[Zhang, Jianming;Lin, Yaping;Ouyang, Jingcheng] Hunan Univ, Coll Comp & Commun, Changsha 410082, Hunan, Peoples R China.^[Zhang, Jianming;Zhou, Cuihong] Hunan City Univ, Dept Comp Sci, Yiyang 413000, Hunan, Peoples R China.^[Lin, Yaping] Hunan Univ, Coll Software, Changsha 410082, Hunan, Peoples R China.