Formal description and verification of Hybrid Rule/Frame-based Expert Systems

摘要

A Hybrid Expert System combines multiple representation paradigms into a single integrated environment for modeling and reasoning of complicated real world phenomena. For a Rule- and Frame-based integration, it models the problem domain using the concepts of Classes and Rules together. If Domain knowledge (concepts) is related by production rules and frame hierarchy, then anomalies may arise among this knowledge (concepts) due to the existence of two mutually independent formalism of relations. A contribution is made in this paper to developing formal description techniques for the detection of anomalies attributed to the integration of production rules with the inheritance of object properties within the object hierarchy. The main idea is to convert the HES into a State Controlled Coloured Petri Net (SCCPN) where the object hierarchy, property inheritance and production rules are modelled as separated components in the same SCCPN. The detection and analysis of the anomalies (i.e. Correctness, Consistency and Completeness) in the system are done by constructing and examining the reachability tree spanned by the knowledge inference.