1. Postdoctoral Fellow, Dept. of Computer Science, North Carolina State Univ., Raleigh, NC 27695.
2. Assistant Professor, Facultad de Ingeniería, Universidad Autónoma de Sinaloa, Culiacán, Sinaloa 80040, México.
3. Ph.D. Student, Dept. of Civil Engineering and Engineering Mechanics, Univ. of Arizona, Tucson, AZ 85721.
4. Professor, Dept. of Civil Engineering and Engineering Mechanics, Univ. of Arizona, Tucson, AZ 85721 (corresponding author).