Ping Xuan Research

Assistant Professor Department of Mathematics and Computer Science Clark University 950 Main Street Worcester, MA 01610-1477

Description of My Main Research Areas Toward a Richer Model of Agent Commitments: Since each agent only sees a partial view of the overall (multiagent) task network, they must rely on commitments established between the agents in order to formulate their plans and facilitate coordination. However, due to uncertain task outcomes, commitments may not always get fulfilled, which lead to bad performance. A quantified model of commitment, with richer semantics, is needed. Commitments themselves can be viewed as dynamic processes, and they encapsulate the information needed in the coordination part of multiagent planning. Ping Xuan and Victor Lesser. Incorporating uncertainty in agent commitments. In N.R. Jennings and Y. Lesperance, editors, Intelligent Agents VI --- Proceedings of the Sixth International Workshop on Agent Theories, Architectures, and Languages (ATAL-99), Lecture Notes in Artificial Intelligence. Springer-Verlag, Berlin, 2000. This paper won the Best Student Paper Award at ATAL-99. A longer version: Ping Xuan and Victor Lesser Using Agent Commitments as Planning Contexts. 2006. Decentralized Multiagent Markov Processes DEC-MDPs and DEC-POMDPs are computationally very complex. This gives us strong incentives to search for approximation solutions and heuristics methods. While other researchers focus more on improving computational methods and classifying sub-classes of these complex problems, I believe we can also draw upon a lot of knowledge developed in traditional multiagent planning. The dichotomy of local reasoning and coordination will be the key for scalable models and solutions. Ping Xuan, Victor Lesser, and Shlomo Zilberstein. Communication Decisions in Multi-agent Cooperation: Model and Experiments. In Proceedings of the Fifth International Conference on Autonomous Agents (AGENTS 2001), Montreal, Canada, 2001. Ping Xuan, Victor Lesser, and Shlomo Zilberstein. Modeling Cooperative Multiagent Problem Solving as Decentralized Decision Processes. 2005. Ping Xuan, Modeling Plan Coordination in Multiagent Decision Processes. Proceedings of the Sixth International Joint Conference on Autonomous Agents and Multi-Agent Systems (AAMAS-07). Poster session. May, 2007. Ping Xuan. Use Plan Abstractions for Better Coordination. 2008. Communication and Coordination One way of handling uncertainty is to communicate, and sharing nonlocal information is central to coordination. Developing a more precise model of commitments is one aspect of this problem, but it is equally important to determine when to communicate. These communication decisions are tied to the agent's beliefs about agent commitments. Ping Xuan and Victor Lesser. Multi-agent policies: from centralized ones to decentralized ones. In Proceedings of the First International Joint Conference on Autonomous Agents and Multi-Agent Systems (AAMAS-02), Bologna, Italy, 2002. A longer version: Ping Xuan and Victor Lesser, Decomposing Centralized Multiagent Policies. (Also as UMass Technical Report, 2007.) Ping Xuan. Managing Plan Uncertainty in Multiagent Cooperation. 2008. Issues in Agent Virtual Organizations Managing uncertainty is not limited at agent level - it is also essential at organizational level. I am interested at a variety of issues, such as plan robustness, organizational monitoring, and decommitments in multiagent organizations (collaboration with Professor S. Zhang's group at UMass Dartmouth.) Ping Xuan. Techniques for Robust Planning in Degradable Multiagent Systems. In P. Scerri, et al, editors, Challenges in the Coordination of Large Scale Multiagent Systems, Springer, 2005. Ping Xuan. An MDP Approach for Agent Self Monitoring. In Proceedings of the AAAI-04 Workshop on Agent Organizations: Theory and Practice, San Jose, California, 2004. Shelley Zhang, Ping Xuan, and Bhumit Patel. Managing the Operations of Multiagent Virtual Organizations. 2008.

pxuan@clarku.edu

2005