Yuriko Hachiya

Fatigue evaluation for work load of Visual Display Terminals (VDT) operation

A method for the analysis of fatigue parameters has been rarely researched in VDT operation. Up to now, fatigue was evaluated by changing of biological information. If signals regarding fatigue are detected, fatigue can be measured. This study proposes an experiment and analysis method to extract parameters related to fatigue from the biological information during VDT operation using the independent component analysis (ICA). An experiment had 11 subjects. As for the experiment were light loaded VDT operation and heavy loaded VDT operation. A measurement item were amount of work, a mistake number, subjective symptom, surface skin temperature (forehead and apex nasi), heart rate, skin blood flow of forearm and respiratory rate. In the heavy loaded operation group, mistake number and subjective symptom score were increased to compare with the other. And Two-factor ANOVA was used for analysis. The result of mistake number was confirmed that heavy loaded. After the moving averages of waveshapes were calculated, it was made to extract independent components by using the ICA. The results of the ICA suggest that the independent components increase according to accumulation of fatigue. Thus, the independent components would be a possible parameter of fatigue.

[Obesity and liver dysfunction in UOEH employees--multiple regression analysis of the annual physical checkup data of 1991].

For the purpose of evaluating the significance of obesity as a risk factor toward various chronic geriatric diseases, a multiple regression analysis was performed on the annual physical checkup data of UOEH employees in 1991. The following results were obtained. (1) The average obesity index of the UOEH employees showed a progressive and significant increase in the 10 years from 1981 to 1991. (2) A close relation between the obesity index and serum GPT was recognized by elevation of the standard partial regression coefficients of serum GPT to obesity index and that of the obesity index to serum GPT when the data from all 1591 UOEH employees were analysed in one group. This finding was derived from a significant contribution of obesity to the liver dysfunction in the young male obese population under 30 years of age. (3) Systolic blood pressure was related to age rather than the obesity index, indicating that the development of hypertension is more closely related to aging than obesity. (4) No significant relation was found between the serum total cholesterol level and the obesity index in any group analysed. From the above findings, it can be suggested that the obesity in young male employees is more closely related to liver dysfunction than other abnormalities.