1. Department of Mechanical Engineering, Gifu National College of Technology Shinsei-cho, Motosu-gun, Gifu, 501-04, Japan
2. Software Development Center, Nippon Sharyo, Ltd, Sanbonmotsu-cho, Atsuta-ku, Nagoya City, 456-91, Japan
3. Department of Mechanical Engineering, Faculty of Engineering, University of Gifu, Yanagido, Gifu City, 501-11, Japan