1. Professor, Dept. of Hydraulic Engineering, Tsinghua Univ., Beijing 100084, People’s Republic of China.
2. Graduate Assistant, Dept. of Hydraulic Engineering, Tsinghua Univ., Beijing 100084, People’s Republic of China.
3. Professor, Dept. of Civil & Materials Engineering, Univ., of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607-7023.
4. Senior Engineer, Research Dept., Beijing General Municipal Engineering Design and Research Institute, Beijing 100035, People’s Republic of China.