Subjective experiments on productivity under 800LX and 3LX lighting conditions

Masaya Nishikawa*, Naoe Nishihara, Shin Ichi Tanabe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In previous studies, it was difficult to evaluate the productivity only by task performance. In this study, we tried to evaluate productivity not only by task performance but also by human reaction, which especially meant fatigue. Fatigue was measured by subjective votes and biological signal, which were human voice and flicker value. It is said that the Lyapunov index of human voice has possibility to evaluate fatigue. The experiment was conducted under the condition of 800k and 3k to examine the effect of light environment on productivity. Subjects were fourteen. As a result of the experiment, we could not find a significant difference on task performance of addition task between 31x and 8001x conditions. On the other hand, the increasing rate of symptoms from subjective votes was significantly higher on 3k conditions than on 800k, and a standard deviation of Lyapunov index of "g", "p" increased more under 3k than 800k. There were significant differences on fatigue in the experiment.

Original languageEnglish
Pages (from-to)349-353
Number of pages5
JournalJournal of Environmental Engineering
Issue number625
Publication statusPublished - 2008 Mar


  • Fatigue
  • Human voice
  • Light environment
  • Lyapunov index
  • Productivity

ASJC Scopus subject areas

  • Environmental Engineering


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