facture of chemicals, petroleum, and discrete parts. By "monitoring" we mean the systematic observation by a human operator of mul tiple sources of information, e. g. , ranging from integrated display consoles to disparate "live situations". The monitor's purpose is to determine whether operations are normal and proceeding as desired, and to diagnose difficulties in the case of abnormality or undesirable outcomes. By "supervisory control" we mean control by a human operator of a computer which, at a lower level, is controlling a dynamic system. In such systems, the computer-control normally operates continuously or at high data rates in loops closed through electromechanical sensors and motors. By contrast, the human operator normally signals or reprograms the computer intermittently or at a much slower pace. The human operator handles the higher level tasks and determines the goals of the overall system.