1. School of Information Engineering, Jimei University, Xiamen, Fujian 361021, PR China
2. Department of Aero-Electronic Engineering, Air Force Institute of Technology, Kaohsiung 820, Taiwan
3. Department of Electro-Optical Engineering, Southern Taiwan University, Tainan 710, Taiwan
4. Department of Chemical and Material Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan