尽管经过验证的大型变压器模型已被证明具有很高的能力解决自然语言任务,但处理长序列输入仍然是一个重大挑战。这样的任务之一就是长输入摘要,其中输入比大多数预验证的模型的最大输入上下文更长。通过一系列广泛的实验,我们研究了哪些模型架构变化和预处理范式可以最有效地适应经过预定的变压器以进行长输入摘要。我们发现,带有全局编码器代币的交错,块状变压器可以达到良好的性能和效率平衡,并且在长序列上有意义地改善了下游摘要性能。根据我们的发现,我们介绍了Pegasus-X,这是Pegasus模型的扩展,并具有额外的长输入预处理,以处理最多16K令牌的输入。 Pegasus-X在长输入摘要任务上实现了强劲的性能,与更大的模型相当,同时添加了很少的其他参数,并且不需要模型并行训练。
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我们提出了一项实证研究,以适应现有的经过验证的文本对文本模型,以备长期输入。通过沿预训练管道的三个轴的全面研究 - 模型架构,优化目标和训练式语料库,我们提出了一种有效的食谱,以从现有的短篇小说模型中构建长篇小说模型。具体而言,我们用汇总仪的块关注替换了变压器中的全部注意力,并使用蒙版的跨度预测任务为模型预算,长度不同。就训练训练的语料库而言,我们发现,与使用通常在其域覆盖范围中通常受到限制的现有长文档语料库相比,使用大型开放域语料库的随机串联的短篇小说可以提高性能。通过这些发现,我们建立了一个长篇文本模型,该模型可以在长篇文本质量检查任务上实现竞争性能,并在五个长文本摘要数据集上建立新的最新技术,通常优于先前的方法,具有较大的模型大小。
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最近的工作表明,(1)增加输入长度或(2)增加模型大小可以提高基于变压器的神经模型的性能。在本文中,我们提出了一个名为Longt5的新模型,我们探讨了同时缩放输入长度和模型大小的效果。具体而言,我们综合了从长输入变压器(ETC)的关注思路,并采用了从摘要预训练(PEGASU)的预训练策略进入可扩展的T5架构。结果是我们称之为{\ EM瞬态全球}(TGLOBAL)的新关注机制,这些机制是模仿等本地/全球注意力机制,但不需要额外的侧面输入。我们能够实现最先进的结果,以若干摘要任务,优于问题应答任务的原始T5模型。
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基于变压器的预审前的语言模型(LMS)在自然语言的理解中无处不在,但由于其二次复杂性,无法应用于故事,科学文章和长文档等长序列。尽管已经提出了无数有效的变压器变体,但它们通常是基于需要从头开始的昂贵预处理的自定义实现。在这项工作中,我们提出了雪橇:滑动编码器和解码器,这是一种处理长序列的简单方法,可以重新使用和利用经过战斗测试的短文本预处理的LMS。具体而言,我们将输入分配到重叠的块中,用短文本LM编码器编码每个块,然后使用预审计的解码器将信息融合到跨块(Fusion-In-In-In-In-indecoder)之间。我们通过受控实验说明,雪橇提供了一种可行的策略,可以长期理解并评估我们在卷轴上的方法,这是一个基准,该基准在各种语言理解任务中具有七个数据集。我们发现,雪橇与高达50倍的专业型号具有竞争力,并且需要专用且昂贵的预处理步骤。
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The task of automatic text summarization produces a concise and fluent text summary while preserving key information and overall meaning. Recent approaches to document-level summarization have seen significant improvements in recent years by using models based on the Transformer architecture. However, the quadratic memory and time complexities with respect to the sequence length make them very expensive to use, especially with long sequences, as required by document-level summarization. Our work addresses the problem of document-level summarization by studying how efficient Transformer techniques can be used to improve the automatic summarization of very long texts. In particular, we will use the arXiv dataset, consisting of several scientific papers and the corresponding abstracts, as baselines for this work. Then, we propose a novel retrieval-enhanced approach based on the architecture which reduces the cost of generating a summary of the entire document by processing smaller chunks. The results were below the baselines but suggest a more efficient memory a consumption and truthfulness.
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以查询为中心的摘要(QFS)旨在产生应答感兴趣的特定问题的摘要,从而实现更大的用户控制和个性化。虽然最近发布的数据集如QMSUM或Aquamuse,促进QFS中的研究工作,但该领域缺乏对适用建模方法的广泛空间的全面研究。在本文中,考虑到两种普遍的方法,我们对QFS进行了系统探索,探讨了QFS:两阶段的采掘解决方案和端到端模型。在这些类别中,我们调查现有方法,并呈现了在QMSUM数据集上实现最先进的性能的两个模型扩展,其边缘高达3.38 Rouge-1,3.72 Rouge-2和3.28 Rouge-L。通过定量实验,我们突出了不同模型配置之间的权衡,并探讨了摘要任务之间的转移能力。代码和检查点公开可用:https://github.com/salesforce/query-focused-sum。
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诸如学术文章和商业报告之类的长期文件一直是详细说明重要问题和需要额外关注的复杂主题的标准格式。自动汇总系统可以有效地将长文档置于简短而简洁的文本中,以封装最重要的信息,从而在帮助读者的理解中很重要。最近,随着神经体系结构的出现,已经做出了重大的研究工作,以推动自动文本摘要系统,以及有关将这些系统扩展到长期文档领域的挑战的大量研究。在这项调查中,我们提供了有关长期文档摘要的研究的全面概述,以及其研究环境的三个主要组成部分的系统评估:基准数据集,汇总模型和评估指标。对于每个组成部分,我们在长期汇总的背景下组织文献,并进行经验分析,以扩大有关当前研究进度的观点。实证分析包括一项研究基准数据集的内在特征,摘要模型的多维分析以及摘要评估指标的综述。根据总体发现,我们通过提出可能在这个快速增长的领域中提出未来探索的方向来得出结论。
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在这项工作中,我们通过傅里叶变换(FNET)广泛地重新设计了新引入的令牌混合方法,以更换一个长文件摘要任务(> 512令牌)的完整变压器实现中的计算昂贵的自我关注机制。作为基线,我们还使用能够处理超过8000令牌的冗长的诸如冗长的方法和大型鸟类变压器模型进行了长期文件摘要,并且目前是这些类型问题的现有方法的状态。原始FNET纸张在编码器中实现了这一点,而抽象总结需要编码器和解码器。由于这种预磨削的变压器模型目前没有在公共领域中存在,我们决定基于该傅立叶令牌混合方法实现一个完整的变压器,在编码器/解码器架构中,我们从语料库中的单个单词开始培训我们接受培训。我们调查了许多不同的扩展到原始FNET架构,并在摘要任务上评估它们的胭脂F1-Score性能。所有修改都显示出摘要任务的更好性能,而不是在变压器架构中使用原始FNET编码器时的性能。
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查询聚焦的文本摘要(QFTS)任务旨在构建基于给定查询的文本文档摘要的构建系统。解决此任务的关键挑战是缺乏培训摘要模型的大量标记数据。在本文中,我们通过探索一系列域适应技术来解决这一挑战。鉴于最近在广泛的自然语言处理任务中进行预先接受的变压器模型的成功,我们利用此类模型为单文档和多文件方案的QFTS任务产生抽象摘要。对于域适应,我们使用预先训练的变压器的摘要模型应用了各种技术,包括转移学习,弱监督学习和远程监督。六个数据集的广泛实验表明,我们所提出的方法非常有效地为QFTS任务产生抽象摘要,同时在一组自动和人类评估指标上设置新的最先进的结果。
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Transfer learning, where a model is first pre-trained on a data-rich task before being finetuned on a downstream task, has emerged as a powerful technique in natural language processing (NLP). The effectiveness of transfer learning has given rise to a diversity of approaches, methodology, and practice. In this paper, we explore the landscape of transfer learning techniques for NLP by introducing a unified framework that converts all text-based language problems into a text-to-text format. Our systematic study compares pre-training objectives, architectures, unlabeled data sets, transfer approaches, and other factors on dozens of language understanding tasks. By combining the insights from our exploration with scale and our new "Colossal Clean Crawled Corpus", we achieve state-of-the-art results on many benchmarks covering summarization, question answering, text classification, and more. To facilitate future work on transfer learning for NLP, we release our data set, pre-trained models, and code.
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In long document controllable summarization, where labeled data is scarce, pretrained models struggle to adapt to the task and effectively respond to user queries. In this paper, we introduce Socratic pretraining, a question-driven, unsupervised pretraining objective specifically designed to improve controllability in summarization tasks. By training a model to generate and answer relevant questions in a given context, Socratic pretraining enables the model to more effectively adhere to user-provided queries and identify relevant content to be summarized. We demonstrate the effectiveness of this approach through extensive experimentation on two summarization domains, short stories and dialogue, and multiple control strategies: keywords, questions, and factoid QA pairs. Our pretraining method relies only on unlabeled documents and a question generation system and outperforms pre-finetuning approaches that use additional supervised data. Furthermore, our results show that Socratic pretraining cuts task-specific labeled data requirements in half, is more faithful to user-provided queries, and achieves state-of-the-art performance on QMSum and SQuALITY.
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当前有效的微调方法(例如,适配器,前缀调整等)通过培训一小组神经语言模型的额外参数进行优化的条件文本生成,同时冻结其余效率。虽然在某些一代任务中显示出强大表现,但它们不会概括所有一代任务。在这项工作中,我们表明可以提高基于迅速的条件文本生成,简单而有效的方法模拟了人类书面文本的话语结构建模。我们介绍了两个关键设计选择:首先,我们表明人写文本的更高级别的话语结构可以用前缀参数上的\ Textit {分层阻塞}建模,使得能够跨越输入和输出文本的不同部分,并产生更长度的输出几代人。其次,我们通过在网络上的不同层的前缀参数上引入\ texit {注意稀疏性}来提出稀疏的前缀调整,并分别学习SoftMax函数上的稀疏变换。我们发现稀疏的注意力使前缀调整能够更好地控制输入内容(突出事实),从而更有效地调整前缀参数。在各种文本生成任务上的实验表明,前缀参数的结构化设计可以实现可比的结果,以微调所有参数,同时即使在低资源设置中也表现出所有生成任务的标准前缀调整。
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本文介绍了Z-Code ++,这是一种针对抽象文本摘要优化的新的预训练的语言模型。该模型使用三种技术扩展了艺术编码器模型的状态。首先,我们使用两阶段的预训练过程来改善模型在低资源摘要任务上的性能。该模型首先是使用文本语料库进行语言理解的预先培训的,然后在汇总语料库中不断预先培训,以进行基础文本生成。其次,我们用分离的注意力层代替编码器中的自我发项层,其中每个单词都使用两个向量分别代表其内容和位置。第三,我们使用融合编码器,这是一种以层次方式编码长序列的简单而有效的方法。 Z-Code ++在13个文本摘要任务中的9个跨5种语言中创建了新的艺术状态。我们的模型的参数有效,因为它的表现优于XSUM上600倍较大的Palm-540b,并且在Samsum上的易经的200倍GPT3-175B较大。在零射击和少量设置中,我们的模型大大优于竞争模型。
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Transformers-based models, such as BERT, have been one of the most successful deep learning models for NLP. Unfortunately, one of their core limitations is the quadratic dependency (mainly in terms of memory) on the sequence length due to their full attention mechanism. To remedy this, we propose, BIGBIRD, a sparse attention mechanism that reduces this quadratic dependency to linear. We show that BIGBIRD is a universal approximator of sequence functions and is Turing complete, thereby preserving these properties of the quadratic, full attention model. Along the way, our theoretical analysis reveals some of the benefits of having O(1) global tokens (such as CLS), that attend to the entire sequence as part of the sparse attention mechanism. The proposed sparse attention can handle sequences of length up to 8x of what was previously possible using similar hardware. As a consequence of the capability to handle longer context, BIGBIRD drastically improves performance on various NLP tasks such as question answering and summarization. We also propose novel applications to genomics data.
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We present BART, a denoising autoencoder for pretraining sequence-to-sequence models. BART is trained by ( 1) corrupting text with an arbitrary noising function, and (2) learning a model to reconstruct the original text. It uses a standard Tranformer-based neural machine translation architecture which, despite its simplicity, can be seen as generalizing BERT (due to the bidirectional encoder), GPT (with the left-to-right decoder), and many other more recent pretraining schemes. We evaluate a number of noising approaches, finding the best performance by both randomly shuffling the order of the original sentences and using a novel in-filling scheme, where spans of text are replaced with a single mask token. BART is particularly effective when fine tuned for text generation but also works well for comprehension tasks. It matches the performance of RoBERTa with comparable training resources on GLUE and SQuAD, achieves new stateof-the-art results on a range of abstractive dialogue, question answering, and summarization tasks, with gains of up to 6 ROUGE. BART also provides a 1.1 BLEU increase over a back-translation system for machine translation, with only target language pretraining. We also report ablation experiments that replicate other pretraining schemes within the BART framework, to better measure which factors most influence end-task performance.
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NLP基准在很大程度上主要集中在短篇文本上,例如句子和段落,即使长文本在野外占相当数量的自然语言。我们介绍卷轴,这是一套需要在长文本上推理的任务套件。我们检查现有的长文本数据集,文本自然是长期的,同时优先考虑涉及在输入上扫描信息的任务。滚动包含概述,问题应答和自然语言推理任务,包括多个域,包括文学,科学,业务和娱乐。初始基线(包括啰覆编码器),表明滚动有充足的改进空间。我们以统一的文本到文本格式提供所有数据集,并托管Live Refordboard,以促进模型架构和预用方法的研究。
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许多NLP任务需要处理超出预磨模模型的长度限制的长语境。为了将这些模型扩展到更长的文本序列,已经提出了许多有效的远程注意力变体。尽管沿着这个方向进行了丰富的研究,但仍然难以在实际用例中衡量这些模型的相对有效性,例如,如果我们在预先rain-yfetune范式之后应用这些模型。在这项工作中,我们的目标是对这些具有大规模和受控实验的这些新兴模型进行彻底的分析。对于每个关注变体,我们使用相同的长DOC语料库,然后使用相同的长DOC语料库,然后为现实世界的长情节任务进行芬特这些模型。我们的调查结果揭示了现有广泛使用的远程基准的陷阱,并显示任何经过测试的高效关注可以在标准预介质范式下击败一个简单的本地窗口关注。对本地注意力变化的进一步分析表明,即使是常用的注意力窗口重叠也没有必要实现良好的下游结果 - 使用不相交的本地关注,我们能够构建符合性能的更简单且更高效的Long-Doc QA模型霍尔福勒〜\ citep {longformer}其预先花费的一半。
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Transformer models have achieved superior performance in various natural language processing tasks. However, the quadratic computational cost of the attention mechanism limits its practicality for long sequences. There are existing attention variants that improve the computational efficiency, but they have limited ability to effectively compute global information. In parallel to Transformer models, state space models (SSMs) are tailored for long sequences, but they are not flexible enough to capture complicated local information. We propose SPADE, short for $\underline{\textbf{S}}$tate s$\underline{\textbf{P}}$ace $\underline{\textbf{A}}$ugmente$\underline{\textbf{D}}$ Transform$\underline{\textbf{E}}$r. Specifically, we augment a SSM into the bottom layer of SPADE, and we employ efficient local attention methods for the other layers. The SSM augments global information, which complements the lack of long-range dependency issue in local attention methods. Experimental results on the Long Range Arena benchmark and language modeling tasks demonstrate the effectiveness of the proposed method. To further demonstrate the scalability of SPADE, we pre-train large encoder-decoder models and present fine-tuning results on natural language understanding and natural language generation tasks.
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变压器编码器模型在对话建模中显示出令人印象深刻的性能。但是,由于变压器在处理长序列方面效率低下,对话历史的长度通常需要被截断。为了解决此问题,我们提出了一种新的内存启动变压器,该变压器与现有的预训练编码器模型兼容,并可以有效地保存历史记录信息。它将单独的内存模块与预训练的变压器一起结合在一起,以在内存状态和当前输入上下文之间有效互换信息。我们在三个对话数据集和两个语言建模数据集上评估我们的模型。实验结果表明,与其他预训练的变压器基线相比,我们的方法已经达到了较高的效率和性能。
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Bidirectional Encoder Representations from Transformers (BERT; Devlin et al. 2019) represents the latest incarnation of pretrained language models which have recently advanced a wide range of natural language processing tasks. In this paper, we showcase how BERT can be usefully applied in text summarization and propose a general framework for both extractive and abstractive models. We introduce a novel document-level encoder based on BERT which is able to express the semantics of a document and obtain representations for its sentences. Our extractive model is built on top of this encoder by stacking several intersentence Transformer layers. For abstractive summarization, we propose a new fine-tuning schedule which adopts different optimizers for the encoder and the decoder as a means of alleviating the mismatch between the two (the former is pretrained while the latter is not). We also demonstrate that a two-staged fine-tuning approach can further boost the quality of the generated summaries. Experiments on three datasets show that our model achieves stateof-the-art results across the board in both extractive and abstractive settings. 1
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