|Budget Amount *help
¥2,500,000 (Direct Cost : ¥2,500,000)
Fiscal Year 1996 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1995 : ¥1,500,000 (Direct Cost : ¥1,500,000)
The main object of this research is to develop methodology to analyze the safety of man-machine systems at their design or planning stage.
In the first year of the project, the following subjects are studied : situation-dependency models of human and machine behaviors and their application to the derivation of event sequences leading to a system failure or accident, and a systematic method to prevent system accidents. Firstly, influencing factors are obtained by specifying interactions between man and machine to express their dependency. Regarding an influencing factor as external input to human or machine, each behavior model can be represented in terms of if-then rules such as condition-action relations. Although human behaviors are not necessarily be represented in the same manner as machine behaviors, they can be modeled similarly by introducing the modification of available rules depending on the situation. Since the human and machine models interact on each other, the event sequen
ce of human behaviors must be obtained in terms of (system condition, human behavior) -pair.
In the second year, the safety analysis system using event sequences in man-machine systems is developed. In the analysis of simple tank-filling and lamp-lighting tasks, the effect of human errors is evaluated based on the deviation in their event sequence to achieve its object. In modeling human behaviors, the experience factor is considered as follows. A man who met the same situation beforehand can deal with it automatically (skill-based behavior) or has know-how to deal with it (rule-based behavior), while an unexperienced man must deal with it based on his general knowledge (knowledge-based behavior). To predict what kind of error occurs in the event sequence, the result of cognitive engineering on human behaviors must be utilized. Relating to the safety analysis of man-machine systems, the failure effect analysis method is also developed based on the bond graph, which represents the system behavior from the viewpoint of energy flow. The proposed method can evaluate the effect of a component failure on any specific system variable. Less