Wireless mobile computing breaks the stationary barrier and allows users to compute and access information anywhere and anytime. However, this new freedom of movement does not come without new challenges.

The mobile computing environment is constrained in many ways. Mobile elements are resource-poor and unreliable. Their network connectivity is often achieved through low-bandwidth wireless links. Furthermore, connectivity is frequently lost for variant periods of time. The difficulties raised by these constraints are compounded by mobility that induces variability in the availability of both communication and computational resources.

These severe restrictions have a great impact on the design and structure of mobile computing applications and motivate the development of new computing models. To this end, a number of extensions to the traditional distributed system architectures have been proposed.

These new software models, however, are static and require a priori set up and configuration. This in effect limits their potential in dynamically serving the mobile client; the client can not access a site where an appropriate model is not configured in advance. The contribution of this work is twofold. First, it shows how an implementation of the proposed models using mobile agents eliminates this limitation and enhances the utilization of the models. Second, new frameworks for Web-based distributed access to databases are proposed and implemented via mobile agents.

ABOUT AUTHOR

George Samaras

George Samaras received a PhD in computer science from Rensselaer Polytechnic Institute, USA, in 1989. He is currently an Associate Professor at the University of Cyprus.

He was previously at IBM Research Triangle Park, USA and taught at the University of North Carolina at Chapel Hill (adjunct Assistant Professor, 1990-93). He served as the lead architect of IBM's distributed commit architecture (1990-94) and coauthored the final publication of the architecture (IBM Book, SC31-8134- 00, September 1994).

He was member of IBM's wireless division and participated in the design/architecture of IBM's WebExpress, a wireless Web browsing system. He recently (1997) co-authored a book on data management for mobile computing (Kluwer A.P). He has a number of patents relating to transaction processing technology and numerous technical conference and journal publications. His work on utilizing mobile agents for Web database access has received the best paper award of the 1999 IEEE International Conference on Data Engineering (ICDE'99). He has served as proposal evaluator at a national and international level and he is regularly invited by the European Commission to serve as project evaluator and auditor in areas related to mobile computing and mobile agents. He also served on the University's Board of Information Systems (1995-1997) and he is a member of the committee formed by the Planning Bureau, Ministry of Finance, for establishing Cyprus as an Information Service Center.

In addition he served as a advisory and consultant at an international and local level in numerous occasions. He also served on IBM's internal international standards committees for issues related to distributed transaction processing (OSI/TP, XOPEN, OMG).

His research interest includes mobile computing, mobile agents, transaction processing, commit protocols and resource recovery, and electronic commerce systems. He is a voting member of the ACM and IEEE Computer Society.

Литература:

1. E.Pitoura and G. Samaras, "Data Management for Mobile Computing", Kluwer Academic Publishers, ISBN 0-7923-8053-3, 1998.
2. Evripidou P., Samaras G., Pitoura E., Christoforos P., "The PacMan Metacomputer: Parallel Computing with Java Mobile Agents", Journal FGCS special issue on JAVA in High Performance Computing, 2000. (in print)
3. Constantinos Spyrou, George Samaras, Evangelia Pitoura, Evripidou Paraskevas "Mobile Agents for Wireless Computing: The Convergence of Wireless Computational Models with Mobile-Agent Technologies", Journal of ACM/Baltzer Mobile Networking and Applications (MONET), special issue on "Mobility in Databases & Distributed Systems ", 2000. (in print)
4. E. Pitoura, and Samaras, G., "Locating Objects in Mobile Computing". IEEE Transactions on Knowledge and Data Engineering Journal (TKDE). 2000 (In print)
5. Stavros Papastavrou, Panos K. Chrysanthis, George Samaras, Evaggelia Pitoura, "A Survey on the Java-based Approaches for Web Database Connectivity", Proc. of the Medicon 2000 Conference, September 2000.
6. Samaras G., Dikaiakos M., Spyrou C., Liberdos A., "Mobile Agent Platforms for Web-Databases: A Qualitative and Quantitative Assessment", The Joint Symposium ASA/MA'99. First International Symposium on Agent Systems and Applications (ASA'99). Third International Symposium on Mobile Agents (MA'99), pp. 50-64, USA, 1999.
7. Evripidou P., Samaras G., Pitoura E., Christoforos P., "PacMan: Parallel Computing Using Java Mobile Agents", 13th ACM International Conference on Supercomputing (ICS), Workshop on "Java for High Performance Computing", Rhodes, Greece, June 1999.
8. Constantinos Spyrou, George Samaras, Evangelia Pitoura, Evripidou Paraskevas, "Wireless Computational Models: Mobile Agents to the Rescue", 2nd International Workshop "Mobility in Databases & Distributed Systems" DEXA?99, Florence, Italy, September 1999.
9. Christoforos P., Samaras G., Pitoura E., Evripidou P., "Parallel Computing Using Java Mobile Agents", 25th Euromicro Conference, Workshop on Network Computing, September 1999. Also technical report TR-99-7, University of Cyprus, February 1999.
10. Barelos, D., E. Pitoura, G. Samaras, "Mobile Agents Procedures: Metacomputing in Java", Proc. Of the ICDCS Workshop on Distributed Middleware (in conjunction with the 19th IEEE International Conference on Distributed Computing Systems (ICDCS99)), pp. 90-95, Austin, TX USA, June 1999.
11. Papastavrou S., G. Samaras, E. Pitoura, "Mobile Agents for WWW Distributed Database Access", Proc. 15th International Data Engineering Conference, Sydney, Australia, March 1999. ICDE?99 Best Paper Award.
12. Barron C. Housel, George Samaras, David B. Lindquist, "WebExpress: A Client/Intercept Based System for Optimizing Web Browsing in a Wireless Environment", Journal of ACM/Baltzer Mobile Networking and Applications (MONET), special issue on "Mobile Networking on the Internet", 3(4): 419-431, December, 1998.
13. Samaras, G., A. Pitsillides, "Client/Intercept: a Computational Model for Wireless Environments", Proc. 4th International Conference on Telecommunications (ICT'97), Melbourne, Australia, April 1997.
14. Constantinos Spyrou, George Samaras, Evaggelia Pitoura, Stavros Papastavrou, and Panos K. Chrysanthis, "Mobile Agents to Support Views for Wireless and Mobile Clients", to the VLDB 2000.
15. Stavros Papastavrou, Panos K. Chrysanthis, George Samaras, Evaggelia Pitoura, "An Evaluation of the Java-based Approaches for Web Database Access", to the COOPIS 2000.