Kyungsoo Kim
[
Department of Mathematics, Kyonggi University, Suwon 443-760, Republic of Korea
]
Yoon Hyuk Kim
[
Department of Mechanical Engineering & e-Spine Center, Kyung Hee University, Yongin 446-701, Republic of Korea
]
SuKyoung Lee
[
Department of Computer Science, Yonsei University, Seoul 120-749, Republic of Korea
]