[Fei, Xiongwei;Li, Kenli;Yang, Wangdong] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha, Peoples R China.^[Fei, Xiongwei] Hunan City Univ, Coll Informat & Elect Engn, Yiyang, Peoples R China.^[Li, Keqin] SUNY Coll New Paltz, Dept Comp Sci, New Paltz, NY USA.