Measuring fractal nature of heart rate variability and task loads for establishing navigation support system

The thinking faculty and operating ability of ship operators tend to be affected by their mental task loads under the pressures from navigating environment. The suitable navigation support system has to be considered the relation between incidence of human errors and tensional stress degree of operators during ship navigation. For clarifying an issue of tensional stresses for task loads of ship operators, this paper describes that the tensional stresses were analyzed quantitatively by measuring the heart rate variability under mental work-load during navigations of several car-ferries, and the suitable measures were examined in order to reduce the work-load and the incidence of human errors caused by the task with high-tension under severe navigation environment