1. School of Mechanical and Aerospace Engineering, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea; Wind Power Engineering Team, Doosan Heavy Industries and Construction Co., Ltd., 463-1 Jeonmin-dong, Yuseong-gu, Daejeon 305-811, Republic of Korea
2. School of Mechanical and Aerospace Engineering and Institute of Advanced Aerospace Technology, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
3. School of Mechanical and Aerospace Engineering, Sejong University, 98 Gunja-dong, Kwangjin-ku, Seoul 143-747, Republic of Korea
4. Wind Power Engineering Team, Doosan Heavy Industries and Construction Co., Ltd., 463-1 Jeonmin-dong, Yuseong-gu, Daejeon 305-811, Republic of Korea