1. College of Computer Science, Neijiang Normal University, Neijiang, Sichuan, China
2. Engineering and Technical College, Chengdu University of Technology, Leshan, Sichuan, China
3. State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau, China
4. Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China