1. Graduate School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea
2. The 4th R&D Institute, Agency for Defense Development, 4-4 Yuseong, P.O. Box 35, Daejeon 305-600, South Korea
3. School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea