1. School of Electronic Engineering, Soongsil University, 369 Sangdoro, Dongjak-gu, Seoul 156-743, Republic of Korea
2. Department of Electronic Engineering, Yeungnam University, 280 Daehak-ro Gyeongsan, Gyeongbuk 712-749, Republic of Korea
3. Department of Electronics and Communications Engineering, Kwangwoon University, 20 Gwangun-ro, Nowon-gu, Seoul 139-701, Republic of Korea