| http://www.w3.org/ns/prov#value | - Sets of patterns learned by LIEP for a sample extraction task perform nearly at the level of a hand-built dictionary of patterns. 1 Introduction Although significant progress has been made on information extraction systems in recent years (for instance through the MUC conferences [MUC, 1992; MUC, 1993]), coding the knowledge these systems need to extract new kinds of information and events is an a
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