Efficient Representation and Effective Reasoning for Multi-Agent Systems

A multi-agent system consists of a collection of agents that interact with each other to fulfil their tasks. Individual agents can have different motivations for engaging in interactions. Also, agents can possibly recognise the goals of the other participants in the interaction. To successfully interact, an agent should exhibit the ability to balance reactivity, pro-activeness (autonomy) and sociability. That is, individual agents should deliberate not only on what they themselves know about the working environment and their desires, but also on what they know about the beliefs and desires of the other agents in their group. Multi-agent systems have proven to be a useful tool for modelling and solving problems that exhibit complex and distributed structures. Examples include real-time traffic control and monitoring, work-flow management and information retrieval in computer networks. There are two broad challenges that the agent community is currently investigating. One is the development of the formalisms for representing the knowledge the agents have about their actions, goals, plans for achieving their goals and other agents. The second challenge is the development of the reasoning mechanisms agents use to achieve autonomy during the course of their interactions. Our research interests lie in a model for the interactions among the agents, whereby the behaviour of the individual agents can be specified in a declarative manner and these specifications can be made executable. Therefore, we investigate the methods that effectively represent the agents' knowledge about their working environment (which includes other agents), to derive unrealised information from the agents' knowledge by considering that the agents can obtain only a partial image of their working environment. The research also deals with the logical reasoning about the knowledge of the other agents to achieve a better interaction. Our approach is to apply the notions of modality and non-monotonic reasoning to formalise and to confront the problem of incomplete and conflicting information when modelling multi-agent systems. The approach maintains the richness in the description of the logical method while providing an efficient and easy-to-implement reasoning mechanism. In addition to the theoretical analysis, we investigate n-person argumentation as an application that benefits from the efficiency of our approach