Integrating Models of Correct Behavior into Abductive Diagnosis

The combined use of fault models and models of the correct behavior of the system to be diagnosed seems to be a promising approach to "model-based" diagnosis. The aim of this paper is twofold. First of all, we extend the abductive definition of diagnosis we provided in the past for fault models to the case where a (partial) model of the correct behavior of the system to be diagnosed is available. In the second part of the paper we generalize such a definition showing that many definitions of diagnosis can be regarded as different alternatives in a continuum. Particular attention will be devoted to discussing the differences between such alternatives.