FLEXIBLE SHARED WINDOWS

Prasun Dewan
Kevin Jeffay

Department of Computer Science
University of North Carolina

CONTACT INFORMATION

University of North Carolina
CB#3175, Sitterson Hall
Chapel Hill, NC 27599-3175
Phone: 919 962 1823
Fax : 919 962 1799
Email: dewan@cs.unc.edu
and jeffay@cs.unc.edu

WWW PAGE

http://www.cs.unc.edu/~dewan/sw.html

PROGRAM AREA

Choose one of these 6 areas that best fits your project
NOTE: The complete descriptions of the areas are included in the explanation page:

KEYWORDS

Collaboration, Migration, Real-Time, Replication, Toolkit, Video Conferencing, Window System.

PROJECT SUMMARY

A shared window system is a software infrastructure that allows users to share the contents of application windows and provides audio/video conferencing to its users. The goal of this work is to develop techniques that significantly increase the flexibility and performance of shared window systems. We are investigating migration of existing single-user X clients, a new window-architecture that inverts the traditional client-server architecture, efficient latecomer support, and techniques for adapting audio/video media streams in response to congestion.

PROJECT REFERENCES

Goopeel Chung, Prasun Dewan, and Sadagopan Rajaram, "Generic and composable latecomer accommodation service for centralized shared systems ," Proc. Conference on Engineering for Human Computer Interaction, September 1998.

Chung, G., and Dewan, P. Proceedings of the Ninth User Interface Software and Technology, November 1996, pages 11-20.

Goopeel Chung and Prasun Dewan , "A Mechanism for Supporting Client Migration in a Shared Window System," Proceedings of the Ninth Conference on User Interface Software and Technology, October 1996, pp. 11-20.

P. Nee, K. Jeffay, and Gunner Danneels, The Performance of Two-Dimensional Media Scaling for Internet Videoconferencing Network and Operating System Support for Digital Audio and Video, Proceedings, Seventh Intl. Workshop St. Louis, MO, May 1997.

AREA BACKGROUND

The recent advances in communication and computing technology have lead to the area of multiuser or collaborative applications - applications that interact with multiple, distributed users. There are two main reasons for studying these applications: The popular and compelling motivation is that that these applications can simulate face-to-face meetings with remote users, giving them the illusion of ''being there''. However, if all collaborative applications did was simulate ''being there,'' then they would always support meetings that are inferior to the real face-to-face meetings, and thus be considered necessary evils by those who cannot be physically colocated. In fact, these applications can allow us to go ``beyond being there,'' offering benefits we cannot get in meetings supported without the computer.

The idea of multiuser applications is not practical unless infrastructures are developed to automate the complex tasks of these applications such as coupling the view of different users and supporting real-time interaction. An important instance of a multiuser infrastructure is a shared window system, which provides the abstraction of a shared window, which is a single logical window that can be viewed and manipulated by multiple, distributed users. Shared window systems hold the promise of truly general deployment and use of multiuser applications. Windows are the heart of contemporary applications in that these applications directly or indirectly (via toolkits and terminal emulators) create windows to interact with their users. By providing sharing of windows, window systems can convert these single-user window applications into corresponding multiuser applications. However, a serious flaw with these systems is that they provide a single, simplistic sharing schemes. The scheme, called WYSIWIS (What You See Is What I See), mimics face-to-face collaboration by ensuring all users sharing a window see the same presentation at all times. It suffers from performance problems, since every window change made by every user must be sent to all other users. Moreover, from the usage point of view, it does not offer any of the benefits of `beyond being there'. To overcome these limitations of shared window systems, several higher-level multiuser infrastructures such as shared toolkits and user interface management systems, but these are targeted at a narrower domain of user-interfaces. Current research in this area, therefore, is trying to offer systems that offer advantages of both kinds of infrastructures.

AREA REFERENCES

Sunil Sarin, Irene Greif, Computer-Based Real-Time Conferencing Systems, IEEE Computer, 18:10, October 1985, pages 33-49

Mark Stefik Gregg Foster, Daniel G. Bobrow, Kenneth Kahn, Stan Lanning, and Lucy Suchman, Beyond the Chalkboard: Computer Support for Collaboration and Problem Solving in Meetings, CACM, 30:1 January 1987, pages 32-47.

Clarence A. Ellis, Simon J. Gibbs, Gail L. Rein, Groupware: Some Issues and Experiences, CACM, 34: 1, January 1991, pages 38-58.

J.C. Lauwers and K.A. Lantz, Collaboration Awareness in Support of Collaboration Transparency: Requirements for the Next Generation of Shared Window Systems, Proceedings of ACM CHI'90, April 1990, pages 303-312

P. Dewan, Tools for Implementing Multiuser User Interfaces, Trends in Software: Issue on User Interface Software, 1993, Wiley, Volume 1, pages 149-172.

RELATED PROGRAM AREAS

List other areas within the ISP that you think might form plausible collaborations with your work. (Choose from the same 6 ISP program areas under "Program Area" above.) I will index on these also.
  • 1. Virtual Environments.
  • 2. Speech and Natural Language Understanding.
  • 3. Other Communication Modalities
  • 5. Usability and User-Centered Design.
  • 6. Intelligent Interactive Systems for Persons with Disabilities.

    POTENTIAL RELATED PROJECTS

    Collaborative Virtual Environments

    Abstract Awareness of Collaborators' Actions based on Speech and Natural Language Understanding of Collaborators' Dialogue.

    Usable Designs of Collaborative User Interfaces.

    Intelligent Collaborative Interactive Systems for Persons with Disabilities.