E-mail: wangxite@ research.neu.edu.cn,Xite Wang is a PhD candidate in the College of Information Science & Engineering, Northeastern University, China, from where he also received his BS and MS in 2009 and 2011, respectively. His research interests include cloud computing and big-data management. Derong Shen is a full professor and a PhD supervisor in the College of Information Science & Engineering, Northeastern University, China, from where she received her PhD in 2004. She received her BS and MS from Jilin University, China in 1987 and 1990, respectively. Her interests include entity search and distributed computing. Mei Bai is a PhD candidate in the College of Information Science & Engineering, Northeastern University, China, from where she received her BS and MS in 2009 and 2011, respectively. Her research interests include sensor data management and uncertain data management. Tiezheng Nie is an associate professor in the College of Information Science & Engineering, Northeastern University, China, from where he received his BS, MS, and PhD in 2002, 2005, and 2009, respectively. His interests include data quality and data integration. Yue Kou is an associate professor in the College of Information Science & Engineering, Northeastern University, China, from where she also received her BS, MS, and PhD in 2002, 2005, and 2009, respectively. Her interests include entity resolution and Web data management. Ge Yu is a full professor and a PhD supervisor in the College of Information Science & Engineering, Northeastern University, China, from where he received his BS and MS in 1982 and 1985, respectively. He received his PhD from Kyushu University of Japan in 1996. He is a senior member of the CCF, and a member of the ACM, IEEE.His interests include databases and big-data management.