中文摘要：

Ran Liu is currently a postdoctoral fellowship as faculty member in Information Security Department, School of Computer Science, China University of Geosciences （Wuhan）. He received his BS degree of computer science from Central China Normal University in 2007. He obtained his PhD of computer science from University of Science and Technology of China in 2013. His research interests mainly focus on negative representation, cloud computing, security in cloud platform and privacy in cloud platform. E-mail： wjluo@ ustc.edu.cn Wenjian Luo received the BS and PhD degrees from Department of Com- puter Science and Technology, University of Science and Technology of China, Hefei, China, in 1998 and 2003. He is presently an associate professor of School of Computer Science and Technology, University of Science and Technology of China. His current research interests include computational intelligence and applications. Lihua Yue has been a full professor in the School of Computer Science and Technology at University of Science and Technology of China （USTC） since 2001. She received her BS and MS degrees in computer science both from USTC. Her research interests include flash-based databases, spatiotem- poral databases, information retrieval,and image processing. She is a committee of Database Society of the China Computer Federation （CCF DBS） and served as a PC member of many conferences.