On the semantics of protocols among distributed intelligent agents

Abstract

The continuing exapnsion of distributed intelligent systems makes new demands on theories of communication in Computer Science. It is customary to describe the individual nodes or agents in an intelligent system in terms of higher-level concepts such as intentions, know-how and beliefs. However, current theories of the communication among such agents provide no form of a formal or rigorous semantics for the messages exchanged at a corresponding level of abstraction - they either concern themselves with implementational details or address what is, for artificial systems, an irrelevant aspect of the problem. A recent theory of communication that gives the objective model-theoretic semantics for speech acts is applied to this problem. This allows important properties of protocols to be formalized abstractly, i.e., at the level of the application, not the implementation. Further constraints on "good" designs can also be stated, which simplify the requirements imposed on the member agents. The resulting theory not only provides some insights into designing distributed intelligent systems, but also helps in their validation. As an example, it is applied to a logical reconstruction of the classical Contract Net protocol.