He was most recently an assistant professor at the City University of New York (CUNY) and a part-time research scientist at IBM T. J. Watson Research Center. He graduated in 2008 from the University of Pennsylvania and has worked as a research scientist at Google and a research assistant professor at USC/ISI. Most of his work develops fast algorithms and provable theory to speedup large-scale natural language processing and structured machine learning. He has received a Best Paper Award at ACL 2008, several best paper nominations (ACL 2007, EMNLP 2008, and ACL 2010), two Google Faculty Research Awards (2010 and 2013), a Yahoo Faculty Research Award (2015), and a University Teaching Prize at Penn (2005). His research has been supported by DARPA, NSF, Google, and Yahoo. He also co-authored a best-selling textbook in China on algorithms for programming contests.