1. Doctor, Dept. of Bioenvironmental Systems Engrg., Nat. Taiwan Univ., Taipei, Taiwan. E-mail: jimmy@cc.hwh.edu.tw
2. Prof., Dept. of Bioenvironmental Systems Engrg., and Hydrotech Res. Inst., Nat. Taiwan Univ., Taipei, Taiwan (corresponding author). E-mail: yctan@ccms.ntu.edu.tw
3. Prof., Dept. of Civ. Engrg., Chung Kuo Institute of Technology, Taipei, Taiwan.