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Publication . Article . Conference object . Preprint . 2019

A Morpho-Syntactically Informed LSTM-CRF Model for Named Entity Recognition

Lilia Simeonova; Kiril Simov; Petya Osenova; Preslav Nakov;
Open Access
English
Abstract

We propose a morphologically informed model for named entity recognition, which is based on LSTM-CRF architecture and combines word embeddings, Bi-LSTM character embeddings, part-of-speech (POS) tags, and morphological information. While previous work has focused on learning from raw word input, using word and character embeddings only, we show that for morphologically rich languages, such as Bulgarian, access to POS information contributes more to the performance gains than the detailed morphological information. Thus, we show that named entity recognition needs only coarse-grained POS tags, but at the same time it can benefit from simultaneously using some POS information of different granularity. Our evaluation results over a standard dataset show sizable improvements over the state-of-the-art for Bulgarian NER.

named entity recognition; Bulgarian NER; morphology; morpho-syntax

Subjects by Vocabulary

Microsoft Academic Graph classification: Granularity Morpho biology.organism_classification biology Character (mathematics) Computer science Bulgarian language.human_language language Artificial intelligence business.industry business Word (computer architecture) Named-entity recognition computer.software_genre computer Natural language processing Architecture

Subjects

Computer Science - Computation and Language, 68T50, I.2.7, Computation and Language (cs.CL), FOS: Computer and information sciences

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