1. Ph.D. Student, Dept. of Civil Engineering, National Chiao Tung Univ., 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010, R.O.C.
2. Assistant Professor, Dept. of Civil and Water Resources Engineering, National Chiayi Univ., 300 Syuefu Rd., Chiaya City, Taiwan 60004, R.O.C.
3. Professor, Dept. of Civil Engineering, National Chiao Tung Univ., 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010, R.O.C.
4. Professor, Dept. of Civil Engineering, Hong Kong Univ. of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.