Affiliation: | 1. Department of Electrical Engineering , Da‐Yeh University , Chang‐Hua 515, Taiwan, R.O.C. Phone: 886–4–7135896 ext. 120 Fax: 886–4–7135896 ext. 120 E-mail: ynchung@cc.ncue.edu.tw;2. National Changhua University of Education , Changhua 500, Taiwan, R.O.C.;3. Department of Electrical Engineering , Da‐Yeh University , Chang‐Hua 515, Taiwan, R.O.C. |