The purpose of this research is to clarify the human physiological responses under mentally-stressed condition and to propose a human monitoring system for the preventative safety in sea transportation. Measurements of electrocardiograms, respiration, cerebral blood flow, arterial blood flow at the wrist and electrogastrograms were carried out during the Uchida-Kraepelin test and rest conditions before and after the test. Heart rate variability was analysed using the CGSA (coarse graining spectral analysis) method while also taking account of effect of respiration. The authors concluded that the sympathetic nervous system can be a useful index for detecting the loss of subject's concentration.
In recent years, a number of serious accidents have occurred in public transportation; e.g., train derailment, incidents involving malfunctions in aeroplanes and a series of collisions and stranding accidents at sea. Overcrowding in waters around Japan, e.g., Tokyo Bay, Osaka Bay, the Inland Sea is becoming serious. An average of over 800 ships a day navigates through the shipping lane of the Akashi Straits which has a width of 750 m. A serious multiple-collision, sinking and fatal accident occurred there just last year. The Japan Coast Guard has announced that over eighty percent of maritime accidents have been due to human error during operation of a vessel. Careless watch duty, inappropriate steering, sleeping, drowsiness and inattention to details were the major causes of these accidents at sea. The Ministry of Land, Infrastructure and Transport Japan has established a committee specifically for "Preventive Measures against Human Error in Public Transport". The committee has concluded in its final report that the development of human monitoring techniques is an urgent objective in ensuring preventative safety (2006). An example of preventative safety measures is an alarm system using an infrared detector at the navigation bridge to prevent falling asleep which works by detecting when a crew member on duty does not move at all for a certain period.
