1. School of Control Science and Engineering Shandong University Jinan P. R. China
2. Institute of Complexity Science, College of Automation Qingdao University Qingdao P. R. China
3. Department of Applied Mathematics The Hong Kong Polytechnic University Kowloon, Hong Kong P. R. China
4. College of Electrical Engineering and Automation Shandong University of Science and Technology Qingdao P. R. China