1. College of Mathematical Sciences, Bohai University, Jinzhou, China
2. Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian, China
3. School of Information Science and Engineering, Shandong Normal University, Jinan, China
4. School of Electronic and Information Engineering, University of Science and Technology at Liaoning, Anshan, China
5. College of Engineering, Shenyang Agricultural University, Shenyang, China