1. Graduate Student Researcher, Dept. of Civil Engineering, Univ. of California at Berkeley, 1301 South 46th St., Berkeley, CA 94720.
2. Associate Professor, Dept. of Civil, Structural, and Environmental Engineering, Univ. at Buffalo, 230 Ketter Hall, Buffalo, NY 14260.
3. Research Engineer, Pacific Earthquake Engineering Research Center, Univ. of California at Berkeley, 1301 South 46th Street, Richmond, CA 94804.
4. Emeritus Professor, Dept. of Civil Engineering, Univ. of California, Berkeley, CA 94720.
5. Visiting Scholar, Pacific Earthquake Engineering Research Center, Univ. of California at Berkeley, 1301 South 46th Street, Richmond, CA 94804.