1. Associate Professor, Dept. of Civil and Environmental Engineering, Southern Methodist Univ., P.O. Box 750340, Dallas, TX 75205.
2. Professor, Dept. of Mechanical Engineering, Southern Methodist Univ., Dallas, TX 75205.
3. Formerly, Graduate Student, Dept. of Mechanical Engineering, Southern Methodist Univ., Dallas, TX 75205.
4. Formerly, Graduate Student, Dept. of Civil and Environmental Engineering, Southern Methodist Univ., Dallas, TX 75205.