1. Institute for Mathematical Research, Universiti Putra Malaysia (UPM), Serdang 43400, Malaysia
2. School of Education, Linyi University, Linyi 276005, China
3. School of Information Science and Engineering, Linyi University, Linyi 276005, China
4. School of Computer Science and Technology, Shandong University of Finance and Economics, Jinan 250014, China
5. School of Computer and Information, Anhui Polytechnic University, Wuhu 241003, China