1. Professor, Dept. of Civil Engineering, Vanung Univ., No.1 Vannung Rd., Chungli, Taoyuan 320, Taiwan.
2. Postdoctoral Researcher, Institute of Environmental Engineering, National Chiao Tung Univ., No.1001 University Rd., Hsinchu 300, Taiwan.
3. M.S. Student, Institute of Environmental Engineering, National Chiao Tung Univ., No.1001 University Rd., Hsinchu 300, Taiwan.
4. Professor, Institute of Environmental Engineering, National Chiao Tung Univ., No.1001 University Rd., Hsinchu 300, Taiwan (corresponding author).