1. a Department of Mechano-Informatics and Systems, Nagoya University, Chikusa-ku, Nagoya 464-01, Japan
2. b Department of Mechano-Informatics and Systems, Nagoya University, Chikusa-ku, Nagoya 464-01, Japan
3. c Takenaka Corporation, Insei-cho, Inba-gun, Chiba 270-13, Japan
4. d Takenaka Corporation, Insei-cho, Inba-gun, Chiba 270-13, Japan
5. e Department of Mechano-Informatics and Systems, Nagoya University, Chikusa-ku, Nagoya 464-01, Japan