USING GOALS TO DESIGN AND VERIFY RULE BASES

The design of rule-based systems is often plagued by errors and anomal ies. The verification and validation (V and V) processes to detect err ors and anomalies in a rule base are complex. Methods that are general enough for comprehensive anomaly detection suffer from heavy computat ion. Special methods for V and V that have reduced computational needs lack in their scope and applicability. Most of the existing verificat ion tools perform their checking based on the syntax of rule base enco ding often ignoring useful meta knowledge of the domain. In this paper , we propose a way to abstract domain knowledge using goals. At the de sign level, goals are realized in a rule base using one of several des ign schemes, where a design scheme is a goal-to-hypothesis mapping sat isfying certain constraints. At the implementation level, goals are in ferred using partially ordered rule sequences called paths. Verificati on of a rule base can be performed by identifying certain rule aberrat ions, that can be indicative of the rule base anomalies circularity, a mbivalence, redundancy, and deficiency. A case study is presented to h ighlight that the goal-based approach is useful for preventing rule su bsumption (a form of redundancy) and for enhancing the (run time) perf ormance of a rule base. (C) 1997 Elsevier Science B.V.