A training system for improving the performance of self-threading screw tightening operations was developed. The system consists of two parts: (1) Training for the use of a driver without screws in order to make trainees learn the control of a driver to maintain the ideal and alowable maximum vertical pressure ad driver tilt, and the ideal timing for releasing the driver from the screw: (2) Training for actual operation by referring to the visual feedback information. The result of the experiment using 20 subjects showed that using this training system the maximum vertical pressure level was improved by the fctor of twice (doubled) and the performance index was improved 1.4 times.

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Train drivers must turn on the train protection radio to prevent secondary accidents when their train has infringed adjacent tracks at a collision accident. In this context, an automatic turn-on device has been proposed in case the train driver is injured to become incapable. Among a number of conceivable criteria that should be considered in determining whether the automatic device be turned on, this paper proposes a criterion to detect collision based on the minimum acceleration in the longitudinal direction that will cause the driver to fall from its seat. Collision experiments with a dummy driver proved that the minimum acceleration for a specified time length for this purpose was 26m/s² for 0.02s, 23m/s² for 0.04s, and 16m/s² for 0.06s. As train drivers are safe when the acceleration is lower than these values, the minimum acceleration thus obtained is valid as a criterion to automatically turn on the train protection radio.

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The psychological effects of external noise on participants were experimentally investigated. The study involved the analysis of the annoyance, subjective feelings of fatigue and performance of participants exposed to meaningless external noise at various sound pressure levels during a mental task such as reading and arithmetic that do not involve auditory processing. The task was the addition of one digit numbers, and the external noise was steady broad-band white-noise. The relationship between the sound pressure level of the external noise and the psychological response of the participants was discussed, as was the difference between the subjective feelings of fatigue after the arithmetic task with and without noise, and the effect of noise on their performance.

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The role of peripheral vision while walking is clarified by comparing two experiments. The first studies visual behavior within a normal visual field and the second is conducted within a restricted visual field. In the first experiment the subject navigates a corridor and staircase wearing an eye camera, while in the second the same task is performed wearing a mask developed by the authors which has two small eye perforations restricting peripheral vision. A comparison of the results of the two experiments reveals the following behavior traits when the visual field is restricted: 1. a tendency to look at the boundary between floor and wall when walking in a specified direction; 2. taking a detour when turning a corner; 3. reaching short of a step or of a doorknob by the foot or hand; 4. extreme slowing down before descending a staircase; 5. sliding the foot to find the first step before ascending. These findings clarify how peripheral vision helps in perceiving distance and spatial relationships between a body in motion and its surroundings.

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In few studies, the display-height of the notebook personal computer (NPC) has been discussed from the view of the operator's body dimensions data. This study aimed to propose the method for calculating the suitable display-height of the NPC by using the operator's height. At first, the layout equation model for the work with the NPC was developed originally, which represented the two dimensional relationship of the position between the operator and the NPC. Next, the method for calculating the suitable display-height of the NPC (Mdh), in which the VDT guidelines about the operator's posture to the NPC were followed by means of the layout equation model with operator's height, was proposed. The suitability of Mdh was also discussed by comparing between Mdh and the conventional display-height (Cdh) in terms of the measurements of the operator's performance, posture, muscular strain, and feelings in use through experiments by word processing tasks. The experimental results of the posture measurements and the feelings in use suggested that Mdh was more suitable than Cdh.

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