1. Department of Electrical Engineering, Institute of Computer and Communication Engineering, National Cheng Kung University, Taiwan, ROC. E-mails: shieh@ee.ncku.edu.tw, frankyu0326@gmail.com, jhlin5@hpds.ee.ncku.edu.tw
2. Department of Computer Science and Information Engineering, National Quemoy University, Taiwan, ROC. E-mail: smallko@gmail.com