1. Office of Society-Academia Collaboration for Innovation; Kyoto University, Gokasho, Uji; Kyoto 611-0011 Japan
2. Research & Development Group, Hitachi Ltd 1-1, Omika-cho 7-chome, Hitachi; Ibaraki 319-1292 Japan
3. Graduate School of Engineering; Kyoto University, Nishikyo-ku; Kyoto 615-8510 Japan