Back Room Front Room 2

104
ENTERPRISE INFORMATION SYSTEMS VI
...
Movies Parameters
...
Recording Devices
by the Linear Constraints Checking module, which
enforces the service requirements formulated in
Section 4.2.2. The solutions that satisfy the service
requirements will be further verified by the Statistical
Admission Control module described in Section 4.2.3,
which provides the statistical service guarantees for
the recording system. After exhausting the search
space, the load space navigator forwards the highest
Nmax to the Minimum Buffer Size Computation
module, which computes the minimal buffer size
S buf
min .
We conclude by providing an algorithm that solves
the MSB problem in exponential time shown in Figure
6, based on the process illustrated in Figure 5.
5 CONCLUSIONS AND FUTURE
RESEARCH DIRECTIONS
We have presented a novel buffer minimization problem
(MSB) motivated by the design of our large scale
data stream recording system HYDRA. We formally
proved that MSB is NP-complete, and we also provided
an initial exponential-time algorithm to solve
the problem. As part of our future work, we will focus
on finding an approximation algorithm which solves
the MSB problem in polynomial-time. Furthermore,
we plan to evaluate the memory management module
in the context of the other system components
that manage data placement, disk scheduling, block
prefetching and replacement policy, and QoS requirements.
Finally, we plan to implement and evaluate the
memory management module in our HYDRA prototype
system.
REFERENCES
Compute the maximum
number of streams Nmax
Load Space
Navigator
Linear
Constraints
Checking
Service
Requirements
Aref, W., Kamel, I., Niranjan, T. N., and Ghandeharizadeh,
S. (1997). Disk Scheduling for Displaying and
Figure 5: Process to solve the MSB problem
Statistical
Admission
Control Nmax
Compute
Minimum
Buffer Size
...
Disks Parameters
Recording Video in Non-Linear News Editing Systems.
In Proceedings of the Multimedia Computing
and Networking Conference, pages 228–239, San
Jose, California. SPIE Proceedings Series, Volume
3020.
Chae, Y., Guo, K., Buddhikot, M. M., Suri, S., and Zegura,
E. W. (2002). Silo, rainbow, and caching token:
Schemes for scalable, fault tolerant stream caching.
Special Issue of IEEE Journal of Selected Area in
Communications on Internet Proxy Services.
Cui, Y. and Nahrstedt, K. (2003). Proxy-based asynchronous
multicast for efficient on-demand media
distribution. In The SPIE Conference on Multimedia
Computing and Networking 2003 (MMCN 2003),
Santa Clara, California, pages 162–176.
Garey, M. R. and Johnson, D. S. (1979). Computers and Intractability:
A Guide to Theory of NP-Completeness.
W.H.Freeman and Company, New York.
Huffstutter, P. J. and Healey, J. (2002). Filming Without the
Film. Los Angeles Times, page A.1.
Lee, S.-H., Whang, K.-Y., Moon, Y.-S., and Song, I.-
Y. (2001). Dynamic Buffer Allocation in Video-
On-Demand Systems. In Proceedings of the international
conference on Management of data (ACM
SIGMOD’2001), Santa Barbara, California, United
States, pages 343–354.
Makaroff, D. J. and Ng, R. T. (1995). Schemes for Implementing
Buffer Sharing in Continuous-Media Systems.
Information Systems, Vol. 20, No. 6., pages 445–
464.
Papadimitriou, C. H. and Steiglitz, K. (1982). Combinatorial
Optimization: Algorithms and Complexity. Prentice
Hall, Inc., Englewood Cliffs, New Jersey 07632.
Ramesh, S., Rhee, I., and Guo, K. (2001). Multicast with
cache (mcache): An adaptive zero delay video-ondemand
service. In IEEE INFOCOM ’01, pages 85–
94.
Sen, S., Rexford, J., and Towsley, D. F. (1999). Proxy prefix
caching for multimedia streams. In IEEE INFOCOM
’99, pages 1310–1319.