His research interests encompass spatio-temporal data mining, social-network and graph data mining, and big data analysis with Hadoop/MapReduce and Spark. His work on trajectory clustering published at ACM SIGMOD 2007 is the most cited paper in trajectory data mining. In addition, he received the Best Paper Award at AAAI ICWSM 2013 and recently served as the Program Committee Co-Chair of PAKDD 2017.