1. School of Mathematical Science, Qufu Normal University, Qufu, China
2. Big Data Institute, Qilu University of Technology, Jinan, Shandong, China
3. School of Mathematics and Statistics and the Big Data Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, China
4. School of Computer Science, Qufu Normal University, Rizhao, China