1. Assistant Professor, Dept. of Civil and Environmental Engineering, Carnegie Mellon Univ., Pittsburgh, PA 15213-3890.
2. Associate Professor, Dept. of Civil and Environmental Engineering and (by courtesy) Computer Science, Director, Center for Integrated Facility Engineering, Stanford Univ., Stanford, CA 94305.
3. Professor, Dept. of Civil and Environmental Engineering, Stanford Univ., Stanford, CA 94305.
4. Professor, Dept. of Management Science and Engineering, Stanford Univ., Stanford, CA 94305.