Manuscript received April 5, 2019; revised August 9, 2019 and March 10, 2020 and March 17, 2020; accepted April 12, 2020. Date of publication April 20, 2020; date of current version September 16, 2020. This work was supported by the National Natural Science Foundation of China under Grant 61937001 and Grant 61877027. (Corresponding author: Jui-Long Hung.) Zongkai Yang, Juan Yang, and Xu Du are with the National Engineering Research Center for E-Learning, Central China Normal University, Wuhan 430079, China (e-mail: zkyang@mail.ccnu.edu.cn; yangjuan_hust@163.com; duxu@mail.ccnu.edu.cn).