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Dependency-Guided LSTM-CRF for Named Entity Recognition

2019-09-23IJCNLP 2019Code Available0· sign in to hype

Zhanming Jie, Wei Lu

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Abstract

Dependency tree structures capture long-distance and syntactic relationships between words in a sentence. The syntactic relations (e.g., nominal subject, object) can potentially infer the existence of certain named entities. In addition, the performance of a named entity recognizer could benefit from the long-distance dependencies between the words in dependency trees. In this work, we propose a simple yet effective dependency-guided LSTM-CRF model to encode the complete dependency trees and capture the above properties for the task of named entity recognition (NER). The data statistics show strong correlations between the entity types and dependency relations. We conduct extensive experiments on several standard datasets and demonstrate the effectiveness of the proposed model in improving NER and achieving state-of-the-art performance. Our analysis reveals that the significant improvements mainly result from the dependency relations and long-distance interactions provided by dependency trees.

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Benchmark Results

DatasetModelMetricClaimedVerifiedStatus
CoNLL 2003 (English)DGLSTM-CRF + ELMo (L=2) 3.0pt1-4.51.5F192.4Unverified
Ontonotes v5 (English)DGLSTM-CRF + ELMoF189.88Unverified
Ontonotes v5 (English)DGLSTM-CRF (L=2)F188.52Unverified

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