Probabilistic coalition formation in distributed knowledge environments

In a distributed system, a group of agents have a potential for improved performance depending on their ability to utilize shared resources. This potential synergy raises the question of whether agents should work together in a system-wide group, i.e., a coalition, or whether they should work alone. In general, there is uncertainty as to whether a coalition will form; this uncertainty can arise for various reasons, such as adaptive strategies of the agents or random faults in the system. In this paper, we present a model for performance based upon the probability of coalition formation. The results indicate a limit in potential performance for adaptive agents and, in particular, the global and local maxima along with regions of nonstability. In addition, the model shows how performance is affected by the knowledge environment of the distributed system, that is, the architecture of the system with respect to the distribution of information. Four environments are examined as illustrations of these general categories of information distribution: global information; inaccessible information; local information residing in autonomous agents; and information residing in a master control agent. The results show the distinctions between the environments with respect to probabilistic coalition formation and also demonstrate the loss in environments without communication as compared to a baseline communication environment