1. Research Assistant, Croucher Laboratory of Environmental Hydraulics, Dept. of Civil Engineering, The Univ. of Hong Kong, Hong Kong.
2. Ph.D. Candidate, School of Civil and Environmental Engineering, Cornell Univ., Ithaca, NY 14853.
3. Chair Professor, Dept. of Civil and Environmental Engineering, Hong Kong Univ. of Science and Technology, Hong Kong (corresponding author).