1. Assistant Professor, Rice Univ., Dept. of Civil and Environmental Engineering, MS-318, 6100 Main St., Houston, TX 77005.
2. Professor, Georgia Inst. of Technology, School of Aerospace Engineering, 270 Ferst Dr., Atlanta, GA 30332-0150.
3. Professor, Georgia Inst. of Technology, School of Civil and Environmental Engineering, 790 Atlantic Dr., Atlanta, GA 30332-0355.
4. Associate Professor, Georgia Inst. of Technology, School of Public Policy, 685 Cherry St., Atlanta, GA 30332-0345.