[1] Sichuan Univ, Coll Comp Sci, Chengdu, Sichuan, Peoples R China
[2] Yunnan Minzu Univ, Sch Math & Comp Sci, Kunming, Yunnan, Peoples R China
[3] Yunnan Minzu Univ, Key Lab IOT Applicat Technol Univ Yunnan Prov, Kunming, Yunnan, Peoples R China
[4] Univ Waterloo, Dept Appl Math, Waterloo, ON, Canada