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