Zhi Cai is an associate professor in the College of Computer Science, Beijing University of Technology, China. He obtained his M.Sc. in 2007 from the School of Computer Science at the University of Manchester and his Ph.D. in 2011 from the Department of Computing and Mathematics of the Manchester Metropolitan University, U.K. His research interests include Information Retrieval, Ranking in Relational Databases, Keyword Search, and Intelligent Transportation Systems.