1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Rice Univ., Houston, TX 77005.
2. Associate Professor, Dept. of Sociology, Rice Univ., Houston, TX 77005.
3. Associate Professor, Dept. of Civil and Environmental Engineering, Rice Univ., Houston, TX 77005 (corresponding author).
4. Research Engineer, Dept. of Civil and Environmental Engineering, Rice Univ., Houston, TX 77005.
5. Professor, Dept. of Civil and Environmental Engineering, Rice Univ., Houston, TX 77005.