中文摘要：

E-mail： cqjin@sei.ecnu.edu.cnCheqing Jin is a professor at East China Normal University, China. He received his master and bachelor degrees from Zhejiang University （ECNU）, China in 1999 and 2002 respectively, and his PhD degree from Fudan University, China in 2005, all in computer science. He worked as an assistant professor in East China University;Jie Chen received his undergraduate and master degree from East China Normal University, China in 2011 and 2014, re- spectively. As of now, he is working in PayPal, Risk Management team to be a risk analyst. His research area is data quality and data mining, especially for handling big data.;Huiping Liu received the BS degree in software engineering from East China Normal University, China in 2013. Currently, he is a PhD student supervised by Prof. Cheqing Jin. His research mainly focuses on data quality, massive data mining and processing, and location-based services.