CONG GAO1,2, ZHENZHOU TIAN1,2, YANPING CHEN1,2 AND ZHONGMIN WANG1,2
1School of Computer Science and Technology
2Shaanxi Key Laboratory of Network Data Analysis and Intelligent Processing
Xi'an University of Posts and Telecommunications
Xi'an, 710121 P.R. China
E-mail: {cgao; zztian; chenyp; zmwang}@xupt.edu.cn