Human linguistic capacity is often characterized by compositionality and the generalization it enables -- human learners can produce and comprehend novel complex expressions by composing known parts. Several benchmarks exploit distributional control across training and test to gauge compositional generalization, where certain lexical items only occur in limited contexts during training. While recent work using these benchmarks suggests that pretrained models achieve impressive generalization performance, we argue that exposure to pretraining data may break the aforementioned distributional control. Using the COGS benchmark of Kim and Linzen (2020), we test two modified evaluation setups that control for this issue: (1) substituting context-controlled lexical items with novel character sequences, and (2) substituting them with special tokens represented by novel embeddings. We find that both of these setups lead to lower generalization performance in T5 (Raffel et al., 2020), suggesting that previously reported results have been overestimated due to uncontrolled lexical exposure during pretraining. The performance degradation is more extreme with novel embeddings, and the degradation increases with the amount of pretraining data, highlighting an interesting case of inverse scaling.
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语言模型通常仅在文本上进行培训,而无需其他基础。关于从这种过程中可以推断出多少自然语言语义的争论。我们证明,可以从理想的语言模型中提取句子之间的判断,该模型可以完美地了解其目标分布,假设训练句子是由Gricean Agents产生的,即遵循实用学语言学理论的基本交流原理的代理人。我们还表明,可以从对这种Gricean数据训练的语言模型的预测中解码需要判断。我们的结果揭示了一种理解未标记的语言数据中编码的语义信息的途径,以及从语言模型中提取语义的潜在框架。
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语言模型既展示了定量的改进,又展示了新的定性功能,随着规模的增加。尽管它们具有潜在的变革性影响,但这些新能力的特征却很差。为了为未来的研究提供信息,为破坏性的新模型能力做准备,并改善社会有害的效果,至关重要的是,我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战,我们介绍了超越模仿游戏基准(Big Bench)。 Big Bench目前由204个任务组成,由132家机构的442位作者贡献。任务主题是多样的,从语言学,儿童发展,数学,常识性推理,生物学,物理学,社会偏见,软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号,Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为,跨越了数百万到数十亿个参数。此外,一个人类专家评估者团队执行了所有任务,以提供强大的基准。研究结果包括:模型性能和校准都随规模改善,但绝对的术语(以及与评估者的性能相比);在模型类中的性能非常相似,尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分,而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标;社交偏见通常会随着含糊不清的环境而随着规模而增加,但这可以通过提示来改善。
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已显示通用非结构化神经网络在分布外的组成概述上挣扎。通过示例重组的组成数据增强已经转移了一些关于组成性的关于多个语义解析任务的黑盒神经模型的先前知识,但这通常需要特定于任务的工程或提供有限的收益。我们使用称为组成结构学习者(CSL)的型号提供更强大的数据重组方法。 CSL是一种具有拟同步无线语法骨干的生成模型,我们从训练数据中诱导。我们从CSL中进行重组的例子,并将其添加到预先训练的序列到序列模型(T5)的微调数据中。该程序有效地将大多数CSL的组成偏差转移到T5以进行诊断任务,并导致模型比在两个真实世界的组成泛化任务上的T5-CSL集合更强。这导致新的最先进的性能,这些挑战性的语义解析任务需要泛化自然语言变异和元素的新组成。
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当前的语言模型可以产生高质量的文本。他们只是复制他们之前看到的文本,或者他们学习了普遍的语言抽象吗?要取笑这些可能性,我们介绍了乌鸦,这是一套评估生成文本的新颖性,专注于顺序结构(n-gram)和句法结构。我们将这些分析应用于四种神经语言模型(LSTM,变压器,变换器-XL和GPT-2)。对于本地结构 - 例如,单个依赖性 - 模型生成的文本比来自每个模型的测试集的人类生成文本的基线显着不那么新颖。对于大规模结构 - 例如,总句结构 - 模型生成的文本与人生成的基线一样新颖甚至更新颖,但模型仍然有时复制,在某些情况下,在训练集中重复超过1000字超过1,000字的通道。我们还表现了广泛的手动分析,表明GPT-2的新文本通常在形态学和语法中形成良好,但具有合理的语义问题(例如,是自相矛盾)。
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神经网络模型通常概括到不匹配的域或分布不符。在NLP中,特别是当预期模型概括为合作的模型,即熟悉词汇和建筑的新组合时,尤其产生这个问题。我们调查促进从一个组成任务转移到另一个组成任务的学习的学习陈述:模型的代表和任务特定层在预先驾驶任务上具有不同的培训,使得它们概括为需要合成性的不匹配分裂。我们将此方法应用于语义解析,使用三个非常不同的数据集,COG,地理信息集和扫描,作为FineTuning和目标任务交替使用。我们的方法显着改善了在目标任务的测试组上的基线上的组成概括,在微调期间被列出。消融研究表征了所提出的算法中主要步骤的效用,并支持我们的假设。
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Knowledge-grounded dialogue systems powered by large language models often generate responses that, while fluent, are not attributable to a relevant source of information. Progress towards models that do not exhibit this issue requires evaluation metrics that can quantify its prevalence. To this end, we introduce the Benchmark for Evaluation of Grounded INteraction (BEGIN), comprised of 12k dialogue turns generated by neural dialogue systems trained on three knowledgegrounded dialogue corpora. We collect human annotations assessing the extent to which the models' responses can be attributed to the given background information. We then use BEGIN to analyze eight evaluation metrics. We find that these metrics rely on spurious correlations, do not reliably distinguish attributable abstractive responses from unattributable ones, and perform substantially worse when the knowledge source is longer. Our findings underscore the need for more sophisticated and robust evaluation metrics for knowledge-grounded dialogue. We make BEGIN publicly available at https://github.com/ google/BEGIN-dataset.
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A machine learning system can score well on a given test set by relying on heuristics that are effective for frequent example types but break down in more challenging cases. We study this issue within natural language inference (NLI), the task of determining whether one sentence entails another. We hypothesize that statistical NLI models may adopt three fallible syntactic heuristics: the lexical overlap heuristic, the subsequence heuristic, and the constituent heuristic. To determine whether models have adopted these heuristics, we introduce a controlled evaluation set called HANS (Heuristic Analysis for NLI Systems), which contains many examples where the heuristics fail. We find that models trained on MNLI, including BERT, a state-of-the-art model, perform very poorly on HANS, suggesting that they have indeed adopted these heuristics. We conclude that there is substantial room for improvement in NLI systems, and that the HANS dataset can motivate and measure progress in this area.
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As the accuracy of machine learning models increases at a fast rate, so does their demand for energy and compute resources. On a low level, the major part of these resources is consumed by data movement between different memory units. Modern hardware architectures contain a form of fast memory (e.g., cache, registers), which is small, and a slow memory (e.g., DRAM), which is larger but expensive to access. We can only process data that is stored in fast memory, which incurs data movement (input/output-operations, or I/Os) between the two units. In this paper, we provide a rigorous theoretical analysis of the I/Os needed in sparse feedforward neural network (FFNN) inference. We establish bounds that determine the optimal number of I/Os up to a factor of 2 and present a method that uses a number of I/Os within that range. Much of the I/O-complexity is determined by a few high-level properties of the FFNN (number of inputs, outputs, neurons, and connections), but if we want to get closer to the exact lower bound, the instance-specific sparsity patterns need to be considered. Departing from the 2-optimal computation strategy, we show how to reduce the number of I/Os further with simulated annealing. Complementing this result, we provide an algorithm that constructively generates networks with maximum I/O-efficiency for inference. We test the algorithms and empirically verify our theoretical and algorithmic contributions. In our experiments on real hardware we observe speedups of up to 45$\times$ relative to the standard way of performing inference.
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Prior works on improving speech quality with visual input typically study each type of auditory distortion separately (e.g., separation, inpainting, video-to-speech) and present tailored algorithms. This paper proposes to unify these subjects and study Generalized Speech Enhancement, where the goal is not to reconstruct the exact reference clean signal, but to focus on improving certain aspects of speech. In particular, this paper concerns intelligibility, quality, and video synchronization. We cast the problem as audio-visual speech resynthesis, which is composed of two steps: pseudo audio-visual speech recognition (P-AVSR) and pseudo text-to-speech synthesis (P-TTS). P-AVSR and P-TTS are connected by discrete units derived from a self-supervised speech model. Moreover, we utilize self-supervised audio-visual speech model to initialize P-AVSR. The proposed model is coined ReVISE. ReVISE is the first high-quality model for in-the-wild video-to-speech synthesis and achieves superior performance on all LRS3 audio-visual enhancement tasks with a single model. To demonstrates its applicability in the real world, ReVISE is also evaluated on EasyCom, an audio-visual benchmark collected under challenging acoustic conditions with only 1.6 hours of training data. Similarly, ReVISE greatly suppresses noise and improves quality. Project page: https://wnhsu.github.io/ReVISE.
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