Faculty of Computer Science and Engineering, HCMC University of Technology, 268 Ly Thuong Kiet, Q10, HCM City, Vietnam. vinhlv@fit.hcmute.edu.vn.|Institute of Applied Mechanics and Informatics, Vietnam Academy of Science and Technology, 01 Mac Dinh Chi, Q1, HCM City, Vietnam. langtv@vast.vn.|Faculty of Computer Science and Engineering, HCMC University of Technology, 268 Ly Thuong Kiet, Q10, HCM City, Vietnam. hoai@cse.hcmut.edu.vn.