Mitsugu Sawa

Experimental results of measuring human fatigue by utilizing uttered voice processing

It is possible to measure human cerebral activity by utilizing a new chaotic method for analyzing the spoken voice. In experiments, we measured the Flicker Frequency and voice-derived Cerebral Exponents of subjects at 12-minutes intervals during a ten-hour railway driving simulation exercise. The results confirm that our analysis method is able to measure human central nervous system activity levels, as is possible using the Flicker Tester, from speech. We believe that it will be possible to evaluate the mental and physical condition of critical workers in real-time in their working environments by monitoring only their speech. We also believe that workspace safety will be much improved by the introduction of the new chaotic voice analyzer.

Tolerance Estimation of Human Postural Stability Against Train Drafts

A wind tunnel experiment was conducted in order to study the effects of train-generated drafts on human postural stability. In the experiment, 29 people were exposed to a transient wind force similar to a draft from a passing train, and the results suggested that both wind speed and wind duration affect postural stability. In this paper, we estimated the tolerance of postural stability against transient wind based on a statistical model and a physical model, and discussed the validity of these models.