1. Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
2. OMRON SINIC X Corporation, Bunkyo, Tokyo, Japan
3. School of Engineering, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo, Japan
4. Department of Electrical Engineering, Tokyo University of Science, Katsushika, Tokyo, Japan
5. Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan