BIO
In May 1999 I received my BA with honors in Computer Science from Grinnell College. From there I joined the Computer Science Department at the University of Massachusetts, Amherst as a graduate student. Here I work with both the Multi-Agent Systems Lab and the Resource Bounded Reasoning Lab, and I am co-advised by Shlomo Zilberstein and Victor Lesser. In January 2003, I received my MS in Computer Science. I am currently working on my thesis proposal.

RESEARCH INTERESTS
My primary research interest is in optimal control of agents within a mutli-agent system. There has been a lot of research that focuses on optimal control of single agents, but very little has been done for multiple agents. A large part of the reason why lies in the complexity of dealing with multiple agents with disparate world views. Single agent frameworks, like the Markov Decision Process (MDP) and the Partially Observable Markov Decision Process (POMDP) have comparatively low complexity, P and PSPACE respectively. When we start looking at frameworks for multiple agents, like the Decentralized Markov Decision Process (DEC-MDP) the complexity explodes up to NEXP-hard. My focus in this area is to look for structure common to many multi-agent systems that could be exploited to reduce the complexity of finding optimal solutions.

My secondary area of interest is in Reinforcement Learning (RL). The focus of RL is in how to solve agent decision problems more efficiently (tractably) when an optimal solution is not required. Practically, even the frameworks that I called easy (MDP, POMDP) can often be too difficult to solve optimally within a reasonable time, and near-optimal solutions are usually good enough. Again, the primary focus of RL research has been in the single agent case. My focus in this area is to look for algorithms and ideas that have been used for single-agent problems and modify them to apply to the multi-agent problems that I work with.

RECOMMENDED PUBLICATIONS

• Solving Transition Independent Decentralized Markov Decision Processes.
  Becker, Raphen; Zilberstein, Shlomo; Lesser, Victor; Goldman, Claudia V.. Journal of Artificial Intelligence Research, Volume 22, Morgan Kaufmann Publishers, pp. 423-455. December 2004.
• Decentralized Markov Decision Processes with Event-Driven Interactions.
  Becker, Raphen; Lesser, Victor; Zilberstein, Shlomo. In Proceedings of the Third International Joint Conference on Autonomous Agents and Multi Agent Systems, Volume 1, IEEE Computer Society, pp. 302-309. 2004.
• Transition-Independent Decentralized Markov Decision Processes.
  R. Becker, S. Zilberstein, V. Lesser, and C. V. Goldman. Proceedings of the Second International Conference on Autonomous Agents and Multi-agent Systems, Melbourne, Australia, 2003. (winner of the AAMAS-03 best paper award)

CONTACT INFORMATION
My preferred way to be contacted is via email: raphen@cs.umass.edu

My office phone will occasionally reach me: (413)545-1985.

Snail mail sent here will also reach me eventually:
Raphen Becker
Department of Computer Science
140 Governor's Drive
University of Massachusetts, Amherst
Amherst, MA 01003-9264

Those on campus can locate me here:
Computer Science Research Center
Room 326, Cube #8