1. Tokyo Polytechnic University, Faculty of Engineering, 1583 Iiyama, Atsugi-shi, Kanagawa, 243-0297, JapanbHakuto Corporation, Design and Development Section, Electric Equipment Division, 1-13, Shinjuku 1-Chome, Shinjuku-Ku, Tokyo 160-8910, Japan
2. Tokyo Polytechnic University, Faculty of Engineering, 1583 Iiyama, Atsugi-shi, Kanagawa, 243-0297, Japan