1. Department of Mechanical Engineering; Chin-Yi University of Technology; Taichung 400 Taiwan, ROC
2. Department of Automation Engineering; Nan Kai University of Technology; Nantou 54243 Taiwan, ROC
3. Department of Electrical and Information Technology; Nan Kai University of Technology; Nantou 54243 Taiwan, ROC
4. Department of Electrophysics; National Chiao Tung University; Hsinchu 300 Taiwan, ROC