Effective vector representation for the Korean named-entity recognition

Abstract

Named-entity recognition, part of information extraction, is the task of finding the position of a proper names in a sentence and assigning it to the correct category. Existing studies have access to Korean named-entity recognition by a morphological-level method that performs named-entity recognition processes by using the results of morphological analysis as input. While this method has the advantage of using various linguistic clues, it suffers from the error propagation problem of morphological analysis. In this paper, we propose an effective method for Korean syllable-level named-entity recognition to solve the above problem. Firstly, we suggest an approach to use the syllable bi-gram vector representation for Korean syllable-level named-entity recognition. Secondly, influenced by the linguistic characteristics of Korean, we suggest a novel way to make the joint vector representation of syllable bi-gram and Korean eojeol's positional information. In the experiment, we have evaluated our methods on the two Korean named-entity recognition corpora using Bi-directional LSTM-CRFs as a sequence labeler. Experimental results verify that our methods significantly improve the performance of syllable-level named-entity recognition and have similar performance to existing morphological-level named-entity recognition. Besides, additional experiments have shown that our syllable-level named-entity recognition is not only more robust but also faster than traditional morphological-level named-entity recognition by eliminating the morphological analysis process.