1. Associate Professor, Aeronautic and Mechanical Engineering Dept., Chinese Air Force Academy, P.O. Box 90277-11 Kang-Shan, Kaohsiung County, Taiwan, Republic of China.
2. Professor, Mechanical Engineering Dept., National Chiao Tung Univ., Hsin Chu 300, Taiwan, Republic of China (corresponding author). E-mail: tykam@mail.nctu.edu.tw
3. Research Assistant, Mechanical Engineering Dept., National Chiao Tung Univ., Hsin Chu 300, Taiwan, Republic of China.