[Liu, Libin] Chizhou Univ, Dept Math & Comp Sci, Chizhou 247000, Anhui, Peoples R China.^[Hao, Libo] Hunan Mech & Elect Polytech, Dept Informat Engn, Changsha 410151, Hunan, Peoples R China.^[Ouyang, Aijia] Hunan Sci & Technol Econ Trade Vocat Coll, Coll Comp, Hengyang 421001, Peoples R China.^[Ouyang, Aijia] Hunan City Univ, Sch Informat Sci & Engn, Hunan 413000, Peoples R China.