1. Graduate Student, Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
2. Senior Researcher, Mechanical System Development Dept., Korea Atomic Energy Research Institute, Daejeon 305-353, Korea.
3. Senior Researcher, Ocean Development System Research Division, Korea Research Institute of Ships and Ocean Engineering, P.O. Box 23, Daejeon 305-600, Korea.
4. Professor, Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.