An Expectation Maximization Approach to Pronoun Resolution

We propose an unsupervised Expectation Maximization approach to pronoun resolution. The system learns from a fixed list of potential antecedents for each pronoun. We show that unsupervised learning is possible in this context, as the performance of our system is comparable to supervised methods. Our results indicate that a probabilistic gender/number model, determined automatically from unlabeled text, is a powerful feature for this task.

[1]  Hermann Ney,et al.  Discriminative Training and Maximum Entropy Models for Statistical Machine Translation , 2002, ACL.

[2]  L. M. M.-T. Theory of Probability , 1929, Nature.

[3]  Claire Gardent,et al.  Improving Machine Learning Approaches to Coreference Resolution , 2002, ACL.

[4]  Branimir Boguraev,et al.  Anaphora for Everyone: Pronominal Anaphora Resolution without a Parser , 1996, COLING.

[5]  Claire Cardie,et al.  Weakly Supervised Natural Language Learning Without Redundant Views , 2003, NAACL.

[6]  Hwee Tou Ng,et al.  A Machine Learning Approach to Coreference Resolution of Noun Phrases , 2001, CL.

[7]  Shane Bergsma,et al.  Automatic Acquisition of Gender Information for Anaphora Resolution , 2005, Canadian Conference on AI.

[8]  Ellen Riloff,et al.  Unsupervised Learning of Contextual Role Knowledge for Coreference Resolution , 2004, NAACL.

[9]  Dekang Lin,et al.  PRINCIPAR - An Efficient, Broad-coverage, Principle-based Parser , 1994, COLING.

[10]  Shalom Lappin,et al.  An Algorithm for Pronominal Anaphora Resolution , 1994, CL.

[11]  Richard Evans,et al.  A New, Fully Automatic Version of Mitkov's Knowledge-Poor Pronoun Resolution Method , 2002, CICLing.

[12]  Michael Strube,et al.  Applying Co-Training to Reference Resolution , 2002, ACL.

[13]  Adam L. Berger,et al.  A Maximum Entropy Approach to Natural Language Processing , 1996, CL.

[14]  Claire Cardie,et al.  Noun Phrase Coreference as Clustering , 1999, EMNLP.

[15]  Ellen M. Voorhees,et al.  Overview of the TREC 2004 Novelty Track. , 2005 .

[16]  Andrew Kehler,et al.  Probabilistic Coreference in Information Extraction , 1997, EMNLP.

[17]  John Hale,et al.  A Statistical Approach to Anaphora Resolution , 1998, VLC@COLING/ACL.

[18]  Mats Rooth,et al.  Structural Ambiguity and Lexical Relations , 1991, ACL.

[19]  Rob Malouf,et al.  A Comparison of Algorithms for Maximum Entropy Parameter Estimation , 2002, CoNLL.

[20]  D. Rubin,et al.  Maximum likelihood from incomplete data via the EM - algorithm plus discussions on the paper , 1977 .

[21]  Robert L. Mercer,et al.  The Mathematics of Statistical Machine Translation: Parameter Estimation , 1993, CL.