A deliberative and reactive diagnosis agent based on logic programming

In this article we formally specify and implement a diagnostic agent based on extended logic programming. Motivated by the application of decentralised diagnosis of distributed systems we develop an architecture for such agents that consists of a deliberative layer with a knowledge base, an inference machine and a reactive layer for communication and control. Throughout the layers we employ logic and logic programming to solve these tasks: the knowledge base uses extended logic programming to specify the agent's behaviour and its knowledge about the system to be diagnosed. The inference machine, which provides algorithms to compute diagnoses, as well as the reactive layer, that realises a meta interpreter for the agent behaviour, are implemented in PVM-Prolog, wich enhances standard Prolog with message passing facilities.