After just a few hundred training updates, a standard probabilistic model for language generation has likely not yet learnt many semantic or syntactic rules of natural language, which inherently makes it difficult to estimate the right probability distribution over next tokens. Yet around this point, these models have identified a simple, loss-minimising behaviour: to output the unigram distribution of the target training corpus. The use of such a crude heuristic raises the question: Rather than wasting precious compute resources and model capacity for learning this strategy at early training stages, can we initialise our models with this behaviour? Here, we show that we can effectively endow our model with a separate module that reflects unigram frequency statistics as prior knowledge. Standard neural language generation architectures offer a natural opportunity for implementing this idea: by initialising the bias term in a model's final linear layer with the log-unigram distribution. Experiments in neural machine translation demonstrate that this simple technique: (i) improves learning efficiency; (ii) achieves better overall performance; and (iii) appears to disentangle strong frequency effects, encouraging the model to specialise in non-frequency-related aspects of language.
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神经自回归序列模型涂抹许多可能​​序列之间的概率,包括退化的序列,例如空或重复序列。在这项工作中,我们解决了一个特定的情况,其中模型为不合理的短序列分配高概率。我们定义了量化速率以量化此问题。在确认神经机翻译中高度过度的过天气后,我们建议明确地减少培训期间的过天平率。我们进行一组实验来研究建议的正规化对模型分布和解码性能的影响。我们使用神经电脑翻译任务作为测试用,并考虑三个不同大小的不同数据集。我们的实验显示了三个主要结果。首先,我们可以通过调整正规化的强度来控制模型的过天平率。其次,通过提高过度损失贡献,令牌的概率和等级在不应该是它的位置下降。第三,所提出的正则化影响光束搜索的结果,特别是当使用大梁时。用大梁的翻译质量(在BLEU中测量)的降解显着减少了较低的过天速速率,但与较小光束尺寸相比的劣化仍有剩余状态。从这些观察中,我们得出结论,高度过度的过度性是神经自回归模型中过于可能的短序列的退化情况背后的主要原因。
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The word alignment task, despite its prominence in the era of statistical machine translation (SMT), is niche and under-explored today. In this two-part tutorial, we argue for the continued relevance for word alignment. The first part provides a historical background to word alignment as a core component of the traditional SMT pipeline. We zero-in on GIZA++, an unsupervised, statistical word aligner with surprising longevity. Jumping forward to the era of neural machine translation (NMT), we show how insights from word alignment inspired the attention mechanism fundamental to present-day NMT. The second part shifts to a survey approach. We cover neural word aligners, showing the slow but steady progress towards surpassing GIZA++ performance. Finally, we cover the present-day applications of word alignment, from cross-lingual annotation projection, to improving translation.
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Subword units are an effective way to alleviate the open vocabulary problems in neural machine translation (NMT). While sentences are usually converted into unique subword sequences, subword segmentation is potentially ambiguous and multiple segmentations are possible even with the same vocabulary. The question addressed in this paper is whether it is possible to harness the segmentation ambiguity as a noise to improve the robustness of NMT. We present a simple regularization method, subword regularization, which trains the model with multiple subword segmentations probabilistically sampled during training. In addition, for better subword sampling, we propose a new subword segmentation algorithm based on a unigram language model. We experiment with multiple corpora and report consistent improvements especially on low resource and out-of-domain settings.
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本文介绍了一种新的数据增强方法,用于神经机器翻译,该方法可以在语言内部和跨语言内部实施更强的语义一致性。我们的方法基于条件掩盖语言模型(CMLM),该模型是双向的,可以在左右上下文以及标签上有条件。我们证明CMLM是生成上下文依赖性单词分布的好技术。特别是,我们表明CMLM能够通过在替换过程中对源和目标进行调节来实现语义一致性。此外,为了增强多样性,我们将软词替换的想法纳入了数据增强,该概念用词汇上的概率分布代替了一个单词。在不同量表的四个翻译数据集上进行的实验表明,总体解决方案会导致更现实的数据增强和更好的翻译质量。与最新作品相比,我们的方法始终取得了最佳性能,并且在基线上的提高了1.90个BLEU点。
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机器翻译系统(MTS)是通过将文本或语音从一种语言转换为另一种语言的有效工具。在像印度这样的大型多语言环境中,对有效的翻译系统的需求变得显而易见,英语和一套印度语言(ILS)正式使用。与英语相反,由于语料库的不可用,IL仍然被视为低资源语言。为了解决不对称性质,多语言神经机器翻译(MNMT)系统会发展为在这个方向上的理想方法。在本文中,我们提出了一个MNMT系统,以解决与低资源语言翻译有关的问题。我们的模型包括两个MNMT系统,即用于英语印度(一对多),另一个用于指示英语(多一对多),其中包含15个语言对(30个翻译说明)的共享编码器码头。由于大多数IL对具有很少的平行语料库,因此不足以训练任何机器翻译模型。我们探索各种增强策略,以通过建议的模型提高整体翻译质量。最先进的变压器体系结构用于实现所提出的模型。大量数据的试验揭示了其优越性比常规模型的优势。此外,本文解决了语言关系的使用(在方言,脚本等方面),尤其是关于同一家族的高资源语言在提高低资源语言表现方面的作用。此外,实验结果还表明了ILS的倒退和域适应性的优势,以提高源和目标语言的翻译质量。使用所有这些关键方法,我们提出的模型在评估指标方面比基线模型更有效,即一组ILS的BLEU(双语评估研究)得分。
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Pre-training is an effective technique for ensuring robust performance on a variety of machine learning tasks. It typically depends on large-scale crawled corpora that can result in toxic or biased models. Such data can also be problematic with respect to copyright, attribution, and privacy. Pre-training with synthetic tasks and data is a promising way of alleviating such concerns since no real-world information is ingested by the model. Our goal in this paper is to understand what makes for a good pre-trained model when using synthetic resources. We answer this question in the context of neural machine translation by considering two novel approaches to translation model pre-training. Our first approach studies the effect of pre-training on obfuscated data derived from a parallel corpus by mapping words to a vocabulary of 'nonsense' tokens. Our second approach explores the effect of pre-training on procedurally generated synthetic parallel data that does not depend on any real human language corpus. Our empirical evaluation on multiple language pairs shows that, to a surprising degree, the benefits of pre-training can be realized even with obfuscated or purely synthetic parallel data. In our analysis, we consider the extent to which obfuscated and synthetic pre-training techniques can be used to mitigate the issue of hallucinated model toxicity.
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Diffusion models have quickly become the go-to paradigm for generative modelling of perceptual signals (such as images and sound) through iterative refinement. Their success hinges on the fact that the underlying physical phenomena are continuous. For inherently discrete and categorical data such as language, various diffusion-inspired alternatives have been proposed. However, the continuous nature of diffusion models conveys many benefits, and in this work we endeavour to preserve it. We propose CDCD, a framework for modelling categorical data with diffusion models that are continuous both in time and input space. We demonstrate its efficacy on several language modelling tasks.
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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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The machine translation mechanism translates texts automatically between different natural languages, and Neural Machine Translation (NMT) has gained attention for its rational context analysis and fluent translation accuracy. However, processing low-resource languages that lack relevant training attributes like supervised data is a current challenge for Natural Language Processing (NLP). We incorporated a technique known Active Learning with the NMT toolkit Joey NMT to reach sufficient accuracy and robust predictions of low-resource language translation. With active learning, a semi-supervised machine learning strategy, the training algorithm determines which unlabeled data would be the most beneficial for obtaining labels using selected query techniques. We implemented two model-driven acquisition functions for selecting the samples to be validated. This work uses transformer-based NMT systems; baseline model (BM), fully trained model (FTM) , active learning least confidence based model (ALLCM), and active learning margin sampling based model (ALMSM) when translating English to Hindi. The Bilingual Evaluation Understudy (BLEU) metric has been used to evaluate system results. The BLEU scores of BM, FTM, ALLCM and ALMSM systems are 16.26, 22.56 , 24.54, and 24.20, respectively. The findings in this paper demonstrate that active learning techniques helps the model to converge early and improve the overall quality of the translation system.
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我用Hunglish2语料库训练神经电脑翻译任务的模型。这项工作的主要贡献在培训NMT模型期间评估不同的数据增强方法。我提出了5种不同的增强方法,这些方法是结构感知的,这意味着而不是随机选择用于消隐或替换的单词,句子的依赖树用作增强的基础。我首先关于神经网络的详细文献综述,顺序建模,神经机翻译,依赖解析和数据增强。经过详细的探索性数据分析和Hunglish2语料库的预处理之后,我使用所提出的数据增强技术进行实验。匈牙利语的最佳型号达到了33.9的BLEU得分,而英国匈牙利最好的模型达到了28.6的BLEU得分。
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最近在单语数据和机器翻译(MT)进行微调的预培训方面取得了成功,但尚不清楚如何最好地利用预先训练的模型来完成给定的MT任务。本文在微调MT上的预训练模型时研究了冻结参数的好处和缺点。我们专注于1)微调仅在英语单语言数据的BART上训练的模型。2)微调一个模型,该模型对25种语言的单语言数据进行了培训,Mbart。对于Bart,我们通过冻结大多数模型参数并添加额外的位置嵌入来获得最佳性能。对于MBART,我们将大多数语言对的天真微调的性能与编码器以及大多数解码器搭配。编码器的注意参数对于微调最重要。当将自己限制为越南人对英语的室外训练套装时,我们看到了基线的最大进步。
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Reranking methods in machine translation aim to close the gap between common evaluation metrics (e.g. BLEU) and maximum likelihood learning and decoding algorithms. Prior works address this challenge by training models to rerank beam search candidates according to their predicted BLEU scores, building upon large models pretrained on massive monolingual corpora -- a privilege that was never made available to the baseline translation model. In this work, we examine a simple approach for training rerankers to predict translation candidates' BLEU scores without introducing additional data or parameters. Our approach can be used as a clean baseline, decoupled from external factors, for future research in this area.
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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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诸如变形金刚和LSTMS之类的流行模型将令牌用作其信息单位。也就是说,每个令牌都被编码为向量表示,这些向量直接在计算中使用。但是,人类经常考虑跨令牌(即短语)而不是其组成代币。在本文中,我们介绍了TreeFormer,这是一个受CKY算法和变压器启发的体系结构,该体系结构学习了组成操作员和汇总功能,以构建针对短语和句子的层次编码。我们的广泛实验证明了将层次结构纳入变压器的好处,并且与机器翻译,抽象性摘要和各种自然语言理解任务相比,与基线变压器相比显示出重大改进。
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多语言语言模型(\ mllms),如mbert,xlm,xlm-r,\ textit {etc。}已成为一种可行的选择,使预先估计到大量语言的力量。鉴于他们的成功在零射击转移学习中,在(i)建立更大的\ mllms〜覆盖了大量语言(ii)创建覆盖更广泛的任务和语言来评估的详尽工作基准mllms〜(iii)分析单音零点,零拍摄交叉和双语任务(iv)对Monolingual的性能,了解\ mllms〜(v)增强(通常)学习的通用语言模式(如果有的话)有限的容量\ mllms〜以提高他们在已见甚至看不见语言的表现。在这项调查中,我们审查了现有的文学,涵盖了上述与\ MLLMS有关的广泛研究领域。根据我们的调查,我们建议您有一些未来的研究方向。
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我们想要模型的文本单位是什么?从字节到多字表达式,可以在许多粒度下分析和生成文本。直到最近,大多数自然语言处理(NLP)模型通过单词操作,将那些作为离散和原子令牌处理,但从字节对编码(BPE)开始,基于次字的方法在许多领域都变得占主导地位,使得仍然存在小词汇表允许快速推断。是道路字符级模型的结束或字节级处理吗?在这项调查中,我们通过展示和评估基于学习分割的词语和字符以及基于子字的方法的混合方法以及基于学习的分割的杂交方法,连接多行工作。我们得出结论,对于所有应用来说,并且可能永远不会成为所有应用的银子弹奇异解决方案,并且严重思考令牌化对许多应用仍然很重要。
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Directly training a document-to-document (Doc2Doc) neural machine translation (NMT) via Transformer from scratch, especially on small datasets usually fails to converge. Our dedicated probing tasks show that 1) both the absolute position and relative position information gets gradually weakened or even vanished once it reaches the upper encoder layers, and 2) the vanishing of absolute position information in encoder output causes the training failure of Doc2Doc NMT. To alleviate this problem, we propose a position-aware Transformer (P-Transformer) to enhance both the absolute and relative position information in both self-attention and cross-attention. Specifically, we integrate absolute positional information, i.e., position embeddings, into the query-key pairs both in self-attention and cross-attention through a simple yet effective addition operation. Moreover, we also integrate relative position encoding in self-attention. The proposed P-Transformer utilizes sinusoidal position encoding and does not require any task-specified position embedding, segment embedding, or attention mechanism. Through the above methods, we build a Doc2Doc NMT model with P-Transformer, which ingests the source document and completely generates the target document in a sequence-to-sequence (seq2seq) way. In addition, P-Transformer can be applied to seq2seq-based document-to-sentence (Doc2Sent) and sentence-to-sentence (Sent2Sent) translation. Extensive experimental results of Doc2Doc NMT show that P-Transformer significantly outperforms strong baselines on widely-used 9 document-level datasets in 7 language pairs, covering small-, middle-, and large-scales, and achieves a new state-of-the-art. Experimentation on discourse phenomena shows that our Doc2Doc NMT models improve the translation quality in both BLEU and discourse coherence. We make our code available on Github.
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在这项工作中,我们证明了多种语的大规模序列到序列(SEQ2SEQ)模型,该模型是通过Denoising和因果语言建模(CLM)任务的混合物进行训练的,比仅解码器模型更有效地进行了效率的学习者在各种任务上。特别是,我们培训了一个名为Alexa教师模型(Alexatm 20b)的200亿个参数多语言SEQ2SEQ模型,并表明它在1-Shot摘要任务上实现了最先进的(SOTA)性能,超过了更大的540B PALM DOPODER模型。 Alexatm 20b还可以在1-Shot Machine翻译中实现SOTA,尤其是对于低资源语言,几乎所有语言对(阿拉伯语,英语,法语,德语,德语,印地语,意大利语,日语,以及flores-101数据集上的泰卢固语)。我们还显示了零拍设置,AlexATM 20B在SuperGlue和SqueadV2数据集上的表现优于GPT3(175B),并在XNLI,XCOPA,PAWS-X和XWINOGRAD等多语言任务上提供SOTA性能。总体而言,我们的结果为SEQ2SEQ模型提供了一个令人信服的案例,作为大型语言模型(LLM)培训的仅解码器模型的强大替代方法。
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在本文中,我们试图通过引入深度学习模型的句法归纳偏见来建立两所学校之间的联系。我们提出了两个归纳偏见的家族,一个家庭用于选区结构,另一个用于依赖性结构。选区归纳偏见鼓励深度学习模型使用不同的单位(或神经元)分别处理长期和短期信息。这种分离为深度学习模型提供了一种方法,可以从顺序输入中构建潜在的层次表示形式,即更高级别的表示由高级表示形式组成,并且可以分解为一系列低级表示。例如,在不了解地面实际结构的情况下,我们提出的模型学会通过根据其句法结构组成变量和运算符的表示来处理逻辑表达。另一方面,依赖归纳偏置鼓励模型在输入序列中找到实体之间的潜在关系。对于自然语言,潜在关系通常被建模为一个定向依赖图,其中一个单词恰好具有一个父节点和零或几个孩子的节点。将此约束应用于类似变压器的模型之后,我们发现该模型能够诱导接近人类专家注释的有向图,并且在不同任务上也优于标准变压器模型。我们认为,这些实验结果为深度学习模型的未来发展展示了一个有趣的选择。
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