1. School of Information and Computer Engineering, Ajou University, San 5, Woncheon-dong, Suwon-si, Gyeonggi-do 443-749, Republic of Korea
2. Department of Computer Engineering, Yildirim Beyazit University, Altindag Ulus, 06030 Ankara, Turkey
3. Department of Computer Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea