1. School of Computer, Liaocheng University, Liaocheng, China
2. Macau Institute of Systems Engineering, Macau University of Science and Technology, Macau, China
3. School of Mathematics and Information Science, Yantai University, Yantai, China
4. School of Information Science and Engineering, Shandong Normal University, Jinan, China
5. School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu, China