Abstract
Because of the aggressive progress of automatic technology in human-machine system, the operator has changed to a 'decision-maker' in a control room. Studies on the operator's decision behavior have become an important issue for practitioners of relevant fields, such as human factors, reliability engineering and artificial intelligence. In this proposal, an analytical framework of decision making task is suggested to distinguish between dynamic and static decision making. Also, an event-driven approach called the Dynamic Boolean Expression (DBE) is suggested to model dynamic reasoning. Following the deterministic concept of DBE, a scalar quantity 'causality' is derived to describe the degree to which the decision outcome is driven by the driving events. An experiment based on the popular tic-tac-toe game was performed to verify the validity of the DBE. Based on the DBE, the graphical method "Dynamic Work Context Flowchart (DWCF)" is developed for the improvement of work context representation in written procedures. The nuclear power plant is considered as a typical example to illustrate how the DWCF can be applied to improve the work context representation and downsize the procedures. Moreover, the written procedures can be transferred into a set of DBE equations that are useful in further logical operation.