Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>|Department of Computer Science, National Chung-Hsing University, Taichung, Taiwan, ROC. jjliu@cs.nchu.edu.tw <jjliu@cs.nchu.edu.tw>