Faculty of Mathematics and Computer Science, VNUHCM-University of Science, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam.|School of Biotechnology, VNUHCM-International University, Quarter 6, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, Vietnam.|Faculty of Information Technology, Ho Chi Minh City University of Pedagogy, 280 An Duong Vuong Street, Ward 4, District 5, Ho Chi Minh City, Vietnam.|Faculty of Mathematics and Computer Science, VNUHCM-University of Science, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam. ptbao@hcmus.edu.vn.