1. Assoc. Prof., Dept. of Civ. and Struct. Engrg., Hong Kong Polytechnic Univ., Kowloon, Hong Kong.
2. PhD Student, Dept. of Civ. and Struct. Engrg., Hong Kong Polytechnic Univ., Kowloon, Hong Kong.
3. Assoc. Prof., Inst. of Vibration Engrg., Nanjing Univ. of Aeronautics and Astronautics, Nanjing, People's Republic of China.