1. Department of Industrial Administration, Graduate School of Science and TechnologyTokyo University of Science 2641 Yamazaki, Noda‐shi, Chiba 278‐8510 Japan
2. Department of Industrial Administration, Faculty of Science and TechnologyTokyo University of Science 2641 Yamazaki, Noda‐shi, Chiba 278‐8510 Japan
3. Research Department, National Institution of Academic Degrees and Quality Enhancement of Higher Education 1‐29‐1 Gakuen‐nishimachi, Kodaira‐shi, Tokyo 187‐8587 Japan