1. Associate Professor, National Kaohsiung First Univ. of Science and Technology, No. 1, University Rd., Yenchao, Kaohsiung 824, Taiwan.
2. Professor, Univ., of Houston, Houston, TX 77204.
3. Associate Research Fellow, National Center for Research on Earthquake Engineering, 200, Sec. 3, Xinhai Rd., Taipei 106, Taiwan.