Decision Demands and Task Requirements in Work Environments: What Can be Learnt from Human Operator Modelling

Abstract

Supervisory control can be distinguished from manual control which is a closed loop, skill based action, by four important aspects: The control of highly complex, multivariable processes with mostly large to very large time constants. The discrete action patterns based on decision making processes. The variability in tasks, such as process tuning, start and stop procedures and fault management. The often vague information on the ultimate supervisory control perspectives. Hence, supervisory control tasks are different from those in manual control. Taking into account the three major process control modes which may occur in supervisory control -Normal operation, start and stop, and abnormal operation-it is of interest to classify the different tasks with reference to these control modes, as well as with reference to the three levels of control behavior as introduced by Rasmussen: Skill-based, Rule-based and Knowledge-based behavior. At the Skill-based level only manual control activities play a role; at the Rule-based level activities like process tuning and to a certain extent fault management may occur, whereas at the Knowledge-based level intelligent, cognitive activities such as optimisation, planning and fault management are thought to be.