1. School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang, China
2. School of Mathematics, Computer Science and Engineering, City, University of London, London, U.K.
3. School of Electronic Science and Engineering, Institute of Lightwave Technology, Xiamen University, Xiamen, China
4. Institute of International Engineering, Shenyang Ligong University, Shenyang, China
5. City Graduate School, the School of Mathematics, Computer Science and Engineering, City, University of London, London, U.K.