Coreference resolution in biomedical texts

Coreference resolution recently plays a more and more important role for many natural language processing tasks. In this paper, we propose two methods for the biomedical coreference resolution. One is the single machine learning method (SVM ranker-learning algorithm) which selects appropriate features for the pronoun and noun phrase coreference resolution respectively. The other one is the hybrid method which adopts the rule-based method or the machine learning method for relative pronouns, non-relative pronouns and noun phrases coreference resolution respectively. Experiments are carried out on Biomedical Natural Language Process Shared Task (BioNLP-ST) ¹2011 coreference resolution corpus. In the first method (the single machine learning method), the F-score is 49.36%, higher than that using the same method with the features in the Reconcile system by 10.06%. In the second method (the hybrid method), the F-score is 68.61%, higher than that of the currently best system by 1.21%.