1. a Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8552 Japan
2. b Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8552 Japan
3. c Yaskawa Electric Group, 2-1 Shiroishi Kurosaki, Yahatanishsi-ku, Kitakyusyu-city, Fukuoka, 806-0004, Japan