1. Senior Environmental Specialist, Office of Deputy Administrator, Environmental Protection Administration, 41, Sec. 1, Chung-Hwa Rd., Taipei, Taiwan.
2. Professor, Dept. of Civil Engineering, National Taiwan Univ., 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan.
3. Professor, Dept. of Civil and Environmental Engineering, Northern Arizona Univ., Flagstaff, AZ 86011.