1. Assistant Professor, Dept. of Civil Engineering, National Taiwan Univ., No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan; formerly, Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., Urbana, IL 61801 (corresponding author).
2. Dean, The Fu Foundation School of Engineering and Applied Science, and Morris A. and Alma Schapiro Professor of Civil Engineering and Engineering Mechanics, Earth and Environmental Engineering, and Computer Science, Columbia Univ., 510 S.W. Mudd Bldg., 500 W. 120th St., New York, NY 10027.