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arXiv 2310.04408cs.CL

RECOMP:通过压缩与选择性增强改进检索增强语言模型

RECOMP: Improving Retrieval-Augmented LMs with Compression and Selective Augmentation

The University of Texas at Austin(德克萨斯大学奥斯汀分校);University of Washington(华盛顿大学)

Fangyuan Xu, Weijia Shi, Eunsol Choi

AI总结:

针对检索增强语言模型推理成本高、长文档信息筛选难的问题,提出RECOMP框架,通过抽取式/生成式压缩器压缩检索文档并实现选择性增强,在低压缩率下保持性能且可跨模型迁移。

摘要:

在推理时检索文档并将其作为上下文前置输入,能够提升语言模型(LMs)在各类任务上的性能。但这些文档通常长达数百词,会大幅增加推理成本。我们提出先将检索到的文档压缩为文本摘要,再融入上下文的方案。该方法不仅能降低计算成本,还能减轻语言模型从长检索文档中识别相关信息的负担。\n我们提出两种压缩器:抽取式压缩器从检索文档中选取有用句子,生成式压缩器通过综合多篇文档的信息生成摘要。两种压缩器的训练目标均为:将生成的摘要前置到语言模型输入时,提升模型在下游任务上的性能,同时保持摘要简洁。若检索文档与输入无关,或无法为语言模型提供额外信息,我们的压缩器可返回空字符串,实现选择性增强。\n我们在语言建模任务和开放域问答任务上评估了该方法。在两项任务中,我们实现了低至6%的压缩率,且性能损失极小,显著优于现有的通用摘要模型。实验表明,针对某一语言模型训练的压缩器可迁移至语言建模任务中的其他语言模型,且生成的摘要与检索文档高度一致。

英文摘要:

Retrieving documents and prepending them in-context at inference time improves performance of language model (LMs) on a wide range of tasks. However, these documents, often spanning hundreds of words, make inference substantially more expensive. We propose compressing the retrieved documents into textual summaries prior to in-context integration. This not only reduces the computational costs but also relieves the burden of LMs to identify relevant information in long retrieved documents. We present two compressors -- an extractive compressor which selects useful sentences from retrieved documents and an abstractive compressor which generates summaries by synthesizing information from multiple documents. Both compressors are trained to improve LMs' performance on end tasks when the generated summaries are prepended to the LMs' input, while keeping the summary concise.If the retrieved documents are irrelevant to the input or offer no additional information to LM, our compressor can return an empty string, implementing selective augmentation.We evaluate our approach on language modeling task and open domain question answering task. We achieve a compression rate of as low as 6% with minimal loss in performance for both tasks, significantly outperforming the off-the-shelf summarization models. We show that our compressors trained for one LM can transfer to other LMs on the language modeling task and provide summaries largely faithful to the retrieved documents.

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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