1. School of Mechanical and Aerospace Engineering, Seoul National University, B/D 301-1213 Shinrim9-dong, Kwanak-ku, Seoul 151-742, Republic of Korea
2. Research Development Division, Hyundai Motors Company, 772-1 Jangduk-dong, Hwaseong-Si, Gyeonggi-Do 445-706, Republic of Korea
3. School of Mechanical and Aerospace Engineering, Institute of Advanced Aerospace Technology, Seoul National University, B/D 301-1302 Shinrim9-dong, Kwanak-ku, Seoul 151-742, Republic of Korea