Fumiaki Obayashi

Development of an illumination control method to improve office productivity

A lighting control method has been proposed which adjusts the circadian rhythms of office workers and eliminates a decrease in the arousal level in the afternoon by exposing a high intensity of light in the morning in order to improve their productivity. As a result, it was found that the task performance of the CPTOP test under 2,100 lx was significantly higher than that under 700 lx and more than a 9% improvement of task performance was achieved. Furthermore, a demonstration experiment has been conducted in order to confirm the effectiveness of the proposed lighting control method in actual office rooms. As a result, it was confirmed that the performance of their accounting work was over 10% higher than under normal conditions.

An Intellectual Productivity Evaluation Tool Based on Work Concentration

The authors have proposed a concentration time ratio as a new evaluation index of intellectual productivity, which had been difficult to be quantitatively evaluated, with a concept of concentration on target task, and a measurement tool has been developed based on the index. In addition, a subject experiment was conducted with the tool in which the illumination conditions were changed. As the result, it was found that the index was not affected by learning effect and the difference of intellectual productivity by changing the illumination conditions could be evaluated quantitatively with the index.

Development of productivity evaluation method to improve office environment

The authors have developed a performance test, CPTOP (Cognitive Performance Test of Productivity), which combines 11 basic task testss to evaluate intelligent abilities of office workers in order to quantitatively and objectively evaluate their productivity by controlling office environment. However, in the previous experiment, it was found that the results of CPTOP contain in-fluences of learning effect and variation of difficulties depending on each prob-lem set. In this study, therefore, subjective experiments have been conducted in order to compensate these influences and a correction method has been proposed.

Intellectual productivity under task ambient lighting

An experiment was conducted to evaluate intellectual productivity in three lighting conditions: (a) conventional ambient lighting, (b) task ambient lighting with normal colour temperature (5000 K) and (c) task ambient lighting with high colour temperature (6200 K). In the experiment, cognitive tasks were given to 24 participants. The concentration time ratio, which is a quantitative and objective evaluation index of the degree of concentration, was measured. The results showed that the average concentration time ratio under the task ambient lighting with high colour temperature was 72.5%, which was 5.0% points higher than that under the conventional ambient lighting. It is believed that intellectual work can be performed better when the concentration time ratio is high.

A Study of the Analysis Framework to Construct the Mechanism Model of Intellectual Productivity Changes Affected by Workplace Environment

Many companies have been working on to reduce energy consumption these days. However, it could also reduce efficiency of office work because the office environment becomes uncomfortable by the energy saving. Thus, it is necessary to save energy and keep workplace productivity at the same time. Since quantitative analyses about certain effects of workplace environment to office productivity have been already done in conventional studies, the degree of each environmental effect can be compared. It is however unclear how the environmental condition affects their productivity. The purpose of this study is to propose a systematic combination of various expert statistical methods as a framework of mechanism analysis of productivity changes. The proposed framework was also tested by case studies of some different varied environmental factors.