1. National Cheng Kung Univ., Institute of Aeronautics and Astronautics, Tainan 701, Taiwan (corresponding author).
2. National Defense Univ., Chung Cheng Institute of Technology, Da-Shi, Tao-Yuan 335, Taiwan.
3. National Cheng Kung Univ., Institute of Aeronautics and Astronautics, Tainan 701, Taiwan.