Jiawei Chen


2023

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基于互信息最大化和对比损失的多模态对话情绪识别模型(Multimodal Emotion Recognition in Conversation with Mutual Information Maximization and Contrastive Loss)
Qianer Li (黎倩尔) | Peijie Huang (黄沛杰) | Jiawei Chen (陈佳炜) | Jialin Wu (吴嘉林) | Yuhong Xu (徐禹洪) | Peiyuan Lin (林丕源)
Proceedings of the 22nd Chinese National Conference on Computational Linguistics

“多模态的对话情绪识别(emotion recognition in conversation,ERC)是构建情感对话系统的关键。近年来基于图的融合方法在会话中动态聚合多模态上下文特征,提高了模型在多模态对话情绪识别方面的性能。然而,这些方法都没有充分保留和利用输入数据中的有价值的信息。具体地说,它们都没有保留从输入到融合结果的任务相关信息,并且忽略了标签本身蕴含的信息。本文提出了一种基于互信息最大化和对比损失的多模态对话情绪识别模型MMIC来解决上述的问题。模型通过在输入级和融合级上分级最大化模态之间的互信息(mutual information),使任务相关信息在融合过程中得以保存,从而生成更丰富的多模态表示。本文还在基于图的动态融合网络中引入了监督对比学习(supervised contrastive learning),通过充分利用标签蕴含的信息,使不同情绪相互排斥,增强了模型识别相似情绪的能力。在两个英文和一个中文的公共数据集上的大量实验证明了所提出模型的有效性和优越性。此外,在所提出模型上进行的案例探究有效地证实了模型可以有效保留任务相关信息,更好地区分出相似的情绪。消融实验和可视化结果证明了模型中每个模块的有效性。”

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Learning In-context Learning for Named Entity Recognition
Jiawei Chen | Yaojie Lu | Hongyu Lin | Jie Lou | Wei Jia | Dai Dai | Hua Wu | Boxi Cao | Xianpei Han | Le Sun
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Named entity recognition in real-world applications suffers from the diversity of entity types, the emergence of new entity types, and the lack of high-quality annotations. To address the above problems, this paper proposes an in-context learning-based NER approach, which can effectively inject in-context NER ability into PLMs and recognize entities of novel types on-the-fly using only a few demonstrative instances. Specifically, we model PLMs as a meta-function Lambda_instruction, demonstrations, text.M, and a new entity extractor can be implicitly constructed by applying new instruction and demonstrations to PLMs, i.e., (Lambda . M) (instruction, demonstrations) ->F where F will be a new entity extractor F: text -> entities. To inject the above in-context NER ability into PLMs, we propose a meta-function pre-training algorithm, which pre-trains PLMs by comparing the (instruction, demonstration)-initialized extractor with a surrogate golden extractor. Experimental results on 4 few-shot NER datasets show that our method can effectively inject in-context NER ability into PLMs and significantly outperforms the PLMs+fine-tuning counterparts.

2022

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Few-shot Named Entity Recognition with Self-describing Networks
Jiawei Chen | Qing Liu | Hongyu Lin | Xianpei Han | Le Sun
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Few-shot NER needs to effectively capture information from limited instances and transfer useful knowledge from external resources. In this paper, we propose a self-describing mechanism for few-shot NER, which can effectively leverage illustrative instances and precisely transfer knowledge from external resources by describing both entity types and mentions using a universal concept set. Specifically, we design Self-describing Networks (SDNet), a Seq2Seq generation model which can universally describe mentions using concepts, automatically map novel entity types to concepts, and adaptively recognize entities on-demand. We pre-train SDNet with large-scale corpus, and conduct experiments on 8 benchmarks from different domains. Experiments show that SDNet achieves competitive performances on all benchmarks and achieves the new state-of-the-art on 6 benchmarks, which demonstrates its effectiveness and robustness.

2021

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Honey or Poison? Solving the Trigger Curse in Few-shot Event Detection via Causal Intervention
Jiawei Chen | Hongyu Lin | Xianpei Han | Le Sun
Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing

Event detection has long been troubled by the trigger curse: overfitting the trigger will harm the generalization ability while underfitting it will hurt the detection performance. This problem is even more severe in few-shot scenario. In this paper, we identify and solve the trigger curse problem in few-shot event detection (FSED) from a causal view. By formulating FSED with a structural causal model (SCM), we found that the trigger is a confounder of the context and the result, which makes previous FSED methods much easier to overfit triggers. To resolve this problem, we propose to intervene on the context via backdoor adjustment during training. Experiments show that our method significantly improves the FSED on both ACE05 and MAVEN datasets.