Chaotic analysis of focal accommodation system and pupil area during VDT work

Hirokazu Iwase, Atsuo Murata

Research output: Contribution to journalConference article

3 Citations (Scopus)

Abstract

Evaluation of stress during a VDT task is important when designing proper human-computer interactions. Although a number of studies have been conducted to establish the method for evaluating stress, there exists no effective method. The presence of deterministic chaos has been clarified in many complex systems, including the human brain and autonomic nervous system. However, few studies examine the change of chaotic features of accommodation and pupil area over a number of working hours. The purpose of this research is to show that the stress during VDT task could be evaluated using the chaotic features such as the fractal dimension and the first Lyapunov exponent for the focal accommodation system and the pupil area. As for the step control measurement and the fixed target measurement, the fractal dimension tended to decrease over time. This shows that the fractal dimension for the focal accommodation system and the pupil area can be used to evaluate the stress during VDT task. The first Lyapunov exponent took positive values. Not only the fractal dimension but also the first Lyapunov exponent in the fixed target measurement was larger than those in the linear control and step control measurements. The chaotic property in the fixed target measurement was higher than that in the linear control and step control measurements. However, the first Lyapunov exponent hardly changed over time for all of three accommodation measurements.

Original languageEnglish
Pages (from-to)II-277 - II-282
JournalProceedings of the IEEE International Conference on Systems, Man and Cybernetics
Volume2
Publication statusPublished - Dec 1 1999
Externally publishedYes
Event1999 IEEE International Conference on Systems, Man, and Cybernetics 'Human Communication and Cybernetics' - Tokyo, Jpn
Duration: Oct 12 1999Oct 15 1999

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ASJC Scopus subject areas

  • Control and Systems Engineering
  • Hardware and Architecture

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