1. Project Engineer, Tobolski Watkins Engineering, 9246 Lightwave Ave., Suite 140, San Diego, CA 92123.
2. Professor, Dept. of Structural Engineering, Univ. of California-San Diego, La Jolla, CA 92093-0085 (corresponding author).
3. Professor, Dept. of Computer Science and Engineering, Univ. of California-San Diego, La Jolla, CA 92093-0404.