1. Postdoctoral Fellow, Dept. of Civil Engineering, Univ. of Sherbrooke, Sherbrooke PQ, Canada J1K 2R1.
2. Ph.D. Candidate, Key Laboratory of Structural Engineering and Vibration of China Education Ministry, Dept. of Civil Engineering, Tsinghua Univ., Beijing 100084, China.
3. Associate Professor, Key Laboratory of Structural Engineering and Vibration of China Education Ministry, Dept. of Civil Engineering, Tsinghua Univ., Beijing 100084, China.
4. Professor, Dept. of Civil Engineering, Univ. of Sherbrooke, Sherbrooke PQ, Canada J1K 2R1.
5. Professor, Key Laboratory of Structural Engineering and Vibration of China Education Ministry, Dept. of Civil Engineering, Tsinghua Univ., Beijing 100084, China.