He obtained his PhD at Syracuse University in 1997, his MSc in Library & Information Science at the University of Illinois, Urbana-Champaign in 1987, and a BA from Harvard University. He has also worked for several years as a science reference librarian, cataloger and online information searcher at the National University of Singapore Libraries. His main research interests are in knowledge organization, ontologies, automatic sentiment categorization, human categorization behavior, natural language processing, information extraction, multidocument summarization, and clinical decision support systems.