Optimization of rule-based expert systems via state transition system construction

Embedded rule-based expert systems must satisfy stringent timing constraints when applied to real-time environments. This paper describes a novel approach to reduce the response time of rule-based expert systems. Our optimization method is based on a construction of the reduced cycle-free finite state transition system corresponding to the input rule-based system. The method makes use of rule-base system decomposition, concurrency and state equivalency. The new and optimized system is synthesized from the derived transition system. Compared with the original system, the synthesized system (1) has fewer rule firings to reach the fixed point, (2) is inherently stable and (3) has no redundant rules. The synthesis method also determines the tight response time bound of the new system. The optimized system is guaranteed to compute correct results, independent of the scheduling strategy and execution environment.