His research interests are in multimedia search and computing. He has been serving the technical program committees of numerous multimedia and information retrieval conferences including ACM Multimedia (MM), ACM SIGIR, International Conf. on Multimedia Retrieval (ICMR) and International Conf. on Multimedia and Expo (ICME). In addition, he was an Associate Editor of IEEE Trans. on Multimedia (2011-14), and is on the editorial board of Journal of Multimedia Data Engineering and Management, and Journal of Advances in Multimedia. He is the program area chair of ICME 2015 and ICPR 2014, program co-chair of ACM ICIMCS 2011, ACM MMM 2012 and ACM ICMR 2012, conference chair of PCM 2014 and ACM ICMR 2015. He is founding leader of VIREO (VIdeo REtrieval grOup). He also served as the chairman of ACM (Hong Kong Chapter) during 2008 and 2009.