1. a Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152, Japan
2. b Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152, Japan
3. c Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152, Japan
4. d Takasago Research & Development Center, Mitsubishi Heavy Industries Ltd, 2-1-1, Shinhama, Arai-cho, Takasago, Hyogo 676, Japan