1. Department of Mathematics, Shanghai Normal University, Shanghai 200234, China
2. Scientific Computing Key Laboratory of Shanghai Universities, Shanghai 200234, China
3. Department of Applied Mathematics, National Hsinchu University of Education, Hsinchu 30033, Taiwan
4. Center for Fundamental Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan
5. Department of Information Management, Yuan Ze University, Chung-Li 32003, Taiwan