Abstract
This paper reports about the development of a Named Entity Recognition (NER) system in Bengali by combining the outputs of the two classifiers, namely Conditional Random Field (CRF) and Support Vector Machine (SVM). Lexical context patterns, which are generated from an unlabeled corpus of 10 million wordforms in an unsupervised way, have been used as the features of the classifiers in order to improve their performance. We have post-processed the models by considering the second best tag of CRF and class splitting technique of SVM in order to improve the performance. Finally, the classifiers are combined together into a final system using three weighted voting techniques. Experimental results show the effectiveness of the proposed approach with the overall average recall, precision, and f-score values of 91.33%, 88.19%, and 89.73%, respectively.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Bikel, Daniel, M., Schwartz, R., Weischedel, Ralph, M.: An Algorithm that Learns What’s in Name. Machine Learning (Special Issue on NLP), 1–20 (1999)
Bothwick, A.: A Maximum Entropy Approach to Named Entity Recognition. Ph.D. Thesis, New York University (1999)
Lafferty, J., McCallum, A., Pereira, F.: Conditional Random Fields: Probabilistic Models for Segmenting and Labeling Sequence Data. In: Proc. of 18th ICML, pp. 282–289 (2001)
Yamada, Hiroyasu, Kudo, T., Matsumoto, Y.: Japanese Named Entity Extraction using Support Vector Machine. Transactions of IPSJ 43(1), 44–53 (2003)
Wu, D., Ngai, G., Carpuat, M.: A Stacked, Voted, Stacked Model for Named Entity Recognition. In: Proceedings of CoNLL 2003 (2003)
Florian, R., Ittycheriah, A., Jing, H., Zhang, T.: Named Entity Recognition through Classifier Combination. In: Proceedings of CoNLL 2003 (2003)
Munro, R., Ler, D., Patrick, J.: Meta-learning Orthographic and Contextual Models for Language Independent Named Entity Recognition. In: Proceedings of CoNLL 2003 (2003)
Ekbal, A., Bandyopadhyay, S.: Lexical Pattern Learning from Corpus Data for Named Entity Recognition. In: Proc. of 5th ICON, India, pp. 123–128 (2007)
Ekbal, A., Naskar, S., Bandyopadhyay, S.: Named Entity Recognition and Transliteration in Bengali. Named Entities: Recognition, Classification and Use, Special Issue of Lingvisticae Investigationes Journal 30(1), 95–114 (2007)
Ekbal, A., Haque, R., Bandyopadhyay, S.: Named Entity Recognition in Bengali: A Conditional Random Field Approach. In: Proc. of IJCNLP 2008, India, pp. 589–594 (2008)
Ekbal, A., Bandyopadhyay, S.: Bengali Named Entity Recognition using Support Vector Machine. In: Proc. of NERSSEAL, IJCNLP 2008, India, pp. 51–58 (2008)
Li, W., McCallum, A.: Rapid Development of Hindi Named Entity Recognition Using Conditional Random Fields and Feature Inductions. ACM TALIP 2(3), 290–294 (2003)
Cucerzan, S., Yarowsky, D.: Language Independent Named Entity Recognition Combining Morphological and Contextual Evidence. In: Proc. of the Joint SIGDAT Conference on EMNLP and VLC, pp. 90–99 (1999)
Saha, S., Sarkar, S., Mitra, P.: A Hybrid Feature Set based Maximum Entropy Hindi Named Entity Recognition. In: Proc. of IJCNLP 2008, India, pp. 343–349 (2008)
Kumar, N., Bhattacharyya, P.: Named Entity Recognition in Hindi using MEMM. Technical Report, IIT Bombay, India (2006)
Ekbal, A., Bandyopadhyay, S.: A Web-based Bengali News Corpus for Named Entity Recognition. Language Resources and Evaluation Journal 42(2), 173–182 (2008)
Ekbal, A., Haque, R., Bandyopadhyay, S.: Bengali Part of Speech Tagging using Conditional Random Field. In: Proc. of SNLP, Thailand (2007)
Ekbal, A., Bandyopadhyay, S.: Web-based Bengali News Corpus for Lexicon Development and POS Tagging. Polibits Journal 37, 20–29 (2008)
Niu, C.g., Li, W., Ding, J., Srihari, R.: A Bootstrapping Approach to Named Entity Classification Using Sucessive Learners. In: Proc. of ACL 2003, pp. 335–342 (2003)
Erik, F., Sang, T.K.: Noun Phrase Recognition by System Combination. In: Proceedings of ANLP-NAACL 2000, pp. 50–55 (2000)
Erik, F., Sang, T.K.: Text Chunking by System Combination. In: Proceedings of CoNLL 2000 and LLL 2000, pp. 151–153 (2000)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Ekbal, A., Bandyopadhyay, S. (2009). Improving the Performance of a NER System by Post-processing, Context Patterns and Voting. In: Li, W., Mollá-Aliod, D. (eds) Computer Processing of Oriental Languages. Language Technology for the Knowledge-based Economy. ICCPOL 2009. Lecture Notes in Computer Science(), vol 5459. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-00831-3_5
Download citation
DOI: https://doi.org/10.1007/978-3-642-00831-3_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-00830-6
Online ISBN: 978-3-642-00831-3
eBook Packages: Computer ScienceComputer Science (R0)