利用框架语义知识优化事件抽取

事件抽取旨在把含有事件信息的非结构化文本以结构化的形式予以呈现。现有的基于监督学习的事件抽取方法往往受限于数据稀疏和分布不平衡问题,具有较低的召回率。针对这一问题,该文提出一种利用框架语义优化事件抽取的方法,引入框架类型作为泛化特征,在此基础上进行框架类型和事件类型的映射,然后结合框架类型识别模型和事件类型识别模型进行协作判定,以此优化事件抽取的召回性能。实验结果显示,针对触发词(事件类型)识别任务,相较于仅使用事件类型识别模型,该文提出的框架语义辅助的事件类型识别模型能够提高抽取召回率6.44%(5.74%),提高F值1.45%(0.83%)。

Event Extraction Optimization via Frame Semantic Knowledge

Event extraction aims at detecting certain specified types of events that are mentioned in the source language data. Existing methods based on supervised learning often suffer from date sparseness and imbalanced distribution, producing low recall as a reuslt. In this paper, we investigate the frame semantic knowledge to improve event extraction. Taking the frame type as general feature and mapping the frames into events, we combine the event recognition model with the frame recognition model for a joint decision. Compared to the previous event recognition model, experiments show that this method achieves 6.44%(5.74%) gain in recall and 1.45%(0.83%) gain in F1 for the task of trigger (event) identification.