1. Associate Professor, Dept. of Civil Engineering, Yonsei Univ., Sinchon-Dong 134, Seoul 120-749, Korea.
2. Professor, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado, Boulder, CO 80309-0428.
3. Assistant Professor, Dept. of Architectural Engineering, Seoul National Univ. of Technology, Gongneung-Dong, Seoul, 139-743, Korea.