Department of Computer Science & Engineering, Yuan Ze University, Chung-Li, Taiwan, R.O.C. thtsai@saturn.yzu.edu.tw|Department of Computer Science & Engineering, Yuan Ze University, Chung-Li, Taiwan, R.O.C. thtsai@saturn.yzu.edu.tw|Department of Computer Science & Engineering, Yuan Ze University, Chung-Li, Taiwan, R.O.C. thtsai@saturn.yzu.edu.tw|Department of Computer Science & Engineering, Yuan Ze University, Chung-Li, Taiwan, R.O.C. thtsai@saturn.yzu.edu.tw