Resolving Pronominal Reference to Abstract Entities

Thesis proposal; final thesis appeared as TR 815.Existing algorithms for pronoun resolution typically cast the problem into a coreference task, which means they simply identify an antecedent noun phrase for each pronoun. Selection of the antecedent is usually based on a calculation of salience or focus. This simplified approach is unable to account for pronouns without noun-phrase antecedents. Examples are abstract referents such as events, propositions, and speech acts that might appear in the linguistic surface form as sentential complements, verbal constructions or entire sentences, as well as consequences or outcomes that don't appear in the surface form at all. This paper contains a survey of current methods of pronoun resolution for natural language understanding. It then proposes a strategy for resolving pronominal reference to abstract entities that incorporates semantic information in addition to salience calculations. Preliminary experiments are described that show the strategy to perform well above baseline on a collection of spoken task-oriented dialogs