1. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, 1163 Glenn Martin Hall, College Park, MD 20742.
2. Principal Design Engineer, EMC Corporation, Network Storage Group, 80 South St., Hopkinton, MA 01748.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI 53706.