(An) experimental study on the effect of noise and sleep loss on human performance using the measure of TCI during NPP maintenance

Abstract

There are various stressors in NPP maintenance, such as environmental stressors and work-related stressors. These stressors degrade human performance and increase human error. Stress has not been largely considered as a factor of human error in root cause analyses. Recently, however, regulatory bodies and research institutes have worked to manage the physical condition of the operator and improve the environment and methods of NPP maintenance. These efforts have focused on reducing the incidence of human error due to stress. It is necessary to study how much stress affects human performance before these efforts are complete. The objectives of the present study are to formulate a Task Concentration Index (TCI) based on Electrocardiogram (ECG) signals in order to evaluate the degree to which a person concentrates on a task experimentally. With the TCI, the study will also evaluate the effects of noise and sleep loss on human performance during NPP maintenance tasks. Stress influences the efficiency of information processing and data input and output. Stress and human error are tightly linked in a closed-loop combination. The human body responds to stress by activating the nervous system and specific hormones. Therefore, physiological signals are changed by stress. A spectral analysis of Heart Rate Variability (HRV) provides a noninvasive technique for indirectly measuring sympathetic and parasympathetic modulation during specific tasks. The high-frequency component (HF, 0.15~0.4Hz) reflects momentary respiration and is mediated by the parasympathetic nervous system. The low-frequency component (LF, 0.04~0.15Hz) has been interpreted mainly as an indicator of sympathetic influences (especially when expressed in normalized units). When the level of stress is high, the Normalized Low Frequency component (NoLF) of HRV signals is generally higher than the normal state. The difference in NoLF readings between a normal state and during a task could be used to evaluat...