1. Department of Computer Science and Engineering, School of Computing, Kyung Hee University, Yongin-si, Republic of Korea
2. Virginia Modeling, Analysis, and Simulation Center, Old Dominion University, Suffolk, VA, USA
3. Department of Artificial Intelligence, School of Computing, Kyung Hee University, Yongin-si, Republic of Korea
4. Department of Computer Science and Engineering, Kyung Hee University, Yongin-si, Republic of Korea