A Scheme for Agent Collaboration in Open Multiagent Environments

In multiagent planning, an agent sometimes needs to collaborate with others to construct complex plans, or to accomplish large organizational tasks which it cannot do alone. Since each agent in a group may have incorrect beliefs about the world and incomplete knowledge, and because agent's abilities differ, constructing a coordinated collaborative plan among agents is a difficult proposition. In previous work [Osawa and Tokoro 92], we developed a scheme for constructing collaborative plans from the. possibly incomplete, individual plans of agents. This scheme was designed to provide availability-based assignment of goals to agents, and opportunistic collaboration to distributed planning in open multiagent environments based on the contract net. In this paper, we formalize incomplete individual plans and collaborative planning among rational agents using the Multi-World Model, and provide a utility-based model for rational choice of actions. Agents can effectively balance work-loads based on the utility theory. A condition for incomplete collaborative plans is also presented. 1 Introduction In multiagent planning, agents try to achieve goals, which can be independent, shared, or competitive. Researchers have attempted to address the problem of coordinating interacting plans so as to increase efficiency. The subject of coordination has been of continuing interest in multiagent planning [Corkill 79, Georgeff 83, Zlotkin and Rosenschein 90, Martial 90. Osawa and Tokoro 92, Ephrati and Rosenschein 92, Kinny et al. 92]. Martial has investigated how planning agents can positively cooperate in distributed environments [Mar-tial 90]. Many previous papers on distributed coordinated planning mainly focused on how to resolve conflicts [Corkill 79, Georgeff 83]. Martial, however, studies situations where a positive effect can be reached, as mod-eled by his favor relation. We also focus on the positive effect of cooperation in terms of collaborative plan construction , and have developed a scheme for constructing collaborative plans among agents based upon their, possibly incorrect, beliefs and partial (incomplete) knowledge of the world [Osawa and Tokoro 92]. The partiality of agents 1 skills and inconsistencies among agents 1 beliefs in open multiagent environments are not well treated in most of the previous work involving multiagent planning. In Martial's method, agents broadcast their plans at any time and at different levels of abstraction, so that they may refine their plans in a coordinated way. His method is based on the assumption that there is a collection of autonomous intelligent agents which communicate about, planned actions ahead of time. In our scheme, the investigation …