1. Professor, Dept. of Civil Engineering, The Catholic Univ. of America, Washington, DC 20064 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Cheju National Univ., 66 Jejudaehakno, Jeju-Do 690-756, Korea.
3. Director, U.S. Power Generating Company, LLC, 505 Fifth Ave., 21st Floor, New York, NY 10017.