Dou Zhicheng
2023
Learning on Structured Documents for Conditional Question Answering
Wang Zihan
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Qian Hongjin
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Dou Zhicheng
Proceedings of the 22nd Chinese National Conference on Computational Linguistics
“Conditional question answering (CQA) is an important task in natural language processing thatinvolves answering questions that depend on specific conditions. CQA is crucial for domainsthat require the provision of personalized advice or making context-dependent analyses, such aslegal consulting and medical diagnosis. However, existing CQA models struggle with generatingmultiple conditional answers due to two main challenges: (1) the lack of supervised training datawith diverse conditions and corresponding answers, and (2) the difficulty to output in a complexformat that involves multiple conditions and answers. To address the challenge of limited super-vision, we propose LSD (Learning on Structured Documents), a self-supervised learning methodon structured documents for CQA. LSD involves a conditional problem generation method anda contrastive learning objective. The model is trained with LSD on massive unlabeled structureddocuments and is fine-tuned on labeled CQA dataset afterwards. To overcome the limitation ofoutputting answers with complex formats in CQA, we propose a pipeline that enables the gen-eration of multiple answers and conditions. Experimental results on the ConditionalQA datasetdemonstrate that LSD outperforms previous CQA models in terms of accuracy both in providinganswers and conditions.”
Case Retrieval for Legal Judgment Prediction in Legal Artificial Intelligence
Zhang Han
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Dou Zhicheng
Proceedings of the 22nd Chinese National Conference on Computational Linguistics
“Legal judgment prediction (LJP) is a basic task in legal artificial intelligence. It consists ofthree subtasks, which are relevant law article prediction, charge prediction and term of penaltyprediction, and gives the judgment results to assist the work of judges. In recent years, many deeplearning methods have emerged to improve the performance of the legal judgment prediction task. The previous methods mainly improve the performance by integrating law articles and the factdescription of a legal case. However, they rarely consider that the judges usually look up historicalcases before making a judgment in the actual scenario. To simulate this scenario, we propose ahistorical case retrieval framework for the legal judgment prediction task. Specifically, we selectsome historical cases which include all categories from the training dataset. Then, we retrieve themost similar Top-k historical cases of the current legal case and use the vector representation ofthese Top-k historical cases to help predict the judgment results. On two real-world legal datasets,our model achieves better results than several state-of-the-art baseline models.”
2021
Few-Shot Charge Prediction with Multi-Grained Features and MutualInformation
Zhang Han
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Zhu Yutao
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Dou Zhicheng
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Wen Ji-Rong
Proceedings of the 20th Chinese National Conference on Computational Linguistics
Charge prediction aims to predict the final charge for a case according to its fact descriptionand plays an important role in legal assistance systems. With deep learning based methods prediction on high-frequency charges has achieved promising results but that on few-shot chargesis still challenging. In this work we propose a framework with multi-grained features and mutual information for few-shot charge prediction. Specifically we extract coarse- and fine-grained features to enhance the model’s capability on representation based on which the few-shot chargescan be better distinguished. Furthermore we propose a loss function based on mutual information. This loss function leverages the prior distribution of the charges to tune their weights so the few-shot charges can contribute more on model optimization. Experimental results on several datasets demonstrate the effectiveness and robustness of our method. Besides our method can work wellon tiny datasets and has better efficiency in the training which provides better applicability in realscenarios.