1. Soochow University,School of Electronics and Information Engineering,Suzhou,Jiangsu,P. R. China
2. Lamar University,Phillip M. Drayer Department of Electrical Engineering,Beaumont,TX,USA
3. Lamar University,Department of Computer Science,Beaumont,TX,USA
4. Nanjing University,School of Electronic Science and Engineering,Nanjing,Jiangsu,P. R. China