Petri net methods for reasoning in real-time control systems

In many real-time control systems, inputs to a controller are signals from sensors and outputs of a controller are stimulators of devices. The controller must respond to the signals and function as fast as possible. Predicate-logic rule-based (expert) systems are too slow for use in real-time control applications. In this paper, the authors investigate Petri-net methods for reasoning in propositional logic, as a special case of predicate-logic Petri-net methods. The authors' algorithm based on the Petri net fixpoint can deduce all logically implied propositions (or control signals) with the time complexity O(n/sup 2/*m), where n is de number of rules and m is the number of propositions in the system.