JUNYOUNG HEO1, BONCHEOL GU2, YOOKUN CHO2 AND JIMAN HONG3+
1Department of Computer Engineering
Hansung University
Seoul, 136-792 Korea
2School of Computer Science and Engineering
Seoul National University
Seoul, 151-742 Korea
3School of Computer Science and Engineering
Soongsil University
Seoul, 156-743 Korea