Affiliation: | 1.State Key Laboratory of CAD & CG, Zhejiang University, Hangzhou 310027, China;2.Department of Computer Science, Harbin Finance University, Harbin 150030, China;3.Department of Computer Science, The University of Texas at Dallas, Richardson, TX 75080-3021, U.S.A.;4.Faculty of Information Technology, Macau University of Science and Technology, Macau 999078, China;5.National Engineering Research Center for E-Learning, Central China Normal University, Wuhan 430079, China |