Recurrent neural networks are deep learning topologies that can be trained to classify long documents. However, in our recent work, we found a critical problem with these cells: they can use the length differences between texts of different classes as a prominent classification feature. This has the effect of producing models that are brittle and fragile to concept drift, can provide misleading performances and are trivially explainable regardless of text content. This paper illustrates the problem using synthetic and real-world data and provides a simple solution using weight decay regularization.
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Classification algorithms using Transformer architectures can be affected by the sequence length learning problem whenever observations from different classes have a different length distribution. This problem brings models to use sequence length as a predictive feature instead of relying on important textual information. Even if most public datasets are not affected by this problem, privately corpora for fields such as medicine and insurance may carry this data bias. This poses challenges throughout the value chain given their usage in a machine learning application. In this paper, we empirically expose this problem and present approaches to minimize its impacts.
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Recurrent neural networks are a widely used class of neural architectures. They have, however, two shortcomings. First, they are often treated as black-box models and as such it is difficult to understand what exactly they learn as well as how they arrive at a particular prediction. Second, they tend to work poorly on sequences requiring long-term memorization, despite having this capacity in principle. We aim to address both shortcomings with a class of recurrent networks that use a stochastic state transition mechanism between cell applications. This mechanism, which we term state-regularization, makes RNNs transition between a finite set of learnable states. We evaluate state-regularized RNNs on (1) regular languages for the purpose of automata extraction; (2) non-regular languages such as balanced parentheses and palindromes where external memory is required; and (3) real-word sequence learning tasks for sentiment analysis, visual object recognition and text categorisation. We show that state-regularization (a) simplifies the extraction of finite state automata that display an RNN's state transition dynamic; (b) forces RNNs to operate more like automata with external memory and less like finite state machines, which potentiality leads to a more structural memory; (c) leads to better interpretability and explainability of RNNs by leveraging the probabilistic finite state transition mechanism over time steps.
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Transformers do not scale very well to long sequence lengths largely because of quadratic self-attention complexity. In the recent months, a wide spectrum of efficient, fast Transformers have been proposed to tackle this problem, more often than not claiming superior or comparable model quality to vanilla Transformer models. To this date, there is no well-established consensus on how to evaluate this class of models. Moreover, inconsistent benchmarking on a wide spectrum of tasks and datasets makes it difficult to assess relative model quality amongst many models. This paper proposes a systematic and unified benchmark, Long-Range Arena, specifically focused on evaluating model quality under long-context scenarios. Our benchmark is a suite of tasks consisting of sequences ranging from 1K to 16K tokens, encompassing a wide range of data types and modalities such as text, natural, synthetic images, and mathematical expressions requiring similarity, structural, and visual-spatial reasoning. We systematically evaluate ten well-established long-range Transformer models (Reformers, Linformers, Linear Transformers, Sinkhorn Transformers, Performers, Synthesizers, Sparse Transformers, and Longformers) on our newly proposed benchmark suite. Long-Range Arena paves the way towards better understanding this class of efficient Transformer models, facilitates more research in this direction, and presents new challenging tasks to tackle. Our benchmark code will be released at https://github.com/google-research/long-range-arena.
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In this study, we investigate the generalization of LSTM, ReLU and GRU models on counting tasks over long sequences. Previous theoretical work has established that RNNs with ReLU activation and LSTMs have the capacity for counting with suitable configuration, while GRUs have limitations that prevent correct counting over longer sequences. Despite this and some positive empirical results for LSTMs on Dyck-1 languages, our experimental results show that LSTMs fail to learn correct counting behavior for sequences that are significantly longer than in the training data. ReLUs show much larger variance in behavior and in most cases worse generalization. The long sequence generalization is empirically related to validation loss, but reliable long sequence generalization seems not practically achievable through backpropagation with current techniques. We demonstrate different failure modes for LSTMs, GRUs and ReLUs. In particular, we observe that the saturation of activation functions in LSTMs and the correct weight setting for ReLUs to generalize counting behavior are not achieved in standard training regimens. In summary, learning generalizable counting behavior is still an open problem and we discuss potential approaches for further research.
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从长序列中提取监督信号以进行预测是机器学习中的一项艰巨任务,尤其是当输入序列中的所有元素并非同等贡献所需的输出时。在本文中,我们提出了Spandrop,这是一种简单有效的数据增强技术,可帮助模型以很少的示例以很少的示例识别真实的监督信号。通过直接操纵输入序列,Spandrop一次随机消融序列的一部分,并要求模型执行相同的任务以模拟反事实学习并获得输入属性。基于对其属性的理论分析,我们还根据β-伯努利分布提出了spandrop的变体,该变体产生了不同的增强序列,同时提供了一个与原始数据集更一致的学习目标。我们证明了Spandrop在一系列精心设计的玩具任务中的有效性,以及各种自然语言处理任务,这些任务需要长时间的推理才能得出正确的答案,并证明它有助于在数据稀缺和稀缺时改善模型的性能丰富。
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We present two approaches to use unlabeled data to improve Sequence Learning with recurrent networks. The first approach is to predict what comes next in a sequence, which is a language model in NLP. The second approach is to use a sequence autoencoder, which reads the input sequence into a vector and predicts the input sequence again. These two algorithms can be used as a "pretraining" algorithm for a later supervised sequence learning algorithm. In other words, the parameters obtained from the pretraining step can then be used as a starting point for other supervised training models. In our experiments, we find that long short term memory recurrent networks after pretrained with the two approaches become more stable to train and generalize better. With pretraining, we were able to achieve strong performance in many classification tasks, such as text classification with IMDB, DBpedia or image recognition in CIFAR-10.
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长期数据的分类是一个重要的机器学习任务,并出现在许多应用程序中。经常性的神经网络,变压器和卷积神经网络是从顺序数据学习的三种主要技术。在这些方法中,在时间序列回归中缩放到非常长序列的时间卷积网络(TCN)已经取得了显着的进展。但是,对于序列分类的TCNS的性能并不令人满意,因为它们在最后位置使用偏斜连接协议和输出类。这种不对称限制了它们对分类的性能,这取决于整个序列。在这项工作中,我们提出了一种称为循环扩张卷积神经网络(CDIL-CNN)的对称的多尺度架构,其中每个位置具有相同的机会从前一层处接收来自其他位置的信息。我们的模型在所有位置提供分类登录,我们可以应用一个简单的集合学习来实现更好的决定。我们在各种长期数据集上测试了CDIL-CNN。实验结果表明,我们的方法在许多最先进的方法上具有卓越的性能。
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Deep Learning and Machine Learning based models have become extremely popular in text processing and information retrieval. However, the non-linear structures present inside the networks make these models largely inscrutable. A significant body of research has focused on increasing the transparency of these models. This article provides a broad overview of research on the explainability and interpretability of natural language processing and information retrieval methods. More specifically, we survey approaches that have been applied to explain word embeddings, sequence modeling, attention modules, transformers, BERT, and document ranking. The concluding section suggests some possible directions for future research on this topic.
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Short text classification is a crucial and challenging aspect of Natural Language Processing. For this reason, there are numerous highly specialized short text classifiers. However, in recent short text research, State of the Art (SOTA) methods for traditional text classification, particularly the pure use of Transformers, have been unexploited. In this work, we examine the performance of a variety of short text classifiers as well as the top performing traditional text classifier. We further investigate the effects on two new real-world short text datasets in an effort to address the issue of becoming overly dependent on benchmark datasets with a limited number of characteristics. Our experiments unambiguously demonstrate that Transformers achieve SOTA accuracy on short text classification tasks, raising the question of whether specialized short text techniques are necessary.
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Modern machine learning requires system designers to specify aspects of the learning pipeline, such as losses, architectures, and optimizers. Meta-learning, or learning-to-learn, instead aims to learn those aspects, and promises to unlock greater capabilities with less manual effort. One particularly ambitious goal of meta-learning is to train general-purpose in-context learning algorithms from scratch, using only black-box models with minimal inductive bias. Such a model takes in training data, and produces test-set predictions across a wide range of problems, without any explicit definition of an inference model, training loss, or optimization algorithm. In this paper we show that Transformers and other black-box models can be meta-trained to act as general-purpose in-context learners. We characterize phase transitions between algorithms that generalize, algorithms that memorize, and algorithms that fail to meta-train at all, induced by changes in model size, number of tasks, and meta-optimization. We further show that the capabilities of meta-trained algorithms are bottlenecked by the accessible state size (memory) determining the next prediction, unlike standard models which are thought to be bottlenecked by parameter count. Finally, we propose practical interventions such as biasing the training distribution that improve the meta-training and meta-generalization of general-purpose learning algorithms.
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Common to all different kinds of recurrent neural networks (RNNs) is the intention to model relations between data points through time. When there is no immediate relationship between subsequent data points (like when the data points are generated at random, e.g.), we show that RNNs are still able to remember a few data points back into the sequence by memorizing them by heart using standard backpropagation. However, we also show that for classical RNNs, LSTM and GRU networks the distance of data points between recurrent calls that can be reproduced this way is highly limited (compared to even a loose connection between data points) and subject to various constraints imposed by the type and size of the RNN in question. This implies the existence of a hard limit (way below the information-theoretic one) for the distance between related data points within which RNNs are still able to recognize said relation.
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本文介绍了关于剧透筛选的研究。在这种用例中,我们描述了微调和组织基于文本的模型任务的方法,并具有最新的深度学习成果和技术来解释模型的结果。到目前为止,文献中的剧透研究很少描述。我们在带有带注释的扰流板(ROC AUC以上的TV Tropes Point DataSet上超过81 \%的Roc Auc以上的Roc Auc上超过81 \%)的转移学习方法和不同的最新变压器架构。我们还收集了数据并使用细粒度注释组装了新数据集。为此,我们采用了可解释技术和措施来评估模型的可靠性并解释其结果。
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本教程展示了工作流程,将文本数据纳入精算分类和回归任务。主要重点是采用基于变压器模型的方法。平均长度为400个单词的车祸描述的数据集,英语和德语可用,以及具有简短财产保险索赔的数据集用来证明这些技术。案例研究应对与多语言环境和长输入序列有关的挑战。他们还展示了解释模型输出,评估和改善模型性能的方法,通过将模型调整到应用程序领域或特定预测任务。最后,该教程提供了在没有或仅有少数标记数据的情况下处理分类任务的实用方法。通过使用最少的预处理和微调的现成自然语言处理(NLP)模型的语言理解技能(NLP)模型实现的结果清楚地证明了用于实际应用的转移学习能力。
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命名实体识别是一项信息提取任务,可作为其他自然语言处理任务的预处理步骤,例如机器翻译,信息检索和问题答案。命名实体识别能够识别专有名称以及开放域文本中的时间和数字表达式。对于诸如阿拉伯语,阿姆哈拉语和希伯来语之类的闪族语言,由于这些语言的结构严重变化,指定的实体识别任务更具挑战性。在本文中,我们提出了一个基于双向长期记忆的Amharic命名实体识别系统,并带有条件随机字段层。我们注释了一种新的Amharic命名实体识别数据集(8,070个句子,具有182,691个令牌),并将合成少数群体过度采样技术应用于我们的数据集,以减轻不平衡的分类问题。我们命名的实体识别系统的F_1得分为93%,这是Amharic命名实体识别的新最新结果。
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建模法检索和检索作为预测问题最近被出现为法律智能的主要方法。专注于法律文章检索任务,我们展示了一个名为Lamberta的深度学习框架,该框架被设计用于民法代码,并在意大利民法典上专门培训。为了我们的知识,这是第一项研究提出了基于伯特(来自变压器的双向编码器表示)学习框架的意大利法律制度对意大利法律制度的高级法律文章预测的研究,最近引起了深度学习方法的增加,呈现出色的有效性在几种自然语言处理和学习任务中。我们通过微调意大利文章或其部分的意大利预先训练的意大利预先训练的伯爵来定义Lamberta模型,因为法律文章作为分类任务检索。我们Lamberta框架的一个关键方面是我们构思它以解决极端的分类方案,其特征在于课程数量大,少量学习问题,以及意大利法律预测任务的缺乏测试查询基准。为了解决这些问题,我们为法律文章的无监督标签定义了不同的方法,原则上可以应用于任何法律制度。我们提供了深入了解我们Lamberta模型的解释性和可解释性,并且我们对单一标签以及多标签评估任务进行了广泛的查询模板实验分析。经验证据表明了Lamberta的有效性,以及对广泛使用的深度学习文本分类器和一些构思的几次学习者来说,其优越性是对属性感知预测任务的优势。
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仇恨言论是一种在线骚扰的形式,涉及使用滥用语言,并且在社交媒体帖子中通常可以看到。这种骚扰主要集中在诸如宗教,性别,种族等的特定群体特征上,如今它既有社会和经济后果。文本文章中对滥用语言的自动检测一直是一项艰巨的任务,但最近它从科学界获得了很多兴趣。本文解决了在社交媒体中辨别仇恨内容的重要问题。我们在这项工作中提出的模型是基于LSTM神经网络体系结构的现有方法的扩展,我们在短文中适当地增强和微调以检测某些形式的仇恨语言,例如种族主义或性别歧视。最重要的增强是转换为由复发性神经网络(RNN)分类器组成的两阶段方案。将第一阶段的所有一Vs式分类器(OVR)分类器的输出组合在一起,并用于训练第二阶段分类器,最终决定了骚扰的类型。我们的研究包括对在16K推文的公共语料库中评估的第二阶段提出的几种替代方法的性能比较,然后对另一个数据集进行了概括研究。报道的结果表明,与当前的最新技术相比,在仇恨言论检测任务中,所提出的方案的分类质量出色。
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当前信息时代在互联网上产生的数据的指数增长是数字经济的推动力。信息提取是累积大数据中的主要价值。对统计分析和手工设计的规则机器学习算法的大数据依赖性被人类语言固有的巨大复杂性所淹没。自然语言处理(NLP)正在装备机器,以了解这些人类多样化和复杂的语言。文本分类是一个NLP任务,它会自动识别基于预定义或未定标记的集合的模式。常见的文本分类应用程序包括信息检索,建模新闻主题,主题提取,情感分析和垃圾邮件检测。在文本中,某些单词序列取决于上一个或下一个单词序列以使其充分含义。这是一项具有挑战性的依赖性任务,要求机器能够存储一些以前的重要信息以影响未来的含义。诸如RNN,GRU和LSTM之类的序列模型是具有长期依赖性任务的突破。因此,我们将这些模型应用于二进制和多类分类。产生的结果非常出色,大多数模型在80%和94%的范围内执行。但是,这个结果并不详尽,因为我们认为如果机器要与人类竞争,可以改进。
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本文通过自然应用程序对网页和元素分类来解决复杂结构数据的高效表示的问题。我们假设网页内部元素周围的上下文对问题的价值很高,目前正在被利用。本文旨在通过考虑到其上下文来解决将Web元素分类为DOM树的子树的问题。为实现这一目标,首先讨论当前在结构上工作的专家知识系统,如树 - LSTM。然后,我们向该模型提出上下文感知扩展。我们表明,在多级Web分类任务中,新模型实现了0.7973的平均F1分数。该模型为各种子树生成更好的表示,并且可以用于应用此类元素分类,钢筋在网上学习中的状态估计等。
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本次调查绘制了用于分析社交媒体数据的生成方法的研究状态的广泛的全景照片(Sota)。它填补了空白,因为现有的调查文章在其范围内或被约会。我们包括两个重要方面,目前正在挖掘和建模社交媒体的重要性:动态和网络。社会动态对于了解影响影响或疾病的传播,友谊的形成,友谊的形成等,另一方面,可以捕获各种复杂关系,提供额外的洞察力和识别否则将不会被注意的重要模式。
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