arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1909.05166cs.CL
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具有相对和全局关注的依赖感知命名实体识别

Dependency-Aware Named Entity Recognition with Relative and Global Attentions

University of Houston(休斯顿大学)

Gustavo Aguilar, Thamar Solorio

摘要:

命名实体识别是自然语言处理的核心任务之一。虽然在过去的几年中,在这项任务上已经做出了许多改进,但最先进的系统并没有明确考虑到语言的递归性质。而不是只把文本作为一个普通的单词序列,我们采用了一种语言启发的方式来识别基于语法和树结构的实体。我们的模型使用依赖树引导的Tree-LSTM来利用单词之间的语法关系。然后,我们通过应用相对和全局注意力机制来增强这些特征。一方面,相对注意力检测句子中相对于被评估的词信息量最大的词。另一方面,全局注意力会发现序列中最相关的单词。最后,我们将加权向量线性投影到标签空间中,以便条件随机场分类器预测实体标签。我们的研究结果表明,该模型基于句子中的句法角色(例如,当实体类型是PERSON时,诸如speak和write之类的动词被关注,而meet和travel与LOCATION强烈相关)。我们证实了我们的发现,并在两个数据集上建立了一个新的最先进的状态。

英文摘要:

Named entity recognition is one of the core tasks in NLP. Although many improvements have been made on this task during the last years, the state-of-the-art systems do not explicitly take into account the recursive nature of language. Instead of only treating the text as a plain sequence of words, we incorporate a linguistically-inspired way to recognize entities based on syntax and tree structures. Our model exploits syntactic relationships among words using a Tree-LSTM guided by dependency trees. Then, we enhance these features by applying relative and global attention mechanisms. On the one hand, the relative attention detects the most informative words in the sentence with respect to the word being evaluated. On the other hand, the global attention spots the most relevant words in the sequence. Lastly, we linearly project the weighted vectors into the tagging space so that a conditional random field classifier predicts the entity labels. Our findings show that the model detects words that disclose the entity types based on their syntactic roles in a sentence (e.g., verbs such as speak and write are attended when the entity type is PERSON, whereas meet and travel strongly relate to LOCATION). We confirm our findings and establish a new state of the art on two datasets.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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