1. Interdisciplinary Research Institute, School of Mathematics, Statistics and Mechanics, Beijing University of Technology, Beijing 100124, China
2. Department of Mathematics and Physics, School of Arts and Science, American University of Ras al Khaimah, Ras al Khaimah 72603, United Arab Emirates
3. Institute of Life Sciences and Technologies, Daugavpils University, 13 Vienibas Street, LV-5401 Daugavpils, Latvia
4. Institute of Applied Mathematics, Riga Technical University, LV-1048 Riga, Latvia
5. Department of Mathematics, Faculty of Science, Beijing University of Technology, Beijing 100124, China
6. Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China