1. Business School, Yulin Normal University, Yulin 537000, China
2. Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan
3. Department of Aeronautical Engineering, Chaoyang University of Technology, Taichung 413, Taiwan
4. Prospective Technology of Electrical Engineering and Computer Science, National Chin-Yi University of Technology, Taichung 411, Taiwan