1. Department of Computer Science and Information Engineering, National University of Kaohsiung, Kaohsiung, 811, Taiwan, R.O.C.
2. Department of Computer Science and Engineering, National Sun Yat-sen University, Kaohsiung, 804, Taiwan, R.O.C.
3. Information & Communications Research Lab, Industrial Technology Research Institute, Hsinchu, 310, Taiwan, R.O.C.
4. Department of Computer Science and Information Engineering, General Education Center, National University of Kaohsiung, Kaohsiung, 811, Taiwan, R.O.C.