[Liu, Yong-Min;Xiao, Bi-Wu] Cent South Univ Forestry & Technol, Coll Comp & Informat Engn, Changsha 410004, Hunan, Peoples R China.^[Lu, Wu-Yi] Cent S Univ, Sch Informat Sci & Engn, Changsha 410075, Hunan, Peoples R China.^[Huang, Wei-Dong] CSIRO ICT Ctr, Epping, NSW 1710, Australia.