RESCU: a real-time knowledge based system for process control

The paper reports the activities of a community club formed to design and build an operational real-time knowledge based system for process control. It gives the background to the club and the mechanisms developed to ensure the dissemination of the knowledge gained during the development of the project. A set of requirements for real-time knowledge based systems is presented, and a description of the system developed to satisfy this is given. This provides for the representation of procedural and declarative knowledge sources, allows temporal reasoning, and has facilities for representing and reasoning with uncertain information. It also describes an advanced system for time-constrained reasoning in terms of a priority scheduler dealing with autonomous activities. A description of the application demonstrator chosen from the club members is given. This is a quality control task on a batch chemical process with wide variation in feedstcok quality and uncertain and inaccessible measurements. An extensive performance evaluation of the operational system is presented, showing that the performance of the system is comparable to that of the best operators and considerably better than the standard operating procedures. Finally, conclusions on the success of the club and the technology are given, and suggestions for future work provided.