1. Ph.D. Student, Dept. of Civil and Environmental Engineering and Geodetic Science, The Ohio State Univ., 470 Hitchcock Hall, 2070 Neil Ave., Columbus, OH 43210.
2. Lichtenstein Professor, Dept. of Civil and Environmental Engineering and Geodetic Science, The Ohio State Univ., 470 Hitchcock Hall, 2070 Neil Ave., Columbus, OH 43210.