1. Department of Electrical Engineering and Computer Science, Graduate School of Engineering and Science, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan
2. Department of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama 337-8570, Japan
3. Nippon Shizai Company Ltd., 1-5-6 Bakurou-machi, Chuo-ku, Osaka 541-0059, Japan