Abstract
The system and the alarm were designed as the operator operates properly it. However, the operator sometimes disregards consciously the alarms. In this paper, we discuss the new method of the estimation of accident rate, using the operator-machine-alarm model. If the operater always did right operation, the reliability of the alarm imformation was 1 and the accident rate was decided by the alarm failure rate and the machine failure rate. However, If the reliability of the alarm information wasn't 1,the accident rate was varied. For example, if the alarm failure rate was set to 0.1 and the machine failure rate was set to 0.9 and the reliability of alarm information was set to 1, then the accident rate was 0.09. However, when the reliability of alarm information was set to 0.1, the accident rate increased to 0.73.
