtual 

Library for Chemistry. 

The ViFaChem project provides a digital library infrastructure 

for creating personalized information spaces. The 

value added services and scientific Web 2.0 techniques 

proactively support academic and industrial researchers in 

retrieval tasks, as well as in deriving new knowledge from 

the collected information. 

The rapid changes in information technology have heavily 

influenced the scientific way of working: this includes 

interaction with digital media, communication style, etc. 

Global communication technologies enable a fast and ubiquitous 

information access. Moreover, the time between 

the generation of new results and their subsequent publi- 

NEWS & EVENTS 

cation (innovation cycles) is becoming shorter. Obviously, 

this information flood cannot be handled manually by the 

individual reader. 

Classical libraries offered services mostly in the form of 

printed material, digital services, such as subscriptions to 

online journals or topic-centered databases, is becoming 

a necessary ingredient for innovation in the scientific community. 

As a national leader for science and technology, 

TIB is at the forefront of developing new digital services. 

The ViFaChem project assists chemists in their search for 

the right piece of information at the right time. This is facilitated 

by creating metadata enriched document collections, 

which will allow specialized search, taking individual 

retrieval strategies into account. Thus, every user can build 

his own personalized knowledge space of chemistry. The 

novel information retrieval interface provides the user with 

a new experience in searching large document collections, 

combined with Web 2.0 features such as social tagging. 

Further information: http://www.L3S.de/vifachem 


88 

NEWS & EVENTS 

KDubiq – Knowledge Discovery in Ubiquitous Environments 

KDubiq is a Coordination Action, which was funded by 

the European Commission in the 6th Framework. It has 

supported activities in the upcoming area of ubiquitous 

Knowledge Discovery. The major challenge was to identify 

the emerging research topics on the edge of highly 

distributed (and mobile) systems and Knowledge Discovery 

systems. Within KDubiq, we co-chaired the Working 

group on ubiquitous Data Types. 

The working group focuses on the aspect of the ubiquity 

of data used for data mining. In many current applications, 

data emerges in a ubiquitous way rather than in cooperate 

data bases. In contrast to “classical” data, ubiquitous data 

can be defined as data that emerges in an asynchronous, 

decentralized way from many different, loosely-coupled, partially 

overlapping, possibly contradicting sources. Two typical 

application areas with ubiquitously emerging data are Web 

2.0 environments and distributed sensor networks. 

Web 2.0 denotes a shift in the way the Internet is used. 

Instead of a small number of users that produce all content; 

now a very large number of users actively contribute. Applying 

data mining to this data is on the one hand very appealing, 

as it helps to consolidate the information and to make it 

maximally useful. On the other hand it is very challenging, as 

different data types are involved, data is produced by many 

different users distributed all over the world, it is often noisy 

and contradicting, or partially overlapping. 

A seemingly completely different area is sensor networks. 

In sensor networks, a large number of distributed, partially 

connected sensors are used to measure some properties in 

The Adaptive Hypermedia conferences are the major 

forums for the scientific exchange and presentation of 

research on adaptive hypermedia and adaptive Webbased 

systems. This year’s fifth edition of the conference 

was organized by the L3S Research Center in the city of 

Hannover, germany. 

The conference attracted participants from all corners of the 

world. Numerous workshops and thematic sessions were 

given, dedicated to topics as varied as e-learning, ubiquitous 

computing and recommender systems. The keynote 

speeches – provided by Peter Brusilovsky (Univ. of Pittsburgh), 

John Riedl (Univ. of Minnesota) and Jan Borchers 

(RWTH Aachen) – were well received and fostered fruitful 

discussion. 

The Best Paper Award went to the paper “Social Information 

Access for the Rest of Us: An Exploration of Social You- 

Tube”, written by Maurice Coyle, Jill Freyne, Peter Brusilovsky 

and Barry Smyth. Two more awards were given for the Best 

Student Papers. The Conference Website provides further 


a given domain. Measurements of different sensors may 

overlap (neighboring sensors), but may also contradict (e.g., 

if a sensor does not work properly). Sensors can be connected 

within networks of cascading sensors. Finally, sensors 

can capture many different data types, including images, 

video, etc. 

Upon closer inspection, sensor networks and Web 2.0 data 

are very similar, as both expose the typical characteristics of 

ubiquitous data. In both cases, data emerges asynchronously 

in a distributed way, and there is usually no way of collecting 

this data in a single data base. Research in both areas 

has developed almost completely independently, despite 

these strong connections. Within the Working Group, we 

discussed the common vision of both areas, by analyzing 

which challenges they have in common and which methods 

will be mutually applicable. 

Contact: Prof. Dr. Gerd Stumme, stumme@L3S.de 

URL: http://www.kdubiq.org/kdubiq/ 

L3S Organized Adaptive Hypermedia 2008 

information related to the workshops, discussion sessions, 

as well as pictures and reports from the event. 

Starting 2009, the Adaptive Hypermedia conference will be 

organized together with its sister conference on User Modeling. 

The merged conference on User Modeling, Adaptation and 

Personalization UMAP 2009 will take place in Trento, Italy. 

Adaptive Hypermedia 2008 Website: www.ah2008.org 

UMAP 2009 Website: http://umap09.fbk.eu/

New Managing 

Director at L3S 

In january 2009 gabriele 

Herrmann-Krotz has started as 

our new Managing Director at 

the L3S Research Center. Her 

excellent background in economics 

is based on a Diploma 

Degree in Finance and Public 

Administrations at the johann Wolfgang goethe-university 

in Frankfurt am Main, as well as by positions on 

the executive board for several leading organizations in 

the commercial and noncommercial sectors. 

In the last few years, Mrs. Herrmann-Krotz has focused her 

activities on the Non-Profit Sector, where she extended 

her knowledge in areas such as Corporate Governance. 

Her solid experience in organizational administration is 

an asset for the management team of L3S. Together with 

the Deputy Managing Director, Dr. Thomas Risse, Gabriele 

Herrmann-Krotz is looking forward to a fruitful cooperation 

with the staff, scientists and all partners of L3S. 

ICUWB 2008 

The IEEE 2008 International Conference on ultra-Wideband 

(ICuWB 2008), organized by Institut für Kommunikationstechnik 

(IKT), was held in Hannover on September 

10-12, 2008. This conference provided a forum for 

the latest uWB systems, technologies, and applications 

in both microwave and millimeter wave bands. In total, 

more than 260 leading scientists and engineers in the 

uWB field attended and presented their new research 

results. This year’s ICuWB achieves its wonderful success 

from the technical program, conference organization, 

and social events. 

The topics in the final program covered a broad range of 

UWB issues including: antenna design, RF modules, modulations, 

inter-ferences, channel modeling, ranging and localization, 

sensor networks, and standar-dizations. The final 

program included 4 keynote speech sessions, 29 technical 

sessions , 3 poster sessions, one tutorial, and one panel 

discussion session. Four internationally recognized experts 

were invited as keynote speakers. Dr. R.J. Fontana gave a 

keynote talk on “Ultra-Wideband – 50 Years of Progress in 

Short Pulse Electromagnetics.” Dr. A. Molisch presented an 

overview on “Ultra-wide-band Com-munications and Ranging 

for Sensor Networks.” Dr. S. Wood gave a prospect on 

“The Future of PAN Tech-nologies.” Dr. R. Krishnamoorthy 

gave a speech on “Development of a Ultra Wideband 

Chipset for Highly Reliable Wireless Communications.” One 

panel discussion entitled: “When Will We See UWB?” was 

NEWS & EVENTS 

L3S Student Sukriti 

Ramesh Awarded 

Sukriti Ramesh received the 

annual Best Student Award 

from the, vIT university in vellore, 

India in April 2008. Sukriti 

participated in a 6-month 

research visit at L3S, writing 

her Bachelor thesis on ‘Query 

Optimization in Distributed 

Databases’. 

The Best Student Award is the highest distinction given 

at VIT University. It is awarded on the basis of overall 

academic performance and extra-curricular activities 

over the period of university study. The award is 

accompanied by a gold medal and a scholarship. Currently, 

Sukriti works on terminology evolution in Semantic 

Web in the context of the LiWA project at the L3S 

Research Center. 

organized and moderated by T. Kaiser. The panelists were 

R. Krishnamoorthy, J. Landsford, S. Wood, and S. Zeisberg. 

The panel discussions offered a lively forum for the panelists 

and the audiences to debate issues in realizing future 

developments in UWB technology. 

The conference was jointly financially sponsored by IEEE 

MTT-S and Leibniz University of Hannover. It also received 

technical sponsorship from IEEE ComSoc, IEEE VTS, IEEE 

SSCS, EUWB, and PULSERS-II. 

For details and updated information, please check 

http://www.icuwb2008.org/. 

Contact person: Prof. Dr.-Ing. Thomas Kaiser, General Chair, 

ICUWB 2008, IKT, LUH. Email: kaiser@L3S.de 


90 

NEWS & EVENTS 

Prof. Nejdl Elected as 

Program Committee 

Chair for WWW 2009 

Prof. Wolfgang Nejdl will chair the program committee 

of the 18th International World Wide Web Conference 

(http://www2009.org) together with Yoelle Maarek 

from google. The WWW Conference is a global event 

that brings together key researchers, innovators, decision-makers, 

technologists, businesses, and standards 

bodies working to shape the World Wide Web. Organized 

since 1994, the conference series is the premier 

venue for academics and industry to present, demonstrate, 

and discuss the latest ideas about the Web, its 

infrastructure, relevant algorithms and new innovative 

applications. It is most of all an annual opportunity for 

the international community to discuss and debate the 

state and the evolution of the Web. 

The technical program for the five-day conference, which 

will take place in Madrid in April 2009, will include ref- 

As of April, 2008 L3S’s former 

associate research 

director Wolf-Tilo Balke has 

accepted a full professorship 

for databases and information systems at the university 

of Braunschweig together with the directorship 

of the Institute for Information Systems. 

In November 2008, the L3S Research Center hosted a 

seminar and panel discussion for the students and staff 

of the university of Hannover, focusing on the Opera 

Software company. Opera plays a key role for innovative 

Web browsers, mobile phones, computers as well as 

game consoles. The seminar was presented by Opera’s 

Web standard expert, Anne van Kesteren and Product 

Manager, Roberto Mateu. 

The discussion explored the significance of Open-Web standards, 

the history and future of the Web, the current state 

of the browser industry and the role of the mobile Web. 

The seminar provided students with insightful knowledge 

about the Web, and fostered discussion on important 


ereed paper presentations, plenary sessions, panels, and 

poster sessions. All these discussion will be, among others, 

in the areas of User Interfaces and Mobile Web, Data 

Mining, Industrial Practice and Experience, Internet Monetization, 

Performance and Scalability, Rich Media, Search, 

Security and Privacy, Semantic/Data Web, Social Networks 

and Web 2.0, Web Engineering as well as XML and Web 

Data. The WWW2009 program will also include Tutorials 

and Workshops, a “WWW in Iberoamerica” track, a W3C 

track, a Developers track, and Exhibitions. 

L3S Member Balke Takes a 

Position at TU Braunschweig 

Prof. Balke has been member of the L3S for three years 

contributing mainly in the research on databases and digital 

libraries and now strengthens the bond between the 

L3S Research Center and the University of Braunschweig. 

Infos: http://www.ifis.cs.tu-bs.de 

L3S and Opera Software Organized Seminar 

about the Future of the Internet and Web Standards 

topics currently facing the Web industry and indeed all 

Web users. The students acquired relevant information 

about the company and as well, discussed employment 

and internship opportunities.

NEWS & EVENTS 

European Land Robot Trial (ELROB) 2008 

The research team of the L3S Institute for Systems Engineering, 

Real Time Systems group (RTS) at the Leibniz 

universität Hannover participated in the European Land 

Robot Trial (ELROB) 2008. In four different missions, 

the team’s autonomous robot RTS-HANNA was able to 

achieve twice the second place and twice the first place, 

competing against more than 20 international teams. 

The European Land Robot Trial (ELROB) was organized 

from June 30th through July 3rd in Hammelburg, Germany. 

In four challenging, real-world scenarios, more than 20 

international teams from academia and industry demonstrated 

their capabilities in the field of autonomous mobile 

land robots. 

The L3S Institute for Systems Engineering team participated 

in three trials and achieved 2nd Place in the “Transport- 

Mule” scenario, 2nd Place in the “Autonomous Reconnaissance”. 

In addition, the team won 1st place in the “Convoy” 

scenario. In the “Convoy” trial, a group of at least two 

vehicles were to be moved along a muddy and hilly track 

limited to a single driver. By following the manual driven 

leading vehicle autonomously, the team of the RTS was the 

sole participant able to complete the 10 km track within 

the allotted time of 60 minutes. On the asphalt part of the 

trial, a top speed of 35 Km/h was achieved. 

The L3S Institute for Systems Engineering entered the 

ELROB 2008 with its brand new robotic platform called 

RTS-HANNA. The robot is based on an off-the shelf Kawasaki 

Mule 3010 side-by-side vehicle with diesel engine. 

Fully street licensed, the vehicle is equipped with a driveby-wire 

retrofit kit from PARAVAN GmbH which enables 

manual as well as fully computer control of the vehicle. For 

autonomous operation the vehicle is equipped with a various 

sensors, including two 3D-Laserscanners and a DGPS 

for precise positioning. 

In the context of the M-ELROB 2008, RTS-HANNA is utilized 

as a demonstrator for robotic technology that can be 

adapted to any steer-by-wire platform. 

Additional infos: www.m-elrob.eu 

L3S Launches Future Internet 

Research Seminar Series 

The L3S Research Center is organizing its new “Future 

Internet Research Seminar Series” to provide more information 

on all relevant aspects of the Future Internet and 

to provide a forum for discussions and collaboration on 

related issues. 

The topic “Future Internet” is one of the important federated 

research themes in the European FP7 IST work program 

2009ff, and prominently covered in the FIND/GENI 

activities sponsored by the NSF as well as in the BMBF IT 

Strategy 2020. 

The L3S Research Center is working on various aspects of 

Future Internet design and applications including: new 

transmission schemes and network protocols; innovative 

ways to access and use digital content in digital libraries 

and multimedia search; integration of information in the 

Web in the context of the Internet of Things. 

I3 Research Initiative “Future Internet - Internet, Information 

& I” is significance and L3S builds upon experiences 

gained its numerous projects; such as PHAROS, LiWA, LivingKnowledge 

and UKoLoS. Importantly, competences 

from the Faculty of Electrical Engineering and Computer 

Science, TIB, RRZN, as well as colleagues from other faculties 

at the Leibniz University of Hannover combine to realize 

aspects of this initiative 

To provide more information on all relevant aspects and to 

provide a forum for discussions and collaboration on Future 

Internet related issues, the L3S Research Center is organizing 

its new “Future Internet Research Seminar Series”. Events 

in this series will be organized every two to three weeks, 

from November 2008 to June 2009, providing both an 

overview as well as detailed information about important 

building blocks for the Internet of the Future. 


92 

PARTNERS 

International and Industrial Partners 

Acklin B.V., Wallwijk, Netherlands | Agenzia Nazionale Stampa Associata (ANSA), Rome, Italy | AIE, Milano, Italy | Albert-Ludwigs- 

Universität Freiburg FREIBURG DE, Freiburg, Germany | Alexandru Ioan Cuza’ University of Iasi, Iasi, Romania | ATOS Origin Sociedad 

Anonima Española, Barcelona, Spain | Brandenburg University of Technology COTTBUS DE, Cottbus, Germany | BT Netherlands, 

Amsterdam, Netherlands | Bundesamt für Informationsmanagement und Informationstechnik der Bundeswehr, Koblenz, Germany | 

Centre for Research and Technology Hellas, Thessaloniki, Greece | CINECA, Bologna, Italy | Circom Regional, Paris, France | Cognium 

Systems, Paris, France | ComLinx IT Services, Kassel, Germany | Computer and Automation Research Institute - Hungarian Academy 

of Sciences, Budapest, Hungary | DERI Galway, Galway, Ireland | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, 

Saarbrücken, Germany | Donau Universität Krems, Krems, Austria | École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland 

| EDGE-IT / Mandriva, Paris, France | Editrain, Madrid, Spain | EEA, Bratislava, Slovak Republic | Eigenössische Technische Hochschule 

Zürich, Zürich, Switzerland | Elsevier B.V., Amsterdam, Netherlands | Engineering, Rome, Italy | Europe Unlimited SA, Brussels, Belgium 

| European Archive Foundation, Amsterdam, Netherlands | Expert System, Modena, Italy | Fast Search & Transfer, Oslo, Norway | 

Federal University of Amazonas, Manaus, Brasil | Forschungszentrum Informatik, Universität Karlsruhe, Karlsruhe, Germany | Foundation 

of Research and Technology - Hellas, Heraklion, Greece | France Telecom, Lannion Cedex, France | Fraunhofer IDMT, Ilmenau, Germany 

| Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. (FHG), Stuttgart, Germany | Fundació Barcelona Media 

Universitat Pompeu Fabra, Barcelona, Spain | geno, Stuttgart, Germany | GIUNTI Interactive Labs s.r.l., Sestri Levante, Italy | Götting, 

Lehrte, Germany | Hanzo Archives Limited, London, United Kingdom | Hautes Etudes Commerciales, Paris, France | Helsinki University 

of Technology, Helsinki, Finland | Heriott-Watt University, Edinburgh, United Kingdom | Högskolan i Skövde, Skövde, Sweden | HP 

Galway, Galway, Irland | IBM Galway, Galway, Irland | IDS Scheer, Saarbrücken, Germany | Il Centro per la ricerca scientifica e tecnologica, 

Trento, Italien | imaginary, Milano, Italy | Indire, Firenze, Italy | information multimedia communication AG, Saarbrücken, Germany | 

INMARK, Madrid, Spain | Innofinity GmbH, Kassel, Germany | INRIA - Unité de Recherche Lorraine (LORIA), Nancy, France | INRIA 

Rocquencourt, Paris, France | Inst. National de Recherche en Informatique et en Automatique, Montbonnot, Frankreich | Institut für 

Arbeitswissenschaft und Technologiemanagement (IAT), Stuttgart, Germany | Institut National des Télécommunications, Évry, France 

| Institute of Communication and Computer Systems, National University of Athens, Greece | Institutul National de ercetare-Dezvoltare 

in Informatica Bucharest RO, Bucharest, Romania | Instytut Podstaw Informatyki Polskiej Akademii Nauk WARSAW PL, Warsaw, Poland 

| Irion Management Consulting, Kaiserslautern, Germany | Jakobs Universität, Bremen, Germany | Jozef Stefan Institute, Ljubljana, 

Slovenia | Katholieke Universiteit Leuven / ARIADNE Foundation, Leuven, Belgium | Klett Lernen und Wissen GmbH, Stuttgart, Germany 

| Knowledge Media Institute - Open University, Milton Keynes, UK | Kungliga Teksnika Hoegskolan (KTH), Stockholm, Sweden | LGC 

Wireless Inc, San Jose, USA | Libera Università di Bolzano, Bozen, Italy | Linköpings Universitet, Linköping, Sweden | LogicaCMG, 

Amsterdam, Netherlands | Ludwig-Maximilians Universität München, Munich, Germany | Max-Plank Institut für Informatik, Saarbrücken, 

Germany | Metaware, Pisa, Italy | Moravian Library, Brno, Czech Republic | National Centre for Scientific Research “Demokritos”, 

Athens, Greece | National Library of the Czech Republic, Praha, Czech Republic | National Microelectronics Application Center (MAC), 

Galway, Ireland | National University of Ireland, Galway, Irland | Nielsen BookData, London, UK | Open Universiteit Nederland, Heerlen, 

The Netherlands | PARAVAN, Aichelau, Germany | Politecnico di Milano, Milano, Italy | Politehnica Universität Bukarest, Bucharest, 

Romania | Poznan University of Ecomonics, Poznan, Poland | PRC Group, Athen, Greece | QPR, Helsinki, Finnland | Research Institute 

for Artificial Intelligence of the Romanian Academy, Bukarest, Romania | Rheinisch-Westfälische Technische Hochschule Aachen, 

Aachen, Germany | Rheinmetall Landsysteme, Unterlüß, Germany | SAIL LABS Technology, Vienna, Austria | SAP Research, Karlsruhe, 

Germany | Social Care Institute for Excellence, London, Great Britain | Software de Base S.A, Madrid, Spain | Stad Antwerpen, Antwerp, 

Belgium | Stanford University, Palo Alto, USA | Stichting Nederlands Instituut voor Beeld en Geluid, Hilversum, Netherlands | Stichting 

Telematica Instituut, Enschede, Netherlands | STILL GmbH, Hamburg, Germany | SURF, Utrecht, Netherlands | Synergetics, Antwerp, 

Belgium | Technical Research Centre of Finland VTT (VTT), Espoo, Finland | Technische Universität Dresden, Dresden, Germany | 

Technische Universität Eindhoven, Eindhoven, Netherlands | Technische Universität München, Munich, Germany | Technische Universität 

Wien, Vienna, Austria | Thales Research and Technology, Paris, France | The Chancellor, Master, and Scholars of the University of 


PARTNERS 

Cambridge, Cambridge, Great Britain | The Open University, Milton Keynes, Great Britain | The University of Manchester, Manchester, 

Great Britain | Trinity College Dublin, Dublin, Irland | UNESCO-IHE Institute for Water Education, Delft, Netherlands | Universidad 

Alcala de Henares, Alcala De Henares, Spain | Universidad National de San Juan, San Juan, Argentina | Universidad Politécnica de 

Madrid, Madrid, Spain | Universidad Rey Juan Carlos, Madrid, Spain | Universidad Technologica National, Buenos Aires, Argentina | 

Universidade Nova de Lisboa Lisbon, Lisbon, Portugal | Università Ca’ Foscari Venezia VENICE IT, Venice, Italy | Università degli Studi 

di Torino, Turin, Italy | Università degli Studi di Trento, Trento, Italy | Università della Svizzera Italiana, Lugano, Switzerland | Università 

di Napoli, Naples, Italy | Universität Duisburg-Essen, Duisburg, Germany | Universität für Bodenkultur, Zentrum für Soziale Innovation, 

Vienna, Austria | Universität Göttingen, Göttingen, Germany | Universität Graz, Graz, Austria | Universität Innsbruck, Innsbruck, 

Österreich | Universität Kaiserslautern, Kaiserslautern, Germany | Universität Osnabrück, Osnabrück, Germany | Universitat Politècnica 

de Catalunya, Barcelona, Spain | Universität Siegen, Siegen, Germany | Universität St. Gallen, St. Gallen, Switzerland | Universität 

Swizzera Italiana, Lugano, Switzerland | Universität Zürich, Zürich, Switzerland | Université catholique de Louvain, Leuven, Belgium | 

University of Applied Sciences Northwestern Switzerland, Olten, Switzerland | University of Economics, Prag, Czech Republic | University 

of Liverpool, Liverpool, Great Britain | University of Malaga, Malaga, Spain | University of Malta, Malta, Malta | University of Manchester, 

Manchester, Great Britain | University of Sheffield, Sheffield, Great Britain | University of Warwick, Warwick, United Kingdom | University 

of Aberdeen, Aberdeen, Great Britain | University of Eindhoven, Eindhoven, Netherlands | University of Surrey, Surrey, Great Britain | 

Vrije Universiteit Amsterdam, Amsterdam, Netherlands | Vrije Universiteit Brussel, Brussels, Belgium | Web Models, Como, Italy | 

Wirtschaftsuniversität Wien, Vienna, Austria | Yahoo! Research, Barcelona, Spain 


94 

PUBLICATIONS 

Publications 2008 

1. Abel, Fabian. The Benefit of additional Semantics in Folksonomy 

Systems. Proceedings of the 2nd Ph.D. Workshop in Seventeenth 

ACM Conference on Information and Knowledge Management, 

CIKM 2008, Napa, uSA, October 26-30, 2008. 

2. Abel, Fabian; Bittencourt, Ig Ibert; Henze, Nicola; Krause, 

Daniel; vassileva, julita. A Rule-Based Recommender System 

for Online Discussion Forums. Proceedings of the Adaptive 

Hypermedia and Adaptive Web-Based Systes (AH2008) 

3. Abel, Fabian; Frank, Mischa; Henze, Nicola; Krause, Daniel; 

Siehndel, Patrick. groupMe! – Combining Ideas of Wikis, Social 

Bookmarking, and Blogging. International Conference on Weblogs 

and Social Media (ICWSM 2008) 

4. Abel, Fabian; Henze, Nicola; Krause, Daniel. Exploiting 

additional Context for graph-based Tag Recommendations in 

Folksonomy Systems. Proceedings of International Conference on 

Web Intelligence (WI 2008), Sydney, Australia, Dec 2008 

5. Abel, Fabian; Henze, Nicola; Krause, Daniel. Ranking in 

Folksonomy Systems: Can context help?. Proceedings of the 

Seventeenth ACM Conference on Information and Knowledge 

Management, CIKM 2008, Napa, uSA, October 26-30, 2008 

Folksonomy systems have shown to contribute to the quality of Web 

search ranking strategies. In this paper, we analyze and compare 

different graph-based ranking algorithms, namely FolkRank, 

SocialPageRank, and SocialSimRank. We enhance these algorithms 

by exploiting the context of tag assignmets, and evaluate the results 

on the GroupMe! dataset. In GroupMe!, users can organize and 

maintain arbitrary Web resources in self-defined groups. When users 

annotate resources in GroupMe!, this can be interpreted in context 

of a certain group. The grouping activity delivers valuable semantic 

information about resources and their context. We show how to use 

this information to improve the detection of relevant search results, 

and compare different strategies for ranking result lists in folksonomy 

systems. 

6. Abel, Fabian; Henze, Nicola; Krause, Daniel; Kriesell, Matthias. 

On the Effect of group Structures on Ranking Strategies in 

Folksonomies. Proceedings of the 17th International World Wide 

Web Conference (WWW 2008), Bejing, China 

This paper presents the GroupMe! system, a resource sharing system 

with advanced tagging functionality. GroupMe! provides a novel 

user interface, which enables users to organize and arrange arbitrary 

Web resources into groups. The content of such groups can be 

overlooked and inspected immediately as resources are visualized in 

a multimedia-based fashion. In this paper, we furthermore introduce 

new folksonomy-based ranking strategies that exploit the group 

structure shipped with GroupMe! folksonomies. Experiments show 

that those strategies significantly improve the performance of such 

ranking algorithms. 

7. Abel, Fabian; Henze, Nicola; Krause, Daniel; Plappert, Daniel. 

user Modeling and user Profile Exchange for Semantic Web 

Applications. 16th Workshop on Adaptivity and user Modeling in 

Interactive Systems (ABIS2008) 

8. Alferes, josé júlio; Amador, Ricardo; Kärger, Philipp; Olmedilla, 

Daniel. Towards Reactive Semantic Web Policies: Advanced 

Agent Control for the Semantic Web. Proceedings of the 7th 

International Semantic Web Conference, ISWC 2008, Karlsruhe, 

germany, October 26-30, 2008 (Poster and Demo Session) 

9. Alrifai, Mohammad. Distributed and Scalable QoS Optimization 

for Dynamic Web Service Composition. PhD Symposium at the 

International Conference on Service Oriented Computing, Sydney, 

December 2008 

10. Alrifai, Mohammad; Risse, Thomas. Efficient QoS-aware Web 

Service Composition. 3rd Workshop on Emerging Web Services 

Technology, at the European Conference on Web Services 

(ECOWS’08), Dublin, November 2008 


11. Alrifai, Mohammad; Risse, Thomas; Dolog, Peter; Nejdl, 

Wolfgang. A Scalable Approach for QoS-based Web Service 

Selection. 1st International Workshop on Quality-of-Service 

Concerns in Service Oriented Architectures (QoSCSOA’08) in 

conjunction with ICSOC 2008, Sydney, December 2008 

12. Assche, Frans van; Bruggen, jan van; Ceri, Stefano; Nejdl, 

Wolfgang. Proceedings of the 1st International Workshop on 

Collaborative Open Environments for Project-Centered Learning, 

COOPER-2007, Sissi, Lassithi – Crete greece, 17 September, 2007. 

13. Bähr, Thomas; Denecke, Kerstin. LINSearch – Linguistisches 

Indexieren und Suchen Chancen und Risiken im grenzbereich 

zwischen intellektueller Erschließung und automatisch gesteuerter 

Klassifikation. verfügbarkeit von Informationen. 30.Online-Tagung 

der DgI 

14. Bali, Samer ; Steuer, jan; jobmann, Klaus. Capacity of Ad 

Hoc Networks with Line Topology Based on uWB and WLAN 

Technologies. Wireless Telecommunications Symposium (WTS) 

2008, April 24 - 26, 2008. 

15. Bali, Samer; Steuer, jan; jobmann, Klaus. Routing Protocols 

for ultra-Wideband Mobile Ad-Hoc Networks. IEEE Sarnoff 

Symposium 2008, April 28 - 30, 2008. 

16. Balke, Wolf-Tilo. Skyline Queries for Preference-Based 

Information Systems.. Proceedings of the 20. gI-Workshop on 

Foundations of Databases (grundlagen von Datenbanken), 

Apolda, Thüringen, germany, May 13-16, 2008, pp. 3, 2008, 

School of Information Technology, International university in 

germany. 

17. Balke, Wolf-Tilo; Lofi, Christoph; güntzer, ulrich. Consistency 

Check Algorithms for Multi-Dimensional Preference Trade-Offs. 

International journal of Computer Science & Applications (IjCSA), 

vol. 5(3b) 

18. Balke, Wolf-Tilo; Selke, joachim. Exploiting Conceptual 

Knowledge for Querying Information Systems. Proceedings of 

the Conference on Philosophy’s Relevance in Information Science 

(PRIS 2008), 2008. 

19. Bischoff, Kerstin; Firan, Claudiu-S; Nejdl, Wolfgang; Paiu, 

Raluca. Can All Tags Be used for Search?. Proceedings of the 


Management, CIKM 2008, Napa, uSA, October 26-30, 2008 

Collaborative tagging has become an increasingly popular means for 

sharing and organizing Web resources, leading to a huge amount of 

user generated metadata. These tags represent quite a few different 

aspects of the resources they describe and it is not obvious whether 

and how these tags or subsets of them can be used for search. This 

paper is the first to present an in-depth study of tagging behavior for 

very different kinds of resources and systems ? Web pages (Del.icio. 

us), music (Last.fm), and images (Flickr) ? and compares the results 

with anchor text characteristics. We analyze and classify sample tags 

from these systems, to get an insight into what kinds of tags are used 

for different resources, and provide statistics on tag distributions in 

all three tagging environments. Since even relevant tags may not 

add new information to the search procedure, we also check overlap 

of tags with content, with metadata assigned by experts and from 

other sources. We discuss the potential of different kinds of tags for 

improving search, comparing them with user queries posted to search 

engines as well as through a user survey. The results are promising 

and provide more insight into both the use of different kinds of tags 

for improving search and possible extensions of tagging systems to 

support the creation of potentially search-relevant tags. 

20. Bonatti, Piero A.; De Coi, juri Luca; Olmedilla, Daniel; Sauro, 

Luigi. A framework for semantic web policies. Proceedings of 

the 7th International Semantic Web Conference, ISWC 2008, 

Karlsruhe, germany, October 26-30, 2008 

Bonatti, Piero A.; De Coi, juri Luca; Olmedilla, Daniel; Sauro, 

21. 

Luigi. Policy-Driven Negotiations and Explanations: Exploiting 

Logic-Programming for Trust Management, Privacy & Security. 24th 

International Conference on Logic Programming (ICLP 2008)

22. Brunkhorst, Ingo; Tönnies, Sascha; Balke, Wolf-Tilo. Multimedia 

Content Provisioning using Service Oriented Architectures. 6th 

International Conference on Web Services (ICWS 2008) 

23. Chen, Ling; Hu, Yiqun; Nejdl, Wolfgang. DECK: Detecting 

Events from Web Click-through Data. IEEE International 

Conference on Data Mining (ICDM) 2008 

24. Chen, Ling; Nejdl, Wolfgang. using subspace analysis for event 

detection from web click-through data. Proceedings of the 17th 

International World Wide Web Conference (WWW 2008), Bejing, 

China (poster) 

25. Chernov, Sergey. Task detection for activity-based desktop 

search.. Proceedings of the 31st Annual International ACM 

SIgIR Conference on Research and Development in Information 

Retrieval, SIgIR 2008, Singapore, july 20-24, 2008, pp. 894, 2008, 

ACM, 978-1-60558-164-4. 

The desktop search tools provide powerful query capabilities and 

result presentation techniques. However, they do not take the user 

context into account. We propose to exploit collected information 

about user activities with desktop files and applications for activitybased 

desktop search. When I prepare for a project review and type 

in a search box the name of a colleague, I expect to find her last 

deliverable draft, but not her email with a paper review or our joint 

conference presentation. Ideally, the desktop search system should 

be able to infer my current task from the logs of my previous activities 

and present task-specific search results. 

26. Chernov, Sergey. Converting Desktop into a Personal Activity 

Dataset. Proceedings of the 9th Russian Conference on Digital 

Libraries 

27. Chernov, Sergey; Demartini, gianluca; Herder, Eelco; Kopycki, 

Michal; Nejdl, Wolfgang. Evaluating Personal Information 

Management using an Activity Logs Enriched Desktop Dataset. 

Personal Information Management Workshop at CHI 2008, PIM 

2008, Florence, Italy, April 2008. 

28. Cho, SungRan; Balke, Wolf-Tilo. Order-Preserving Optimization 

of Twig Queries witth Structural Preferences. International 

Database Engineering & Applications Symposium (IDEAS’08) 

29. De Coi, juri Luca; Kärger, Philipp; Kösling, Arne; Olmedilla, 

Daniel. Control your elearning environment: Exploiting policies 

in an open infrastructure for lifelong learning. IEEE Transactions 

on Learning Technologies, 1(1) 

30. De Coi, juri Luca; Olmedilla, Daniel. A Review of Trust 

Management, Security and Privacy Policy Languages. International 

Conference on Security and Cryptography (SECRYPT 2008) 

31. De Coi, juri Luca; Olmedilla, Daniel; Zerr, Sergej; Bonatti, 

Piero A.; Sauro, Luigi. A Trust Management Package for Policy- 

Driven Protection & Personalization of Web Content.. 9th IEEE 

International Workshop on Policies for Distributed Systems and 

Networks (POLICY 2008), 2-4 june 2008, Palisades, New York, uSA, 

pp. 228-230, 2008, IEEE Computer Society, 978-0-7695-3133-5. 

32. Demartini, gianluca. Comparing People in the Enterprise.. 

ICEIS 2008 – Proceedings of the Tenth International Conference on 

Enterprise Information Systems, volume AIDSS, Barcelona, Spain, 

june 12-16, 2008, pp. 455-458, 2008, 978-989-8111-37-1. 

33. Demartini, gianluca. How Many Experts? – A New Task for 

Enterprise Search Evaluation. Workshop on Novel Methodologies 

for Evaluation in Information Retrieval at the 30th European 

Conference on IR Research, ECIR 2008, glasgow, Scotland, April, 

2008. 

34. Demartini, gianluca; Brunkhorst, Ingo; Chirita, Paul- 

Alexandru; Nejdl, Wolfgang. Ranking Categories for Web Search. 

Advances in Information Retrieval , 30th European Conference 

on IR Research, ECIR 2008, glasgow, uK, March 30-April 3, 2008. 

Proceedings, pp. 564-569, 2008, Springer, 978-3-540-78645-0. 

35. Demartini, gianluca; Firan, Claudiu-S; Iofciu, Tereza; Krestel, 

Ralf; Nejdl, Wolfgang. A Model for Ranking Entities and Its 

PUBLICATIONS 

Application to Wikipedia. 6th Latin American Web Congress 

(LA-WEB 2008), vila velha, Espirito Santo, Brasil, October, 2008. 

36. Demartini, gianluca; Niederée, Claudia. Finding Experts on 

the Semantic Desktop. Personal Identification and Collaborations: 

Knowledge Mediation and Extraction (PICKME 2008) Workshop 

at ISWC 2008, Karlsruhe, germany, October, 2008. 

37. Denecke, Kerstin. Zugang zu neuen Kommunikationsformen: 

Analyse medizinischer Internettagebücher. Brückenschlag von 

Medizinischer Informatik, Biometrie und Epidemiologie zur 

Medizintechnik. Tagungsband der gMDS jahrestagung, 2008: 

95-97 

38. Denecke, Kerstin. Informationsextraktion aus medizinischen 

Texten. Dissertation. Technische universitaet Braunschweig, 

Shaker verlag , Aachen 

39. Denecke, Kerstin. Accessing Medical Experiences and 

Information. European Conference on Artificial Intelligence, 

Workshop on Mining Social Data, 2008 

40. Denecke, Kerstin. using SentiWordNet for Multilingual 

Sentiment Analysis. IEEE 24th International Conference on Data 

Engineering 2008, Data Engineering Workshop ICDEW 2008: 

507-512 

41. Denecke, Kerstin. Semantic Structuring of and Information 

Extraction from Medical Documents using the uMLS. Methods of 

Information in Medicine (METHODS), 5(47), 2008. 

This paper introduces SeReMeD (Semantic Representation of Medical 

Documents), a method for automatically generating knowledge 

representations to natural language documents. It will be analyzed 

whether the Unified Medical Language System (UMLS) is suitable as 

domain knowledge for this method. Methods: SeReMeD combines 

existing language engineering methods and semantic transformation 

rules for mapping syntactic information to semantic roles. In this 

way, relevant content of medical documents are mapped to semantic 

structures. In order to extract specific data, these semantic structures 

are searched for concepts and semantic roles. A study is carried out 

that uses SeReMeD to detect specific data in medical narratives such as 

documented diagnoses or procedures. Results: The system is tested on 

chest X-ray reports. In first evaluations of the system’s performance, 

the generation of semantic structures achieves a correctness of 80% 

whereas the extraction of documented findings obtains values of 

93% precision and 83% recall. Conclusions: The results suggest that 

the methods can be used to accurately extract data from medical 

narratives even though there are a few potentials for ameliorating the 

results. The proposed methods provide two main benefits: By using 

existing language engineering methods the efforts for constructing 

a medical information extraction system are reduced. It is possible to 

exchange the domain knowledge and therefore to create a more or 

less specialized system regarding medical sub domains. 

42. Denecke, Kerstin. How to Assess Customer Opinions Beyond 

Language Barriers?. Proceedings of the 3rd IEEE International 

Conference on Digital Information Management, 2008. 

43. Denecke, Kerstin. Enhancing Knowledge Representations 

by Ontological Relations. Studies in health technology and 

informatics. 2008. 136: 791-96 

44. Diederich, jörg; Balke, Wolf-Tilo. FacetedDBLP – Navigational 

Access for Digital Libraries. Bulletin of IEEE Technical Committee 

on Digital Libraries. volume 4 Issue 1, Spring 2008, ISSN 1937- 

7266 

45. Diederich, jörg; Balke, Wolf-Tilo. Automatically Created 

Concept graphs using Descriptive Keywords in the Medical 

Domain. Methods of Information in Medicine (METHODS), vol. 

47(3), pp. 241-250, Schattauer, 2008. 

Besides keyword search, navigational search is an important 

means to find relevant information in digital object collections. 

Such navigation is often supported by categorization systems or 

thesauri, which provide a hierarchical view on a particular domain 

and allow for browsing digital collections. Existing categorization 


96 

PUBLICATIONS 

systems, however, require large and expensive efforts for the manual 

creation and maintenance. Our Semantic GrowBag algorithm fully 

automatically creates concept graphs, i.e. directed graphs similar to 

categorization systems but without strong subsumption semantics. 

This article sketches our algorithm and evaluates it for the medical 

domain. Methods: Our Semantic GrowBag algorithm uses descriptive 

keywords and exploits higher-order co-occurrences between them to 

create concept graphs (so-called GrowBag graphs) from anno-tated 

object collections. In this study, we have automatically created more 

than 2000 GrowBag graphs based on the Medline data set to show 

the applicability of our algorithm in the medical domain. For the 

evaluation, we first compared our algorithm to a baseline algorithm 

that does not take higher-order co-occurrences into account, and 

then compared the resulting GrowBag graphs systematically against 

the manually crafted MeSH thesaurus. Results: Our experiments 

revealed that the Semantic GrowBag approach essentially increases 

the number of relevant relation-ships in comparison to a baseline 

approach by about 50%. Fur-thermore, the identified relations 

usually correspond to and hardly ever contradict to relationships 

as stated by MeSH. Conclusions: The Semantic GrowBag algorithm 

allows creating concept graphs fully automatically. While it does not 

systemati-cally exploit specifics of a domain (such as the fundamental 

separation between ‘drugs’ and ‘therapy’ in MeSH), the result-ing 

GrowBag graphs are nevertheless well-suited to support navigation 

in digital object collections. Moreover, they can also be used to help 

maintaining existing categorization systems based on the actual usage 

of categories. 

46. Dolog, Peter; Stuckenschmidt, Heiner; Wache, Holger; 

Diederich, jörg. Relaxing RDF Queries based on user and Domain 

Preferences. journal of Intelligent Information Systems, july 2008. 

DOI: 10.1007/s10844-008-0070-7 

Research in cooperative query answering is triggered by the 

observation that users are often not able to correctly formulate 

queries to databases such that they return the intended result. Due to 

lacking knowledge about the contents and the structure of a database, 

users will often only be able to provide very broad queries. Existing 

methods for automatically refining uch queries based on user profiles 

often overshoot the target resulting in queries that do not return 

any answer. In this article, we investigate methods for automatically 

relaxing such over-constrained queries based on domain knowledge 

and user preferences. We describe a framework for information access 

that combines query refinement and relaxation in order to provide 

robust, personalized access to heterogeneous RDF data as well as an 

implementation in terms of rewriting rules and explain its application 

in the context of e-learning systems. 

47. Feldkamp, Daniela; Siberski, Wolf; Thönssen, Barbara; 

Wache, Holger. E-government for Distributed Autonomous 

Administrations. AAAI 2008 Spring Symposium, March 26-28, 

2008, Stanford university, CA, uSA 

E-Government is no longer a concern of single public administration 

units. State wide E-Government strategies, E-Government architectures 

and frameworks are established now and public administrations are 

willing to suit the action to the word. Also, semantically enriched 

techniques for service description, discovery and invocation are 

ready to come into practice. The challenge is the appropriate use of 

all the relevant parts to meet the technical, organizational and legal 

requirements. The paper at hand provides an approach, how available 

techniques can be implemented in a light-weighted way to build onestop 

E-Government services on completely decentralized components. 

This allows to leave the control to where it belongs (every service 

contributor is responsible for its parts), to execute a service according 

to the local ICT but at the same time to meet the requirements for 

automated cross-administration cooperation. The introduced approach 

is illustrated with the example of Switzerland. 

48. Firan, Claudiu-S; Demartini, gianluca; Iofciu, Tereza; 

Nejdl, Wolfgang. Semantically Enhanced Entity Ranking.. Web 

Information Systems Engineering – WISE 2008, 9th International 

Conference, Auckland, New Zealand, September 1-3, 2008. 



49. gaugaz, julien; Costache, Stefania; Chirita, Paul-Alexandru; 

Firan, Claudiu-S; Nejdl, Wolfgang. Activity Based Links as a 

Ranking Factor in Semantic Desktop Search. 6th Latin American 

Web Congress (LA-WEB 2008), vila velha, Espirito Santo, Brasil, 

October, 2008. 

50. gaugaz, julien; Demartini, gianluca. Entity Identifiers for 

Lineage Preservation. 1st international workshop on Identity and 

Reference on the Semantic Web (IRSW2008) hosted by the 5th 

European Semantic Web Conference ESWC-08, Tenerife, Spain, 

june, 2008. 

51. gommans, Leon; grünter, Egon; Niederberger, Ralph; de 

Smet, Alan; volpato, gian Luca. Requirements in operating grids 

in Firewalled Environment. Open grid Forum gFD-I.142 

52. grimm, Christian; Kunz, Christopher; groeper, Ralf; Piger, 

Stefan. A Comprehensive Approach to Self-Restricted Delegation 

of Rights in grids. 8th IEEE International Symposium on Cluster 

Computing and the grid (CCgrid 2008), Lyon, France, May 2008, 

pp. 114-121, 2008, IEEE Computer Society. 

53. grimm, Christian; Scherp, guido. Security in grid- 

Architekturen. Handbuch der Software-Architektur. Oldenbourg 

verlag, 2. Auflage, 15 Seiten, November 2008 

54. grimm, Christian; Schlüchtermann, georg.; IP Traffic Theory 

and Performance. Springer verlag, Heidelberg, 488 Seiten, 

ISBN 978-3-540-70603-8 

This book presents different approaches in IP traffic theory and 

classifies them, especially towards applications in the Internet. It 

comprises the state of the art in this area, which is currently presented 

only by numerous research papers and overview articles. The book 

provides an ideal starting point for detailed studies of traffic analysis 

in IP networks. It gives the reader the possibility to judge on different 

models and to select the appropriate for his individual needs in 

applications. The mathematical toolbox for this is kept as low as low as 

possible – the authors build a bridge between abstract representation 

of mathematical tools and applications. This, in turn, is certainly the 

most interesting topic for experts planning large data networks as well 

as practitioners and researchers working in this area. The book also 

serves as useful reference for lecturers and students at universities. 

55. grimm, Christian; volpato, gian Luca; janitschke, Martin. 

Automatic verification of SLA for Firewall Configuration in grid 

Environments. 8th Cracow grid Workshop ‘08, Cracow, Poland, 

October 2008 

56. grünter, Egon; grimm, Christian; volpato, gian Luca. 

Konfiguration von Firewalls: So sicher wie möglich, so offen wie 

nötig. DFN-Mitteilungen, Nr. 75, Dezember 2008 

57. Hentschel, Mathias; Wulf, Oliver; Wagner, Bernardo. A gPS 

and Laser-based Localization for urban and Non-urban Outdoor 

Environments. International Conference on Intelligent Robots 

and Systems 2008 

58. Herder, Eelco; Kärger, Philipp. Hybrid Personalization For 

Recommendations. ABIS Workshop 2008, Würzburg, germany 

59. Hotho, Andreas; Cattuto, Ciro; Benz, Dominik; Stumme, gerd. 

Semantic Analysis of Tag Similarity Measures in Collaborative 

Tagging Systems. CoRR abs/0805.2045, 2008. 

60. Hotho, Andreas; Cattuto, Ciro; Benz, Dominik; Stumme, gerd. 

Semantic grounding of Tag Relatedness in Social Bookmarking 

Systems.. Proceedings of the 7th International Semantic Web 

Conference, ISWC 2008, Karlsruhe, germany, October 26-30, 

2008, pp. 615-631, 2008, Springer, 978-3-540-88563-4. 

61. Hotho, Andreas; jäschke, Robert; Benz, Dominik; grahl, 

Miranda; Krause, Beate; Schmitz, Christoph; Stumme, gerd. 

Social Bookmarking am Beispiel BibSonomy. Social Semantic Web, 

Springer 

Hotho, Andreas; Krause, Beate; Schmitz, Christoph; Stumme, 

62. 

gerd. The anti-social tagger: detecting spam in social bookmarking 

systems. AIRWeb 2008, Fourth International Workshop on

Adversarial Information Retrieval on the Web, Beijing, China, 

April 22, 2008, pp. 61-68, 2008, 978-1-60558-159-0. 

63. Hotho, Andreas; Krause, Beate; Stumme, gerd; jäschke, 

Robert. Logsonomy – Social Information Retrieval with Logdata.. 

HYPERTEXT 2008, Proceedings of the 19th ACM Conference on 

Hypertext and Hypermedia, Pittsburgh, PA, uSA, june 19-21, 

2008, pp. 157-166, 2008, ACM, 978-1-59593-985-2. 

64. Hwang, Seung-won; Balke, Wolf-Tilo. Preference Query 

Formulation and Processing: Ranking and Skyline Query 

Approaches. 13th International Conference on Database Systems 

for Advanced Applications (DASFAA), New Delhi, India. 

65. Ioannou, Ekaterini; Niederée, Claudia; Nejdl, Wolfgang. 

Probabilistic Entity Linkage for Heterogeneous Information Spaces. 

Advanced Information Systems Engineering, 20th International 

Conference (CAiSE), Montpellier, France, june 16-20, Proceedings, 

pp. 556-570, 2008, Springer, 978-3-540-69533-2. 

66. jäschke, Robert; Hotho, Andreas; Schmitz, Christoph; ganter, 

Bernhard; Stumme, gerd. Discovering Shared Conceptualizations 

in Folksonomies. journal of Web Semantics 

Social bookmarking tools are rapidly emerging on the Web. In such 

systems users are setting up lightweight conceptual structures called 

folksonomies. Unlike ontologies, shared conceptualizations are not 

formalized, but rather implicit. We present a new data mining task, 

the mining of all frequent tri-concepts, together with an efficient 

algorithm, for discovering these implicit shared conceptualizations. 

Our approach extends the data mining task of discovering all closed 

itemsets to three-dimensional data structures to allow for mining 

folksonomies. We provide a formal definition of the problem, and 

present an efficient algorithm for its solution. Finally, we show the 

applicability of our approach on three large real-world examples. 

67. jäschke, Robert; Krause, Beate; Hotho, Andreas; Stumme, 

gerd. Logsonomy – A Search Engine Folksonomy. Proceedings 

of the Second International Conference on Weblogs and Social 

Media(ICWSM 2008) 

68. Kärger, Philipp. Advanced Semantic Web Policies: Evolution, 

Reactivity, Priority. Proceedings of the 7th International Semantic 

Web Conference, ISWC 2008, Karlsruhe, germany, October 26-30, 

2008 

69. Kärger, Philipp; Lopes, Nuno; Olmedilla, Daniel; Polleres, 

Axel. Towards Logic Programs with Ordered and unordered 

Disjunction. ICLP Workshop on Answer Set Programming and 

Other Computing Paradigms (ASPOCP), udine, Italy, December 

2008 

70. Kärger, Philipp; Olmedilla, Daniel; Abel, Fabian; Herder, Eelco ; 

Siberski, Wolf. What do you prefer? using Preferences to Enhance 

Learning Technology. IEEE journal for Transactions on Learning 

Technologies, 1(1) 

71. Kohlschütter, Christian; Nejdl, Maria; Höppner, Dierk. Enhanced 

Federated Search for Digital Object Repositories. 2nd European 

Workshop on the use of Digital Object Repository Systems in Digital 

Libraries (DORSDL2) in conjunction with ECDL 2008 

72. Kohlschütter, Christian; Nejdl, Wolfgang. A Densitometric 

Approach to Web Page Segmentation. Proceedings of the 


Management, CIKM 2008, Napa, uSA, October 26-30, 2008. 

Web Page segmentation is a crucial step for many applications in 

Information Retrieval, such as text classification, de-duplication and 

full-text search. In this paper we describe a new approach to segment 

HTML pages, building on methods from Quantitative Linguistics and 

strategies borrowed from the area of Computer Vision. We utilize 

the notion of text-density as a measure to identify the individual 

text segments of a web page, reducing the problem to solving a 

1D-partitioning task. The distribution of segment-level text density 

seems to follow a negative hypergeometric distribution, described by 

Frumkina’s Law. Our extensive evaluation confirms the validity and 

quality of our approach and its applicability to the Web. 

PUBLICATIONS 

73. Kösling, Arne Wolf; Herder, Eelco ; De Coi, juri Luca; Abel, 

Fabian. Making Legacy LMS adaptable using Policy and Policy 

templates. 16th Workshop on Adaptivity and user Modeling in 

Interactive Systems (ABIS2008) 

74. Kösling, Arne; Krause, Daniel; Herder, Eelco. Flexible Adaptivity 

in AEHS using Policies. Conf. on Adaptive Hypermedia and 

Adaptive Web-Based Systems 

75. Krause, Beate; Hotho, Andreas; Stumme, gerd. A Comparison 

of Social Bookmarking with Traditional Search.. Advances in 

Information Retrieval , 30th European Conference on IR Research, 

ECIR 2008, glasgow, uK, March 30-April 3, 2008. Proceedings, pp. 

101-113, 2008, Springer, 978-3-540-78645-0. 

76. Krause, Daniel; Abel, Fabian; Henze, Nicola. groupme! – 

Where Information Meets. Proceedings of the 17th International 

Conference on World Wide Web, WWW 2008, Beijing, China, April 

21-25, 2008, pp. 1147-1148, 2008, ACM, 978-1-60558-085-2. 

77. Krause, Daniel; Abel, Fabian; Henze, Nicola. A Novel Approach 

to Social Tagging: groupMe! – Enhancing Social Tagging 

Systems with groups.. WEBIST 2008, Proceedings of the Fourth 

International Conference on Web Information Systems and 

Technologies, volume 2, Funchal, Madeira, Portugal, May 4-7, 

2008, pp. 42-49, 2008, INSTICC Press, 978-989-8111-27-2. 

78. Krestel, Ralf; Chen, Ling. The Art of Tagging: Measuring the 

Quality of Tags. 3rd Asian Semantic Web Conference (ASWC 

2008), Bangkok, Thailand, December 8-11, 2008, Proceedings. 

Lecture Notes in Computer Science. 

79. Krestel, Ralf; Chen, Ling. using Co-occurence of Tags and 

Resources to Identify Spammers. ECML/PKDD Discovery Challenge 

(RSDC’08), Workshop at ECML/PKDD 2008, Antwerpen, Belgium, 

September 15th, 2008. 

80. Krestel, Ralf; Mehta, Bhaskar. Predicting News Story 

Importance using Language Features. IEEE / WIC / ACM 

International Conference on Web Intelligence, WI 2008, 9-12 

December 2008, Sydney, Australia, Main Conference Proceedings. 

IEEE Computer Society 2008. To appear. 

81. Krestel, Ralf; Witte, Rene; Bergler, Sabine. Minding the 

Source: Automatic Tagging of Reported Speech in Newspaper 

Articles. Proceedings of the 6th International Conference on 

Language Resources and Evaluation (LREC 2008), May 28-30, 

2008, Marrakech, Morocco. 

82. Krüger, Marc; Weiner, Andreas. Web 2.0 in formellen 

Lernprozessen. Aus- und Weiterbildung in Hochtechnologiefeldern. 

Fachkraeftesichtung in Neuen Technologien. Dokumentation zum 

Kongress vom 29.-30.11.2007 in Berlin. S. 92-94 

83. Kupferschmidt, Claus ; Dimitrov , Emil ; Kaiser, Thomas. 

Multiple Antenna uWB Systems – WP3 of the EuWB Project. The 

2008 IEEE International Conference on ultra-Wideband, ICuWB 

2008, Hannover, September 10-12, 2008 

84. Lecking, Daniel; Wulf, Oliver; Wagner, Bernardo. Localization 

in a wide range of industrial environments using relative 3D 

ceiling features. 13th IEEE International Conference on Emerging 

Technologies and Factory Automation 2008 

85. Lee, jongwuk; You, gae-won; Hwang, Seung-won; Selke, 

joachim; Balke, Wolf-Tilo. Optimal Preference Elicitation for 

Skyline Queries over Categorical Domains.. Proceedings of the 

19th International Conference on Database and Expert Systems 

Applications (DEXA 2008), volume 5181 of Lecture Notes in 

Computer Science, pages 610-624. Springer, 2008. 

86. Lofi, Christoph; Balke, Wolf-Tilo; güntzer, ulrich. Efficiently 

Performing Consistency Checks for Multi-Dimensional Preference 

Trade-Offs. 2nd IEEE International Conference on Research 

Challenges in Information Science (RCIS), Marrakech, Morocco, 

2008 

Lugmayr, Artur; Risse, Thomas; Stockleben, Björn; Kaario, 

87. 

juha; Laurila, Kari. Semantic Ambient Media Experiences SAME 


98 

PUBLICATIONS 

2008 Pre-Workshop Review (NAMu Series). Proceedings of the 

1st Workshop on Semantic Ambient Media Experience (SAME 

2008) in conjunction with ACM Multimedia 2008, vancouver, BC, 

Canada; October 27th - November 1st, 2008 

88. Mana, Antonio; Niederée, Claudia; Stoermer, Heiko; Bouquet, 

Paolo. Entity Name System: The Back-Bone of an Open and 

Scalable Web of Data.. Proceedings of the 2th IEEE International 

Conference on Semantic Computing (ICSC 2008), August 4-7, 

2008, Santa Clara, California, uSA, pp. 554-561, 2008, IEEE 

Computer Society. 

89. Marenzi, Ivana; Demidova, Elena; Nejdl, Wolfgang. LearnWeb 

2.0: Integrating Social Software for Lifelong Learning. World 

Conference on Educational Multimedia, Hypermedia and 

Telecommunications (ED-Media 2008), vienna, Austria, june 

2008 

90. Marenzi, Ivana; Demidova, Elena; Nejdl, Wolfgang; Olmedilla, 

Daniel. Social Software for Lifelong Competence Development: 

Scenario and Challenges. Empowering Learners for Lifelong 

Competence Development: pedagogical, organisational and 

technological issues. Proceedings of the 4th TENCompetence Open 

Workshop Madrid, Spain, April 2008. ISBN 978-90-6813-8474 

91. Marenzi, Ivana; Demidova, Elena; Nejdl, Wolfgang; Olmedilla, 

Daniel; Zerr, Sergej. Social Software for Lifelong Competence 

Development: Challenges and Infrastructure. International journal 

of Emerging Technologies in Learning (ijET), vol 3 (2008). Special 

Issue: Infrastructures for Lifelong Competence Development: 

The 4th TENCompetence Open Workshop in Madrid 2008. ISSN: 

1863-0383. 

92. Marenzi, Ivana; Zerr, Sergej; Nejdl, Wolfgang. Providing Social 

Sharing Functionalities in LearnWeb2.0. 5th TENCompetence 

Open Workshop – Sofia, 30 October 2008 

93. Mehta, Bhaskar; Manish gupta; Nangia, Saurabh; Nejdl, 

Wolfgang. Detecting image spam using visual features and 

near duplicate detection.. Proceedings of the 17th International 

Conference on World Wide Web, WWW 2008, Beijing, China, April 

21-25, 2008, pp. 497-506, 2008, ACM, 978-1-60558-085-2. 

Email spam is a much studied topic, but even though current email 

spam detecting software has been gaining a competitive edge against 

text based email spam, new advances in spam generation have posed 

a new challenge: image-based spam. Image based spam is email 

which includes embedded images containing the spam messages, 

but in binary format. In this paper, we study the characteristics of 

image spam to propose two solutions for detecting image-based 

spam, while drawing a comparison with the existing techniques. 

The first solution, which uses the visual features for classification, 

offers an accuracy of about 98%, i.e. an improvement of at least 6% 

compared to existing solutions. SVMs (Support Vector Machines) are 

used to train classifiers using judiciously decided color, texture and 

shape features. The second solution offers a novel approach for near 

duplication detection in images. It involves clustering of image GMMs 

(Gaussian Mixture Models) based on the Agglomerative Information 

Bottleneck (AIB) principle, using Jensen-Shannon divergence (JS) as 

the distance measure. 

94. Mehta, Bhaskar; Hofmann, Thomas. A Survey of Attack- 

Resistant Collaborative Filtering Algorithms.. IEEE Data 

Engineering Bulletin 31(2), pp. 14-22, 2008. 

95. Mehta, Bhaskar; Nejdl, Wolfgang. Attack Resistant Collaborative 

Filtering. Proceedings of the 31st Annual International ACM 

SIgIR Conference on Research and Development in Information 

Retrieval, SIgIR 2008, Singapore, july 20-24, 2008 

The widespread deployment of recommender systems has lead to user 

feedback of varying quality. While some users faithfully express their 

true opinion, many provide noisy ratings which can be detrimental to 

the quality of the generated recommendations. The presence of noise 

can violate modeling assumptions and may thus lead to instabilities in 

estimation and prediction. Even worse, malicious users can deliberately 

insert attack profiles in an attempt to bias the recommender system 

to their benefit. While previous research has attempted to study 


the robustness of various existing Collaborative Filtering (CF) 

approaches, this remains an unsolved problem. Approaches such as 

Neighbor Selection algorithms, Association Rules and Robust Matrix 

Factorization have produced unsatisfactory results. This work describes 

a new collaborative algorithm based on SVD which is accurate as 

well as highly stable to shilling. This algorithm exploits previously 

established SVD based shilling detection algorithms, and combines 

it with SVD based-CF. Experimental results show a much diminished 

effect of all kinds of shilling attacks. This work also offers significant 

improvement. 

96. Minack, Enrico; Siberski, Wolf; Zenz, gideon; Zhou, Xuan. 

SuITS4RDF: Incremental Query Construction for the Semantic 

Web. International Semantic Web Conference (Posters & Demos) 

2008 

97. Nejdl, Wolfgang. So how can I ask for it?. Proceedings of the 

2008 International Workshop on Data Management in Peer-to- 

Peer Systems, DaMaP 2008, Nantes, France, March 25, 2008, pp. 

1, 2008, ACM. 

98. Nejdl, Wolfgang; Kay, judy; Pu, Pearl; Herder, Eelco. Adaptive 

Hypermedia and Adaptive Web-Based Systems, 5th International 

Conference, AH 2008, Hannover, germany, july 29 - August 1, 

2008. Proceedings. Springer verlag, Heidelberg, ISBN 978-3- 

540-70984-8 

99. Nejdl, Wolfgang; Brusilovsky, Peter. Introduction to the IEEE 

Transactions on Learning Technologies. TLT 1(1): 3-4 (2008) 

100. Nejdl, Wolfgang. Introduction of New Editorial Board 

Members. TLT 1(1): 5-8 (2008) 

101. Nejdl, Wolfgang; Brusilovsky, Peter. EIC Editorial. TLT 1(2): 

103-104 (2008) 

102. Nejdl, Wolfgang; Brusilovsky, Peter. EIC Editorial. TLT 1(3): 

144 (2008) 

103. Stecher, Rodolfo; Niederée, Claudia; Nejdl, Wolfgang ; 

Bouquet, Paolo. Adaptive ontology re-use: finding and re-using 

sub-ontologies. International journal of Web Information Systems 

4(2), pp. 198-214, 2008. 

We present a flexible information integration approach which 

addresses the dynamic integration needs in a personal desktop 

environment where only partial mappings are defined between the 

sources to be integrated. Our approach is based on query rewriting 

using substitution rules. In addition to exploiting defined mappings, 

we employ substitution strategies, which are inspired by the idea of 

using wildcards in querying and filtering tasks. Starting from a triple 

based query language as used for querying RDF data, unmapped 

ontological elements are substituted in a controlled way with variables, 

leading to a controlled form of query relaxation. In addition, the 

approach also provides evidences for refining the existing mapping 

based on the results of executing the relaxed queries. Different 

strategies for replacing non-matched ontology elements with variables 

are presented and evaluated over real-world data sets. 

104. Olmedilla, Daniel; Hagge, Nils H.; Sauro, Luigi; Bonatti, Piero A.. 

Protune: A Framework for Semantic Web Policies. Proceedings of the 

7th International Semantic Web Conference, ISWC 2008, Karlsruhe, 

germany, October 26-30, 2008 (Poster and Demo Session) 

105. Olmedilla, Daniel; Kagal, Lalana; Finin, Timothy W.. 

Proceedings of the ISWC’07 Workshop on Privacy Enforcement 

and Accountability with Semantics (PEAS 2007), Busan, Korea, 

Nov. 12, 2007. 

106. Olmedilla, Daniel; Kärger, Philipp; Balke, Wolf-Tilo. Exploiting 

Preferences for Minimal Credential Disclosure in Policy-Driven 

Trust Negotiations.. Secure Data Management, 5th vLDB 

Workshop, SDM 2008, Auckland, New Zealand, August 24, 2008, 


Paiu, Raluca; Chen, Ling; Firan, Claudiu S.; Nejdl, Wolfgang. 

107. 

PHAROS - Personalizing users’ Experience in Audio-visual Online 

Spaces. PersDB 2008: 40-47

108. Papapetrou, Odysseas. Full-text Indexing and Information 

Retrieval in P2P systems. EDBT PhD Workshop, Nantes, France 

109. Papapetrou, Odysseas; Siberski, Wolf; Leitritz, Fabian; Nejdl, 

Wolfgang. Exploiting Distribution Skew for Scalable P2P Text 

Clustering. 6th International Workshop on Databases, Information 

Systems and Peer-to-Peer Computing (DBISP2P 2008) 

110. Perez guirao, Maria Dolores; Luebben, Ralf; Kaiser, 

Thomas. Evolutionary game Theoretical Approach for IR-uWB 

Sensor Networks. IEEE CoCoNet Workshop 2008 Cognitive and 

Cooperative Wireless Networks – (CoCoNet) collocated with IEEE 

ICC 2008 in Beijing, China, 19-23 May 2008 

111. Perez guirao, Maria Dolores; Luebben, Ralf; Kaiser, Thomas. 

Pulse Rate Adaptive Multiple-Access Scheme for Cognitive 

Autonomous IR-uWB Networks. IEEE International Conference 

on ultra-Wideband – ICuWB 2008, 10.-12. September 2008 

112. Perez guirao, Maria Dolores; Luediger, Heinz; Kull, Birgit. Link 

Adaptation for Autonomous IR-uWB Networks. ICT-MobileSummit 

2008,10-12 june 2008, Stockholm, Sweden 

113. Piger, Stefan; Kunz, Christopher; grimm, Christian; groeper, 

Ralf. Enhancing Security in grids through Self-Restricted 

Delegation of Rights with user-based Policies. Parallel and 

Distributed Computing and Networks 2008 (PDCN 2008), 

Innsbruck, Austria, February 2008 

114. Ramesh, Sukriti; Papapetrou, Odysseas; Siberski, Wolf. 

Optimizing Distributed joins with Bloom Filters. International 

Conference of Distributed Computing and Internet Technology 

(ICDCIT 2008) 

115. Rüsche, Simon-Frederik. The European Switch – A Packet- 

Switched Approach to a Train Control System. IEEE vT Magazine 

116. Rüsche, Simon-Frederik. Increase Of Efficiency In Wireless 

Train Control Systems (Etcs Level 2) By The use Of Actual Packet- 

Oriented Transmission Concepts. Proceedings of the 2008 

IEEE/ASME joint Rail Conference jRC2008; April 22-23, 2008, 

Wilmington, Delaware, uSA 

117. Schäfer, Michael; Dolog, Peter; Nejdl, Wolfgang. An 

environment for flexible advanced compensations of Web service 

transactions.. ACM Transactions on the Web (TWEB) 2(1), 2008. 

118. Schmidt, Paul; Risse, Thomas; Denecke, Kerstin; Firan, 

Claudiu-S; Biesterfeld, jens; Bähr, Thomas. LINSearch – 

Aufbereitung von Fachwissen für die Informationsversorgung. 

KnowTech, 10.Kongress zum Wissensmanagement 

119. Septinus, Konstantin; grimm, Christian; Rumyantsev, 

vladislav; Pirsch, Peter. On the Benefit of Caching Traffic Flow 

Data in the Link Buffer. SAMOS vIII: International Symposium 

on Systems, Architectures, MOdeling and Simulation, Samos, 

greece, june 2008 

120. Simon, Bernd; Dolog, Peter; Klobucar, Tomaz; Nejdl, 

Wolfgang. Personalizing access to learning networks.. ACM 

Transactions on Internet Technology 8(2), 2008. 

121. Stecher, Rodolfo; Demartini, gianluca; Niederée, Claudia. Social 

Recommendations of Content and Metadata. Proceeding of the 10th 

International Conference Information Integration and Web-based 

Applications & Services (Linz, Austria, November 24 - 26, 2008). 

122. Stecher, Rodolfo; Niederée, Claudia; Nejdl, Wolfgang. Query 

rewriting for Lightweight Information Integration. Proceeding 

of the 3rd International Conference on Digital Information 

Management (London, uK, November 13 - 16, 2008). 

123. Stecher, Rodolfo; Niederée, Claudia; Nejdl, Wolfgang. 

Wildcards for Lightweight Information Integration in virtual 

Desktops. Proceedings of the Seventeenth ACM Conference on 

Information and Knowledge Management, CIKM 2008, Napa, 

uSA, October 26-30, 2008. 

We present a flexible information integration approach which 

addresses the dynamic integration needs in a personal desktop 

PUBLICATIONS 

environment where only partial mappings are defined between the 

sources to be integrated. Our approach is based on query rewriting 

using substitution rules. In addition to exploiting defined mappings, 

we employ substitution strategies, which are inspired by the idea of 

using wildcards in querying and filtering tasks. Starting from a triple 

based query language as used for querying RDF data, unmapped 

ontological elements are substituted in a controlled way with variables, 

leading to a controlled form of query relaxation. In addition, the 

approach also provides evidences for refining the existing mapping 

based on the results of executing the relaxed queries. Different 

strategies for replacing non-matched ontology elements with variables 

are presented and evaluated over real-world data sets. 

124. Stewart, Avare; Diaz-Aviles, Ernesto; Nejdl, Wolfgang. 

Mining user Profiles to Support Structure and Explanation in 

Open Social Networking CoRR abs/0812.4461: (2008) 

125. Tahmasebi, Nina; Iofciu, Tereza; Risse, Thomas; Niederée, 

Claudia; Siberski, Wolf. Terminology Evolution in Web Archiving: 

Open Issues. Proceeding of the 8th International Web Archiving 

Workshop in conjunction with ECDL 2008, Aarhus, Denmark 

126. Tönnies, Sascha; Köhncke, Benjamin; Koepler, Oliver; Balke, 

Wolf-Tilo. Personalised Information Spaces for Chemical Digital 

Libraries. 4. german Conference on Chemoinformatics, goslar, 

germany, November 9-11, 2008 

127. Wagner, Bernardo; Hagge, Nils. Analyzing the liveliness of 

IEC 61499 function blocks.. Proceedings of 13th IEEE International 

Conference on Emerging Technologies and Factory Automation, 

ETFA 2008, September 15-18, 2008, Hamburg, germany, pp. 377- 

382, 2008, IEEE. 

128. Wagner, Bernardo; Hagge, Nils H.. Implementation 

alternatives for the OMAC state machines using IEC 61499.. 

Proceedings of 13th IEEE International Conference on Emerging 

Technologies and Factory Automation, ETFA 2008, September 

15-18, 2008, Hamburg, germany, pp. 215-220, 2008, IEEE. 

129. Weber, Ingo; Markovic, Ivan; Scicluna, james; Hoffmann, jörg; 

Kowalkiewicz, Marek; Born, Matthias; Kaczmarek, Tomasz; Zhou, 

Xuan. Semantic Annotation and Composition of Business Processes 

with Maestro.. The Semantic Web: Research and Applications, 

5th European Semantic Web Conference, ESWC 2008, Tenerife, 

Canary Islands, Spain, june 1-5, 2008, Proceedings, pp. 772-776, 

2008, Springer, 978-3-540-68233-2. 

130. Weinreich, Harald; Obendorf, Hartmut; Mayer, Matthias; 

Herder, Eelco. Not quite the average: An empirical study of Web 

use.. ACM Transactions on the Web (TWEB) 2(1), 2008. 

131. Wiebelitz, jan; Dal Pra, Stefano; Müller, Wolfgang; voigt, 

gabriele. The german grid Infrastructure: A uniform Accounting 

Service in Multiple Middleware Environments. grid Economics 

and Business Models, 5th International Workshop, gECON 2008, 

Las Palmas de gran Canaria, Spain, August 26, 2008. Proceedings, 

pp. 208-216, 2008, Springer, 978-3-540-85484-5. 

132. Wiebelitz, jan; Müller, Wolfgang; Brenner, Michael; von 

voigt, gabriele. Towards a Comprehensive Accounting Solution 

in the Multi-Middleware Environment of the D-grid Initiative. 

Proceeding of the Cracow grid Workshop ‘08, Cracow, Poland 

133. Witte, Rene; gitzinger, Thomas; Kappler, Thomas; Krestel, 

Ralf. A Semantic Wiki Approach to Cultural Heritage Data 

Management. Language Technology for Cultural Heritage 

Data (LaTeCH 2008), Workshop at LREC 2008, june 1st, 2008, 

Marrakech, Morocco. 

134. Zaka, Bilal; Kulathuramaiyer, Narayanan; Balke, Wolf-Tilo; 

Maurer, Hermann. Topic-Centered Aggregation of Presentations 

for Learning Object Repurposing. World Conference on E-Learning 

in Corporate, government, Healthcare, & Higher Education 

(E-Learn), Las vegas, Nv, 2008 

Zerr, Sergej; Demidova, Elena; Olmedilla, Daniel; Nejdl, 

135. 

Wolfgang; Winslett, Marianne; Mitra, Soumyadeb. Zerber: 

r-Confidential Indexing for Distributed Documents. 11th 


100 

COMMITTEES 

International Conference on Extending Database Technology 

(EDBT 2008), March 25-30 2008, Nantes, France 

136. Zerr, Sergej; Nejdl, Wolfgang. Privacy Preserving Document 

Indexing Infrastructure for a Distributed Environment. 

Proceedings of the vLDB Endowment, volume 1 , Issue 2 (August 

2008), pp. 1638-1643 

137. Zhu, jianhan; de vries, Arjen P.; Demartini, gianluca; 

Iofciu, Tereza. Relation Retrieval for Entities and Experts. Future 

Challenges in Expertise Retrieval (fCHER 2008), SIgIR 2008 

Workshop, Singapore, july, 2008. 

Programm Committees 

3rd Asian Semantic Web Conference (ASWC), Bangkok, Thailand, 

December 8-11, 2008 (Nejdl, Olmedilla) 

3rd Asian Semantic Web Conference Demo Track, Bangkok, 

Thailand, December 8-11, 2008 (Kärger) 

Workshop on E-Learning for Business needs, Innsbruck, Austria, 

May, 2008 (de Coi) 

3rd Intl. Workshop on Adaptation and Evolution in Web Systems 

Engineering (AEWSE’08), at ICWE, Yorktown Heights, New York, 

uSA, july, 2008 (Herder) 

5th Intl. Conf. Adaptive Hypermedia and Adaptive Web- 

Based Systems (AH2008), Hannover, germany, july, 2008 

(Nejdl,Herder) 

user Modeling, Adaptation and Personalization (uMAP 2009), 

Trento, Italy, 22-26 june 2009 (Herder, Nejdl) 

Workshop on Cognitive Aspects in Intelligent and Adaptive 

Web-based Educational Systems (CIAWES 2008), Taipei, Taiwan, 

October 27 - 31, 2008 (Brunkhorst) 

Workshop on Adaptivity and Personalization in ubiquitous 

Learning Systems (APuLS 2008) graz, Austria, November 18-21, 

2008 (Brunkhorst) 

16th Workshop on Adaptivity and user Modeling in Interactive 

Systems (ABIS 2008) Lernen--Wissen--Adaptivität (LWA), 

Würzburg, germany, October 6-8, 2008 (Brunkhorst, Krause, 

Herder) 

7th International Semantic Web Conference, Karlsruhe, germany, 

October 2008. (Balke, Nejdl, Olmedilla) 

3rd International Applications of Semantic Technologies Workshop 

located at the Informatik 2008, Munich, germany, September 9th, 

2008 (Krause) 

International Workshop on Adaptivity and Personalization 

in ubiquitous Learning Systems in conjunction with the 4th 

Symposium on usability & HCI for Education and Work, graz, 

Austria, November 18-21, 2008 (Krause) 

2nd International Workshop on Personalized Access, Profile 

Management, and Context Awareness: Databases, Auckland, 

New Zealand, 23rd of August, 2008 (Balke, Nejdl) 

8th International Conference on Peer-to-Peer Computing 2008 

(P2P’08), Aachen, germany, September 8-11, 2008 (Balke, 

Nejdl) 

ONTORACT 2008 - 1st International Workshop on Ontologies in 

Interactive Systems; held in conjunction with HCI 2008, Liverpool, 

u.K., 1st of September 2008 (Denecke, Risse) 

WESOA 2008 - 4th International Workshop on Engineering Service- 

Oriented Applications, in conjunction with 6th International 

Conference on Service Oriented Computing (ICSOC 2008), Sydney, 

Australia, December 1-5, 2008 (Risse) 


International Workshop on the Role of Services, Ontologies, and 

Context in Mobile Environments (RoSOC-M ‘08), Beijing, China, 

April 27, 2008 (Risse) 

WEBIST 2008 - 4th International Conference on Web Information 

Systems and Technologies, Funchal, Madeira, Portugal, 4 - 7 May, 

2008, (Risse) 

EATIS 2008 - Euro American Association on Telematics and 

Information Systems, Aracaju, Brazil, September 10-12, 2008 

(Risse) 

23rd Annual ACM Symposium of Applied Computing (SAC) 

Technical Track – The Semantic Web and Applications (SWA), 

Fortaleza, Ceara, Brazil, March16-20, 2008 (Costache) 

2nd International Workshop on Ontologies and Information 

Systems for the Semantic Web (ONISW 2008), at the 17th ACM 

Conference on Information and Knowledge Management (CIKM 

2008), Napa valley, California, October 26-30, 2008 (Costache) 

AAAI-SSS-09: Social Semantic Web: Where Web 2.0 Meets Web 

3.0, Stanford, California, March 23-25, 2009 (jäschke) 

ECAI 2008 Workshop on Mining Social Data, Patras, greece, july 

21, 2008 (jäschke) 

35th EuROMICRO Conference on Software Engineering and 

Advanced Applications (SEAA), Parma, Italy, September 3-5, 2008 

(grimm) 

2nd ACM International Conference on Web Search and Data 

Mining (WSDM) Barcelona, Spain, February 9-12, 2009 (Nejdl) 

European Semantic Web Conference In-use Track, Heraklion, 

greece, june 2009 (Olmedilla) 

European Semantic Web Conference PhD Symposium, Heraklion, 

greece, june 2009 (Balke, Olmedilla) 

European Semantic Web Conference, Heraklion, greece, june 2009 

(Olmedilla, Siberski) 

International Conference on grid and Pervasive Computing (gPC), 

geneva, Switzerland, May 2009 (Olmedilla) 

5th Workshop on Semantic Web and Application Perspectives 

(SWAP), Roma, Italy, December 2008 (Olmedilla) 

3rd Asian Semantic Web Conference, Bangkok, Thailand, 

December 2008 (Olmedilla) 

2nd International Workshop on Combining Context with Trust, 

Security, and Privacy (CAT’08) co-located with joint iTrust and 

PST Conferences on Privacy, Trust Management and Security 

(IFIPTM’2008), Trondheim, Norway, june 2008 (Olmedilla) 

17th International World Wide Web Conference, Posters Track, 

Beijing, China, April 2008 (Olmedilla) 

17th International World Wide Web Conference, Beijing, China, 

April 2008 (Stumme) 

17th International World Wide Web Conference, Web Engineering

Track, Beijing, China, April 2008 (Nejdl) 

IEEE 11th International Conference on Computational Science 

and Engineering, IEEE Computer Society, São Paulo, Brazil, july 

2008 (Olmedilla) 

European Semantic Web Conference PhD Symposium, Tenerife, 

Spain, june 2008. (Olmedilla) 

5th European Semantic Web Conference, Tenerife, Spain, june 

2008. (Olmedilla, Nejdl, Stumme) 

6th European Semantic Web Conference, Heraklion, greece, May 

31 - june 4, 2009 (Nejdl) 

International Conference on grid and Pervasive Computing (gPC), 

Kunming, China, May 2008. (Olmedilla) 

4th ACM Symposium on Applied Computing (SAC) Trust, 

Recommendations, Evidence and other Collaboration Know-how 

(TRECK) Track, Fortaleza, Brazil, March 2008 (Olmedilla) 

6th ACS/IEEE International Conference on Computer Systems and 

Applications, April 1-4, 2008; Doha,Qatar; Databases and Data 

Mining Track (Siberski)” 

18th Intl. World Wide Web Conference, Madrid, Spain, April 20-24, 

2009, Semantic Web Track (Siberski)” 

6th International Workshop on Databases, Information Systems 

and Peer-to-Peer Computing, August 23, 2008; Auckland, New 

Zealand (Siberski) 

Editorial Board Member of the 6th Intl. Conf. on Formal Concept 

Analysis, Montreal, Canada, 25.-28. February 2008 (Stumme) 

Editorial Board Member of the 16th Intl. Conf. on Conceptual 

Structures, Toulouse, France, 7.-11- july 2008 (Stumme) 

Hypertext 2008, Pittsburg, u.S., 19.-21. june 2008 (Stumme) 

18th Europ. Conference on Artificial Intelligence, Patras, greece, 

21.-25. july 2008 (Stumme) 

9th Intl. Conf. on Web Information Systems Engineering, Auckland, 

New Zealand, 1.-3. September 2008 (Balke, Nejdl, Stumme) 

3rd Conceptual Structures Tool Interoperability Workshop at 

ICFCA 2008, Toulouse, France, 7. july 2008 (Stumme) 

16th International Conference on Knowledge Engineering and 

Knowledge Management, Catania, Italien, September 2008 

(Stumme) 

Workshop “Wikis, Blogs, Bookmarking Tools - Mining the Web 

2.0” at ECML/PKDD 2008, Antwerpen, Belgium, September 2008 

(Siberski, Stumme) 

vice Chair of the 7th Intl. Semantic Web Conference, Karlsruhe, 

germany, October 2008 (Stumme) 

2008 IEEE/WIC/ACM Intl. Conference on Web Intelligence, Sydney, 

Australia, December 2008 (Nejdl, Stumme) 

IEEE/WIC/ACM Intl. Conference on Web Intelligence, Milano, Italy, 

September 2009 (Nejdl) 

International Conference on Extending Database Technology 

(EDBT), Nantes, France, 25.-29. March 2008 (Balke) 

International Workshop on Data Management in Peer-to-Peer 

Systems, in conjunction with the 11th International Conference 

on Extending Database Technology, March 25-30 2008, Nantes, 

France (Nejdl) 

4th Multidisciplinary Workshop on Advances in Preference 

Handling (M-Pref), Chicago, Illinois, july 13-14, 2008 (Balke) 

23nd AAAI Conference on Artificial Intelligence, Chicago, Illinois, 

july 13-17, 2008 (Nejdl) 

4th European Conference on Technology Enhanced Learning, 

Cannes, France, September 2009 (Nejdl) 

COMMITTEES 

32nd Annual Conference on Artificial Intelligence, Paderborn, 

germany, September 2009 (Nejdl) 

Intl. Conference for Digital Libraries and the Semantic Web, 

Trento, Italy, September 2009, PC Chair (Nejdl) 

International Conference on Knowledge Management, graz, 

Austria, September 3-5, 2008 (Nejdl) 

9th Intl. Confererence on Knowledge Management and Knowledge 

Technologies, graz, Austria, September 2-4, 2009 (Nejdl) 

DEXA Intl. Conference, Linz, Austria, August 31 - September 4, 

2009 (Nejdl) 

Intl. Conference on Web-based Learning, Aachen, germany, 

August 19-21, 2009 (Nejdl) 

9th IEEE International Conference on Advanced Learning 

Technologies, Riga Latvia, july 14-18, 2009 (Nejdl) 

21st Intl. joint Conference on Artificial Intelligence, Pasadena, uS, 

july 11-17, 2009 (Nejdl) 

8th Intl. Conference on Interaction Design and Children, Como, 

Italy, june 3-5, 2009 (Nejdl) 

17th Intl. Conference on Control Systems and Computer Science, 

Bucharest, Romania, May 26-29, 2009 (Nejdl) 

18th Intl. World Wide Web Conference, Madrid, Spain, April 20-24, 

2009, PC Chair (Nejdl) 

25th Intl. Conference on Data Engineering, Shanghai, China, 

March 29 - April 2, 2009, Track Chair (Nejdl) 

2nd ACM Intl. Conference on Web Search and Data Mining, 

Barcelona, Spain, February 9-12, 2009 (Nejdl) 

The 7th International Conference on Ontologies, DataBases, and 

Applications of Semantics, Monterrey, Mexico, Nov 11 - 13, 2008 

16th International Conference on Cooperative Information 

Systems, Monterrey, Mexico, Nov 12 - 14, 2008 (Nejdl) 

2nd International Conference on Web Reasoning and Rule Systems, 

Karlsruhe, germany, October 31 - November 2, 2008 (Nejdl) 

Third European Conference on Technology Enhanced Learning, 

Maastricht, The Netherlands, September 17-19, 2008 (Nejdl) 

37th International Conference on Parallel Processing, Portland, 

uS, September 8-12, 2008 (Nejdl) 

19th International Conference on Database and Expert Systems 

Applications, Turin, Italy, Sept 1-5, 2008 (Nejdl) 

31st Annual International ACM SIgIR Conference, Singapore, july 

20-24, 2008 (Nejdl) 

8th IEEE International Conference on Advanced Learning 

Technologies Learning Technologies in the Information Society, 

Santander, Spain, july 1- july 5, 2008 (Nejdl) 

11th International Workshop on Web and Databases 2008, 

co-located with ACM SIgMOD/PODS 2008, vancouver, Canada, 

june 9-12, 2008 (Nejdl) 

Workshop on Efficiency Issues in Information Retrieval Workshop, 

in conjunction with the 30th European Conference on Information 

Retrieval, glasgow, Scotland, March 30 - April 3, 2008 (Nejdl) 

13th International Conference on Databases for Advances 

Applications, New Delhi, India, March 19-21, 2008 (Nejdl) 

34th International Conference on Current Trends in Theory and 

Practice of Computer Science, Slovakia, january 19-25, 2008 

(Nejdl) 

6th Workshop on Large-Scale Distributed Systems for Information 

Retrieval, co-located with CIKM’08, Napa valley, California, 

October 26-30, 2009 (Nejdl) 


COMMITTEES 

Organization Committees & Boards 

Dagstuhl Seminar “Social Web Communities”, Dagstuhl, germany, 

21.-26. September 2008 (Stumme) 

Third Conceptual Structures Tool Interoperability Workshop 

(CS-TIW 2008), Toulouse, France, 7th july, 2008 (jäschke) 

Workshop “Knowledge Discovery, Data Mining, Maschinelles 

Lernen 2008” der Fachgruppe KDML, Würzburg, October 6-8, 

2008 (jäschke) 

ECML PKDD Discovery Challenge 2008, Antwerp, Belgium, 

September 15th, 2008 (jäschke) 

7th International Workshop of the Initiative for the Evaluation of 

XML Retrieval, INEX 2008 Dagstuhl Castle, germany, December 

15-18, 2008. Entity Ranking Track Organizers (Demartini, Iofciu) 

7th International Semantic Web Conference, Karlsruhe, germany, 

October 2008. Workshop Chair. (Olmedilla, Siberski) 

IEEE International Policies for Distributed Systems and Networks 

(POLICY 2008), Palisades, NY, uSA, june 2008. IEEE Computer 

Society. System Demonstrations Chair. (Olmedilla) 

16th Workshop on Adaptivity and user Modeling in Interactive 

Systems (ABIS 2008) Lernen--Wissen--Adaptivität (LWA), 

Würzburg, germany, October 6-8, 2008 (Krause) 

102 


5th International Conference on Adaptive Hypermedia and 

Adaptive Web-Based Systems, Hannover, germany, july 28 - 

August 1, 2008, (Herder), general Chair (Nejdl) 

5th Workshop on Positioning, Navigation and Communication 

2008 (WPNC’08), Hannover, germany, March 27, 2008 (Kaiser, 

Bartke, Dimitrov, galler, gerok, Moghaddamnia, Rahmatollahi, 

Sczyslo, Schumacher) 

6th Workshop on Positioning, Navigation and Communication 

2009 (WPNC’09), Hannover, germany, March 19, 2009 (Kaiser, 

Dimitrov, Düvel, galler, gerok, Rahmatollahi, Sczyslo) 

IEEE 2008 International Conference on ultra-Wideband 

(ICuWB2008), Hannover, germany, September 10-12, 2008. 

(Kaiser, Adler, Kupferschmidt, Schröder, Zhao) 

4th Intern. Conf. On Cognitive Radio Oriented Wireless Networks 

And Communications (CrownCom 2009), Hannover, germany, 

june 22-24, 2009 (Kaiser, Adler, Bartke, Daoud, Miranda, Pérezguirao, 

Schumacher, Wilzeck) 

1st ACM International Workshop on Semantic Ambient Media 

Experience, October 31, 2008, vancouver, Canada in conjunction 

with ACM Multimedia 2008 (Risse) 

6th ACS/IEEE International Conference on Computer Systems and 

Applications, April 1-4, 2008; Doha, Qatar; Chair of the Databases 

and Data Mining Track (Risse)


104 

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Tel.: +49 (0)511 762 - 17714 

Fax: +49 (0)511 762 - 17779 

E-Mail: info@L3S.de 

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contact: Dipl.-Vw. Gabriele Herrmann-Krotz 

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