基于迁移学习的细粒度实体分类方法的研究

细粒度实体分类(Fine-grained entity type classification, FETC)旨在将文本中出现的实体映射到层次化的细分实体类别中. 近年来, 采用深度神经网络实现实体分类取得了很大进展. 但是, 训练一个具备精准识别度的神经网络模型需要足够数量的标注数据, 而细粒度实体分类的标注语料非常稀少, 如何在没有标注语料的领域进行实体分类成为难题. 针对缺少标注语料的实体分类任务, 本文提出了一种基于迁移学习的细粒度实体分类方法, 首先通过构建一个映射关系模型挖掘有标注语料的实体类别与无标注语料实体类别间的语义关系, 对无标注语料的每个实体类别, 构建其对应的有标注语料的类别映射集合. 然后, 构建双向长短期记忆(Bidirectional long short term memory, BiLSTM)模型, 将代表映射类别集的句子向量组合作为模型的输入用来训练无标注实体类别. 基于映射类别集中不同类别与对应的无标注类别的语义距离构建注意力机制, 从而实现实体分类器以识别未知实体分类. 实验证明, 我们的方法取得了较好的效果, 达到了在无任何标注语料前提下识别未知命名实体分类的目的.

Fine-grained Entity Type Classification Based on Transfer Learning

The aim of fine-grained entity type classification (FETC) is that mapping the entity appearing in the text into hierarchical fine-grained entity type. In recent years, deep neural network is used to entity classification and has made great progress. However, training a neural network model with precise recognition requires a great quantity labeled data. The labeled dataset of fine-grained entity classification is so rare that hard to classify unlabeled entity. This paper proposes a fine-grained entity classification method based on transfer learning for the task of entity classification with lack labeled dataset. Firstly, we construct a mapping relation model to mining the semantic relationship between labeled entity type and unlabeled entity type, we construct a corresponding labeled entity type mapping set for each unlabeled entity type. Then, we construct a bidirectional long short term memory (BiLSTM) model, the sentence vector combination representing the mapping type set is used as the input of the model to train the unlabeled entity type. Lastly, the attention mechanism is constructed based on the semantic distance between different types in the mapping type set and corresponding unlabeled type, so as to realize entity classifier to recognize the classification of unknown entities. The experiment shows that our method have achieved good results and achieved the purpose of identifying unknown named entity classification with unlabeled dataset.