1. Gwangju
Institute of Science and Technology (GIST), Mechatronics, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea
2. Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery & Materials (KIMM), 156 Gajungbukno, Yuseong-gu, Daejeon 305-343, Republic of Korea