1. School of Computer Science and Technology, Harbin Institute of Technology Shenzhen Graduate School, HIT Campus, Shenzhen University Town, Xili, Shenzhen 518055, China
2. Department of Computer Science and Information Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan
3. Department of Computer Science and Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan
4. Medical School, Shenzhen University, Shenzhen 518060, China