大型文本语料库培训的基于变压器的语言模型在自然语言处理社区中享有巨大的普及,并且通常用作下游任务的起点。虽然这些模型是不可否认的,但这是一种挑战,以量化超出传统准确度指标的性能。在本文中,我们通过在培训过程的顺序阶段的获取知识快照来比较基于BERT的语言模型。可以通过查询具有探测任务的屏蔽语言模型来发现来自培训语料库的结构化关系。我们提出了一种通过在罗伯塔早期训练的各个阶段的CLOZE“填空”陈述中产生知识图表提取物来揭示知识收集时间表的方法。我们将该分析扩展到BERT模型(Distilbert,Bert-Base,Roberta)的预磨损变体进行比较。这项工作提出了通过知识图提取(GED,Graph2VEC)来比较语言模型的定量框架,并且展示了语音分析(波动)以确定每个模型变体的语言强度。使用这些指标,机器学习从业者可以比较模型,诊断其模型的行为优势和劣势,并确定新的目标数据集以提高模型性能。
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Recent progress in pretraining language models on large textual corpora led to a surge of improvements for downstream NLP tasks. Whilst learning linguistic knowledge, these models may also be storing relational knowledge present in the training data, and may be able to answer queries structured as "fillin-the-blank" cloze statements. Language models have many advantages over structured knowledge bases: they require no schema engineering, allow practitioners to query about an open class of relations, are easy to extend to more data, and require no human supervision to train. We present an in-depth analysis of the relational knowledge already present (without fine-tuning) in a wide range of state-of-theart pretrained language models. We find that (i) without fine-tuning, BERT contains relational knowledge competitive with traditional NLP methods that have some access to oracle knowledge, (ii) BERT also does remarkably well on open-domain question answering against a supervised baseline, and (iii) certain types of factual knowledge are learned much more readily than others by standard language model pretraining approaches. The surprisingly strong ability of these models to recall factual knowledge without any fine-tuning demonstrates their potential as unsupervised open-domain QA systems. The code to reproduce our analysis is available at https: //github.com/facebookresearch/LAMA.
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Transformer-based models have pushed state of the art in many areas of NLP, but our understanding of what is behind their success is still limited. This paper is the first survey of over 150 studies of the popular BERT model. We review the current state of knowledge about how BERT works, what kind of information it learns and how it is represented, common modifications to its training objectives and architecture, the overparameterization issue and approaches to compression. We then outline directions for future research.
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大型基于变压器的预训练的语言模型在各种知识密集的任务上取得了令人印象深刻的表现,并可以在其参数中捕获事实知识。我们认为,考虑到不断增长的知识和资源需求,在模型参数中存储大量知识是亚最佳选择。我们认为,更有效的替代方法是向模型提供对上下文相关的结构化知识的明确访问,并训练它以使用该知识。我们提出了LM核 - 实现这一目标的一般框架 - 允许从外部知识源对语言模型培训的\ textit {解耦},并允许后者更新而不会影响已经训练的模型。实验结果表明,LM核心获得外部知识,在知识探索任务上的最先进的知识增强语言模型中实现了重要而强大的优于性能。可以有效处理知识更新;并在两个下游任务上表现良好。我们还提出了一个彻底的错误分析,突出了LM核的成功和失败。
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自然语言处理(NLP)是一个人工智能领域,它应用信息技术来处理人类语言,在一定程度上理解并在各种应用中使用它。在过去的几年中,该领域已经迅速发展,现在采用了深层神经网络的现代变体来从大型文本语料库中提取相关模式。这项工作的主要目的是调查NLP在药理学领域的最新使用。正如我们的工作所表明的那样,NLP是药理学高度相关的信息提取和处理方法。它已被广泛使用,从智能搜索到成千上万的医疗文件到在社交媒体中找到对抗性药物相互作用的痕迹。我们将覆盖范围分为五个类别,以调查现代NLP方法论,常见的任务,相关的文本数据,知识库和有用的编程库。我们将这五个类别分为适当的子类别,描述其主要属性和想法,并以表格形式进行总结。最终的调查介绍了该领域的全面概述,对从业者和感兴趣的观察者有用。
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语言模型(LMS)已被证明在各种下游应用程序中很有用,例如摘要,翻译,问答和文本分类。由于它们可以存储的大量信息,LMS正在成为人工智能中越来越重要的工具。在这项工作中,我们提出了道具(提示为探测),该道具利用GPT-3(最初由OpenAI在2020年提出的大型语言模型)来执行知识基础构建任务(KBC)。 Prop实施了一种多步骤方法,该方法结合了各种提示技术来实现这一目标。我们的结果表明,手动提示策划是必不可少的,必须鼓励LM给出可变长度的答案集,特别是包括空的答案集,True/False问题是提高LM生成的建议精度的有用设备。 LM的大小是至关重要的因素,并且实体字典别名提高了LM评分。我们的评估研究表明,这些提出的技术可以大大提高最终预测的质量:Prop赢得了LM-KBC竞争的轨道2,表现优于基线36.4个百分点。我们的实施可在https://github.com/hemile/iswc-challenge上获得。
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基于变压器的语言模型最近在许多自然语言任务中取得了显着的结果。但是,通常通过利用大量培训数据来实现排行榜的性能,并且很少通过将明确的语言知识编码为神经模型。这使许多人质疑语言学对现代自然语言处理的相关性。在本文中,我介绍了几个案例研究,以说明理论语言学和神经语言模型仍然相互关联。首先,语言模型通过提供一个客观的工具来测量语义距离,这对语言学家很有用,语义距离很难使用传统方法。另一方面,语言理论通过提供框架和数据源来探究我们的语言模型,以了解语言理解的特定方面,从而有助于语言建模研究。本论文贡献了三项研究,探讨了语言模型中语法 - 听觉界面的不同方面。在论文的第一部分中,我将语言模型应用于单词类灵活性的问题。我将Mbert作为语义距离测量的来源,我提供了有利于将单词类灵活性分析为方向过程的证据。在论文的第二部分中,我提出了一种方法来测量语言模型中间层的惊奇方法。我的实验表明,包含形态句法异常的句子触发了语言模型早期的惊喜,而不是语义和常识异常。最后,在论文的第三部分中,我适应了一些心理语言学研究,以表明语言模型包含了论证结构结构的知识。总而言之,我的论文在自然语言处理,语言理论和心理语言学之间建立了新的联系,以为语言模型的解释提供新的观点。
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在NLP社区中有一个正在进行的辩论,无论现代语言模型是否包含语言知识,通过所谓的探针恢复。在本文中,我们研究了语言知识是否是现代语言模型良好表现的必要条件,我们称之为\ Texit {重新发现假设}。首先,我们展示了语言模型,这是显着压缩的,但在预先磨普目标上表现良好,以便在语言结构探讨时保持良好的分数。这一结果支持重新发现的假设,并导致我们的论文的第二款贡献:一个信息 - 理论框架,与语言建模目标相关。该框架还提供了测量语言信息对字词预测任务的影响的度量标准。我们通过英语综合和真正的NLP任务加固我们的分析结果。
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Natural Language Processing (NLP) has been revolutionized by the use of Pre-trained Language Models (PLMs) such as BERT. Despite setting new records in nearly every NLP task, PLMs still face a number of challenges including poor interpretability, weak reasoning capability, and the need for a lot of expensive annotated data when applied to downstream tasks. By integrating external knowledge into PLMs, \textit{\underline{K}nowledge-\underline{E}nhanced \underline{P}re-trained \underline{L}anguage \underline{M}odels} (KEPLMs) have the potential to overcome the above-mentioned limitations. In this paper, we examine KEPLMs systematically through a series of studies. Specifically, we outline the common types and different formats of knowledge to be integrated into KEPLMs, detail the existing methods for building and evaluating KEPLMS, present the applications of KEPLMs in downstream tasks, and discuss the future research directions. Researchers will benefit from this survey by gaining a quick and comprehensive overview of the latest developments in this field.
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Contextual word representations derived from large-scale neural language models are successful across a diverse set of NLP tasks, suggesting that they encode useful and transferable features of language. To shed light on the linguistic knowledge they capture, we study the representations produced by several recent pretrained contextualizers (variants of ELMo, the OpenAI transformer language model, and BERT) with a suite of seventeen diverse probing tasks. We find that linear models trained on top of frozen contextual representations are competitive with state-of-the-art task-specific models in many cases, but fail on tasks requiring fine-grained linguistic knowledge (e.g., conjunct identification). To investigate the transferability of contextual word representations, we quantify differences in the transferability of individual layers within contextualizers, especially between recurrent neural networks (RNNs) and transformers. For instance, higher layers of RNNs are more taskspecific, while transformer layers do not exhibit the same monotonic trend. In addition, to better understand what makes contextual word representations transferable, we compare language model pretraining with eleven supervised pretraining tasks. For any given task, pretraining on a closely related task yields better performance than language model pretraining (which is better on average) when the pretraining dataset is fixed. However, language model pretraining on more data gives the best results.
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The remarkable success of pretrained language models has motivated the study of what kinds of knowledge these models learn during pretraining. Reformulating tasks as fillin-the-blanks problems (e.g., cloze tests) is a natural approach for gauging such knowledge, however, its usage is limited by the manual effort and guesswork required to write suitable prompts. To address this, we develop AUTOPROMPT, an automated method to create prompts for a diverse set of tasks, based on a gradient-guided search. Using AUTO-PROMPT, we show that masked language models (MLMs) have an inherent capability to perform sentiment analysis and natural language inference without additional parameters or finetuning, sometimes achieving performance on par with recent state-of-the-art supervised models. We also show that our prompts elicit more accurate factual knowledge from MLMs than the manually created prompts on the LAMA benchmark, and that MLMs can be used as relation extractors more effectively than supervised relation extraction models. These results demonstrate that automatically generated prompts are a viable parameter-free alternative to existing probing methods, and as pretrained LMs become more sophisticated and capable, potentially a replacement for finetuning.
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关系提取(RE)是自然语言处理的基本任务。RE试图通过识别文本中的实体对之间的关系信息来将原始的,非结构化的文本转变为结构化知识。RE有许多用途,例如知识图完成,文本摘要,提问和搜索查询。RE方法的历史可以分为四个阶段:基于模式的RE,基于统计的RE,基于神经的RE和大型语言模型的RE。这项调查始于对RE的早期阶段的一些示例性作品的概述,突出了局限性和缺点,以使进度相关。接下来,我们回顾流行的基准测试,并严格检查用于评估RE性能的指标。然后,我们讨论遥远的监督,这是塑造现代RE方法发展的范式。最后,我们回顾了重点是降级和培训方法的最新工作。
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与伯特(Bert)等语言模型相比,已证明知识增强语言表示的预培训模型在知识基础构建任务(即〜关系提取)中更有效。这些知识增强的语言模型将知识纳入预训练中,以生成实体或关系的表示。但是,现有方法通常用单独的嵌入表示每个实体。结果,这些方法难以代表播出的实体和大量参数,在其基础代币模型之上(即〜变压器),必须使用,并且可以处理的实体数量为由于内存限制,实践限制。此外,现有模型仍然难以同时代表实体和关系。为了解决这些问题,我们提出了一个新的预培训模型,该模型分别从图书中学习实体和关系的表示形式,并分别在文本中跨越跨度。通过使用SPAN模块有效地编码跨度,我们的模型可以代表实体及其关系,但所需的参数比现有模型更少。我们通过从Wikipedia中提取的知识图对我们的模型进行了预训练,并在广泛的监督和无监督的信息提取任务上进行了测试。结果表明,我们的模型比基线学习对实体和关系的表现更好,而在监督的设置中,微调我们的模型始终优于罗伯塔,并在信息提取任务上取得了竞争成果。
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自动问题应答(QA)系统的目的是以时间有效的方式向用户查询提供答案。通常在数据库(或知识库)或通常被称为语料库的文件集合中找到答案。在过去的几十年里,收购知识的扩散,因此生物医学领域的新科学文章一直是指数增长。因此,即使对于领域专家,也难以跟踪域中的所有信息。随着商业搜索引擎的改进,用户可以在某些情况下键入其查询并获得最相关的一小组文档,以及在某些情况下从文档中的相关片段。但是,手动查找所需信息或答案可能仍然令人疑惑和耗时。这需要开发高效的QA系统,该系统旨在为用户提供精确和精确的答案提供了生物医学领域的自然语言问题。在本文中,我们介绍了用于开发普通域QA系统的基本方法,然后彻底调查生物医学QA系统的不同方面,包括使用结构化数据库和文本集合的基准数据集和几种提出的方​​法。我们还探讨了当前系统的局限性,并探索潜在的途径以获得进一步的进步。
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We introduce a linguistically enhanced combination of pre-training methods for transformers. The pre-training objectives include POS-tagging, synset prediction based on semantic knowledge graphs, and parent prediction based on dependency parse trees. Our approach achieves competitive results on the Natural Language Inference task, compared to the state of the art. Specifically for smaller models, the method results in a significant performance boost, emphasizing the fact that intelligent pre-training can make up for fewer parameters and help building more efficient models. Combining POS-tagging and synset prediction yields the overall best results.
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Wikidata是一个经常更新,社区驱动和多语言知识图形。因此,Wikidata是实体联系的一个有吸引力的基础,这是最近发表论文的增加显而易见的。该调查侧重于四个主题:(1)存在哪些Wikidata实体链接数据集,它们是多么广泛使用,它们是如何构建的? (2)对实体联系数据集的设计进行Wikidata的特点,如果是的话,怎么样? (3)当前实体链接方法如何利用Wikidata的特定特征? (4)现有实体链接方法未开发哪种Wikidata特征?本次调查显示,当前的Wikidata特定实体链接数据集在其他知识图表中的方案中的注释方案中没有不同。因此,没有提升多语言和时间依赖数据集的可能性,是自然适合维基帽的数据集。此外,我们表明大多数实体链接方法使用Wikidata以与任何其他知识图相同的方式,因为任何其他知识图都缺少了利用Wikidata特定特征来提高质量的机会。几乎所有方法都使用标签等特定属性,有时是描述,而是忽略超关系结构等特征。因此,例如,通过包括超关系图嵌入或类型信息,仍有改进的余地。许多方法还包括来自维基百科的信息,这些信息很容易与Wikidata组合并提供有价值的文本信息,Wikidata缺乏。
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在本文中,我们专注于研究中国问题匹配的鲁棒性评估。以前的大多数关于分析鲁棒性问题的工作专注于只有一种或几种类型的人工对抗例。相反,我们认为有必要制定关于自然文本模型语言能力的综合评估。为此目的,我们创建了一个中国数据集即duqm,其中包含具有语言扰动的自然问题,以评估问题匹配模型的鲁棒性。Duqm包含3个类别和13个子类别,具有32个语言扰动。广泛的实验表明,DUQM具有更好的区分不同模型的能力。重要的是,DuQM中语言现象评估的详细分类有助于我们轻松诊断不同模型的强度和弱点。此外,我们的实验结果表明,人工对抗实例的影响不适用于自然文本。
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Relation extraction (RE) is a sub-discipline of information extraction (IE) which focuses on the prediction of a relational predicate from a natural-language input unit (such as a sentence, a clause, or even a short paragraph consisting of multiple sentences and/or clauses). Together with named-entity recognition (NER) and disambiguation (NED), RE forms the basis for many advanced IE tasks such as knowledge-base (KB) population and verification. In this work, we explore how recent approaches for open information extraction (OpenIE) may help to improve the task of RE by encoding structured information about the sentences' principal units, such as subjects, objects, verbal phrases, and adverbials, into various forms of vectorized (and hence unstructured) representations of the sentences. Our main conjecture is that the decomposition of long and possibly convoluted sentences into multiple smaller clauses via OpenIE even helps to fine-tune context-sensitive language models such as BERT (and its plethora of variants) for RE. Our experiments over two annotated corpora, KnowledgeNet and FewRel, demonstrate the improved accuracy of our enriched models compared to existing RE approaches. Our best results reach 92% and 71% of F1 score for KnowledgeNet and FewRel, respectively, proving the effectiveness of our approach on competitive benchmarks.
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Large pre-trained neural networks such as BERT have had great recent success in NLP, motivating a growing body of research investigating what aspects of language they are able to learn from unlabeled data. Most recent analysis has focused on model outputs (e.g., language model surprisal) or internal vector representations (e.g., probing classifiers). Complementary to these works, we propose methods for analyzing the attention mechanisms of pre-trained models and apply them to BERT. BERT's attention heads exhibit patterns such as attending to delimiter tokens, specific positional offsets, or broadly attending over the whole sentence, with heads in the same layer often exhibiting similar behaviors. We further show that certain attention heads correspond well to linguistic notions of syntax and coreference. For example, we find heads that attend to the direct objects of verbs, determiners of nouns, objects of prepositions, and coreferent mentions with remarkably high accuracy. Lastly, we propose an attention-based probing classifier and use it to further demonstrate that substantial syntactic information is captured in BERT's attention. 1 Code will be released at https://github.com/ clarkkev/attention-analysis.2 We use the English base-sized model.
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学术知识图(KGS)提供了代表科学出版物编码的知识的丰富的结构化信息来源。随着出版的科学文学的庞大,包括描述科学概念的过多的非均匀实体和关系,这些公斤本质上是不完整的。我们呈现Exbert,一种利用预先训练的变压器语言模型来执行学术知识图形完成的方法。我们将知识图形的三元组模型为文本并执行三重分类(即,属于KG或不属于KG)。评估表明,在三重分类,链路预测和关系预测的任务中,Exbert在三个学术kg完成数据集中表现出其他基线。此外,我们将两个学术数据集作为研究界的资源,从公共公共公报和在线资源中收集。
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