Friday, February 8, 2008, 12-2 p.m.

Deep Lexical Semantics

In the project I will describe, we have taken a basic core of about 5000 synsets in WordNet that are the most frequently used, and we have categorized these into sixteen broad categories, including, for example, time, space, scalar notions, composite entities, and event structure. We have sketched out the structure of some of the underlying abstract core theories of commonsense knowledge, including those for the mentioned areas. These theories explicate the basic predicates in terms of which the most common word senses need to be defined or characterized. We are now encoding axioms that organize the word senses by their inferential relations with each other and that link the word senses to the core theories. This may be thought of as a kind of ``advanced lexical decomposition", where the ``primitives" into which words are ``decomposed" are elements in coherently worked-out theories. In this talk I will focus on our work on the 450 of these synsets that are concerned with events and their structure.

Bio: Dr. Jerry R. Hobbs is a prominent researcher in the fields of computational linguistics, discourse analysis, and artificial intelligence. He earned his doctor's degree from New York University in 1974 in computer science. He has taught at Yale University and the City University of New York. From 1977 to 2002 he was with the Artificial Intelligence Center at SRI International, Menlo Park, California, where he was a principal scientist and program director of the Natural Language Program. He has written numerous papers in the areas of parsing, syntax, semantic interpretation, information extraction, knowledge representation, encoding commonsense knowledge, discourse analysis, the structure of conversation, and the Semantic Web. He is the author of the book "Literature and Cognition", and was also editor of the book "Formal Theories of the Commonsense World". He led SRI's text-understanding research, and directed the development of the abduction-based TACITUS system for text understanding, and the FASTUS system for rapid extraction of information from text based on finite-state automata. The latter system constituted the basis for an SRI spinoff, Discern Communications. In September 2002 he took a position as senior computer scientist and research professor at the Information Sciences Institute, University of Southern California. He has been a consulting professor with the Linguistics Department and the Symbolic Systems Program at Stanford University. He has served as general editor of the Ablex Series on Artificial Intelligence. He is a past president of the Association for Computational Linguistics, and is a Fellow of the American Association for Artificial Intelligence. In January 2003 he was awarded an honorary Doctorate of Philosophy from the University of Uppsala, Sweden.