Nozomi Sato

Power spectral analysis of heart rate variability in type A females during a psychomotor task

This study investigated changes in autonomic nervous activities due to psychological stress in Type A females. Eight Type A and eight Type B females performed a psychomotor task for 30 minutes. Power spectral analysis of heart rate variability (HRV) was used to examine the autonomic nervous activities. Results showed the low frequency (LF) component and LF/HF ratio in Type A females increased after the onset of the task. There were no significant differences in task performance between Type A and Type B females. The subjective mental workload increased gradually in Type A females during the tasks, whereas in Type B females this parameter did not change in a consistent manner. The results suggest that the sympathetic nervous system in Type A females was more stimulated by the task and Type A females felt a greater subjective mental workload than did Type B females.

Biomechanical study on the postures in manual lifting tasks using cusp surface analysis

This study describes applications of the stochastic catastrophe theory in modeling low back injury in view of the elementary cusp catastrophe. It was proposed that low back injury due to manual load lifting should be considered as a discontinuous phenomenon. The main objective of this study is to develop a cusp catastrophe and to model the risk of low back injury quantitatively. The bimodality in the bifurcation set of stochastic catastrophe model was shown using biomechanical data. The relationship among independent variables and a dependent variable under a certain condition was clarified.

Effects of touch screen response time on psychological state and task performance

The purpose of this study was to investigate how touch screen response time affected users psychological state and task performance. Ten male participants performed numeric entry task on the touch screen under six different conditions by crossing speed of touch screen response for pressing buttons and of switching pages. Results suggested that the touch screen with the faster response time would be accepted more favorably than that with the slower response time. However, with regard to the results of task performance, opposite trend was obtained.

Mental model for perceived load on low back

Describes the mental model for perceived load on low back using a cognitive approach in addition to biomechanical and physiological approaches. In the results of experiments, it is clarified that poor cognitive ability of low back strength in the mental model reproducing the same strength is relevant to the low back pain. The studies show that cognitive ability of low back strength in the mental model could be improved by informing the content of working posture previously.

User interface design using mental model transfer

In this paper, the concept of mental model transfer is introduced to overcome the problem of accurate transfer from system developers to end users and that of reducing the software developing time. In addition, mental model will be classified into “model in mental world” and “model of mental world”. The former model is introduced to design user interface of a shell for diagnostic system. This paper describes how to transfer designers mental to maintenance engineer. The effect of this method is discussed.

Relationship between eye movement and visual cognition for ambiguous man/girl figures

In this paper, cognitive mechanism in human being is examined by measuring humans eye movement. A series of extending a Fishers ambiguous figures is used as visual stimulus. During the experimental session, subjects eye movement is measured by eye mark recorder, and eye fixation time, the number of times in eye fixation, eye movement velocity are calculated. On the basis of these data, internal cognitive mechanism in human being is discussed.