1. Ph.D. Student, Graduate School of Engineering Science and Technology, National Yunlin Univ. of Science and Technology, Douliou, Yunlin 640, Taiwan.
2. Professor, Dept. of Leisure and Recreation Management, Taiwan Shoufu Univ., 168 Nan-shih Li, Madou 721, Tainan, Taiwan (corresponding author).
3. Professor, Dept. of Safety Health and Environmental Engineering, National Yunlin Univ. of Science and Technology, Douliou, Yunlin 640, Taiwan.
4. Assistant Professor, Water Resources Agency, Ministry of Economic Affairs, Taipei 106, Taiwan.