1. Graduate Research Assistant, Dept. of Agricultural and Biosystems Engineering, Univ. of Arizona, Tucson, AZ 85721.
2. Assistant Professor, Dept. of Civil Engineering, Kyung Hee Univ., 1 Seocheon-Dong, Giheung-Gu, Yongin-Si, Kyunggi-do 446-701, Republic of Korea; formerly, Assistant Professor, Dept. of Civil Engineering, Univ. of Suwon, 445-743, San 2-2 Wau-ri, Bongdam-eup, Hwaseong-si, Gyeonggi-do, South Korea.
3. Professor, Dept. of Biological Systems Engineering, Univ. of Wisconsin, Madison, WI 53706; formerly, Professor, Dept. of Agricultural and Biosystems Engineering, Univ. of Arizona, Tucson, AZ 85721 (corresponding author).
4. Professor, Dept. of Civil Engineering and Engineering Mechanics, Univ. of Arizona, Tucson, AZ 85721.