[Wang, Zengyun] Hunan First Normal Univ, Dept Math, Changsha 410205, Hunan, Peoples R China.
[Cao, Jinde; Wang, Zengyun] Southeast Univ, Sch Math, Nanjing 210096, Jiangsu, Peoples R China.
[Cao, Jinde; Wang, Zengyun] Southeast Univ, Jiangsu Prov Key Lab Networked Collect Intelligen, Nanjing 210096, Jiangsu, Peoples R China.
[Cai, Zuowei] Hunan Womens Univ, Dept Informat Technol, Changsha 410002, Hunan, Peoples R China.
[Huang, Lihong] Changsha Univ Sci & Technol, Sch Math & Stat, Changsha 410114, Hunan, Peoples R China.