A model of operator behaviour for man-machine system simulation

In this paper, a model of plant operator behaviour is proposed in the context of an architecture for simulating human-machine interaction. In such a model, the cognitive processes leading to decisions as well as the execution of strategies are simulated in details for the study of the management of a plant in incidental conditions. The model foresees the representation of two cognitive levels of reasoning and decision making, namely the High Level Decision Making (HLDM), which allows one to exploit the operator's knowledge by continuously recognising situations and by building supervisory and control strategies, and the Low Level Decision Making (LLDM), which is supported by the working and conscious memory dynamics, when the operator implements a preprogrammed response or a planned strategy in order to satisfy a clearly defined intention. The details of the formalisms and methodologies implemented in the model are described and possible applications in the fields of design and safety of complex plants are discussed.