1. Associate Professor, Dept. of Bioenvironmental Systems Engineering, National Taiwan Univ., No. 1, Section 4, Roosevelt Rd., Taipei 10617, Taiwan (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Tokushima Univ., Tokushima 770-8501, Japan.
3. Formerly, Graduate Student, National Taiwan Univ. of Science and Technology, Taipei 10617, Taiwan.