1. Research Scientist, Construction Research Institute, Hanyang Univ., Seoul, 133-791, Korea.
2. Vecellio Professor, Charles E. Via, Jr., Dept. of Civil and Environmental Engineering, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061-0105., Program Director, Information Technology and Infrastructure Systems, Civil and Mechanical Systems Division, National Science Foundation, Arlington, VA 22230.