1. a Department of Materials Engineering, National Ping-Tung University of Science and Technology, No. 1, Syuefu Rd., Neipu Township, Pingtung County 91201, Taiwan
2. b General Education Center, Wenzao Ursuline College of Languages, Mitsu 1st Road, Kaohsiung 807, Taiwan
3. c Department of Electronics Engineering and Computer Science, Tung-Fang Institute of Technology, No. 110, Tung-Fung Road, Hunei Shiang, Kaohsiung 829, Taiwan