Hierarchical Hidden Conditional Random Fields for Information Extraction
Hierarchical Hidden Conditional Random Fields for Information Extraction
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DOI:
10.1007/978-3-642-25566-3_14
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发表时间:
2011-01
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影响因子:
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通讯作者:
Satoshi Kaneko;A. Hayashi;N. Suematsu;Kazunori Iwata
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文献类型:
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作者:
Satoshi Kaneko;A. Hayashi;N. Suematsu;Kazunori Iwata
Hidden Markov Models (HMMs) are very popular generative models for time series data. Recent work, however, has shown that for many tasks Conditional Random Fields (CRFs), a type of discriminative model, perform better than HMMs. Information extraction is the task of automatically extracting instances of specified classes or relations from text. A method for information extraction using Hierarchical Hidden Markov Models (HHMMs) has already been proposed. HHMMs, a generalization of HMMs, are generative models with a hierarchical state structure. In previous research, we developed the Hierarchical Hidden Conditional Random Field (HHCRF), a discriminative model corresponding to HHMMs. In this paper, we propose information extraction using HHCRFs, and then compare the performance of HHMMs and HHCRFs through an experiment.