Using goals to design and verify rule bases

摘要

The design of rule-based systems is often plagued by errors and anomalies. The verification and validation (V and V) processes to detect errors and anomalies in a rule base are complex. Methods that are general enough for comprehensive anomaly detection suffer from heavy computation. Special methods for V and V that have reduced computational needs lack in their scope and applicability. Most of the existing verification tools perform their checking based on the syntax of rule base encoding often ignoring useful meta knowledge of the domain. In this paper, we propose a way to abstract domain knowledge using goals. At the design level, goals are realized in a rule base using one of several design schemes, where a design scheme is a goal-to-hypothesis mapping satisfying certain constraints. At the implementation level, goals are inferred using partially ordered rule sequences called paths. Verification of a rule base can be performed by identifying certain rule aberrations, that can be indicative of the rule base anomalies circularity, ambivalence, redundancy, and deficiency. A case study is presented to highlight that the goal-based approach is useful for preventing rule subsumption (a form of redundancy) and for enhancing the (run time) performance of a rule base.