Akihiko Nagasaka

The Effects of the Level of Alertness During the Rest Period on Subsequent Performance

The aim of this study was to examine how to take an effective rest to prevent a decline in alertness at work. The relationship between alertness during the rest period and subsequent task performance were investigated. The electroencephalogram (EEG) during the rest period was classified into 3 types, and these types had a significant effect on performance after the rest period. Type 1 (increasing in theta, alpha 2, and beta 1 power) was the best one for carrying out the task, whereas performance gradually declined in Type 3 (no change in EEG activity). In the case of Type 1, the method that would relieve sleep inertia had a more positive impact on performance after the rest period.

A method for system reliability analysis with change-over operation

Abstract When fault tree analysis (FTA) is used in analysing the system reliability including human functions, the correspondence between an abnormal event and the human reaction against it may become ambiguous. In order to supplement this defect, a case study has been conducted in this research to develop a new technique termed ‘Corrective Operation Diagram Analysis’, and an attempt has been made to establish the correspondence between the reliability analysis of equipment/hardware using FTA and human reliability analysis.