James R. Allard, William F. Kaemmerer
We have developed and implemented a plan representation system which has been used as the knowledge representation for COOKER, a real-time process monitoring and operator advisory system for batch manufacturing processes. This representation (called "Goal/Subgoal" or "GSG") associates two hierarchies of subgoals with each goal: a sequence of subgoals which need to be satisfied to satisfy the superior goal, and a set of requisite subgoals which must remain satisfied throughout the process of satisfying the superior goal. By explicitly representing correct process operating behavior instead of the infinite space of problem behaviors, a broad range of process operation anomalies can be recognized and diagnosed in terms of a single, simple description of the system. In this paper we compare GSG to our first approach at representation, describe the GSG representation, show how goals are used to monitor processes, and describe some results of our installation of COOKER in a manufacturing plant.