UCLA VIRTUAL WORLD DATA SERVER

Richard R. Muntz*
Walter Gekelman**
William H. Jepson***
Walter Karplus*
D. Stott Parker*

(*) Computer Science Department
University of California, Los Angeles

(**) Physics Department
University of California, Los Angeles

(***) Department of Architecture & Urban Design
University of California, Los Angeles

Contact Information

Richard R. Muntz
3732 Boelter Hall
Computer Science Dept., UCLA
Los Angeles, CA 90095-1596
City, State ZIP
Phone: (310) 825-3546
Fax : (310) 825-2273
Email: muntz@cs.ucla.edu

WWW PAGE

http://mml.cs.ucla.edu

Keywords

Multimedia Data Server, Real-time I/O, Randomized Data Allocation, 3D Virtual World, Video on Demand, Scientific Visualization.

Project Award Information

Award Number: IRI-9527178
Duration: 3rd year
Title: UCLA Virtual World Data Server Project

Project Summary

We have developed a general real-time multimedia data server using parallel disks, that can simultaneously deliver data to heterogeneous applications with real-time requirements, such as 3D interactive virtual worlds, interactive scientific visualizations, video on demand, etc.

Goals, Objectives, and Targeted Activities

The goals for the next year include:

Porting our current working version of the Virtual World Data Server to a distributed architecture based on a cluster of commodity PCs.
Incorporation of dynamic quality of service that will allow adapting the quality of delivered data (frame rate and level of detail) to the current demand on the system. We will develop definitions of quality of service, methods of specifying how tradeoffs are to be made, and system algorithms for implementation of these policies.
Optimization of the 3D interactive urban simulation application in order to reduce the current bandwidth requirement of individual "fly through" sessions. This will include, compression and progressive transmission of texture images, development of back facing culling algorithms that will avoid retrieving unnecessary objects that are not currently visible, and possibly other techniques to be determined.
Porting the scientific visualizations, for Plasma Physics and Virtual Aneurysms, currently implemented on stand alone machines, to the VWDS Data Server.
Develop the infrastructure necessary to make the VWDS available to the UCLA scientific community to store and deliver data for both real-time and non real-time scientific applications that require high storage capacity and bandwidth. Potential users include researchers at the departments of Architecture & Urban Design, Atmospheric Sciences, Neural Science and Physics.

Indication of Success

A prototype of the VWDS Data Server supporting simultaneous delivery of MPEG encoded videos and 3D urban simulation city models for multiple users has been implemented and successfully demonstrated at several events. Demonstrations, presentations and talks have been invited at more than 40 events including:

UCLA Computer Science Annual Research Review, April 1997.
Internet 2 Demo, Washington DC, April 1998.
ACM 50th Anniversary Celebration.
Schloss Dagstuhl, Germany.
Multimedia Information Systems Workshop, West Point, New York.
The American Planning Association (APA) National Conference.
The California and Los Angeles Chapter's of the APA annual conferences.
The Washington State Chapter of the APA annual conference.
The A/E/C (architecture, engineering, construction) Systems Conference.
I/ITSEC '97 (the Interservice/Industry Training, Simulation and Education Conference).
Intel's National Conference on Graphics.
ACADIA (Association for Computer Aided Design in Architecture, National Conference).
Council for Technology and the Individual, Roundtable in Multimedia Visual Simulation and Interaction Conference.
Caltech, MIT, U. Penn., Washington U., Columbia.

Project Impact

The project has enabled collaborations with the following organizations:

Intel Corporation
Microsoft Corporation
Silicon Graphics Inc.
MultiGen Inc.
Bay Networks
Mayor's Office, City of Los Angeles
Metropolitan Transportation Authority (Los Angeles)
Los Angeles Community Redevelopment Authority
Getty Information, Conservation, Education and Antiquities Institutes

The project has provided research opportunities for several graduate students. Current Ph.D. students working in the Project are:

Jose Renato Santos, UCLA CS Dept. (graduating in June 1998)
Damon Liu, UCLA CS Dept. (advanced to candidacy in May 1997)
Renato Santana, Federal University of Rio de Janeiro (UFRJ) (visiting student at UCLA)
Chris Mitchell, UCLA Physics Dept.
Wai-Man R. Wong, UCLA CS Dept.(advancing to candidacy in May 1998)
Yasuyuki Sato, UCLA CS Dept.(advancing to candidacy in May 1998)
Scott A. Friedman, UCLA CS Dept.(advancing to candidacy in May 1998)

A two-quarter course curriculum devoted entirely to real-time Urban Simulation has been developed and taught in UCLA Department of Architecture and Urban Design. Courses in high performance storage systems and multimedia information systems have been developed and taught in the CS Dept.

Project References

R. Muntz, J.R. Santos, S. Berson. "A Parallel Disk Storage System for Real-time Multimedia Application". To appear in the Special Issue on Multimedia Computing Systems of the International Journal of Intelligent Systems, 1998.

F. Fabbrocino, J.R. Santos, R. Muntz. "An Implicitly Scalable Real-Time Multimedia Storage Server".Technical Report #980009, Computer Science Department, UCLA, March 1998.

R. Muntz, J.R. Santos, and S. Berson. "RIO: A Real-time Multimedia Object Server".ACM Performance Evaluation Review, ACM Press, vol. 25, no. 2, p.29-35, September 1997.

W. Jepson, S. Friedman. "An Efficient Environment for Real-Time Visualization".I/ITSEC '97 19th Interservice/Industry Training Systems and Education Conference, Orlando, Florida, December 1997.

D. Liu, W. Karplus, D. Valentino. "A Framework for the Intelligent Visualization of Large Time-Dependent Flow Datasets in Medical VR Systems".Technical Report 970016, Department of Computer Science, UCLA, May 1997.

S. Berson, R.R. Muntz, and W.R. Wong. "Randomized Data Allocation for Real-time Disk I/O".In Proceedings of Compcon Conference, San Francisco, California, February, 1996.

Area Background

We address the problem of storing and delivering data to multimedia real-time applications. These applications access large amounts of data that typically do not fit in main memory and need to be continuously retrieved from disks. These continuous media data impose deadlines on the retrieval and delivery of information, which must be satisfied to avoid undesired discontinuities on data visualization by the end user. High utilization of resources is desirable to achieve a good cost/performance ratio. However, high utilization is inconsistent with guaranteed real-time service and statistically varying service requirements.The challenge of real-time data servers is to achieve high utilization of system resources and still be able to guarantee low delay bounds on data delivery.

Most of the work on multimedia storage servers has concentrated on video and audio playback, which has highly predictable access patterns. We, however, consider much more general applications, such as 3D interactive virtual worlds, where the high degree of user interaction makes the workload much less predictable. We have developed and implemented,in our Virtual world Data Server, novel solutions for data storage and retrieval that allows the system to provide statistical real-time guarantees with high utilization of resources, for general workloads with unpredictable access patterns.

Area References

[1] P.W. Agnew and A.S. Kellerman. "Distributed Multimedia".Addison Wesley, 1996.

[2] D.J. Gemmell, H.M. Vin, D.P. Kandlur, P.V. Rangan, L. Rowe. "Multimedia Storage Servers:A Tutorial".IEEE Computer, May 1995, pp. 40-51.

[3] W. Jepson, R. Liggett, S. Friedman. "An environment for real-time urban visualization".Proceedings of the Symposium on Interactive 3D Graphics. Monterey, California, April, 1995.

Potential Related Projects

Some ideas of future research include:

Extension of the 3D Virtual World application to support "avatars", "virtual/ synthetic actors", dynamic interaction between multiple participants, etc.
Support for delivering heterogeneous media types on a single user session, as for example video, audio or text associated with different 3D objects of a virtual world model.
Authoring systems for "knowledge repositories" oriented around 3D models. For example, enabling scholors of ancient Rome to annotate a model of Trajan's Forum so that it ventually becomes the container for the world's knowledge of this historical site an a resource for students and scholars alike.