1. Department of Mathematics, Shanghai Normal University, Shanghai 200234, China
2. Department of Healthcare Administration and Medical Informatics, Center for Big Data Analytics & Intelligent Healthcare, and Research Center of Nonlinear Analysis and Optimization, Kaohsiung Medical University, Kaohsiung 807, Taiwan
3. Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
4. Center for Fundamental Science and Research Center for Nonlinear Analysis and Optimization, Kaohsiung Medical University, Kaohsiung 80708, Taiwan