[Cai, Jin; Yang, He] Hubei Univ Educ, Sch Comp, Wuhan 430205, Peoples R China.
[Yang, He] Cent China Normal Univ, Wuhan Huada Natl Elearning Technol Co Ltd, Wuhan 430079, Peoples R China.
[Yang, Harrison Hao] SUNY Coll Oswego, Sch Educ, 4060 Route 104, Oswego, NY 13126 USA.
[Yang, Harrison Hao] Cent China Normal Univ, Natl Engn Res Ctr Elearning, Wuhan 430079, Peoples R China.
[Wang, Xiaochen] Capital Normal Univ, Coll Teacher Educ, Beijing 100091, Peoples R China.