1. Assistant Professor, Dept. of Nuclear Power Plant Engineering, KEPCO International Nuclear Graduate School, Ulsan 689-882, South Korea (corresponding author).
2. Project Engineer, Army Corps of Engineers, 601 East 12th St., Kansas City, MO 64106.
3. Professor and Chair, Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, CA 90095-1593.