arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2212.03496cs.CL
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一种基于对比微调的脚本事件生成预测方法

A Generative Approach for Script Event Prediction via Contrastive Fine-tuning

Harbin Institute of Technology (Shenzhen)(哈尔滨工业大学(深圳));Peng Cheng Laboratory(鹏城实验室);Beijing University of Technology(北京工业大学);Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences(中国科学院深圳先进技术研究院)

Fangqi Zhu, Jun Gao, Changlong Yu, Wei Wang, Chen Xu, Xin Mu, Min Yang, Ruifeng Xu

摘要:

脚本事件预测的目的是预测给定上下文的后续事件。这需要能够推断事件之间的相关性。最近的工作试图通过使用预训练的语言模型并结合外部知识来改进事件相关性推理(例如,话语关系)。虽然取得了可喜的成果,但仍然存在一些挑战。首先,目前的作品所采用的预训练语言模型忽略了事件级知识,导致无法很好地捕捉事件之间的相关性。第二,用话语关系建模事件之间的关联是有限的,因为它只能捕捉事件与话语标记之间的显式关联,而不能捕捉许多隐式关联。为此,我们提出了一种新的生成方法,在这个任务中,一个预训练的语言模型是微调与事件为中心的预训练目标,并预测生成范式内的下一个事件。具体而言,我们首先引入一种新的事件级空白填充策略作为学习目标,将事件级知识注入到预训练的语言模型中,然后设计一种基于似然的对比损失来微调生成模型。我们不使用额外的预测层,而是通过使用生成模型生成的序列似然来执行预测。我们的方法在没有任何外部知识的情况下以软方式对事件之间的相关性进行建模。基于可能性的预测消除了使用额外网络进行预测的需要,并且由于它对事件中的每个单词进行评分,因此在某种程度上是可解释的。在多项选择叙事性完形填空(MCNC)任务上的实验结果表明,我们的方法取得了比其他最先进的基线更好的结果。我们的代码将在https://github.com/zhufq00/mcnc上提供。

英文摘要:

Script event prediction aims to predict the subsequent event given the context. This requires the capability to infer the correlations between events. Recent works have attempted to improve event correlation reasoning by using pretrained language models and incorporating external knowledge~(e.g., discourse relations). Though promising results have been achieved, some challenges still remain. First, the pretrained language models adopted by current works ignore event-level knowledge, resulting in an inability to capture the correlations between events well. Second, modeling correlations between events with discourse relations is limited because it can only capture explicit correlations between events with discourse markers, and cannot capture many implicit correlations. To this end, we propose a novel generative approach for this task, in which a pretrained language model is fine-tuned with an event-centric pretraining objective and predicts the next event within a generative paradigm. Specifically, we first introduce a novel event-level blank infilling strategy as the learning objective to inject event-level knowledge into the pretrained language model, and then design a likelihood-based contrastive loss for fine-tuning the generative model. Instead of using an additional prediction layer, we perform prediction by using sequence likelihoods generated by the generative model. Our approach models correlations between events in a soft way without any external knowledge. The likelihood-based prediction eliminates the need to use additional networks to make predictions and is somewhat interpretable since it scores each word in the event. Experimental results on the multi-choice narrative cloze~(MCNC) task demonstrate that our approach achieves better results than other state-of-the-art baselines. Our code will be available at https://github.com/zhufq00/mcnc.

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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