Human fatigue risk simulations in 24/7 operations

A Circadian alertness simulator (CAS) is presented as an interactive tool for assessing sleep behavior and fatigue risk in 24/7 operations. The simulation model uses as input sleep-wake data and information about individual sleep characteristics (short vs. long sleeper, morning type vs. evening type, napper vs. nonnapper). The validation of the CAS model was based on a figure of merit function reflecting the model's ability to minimize the difference between reported and predicted sleep data. The purpose of the alertness model is the assessment of work schedules in terms of fatigue risk.