1. Research and Development Center, Nestfield Company Ltd., Ansan, South Korea
2. College of Computer Science and Technology, Harbin Engineering University, Harbin, China
3. Department of Information Engineering, Wuhan University of Technology, Wuhan, China
4. Department of Electronic Engineering, Hanyang University, Ansan, South Korea
5. Research Center of Electrical and Information Technology, Seoul National University of Science and Technology, Seoul, South Korea