1. Graduate
School of Convergence Science and Technology, Seoul National University, Iui-dong,
Yeongtong-gu, Suwon 443-270, South Korea
2. School
of Engineering, University of California, Merced, 5200 North Lake
Road, Merced, California 95343, United States
3. Department
of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, South Korea
4. School
of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore