A theory of measurement in diagnosis from first principles

Abstract

Reiter and de Kleer have independently developed a theory of diagnosis from first principles. Reiter's approach to computing all diagnoses for a given faulty system is based upon the computation of all minimal hitting sets for the collection of conflict sets for ( sd,components,obs). Unfortunately, his theory does not include a theory of measurement. De Kleer and Williams have developed GDE—general diagnostic engine. Their procedure computes all minimal conflict sets resulting from a measurement before discriminating the candidate space. However, they do not provide a formal justification for their theory. We propose a general theory of measurement in diagnosis and provide a formal justification for our theory. Several novel contributions make up the central focus of this paper. First, this work provides an efficient incremental method for computing new diagnoses given a new measurement, based on the previous diagnoses predicting the opposite. Second, this work defines the concepts of conflict set resulting from a measurement, equivalence classes and homogeneous diagnoses as the basis of the method. Finally, this work leads to a procedure for computing all diagnoses and discriminating among competing diagnoses resulting from a measurement.