Method and apparatus for learning information extraction patterns from examples

摘要

A system is provided for learning extraction patterns (grammar) for use in connection with an information extraction system. The learning system learns extraction patterns from examples of texts and events. The patterns can then be used to recognize similar events in other input texts. The learning system builds new extraction patterns by recognizing local syntactic relationships between the sets of constituents within individual sentences that participate in events to be extracted. The learning system generalizes extraction patterns it has learned previously through simple inductive learning of sets of words that can be treated synonymously within the patterns. Sets of patterns for a sample extraction task perform nearly at the level of a hand-built dictionary of patterns.