1. College of Automation, Guangdong University of Technology, Guangzhou 510090, P. R. China
2. The Key Laboratory of Systems and Control, Institute of Systems Science, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, P. R. China
3. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
4. Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR, P. R. China