[Yang, Gelan] Hunan City Univ, Dept Comp Sci, Yiyang, Peoples R China.^[Xu, Xue] Univ Sci & Technol China, Dept Automat, Hefei, Peoples R China.^[Yang, Gang] Ecole Super Elect, Dept Power & Energy Syst, Gif Sur Yvette, France.^[Zhang, Jianming] Changsha Univ Sci & Technol, Coll Comp & Commun Engn, Changsha, Peoples R China.