[Liu, Jie;Liu, Jing;Sun, Haiying;Chen, Xiaohong;Du, Dehui;Chen, Mingsong] East China Normal Univ, Shanghai Key Lab Trustworthy Comp, Shanghai 200062, Peoples R China.^[Liu, Jie] Univ South China, Sch Comp Sci & Technol, Hengyang 421001, Peoples R China.^[Zhang, Miaomiao] Tongji Univ, Sch Software Engn, Shanghai 200062, Peoples R China.