LI Xiaofeng1,LIU Gang2,WEI Jin1,WANG Yanwei3
(1. School of Computer Science and Technology,Beijing Institute of Technology,Beijing 100081,China; 2. College of Computer Science and Technology,Harbin Engineering University,Harbin 150001,China; 3. Department of Mechanical Engineering,Purdue University,West lafayette,Indianan IN47906,US)