On the Formal Semantics of Speech-Act Based Communication in an Agent-Oriented Programming Language

TL;DR

This paper develops a formal, computationally grounded semantics for speech-act based communication in AgentSpeak, addressing foundational issues and extending the language to support agent communication.

Contribution

It provides a formal semantics for speech-act messages in AgentSpeak and extends the language to incorporate communication primitives.

Findings

Semantics for speech-act messages in AgentSpeak are formally defined.

AgentSpeak is extended to support communication with well-defined semantics.

Addresses foundational issues in agent communication semantics.

Abstract

Research on agent communication languages has typically taken the speech acts paradigm as its starting point. Despite their manifest attractions, speech-act models of communication have several serious disadvantages as a foundation for communication in artificial agent systems. In particular, it has proved to be extremely difficult to give a satisfactory semantics to speech-act based agent communication languages. In part, the problem is that speech-act semantics typically make reference to the "mental states" of agents (their beliefs, desires, and intentions), and there is in general no way to attribute such attitudes to arbitrary computational agents. In addition, agent programming languages have only had their semantics formalised for abstract, stand-alone versions, neglecting aspects such as communication primitives. With respect to communication, implemented agent programming languages have tended to be rather ad hoc. This paper addresses both of these problems, by giving semantics to speech-act based messages received by an AgentSpeak agent. AgentSpeak is a logic-based agent programming language which incorporates the main features of the PRS model of reactive planning systems. The paper builds upon a structural operational semantics to AgentSpeak that we developed in previous work. The main contributions of this paper are as follows: an extension of our earlier work on the theoretical foundations of AgentSpeak interpreters; a computationally grounded semantics for (the core) performatives used in speech-act based agent communication languages; and a well-defined extension of AgentSpeak that supports agent communication.