ECAI 2004 Conference Paper

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Balancing coordination and synchronization cost in Cooperative Situated Multi-agent Systems with Imperfect Communication

Andrea I. Tavares, Mario F. M. Campos

In this paper, we propose a new Markov team decision model to the decentralized control of cooperative multi-agent systems with imperfect communication: messages may be delayed or lost. We introduce the concept of informational classes, which captures system's communication semantics and uncertainties about transmitted information. Stochastic transmission models, including delayed and lost messages, summarize characteristics of communication devices and protocol. This model provides a quantitative solution to the problem of balancing coordination and synchronization cost in cooperative domains, but its exact solution is computationally infeasible. We propose a generic two-phase heuristic approach. At the off-line phase, a centralized team plan is established. At the on-line phase, decentralized decision-making is based on Bayesian dynamic system estimators and decision-theoretic policy generators. These generators use system estimators to express agent's uncertainty about system state and also to quantify expected effects of communication on local and external knowledge. Probabilities of external team behavior, a byproduct of policy generators, are used into system estimators to infer state transition. Bayesian inference also allows local estimations of external knowledge. Under perfect communication assumptions, we solve two previously proposed multi-agent tasks and compare our results with original ones. We then introduce communication limitations (range and reliability) and solve these new settings.

Keywords: Cooperative Multiagent Systems, Decentralized Markov Decision Process, Decision Theory

Citation: Andrea I. Tavares, Mario F. M. Campos: Balancing coordination and synchronization cost in Cooperative Situated Multi-agent Systems with Imperfect Communication. In R.López de Mántaras and L.Saitta (eds.): ECAI2004, Proceedings of the 16th European Conference on Artificial Intelligence, IOS Press, Amsterdam, 2004, pp.68-73.

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ECAI-2004 is organised by the European Coordinating Committee for Artificial Intelligence (ECCAI) and hosted by the Universitat Politècnica de València on behalf of Asociación Española de Inteligencia Artificial (AEPIA) and Associació Catalana d'Intel-ligència Artificial (ACIA).