a
School of Mechanical and Aerospace Engineering, Division of WCU Multiscale Mechanical Design, Seoul National University, Gwanak_1, Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea
E-mail: sky4u@snu.ac.kr
;
Fax: +82-2-883-0179
;
Tel: +82-2-880-9103
b
Department of Mechanical Engineering, Kyungpook National University, Daehak-ro, Pook-gu, Daegu 702-701, Korea
c
Research & Development Center, Minuta Technology Co., Osan-Si, Korea