1. Department of Mechano-Aerospace Engineering, Faculty of Engineering, Tokyo Institute of Technology, 2-12-1, Ohokayama, Meguro-ku, Tokyo 152, Japan
2. Tomari Power Station, Hokkaido Electric Power, 726 Ohaza-Horikappu-mura, Harum-gum, Tomari-mura, Hokkaidou, Japan
3. Department of Knowledge Engineering, Faculty of Engineering, Doshisha University, Tanabe, Kyoto 610-03, Japan