Affiliations: School of Engineering, the University of Tokyo, 5-1-5
Kashiwanoha, Kashiwa, Chiba, 277-8568, Japan. E-mail:
uchida@race.u-tokyo.ac.jp | Research into Artifacts, Center for Engineering
(RACE), the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8568,
Japan