[Mo, Taiping] Xidian Univ, Dept Mech & Elect Engn, Xidian 710126, Shanxi, Peoples R China.^[Zhao, Huihuang] Hengyang Normal Univ, Dept Comp Sci, Hunan 421008, Peoples R China.^[Mo, Wei] Guilin Univ Elect Technol, Dept Elect Engn & Automat, Guangxi 541004, Peoples R China.