State-of-the-art machine translation evaluation metrics are based on black-box language models. Hence, recent works consider their explainability with the goals of better understandability for humans and better metric analysis, including failure cases. In contrast, we explicitly leverage explanations to boost the metrics' performance. In particular, we perceive explanations as word-level scores, which we convert, via power means, into sentence-level scores. We combine this sentence-level score with the original metric to obtain a better metric. Our extensive evaluation and analysis across 5 datasets, 5 metrics and 4 explainability techniques shows that some configurations reliably improve the original metrics' correlation with human judgment. On two held datasets for testing, we obtain improvements in 15/18 resp. 4/4 cases. The gains in Pearson correlation are up to 0.032 resp. 0.055. We make our code available.
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监督机器翻译的绝大多数评估指标,即(i)假设参考翻译的存在,(ii)受到人体得分的培训,或(iii)利用并行数据。这阻碍了其适用于此类监督信号的情况。在这项工作中,我们开发了完全无监督的评估指标。为此,我们利用评估指标,平行语料库开采和MT系统之间的相似性和协同作用。特别是,我们使用无监督的评估指标来开采伪并行数据,我们用来重塑缺陷的基础向量空间(以迭代方式),并诱导无监督的MT系统,然后提供伪引用作为伪参考作为在中的附加组件中的附加组件指标。最后,我们还从伪并行数据中诱导无监督的多语言句子嵌入。我们表明,我们完全无监督的指标是有效的,即,他们在5个评估数据集中的4个击败了受监督的竞争对手。
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评估指标是文本生成系统的关键成分。近年来,已经提出了几十年前的文本生成质量的人类评估,提出了几个基于伯特的评估指标(包括Bertscore,Moverscore,BLEurt等),这些评估与文本生成质量的人类评估比Bleu或Rouge进行了更好。但是,很少是已知这些度量基于黑盒语言模型表示的指标实际捕获(通常假设它们模型语义相似性)。在这项工作中,我们使用基于简单的回归的全局解释技术来沿着语言因素解开度量标准分数,包括语义,语法,形态和词汇重叠。我们表明,不同的指标捕获了一定程度的各个方面,但它们对词汇重叠大大敏感,就像Bleu和Rouge一样。这暴露了这些新颖性拟议的指标的限制,我们还在对抗对抗测试场景中突出显示。
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As machine translation (MT) metrics improve their correlation with human judgement every year, it is crucial to understand the limitations of such metrics at the segment level. Specifically, it is important to investigate metric behaviour when facing accuracy errors in MT because these can have dangerous consequences in certain contexts (e.g., legal, medical). We curate ACES, a translation accuracy challenge set, consisting of 68 phenomena ranging from simple perturbations at the word/character level to more complex errors based on discourse and real-world knowledge. We use ACES to evaluate a wide range of MT metrics including the submissions to the WMT 2022 metrics shared task and perform several analyses leading to general recommendations for metric developers. We recommend: a) combining metrics with different strengths, b) developing metrics that give more weight to the source and less to surface-level overlap with the reference and c) explicitly modelling additional language-specific information beyond what is available via multilingual embeddings.
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我们介绍了IST和Unmabel对WMT 2022关于质量估计(QE)的共享任务的共同贡献。我们的团队参与了所有三个子任务:(i)句子和单词级质量预测;(ii)可解释的量化宽松;(iii)关键错误检测。对于所有任务,我们在彗星框架之上构建,将其与OpenKIWI的预测估计架构连接,并为其配备单词级序列标记器和解释提取器。我们的结果表明,在预处理过程中合并参考可以改善下游任务上多种语言对的性能,并且通过句子和单词级别的目标共同培训可以进一步提高。此外,将注意力和梯度信息结合在一起被证明是提取句子级量化量化宽松模型的良好解释的首要策略。总体而言,我们的意见书在几乎所有语言对的所有三个任务中都取得了最佳的结果。
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We propose BERTSCORE, an automatic evaluation metric for text generation. Analogously to common metrics, BERTSCORE computes a similarity score for each token in the candidate sentence with each token in the reference sentence. However, instead of exact matches, we compute token similarity using contextual embeddings. We evaluate using the outputs of 363 machine translation and image captioning systems. BERTSCORE correlates better with human judgments and provides stronger model selection performance than existing metrics. Finally, we use an adversarial paraphrase detection task to show that BERTSCORE is more robust to challenging examples when compared to existing metrics.
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最近提出的基于BERT的评估指标在标准评估基准方面表现良好,但容易受到对抗性攻击的影响,例如与事实错误有关。我们认为这(部分原因)是因为它们是语义相似性的模型。相反,我们根据自然语言推断(NLI)制定评估指标,我们认为这是更合适的建模。我们设计了一个基于偏好的对抗攻击框架,并表明我们的基于NLI的指标比最近基于BERT的指标更强大。在标准基准上,我们的基于NLI的指标的表现优于现有的摘要指标,但在SOTA MT指标下执行。但是,当我们将现有指标与NLI指标相结合时,我们可以获得更高的对抗性鲁棒性( +20%至 +30%)和较高质量的指标,如标准基准测量( +5%至 +25%)。
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最先进的实体匹配(EM)方法很难解释,并且为EM带来可解释的AI具有重要的价值。不幸的是,大多数流行的解释性方法无法开箱即用,需要适应。在本文中,我们确定了将本地事后特征归因方法应用于实体匹配的三个挑战:跨记录的交互作用,不匹配的解释和灵敏度变化。我们提出了新颖的模型 - 静态和模式 - 富含模型的方法柠檬柠檬,该方法通过(i)产生双重解释来避免交叉记录的互动效果来应对所有三个挑战,(ii)介绍了归因潜力的新颖概念,以解释两个记录如何能够拥有如何具有匹配,(iii)自动选择解释粒度以匹配匹配器和记录对的灵敏度。公共数据集上的实验表明,所提出的方法更忠实于匹配器,并且在帮助用户了解匹配器的决策边界的工作中比以前的工作更具忠诚度。此外,用户研究表明,与标准的解释相比石灰的适应。
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我们假设现有的句子级机器翻译(MT)指标在人类参考包含歧义时会效率降低。为了验证这一假设,我们提出了一种非常简单的方法,用于扩展预审计的指标以在文档级别合并上下文。我们将我们的方法应用于三个流行的指标,即Bertscore,Prism和Comet,以及无参考的公制Comet-QE。我们使用提供的MQM注释评估WMT 2021指标共享任务的扩展指标。我们的结果表明,扩展指标的表现在约85%的测试条件下优于其句子级别的级别,而在排除低质量人类参考的结果时。此外,我们表明我们的文档级扩展大大提高了其对话语现象任务的准确性,从而优于专用基线高达6.1%。我们的实验结果支持我们的初始假设,并表明对指标的简单扩展使他们能够利用上下文来解决参考中的歧义。
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翻译质量估计(QE)是预测机器翻译(MT)输出质量的任务,而无需任何参考。作为MT实际应用中的重要组成部分,这项任务已越来越受到关注。在本文中,我们首先提出了XLMRScore,这是一种基于使用XLM-Roberta(XLMR)模型计算的BertScore的简单无监督的QE方法,同时讨论了使用此方法发生的问题。接下来,我们建议两种减轻问题的方法:用未知令牌和预训练模型的跨语性对准替换未翻译的单词,以表示彼此之间的一致性单词。我们在WMT21 QE共享任务的四个低资源语言对上评估了所提出的方法,以及本文介绍的新的英语FARSI测试数据集。实验表明,我们的方法可以在两个零射击方案的监督基线中获得可比的结果,即皮尔森相关性的差异少于0.01,同时在所有低资源语言对中的平均低资源语言对中的无人看管竞争对手的平均水平超过8%的平均水平超过8%。 。
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Automated Machine Learning-based systems' integration into a wide range of tasks has expanded as a result of their performance and speed. Although there are numerous advantages to employing ML-based systems, if they are not interpretable, they should not be used in critical, high-risk applications where human lives are at risk. To address this issue, researchers and businesses have been focusing on finding ways to improve the interpretability of complex ML systems, and several such methods have been developed. Indeed, there are so many developed techniques that it is difficult for practitioners to choose the best among them for their applications, even when using evaluation metrics. As a result, the demand for a selection tool, a meta-explanation technique based on a high-quality evaluation metric, is apparent. In this paper, we present a local meta-explanation technique which builds on top of the truthfulness metric, which is a faithfulness-based metric. We demonstrate the effectiveness of both the technique and the metric by concretely defining all the concepts and through experimentation.
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许多可解释性工具使从业人员和研究人员可以解释自然语言处理系统。但是,每个工具都需要不同的配置,并提供不同形式的解释,从而阻碍了评估和比较它们的可能性。原则上的统一评估基准将指导用户解决中心问题:哪种解释方法对我的用例更可靠?我们介绍了雪貂,这是一个易于使用的,可扩展的Python库,以解释与拥抱面枢纽集成的基于变形金刚的模型。它提供了一个统一的基准测试套件来测试和比较任何文本或可解释性语料库的广泛最先进的解释器。此外,雪貂提供方便的编程摘要,以促进新的解释方法,数据集或评估指标的引入。
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变形金刚在NLP中广泛使用,它们始终如一地实现最先进的性能。这是由于他们基于注意力的架构,这使他们能够对单词之间的丰富语言关系进行建模。但是,变压器很难解释。能够为其决策提供推理是人类生命受影响的领域(例如仇恨言论检测和生物医学)的模型的重要特性。随着变压器在这些领域中发现广泛使用,因此需要为其量身定制的可解释性技术。在这项工作中研究了基于注意力的可解释性技术对文本分类中的有效性。尽管担心文献中的基于注意力的解释,但我们表明,通过适当的设置,可以将注意力用于此类任务,结果与最先进的技术相当,同时也更快,更友好。我们通过采用新功能重要性指标的一系列实验来验证我们的主张。
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我们提出了一种可解释的关系提取方法,通过共同训练这两个目标来减轻概括和解释性之间的张力。我们的方法使用多任务学习体系结构,该体系结构共同训练分类器以进行关系提取,并在解释关系分类器的决策的关系中标记单词的序列模型。我们还将模型输出转换为规则,以将全局解释带入这种方法。使用混合策略对此序列模型进行训练:有监督,当可获得预先存在的模式的监督时,另外还要半监督。在后一种情况下,我们将序列模型的标签视为潜在变量,并学习最大化关系分类器性能的最佳分配。我们评估了两个数据集中的提议方法,并表明序列模型提供了标签,可作为关系分类器决策的准确解释,并且重要的是,联合培训通常可以改善关系分类器的性能。我们还评估了生成的规则的性能,并表明新规则是手动规则的重要附加功能,并使基于规则的系统更接近神经模型。
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Automatic machine translation (MT) metrics are widely used to distinguish the translation qualities of machine translation systems across relatively large test sets (system-level evaluation). However, it is unclear if automatic metrics are reliable at distinguishing good translations from bad translations at the sentence level (segment-level evaluation). In this paper, we investigate how useful MT metrics are at detecting the success of a machine translation component when placed in a larger platform with a downstream task. We evaluate the segment-level performance of the most widely used MT metrics (chrF, COMET, BERTScore, etc.) on three downstream cross-lingual tasks (dialogue state tracking, question answering, and semantic parsing). For each task, we only have access to a monolingual task-specific model. We calculate the correlation between the metric's ability to predict a good/bad translation with the success/failure on the final task for the Translate-Test setup. Our experiments demonstrate that all metrics exhibit negligible correlation with the extrinsic evaluation of the downstream outcomes. We also find that the scores provided by neural metrics are not interpretable mostly because of undefined ranges. Our analysis suggests that future MT metrics be designed to produce error labels rather than scores to facilitate extrinsic evaluation.
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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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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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最先进的文本分类器的大尺寸和复杂的决策机制使人类难以理解他们的预测,导致用户缺乏信任。这些问题导致采用Shail和集成梯度等方法来解释分类决策,通过为输入令牌分配重要性分数。然而,使用不同的随机化测试之前的工作表明,通过这些方法产生的解释可能不具有稳健性。例如,对测试集的相同预测的模型可能仍然导致不同的特征重要性排名。为了解决基于令牌的可解释性缺乏稳健性,我们探讨了句子等更高语义层面的解释。我们使用计算指标和人类主题研究来比较基于令牌的句子的解释的质量。我们的实验表明,更高级别的特征属性提供了几个优点:1)由于随机化测试测量,2)当使用近似的基于方法等诸如Shav等的方法来说,它们更加强大,并且3)它们更容易理解在语言相干性在更高的粒度水平上存在的情况下的人类。基于这些调查结果,我们表明,令牌的可解释性,同时是鉴于ML模型的输入接口的方便的首选,不是所有情况中最有效的选择。
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由于机器学习模型变得越来越复杂和他们的应用程序变得越来越高赌注的,用于解释模型预测工具已经变得越来越重要。这促使模型explainability研究乱舞,并已引起了功能属性的方法,如石灰和SHAP。尽管它们的广泛使用,评价和比较不同功能属性的方法仍然具有挑战性:评价非常需要人的研究,以及实证评价指标往往是数据密集型或真实世界的数据集的计算望而却步。与基准特征归属算法库以及一套综合数据集:在这项工作中,我们通过释放XAI,台式解决这个问题。不同于现实世界的数据集,合成数据集允许那些需要评估地面实况夏普利值等指标的条件期望值的高效计算。我们释放合成的数据集提供了多种可配置模拟真实世界的数据参数。我们通过在多个评价指标和跨多种设置基准流行explainability技术展示我们的图书馆的力量。我们图书馆的多功能性和效率将有助于研究人员把他们的explainability方法从开发到部署。我们的代码可在https://github.com/abacusai/xai-bench。
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Some recent works observed the instability of post-hoc explanations when input side perturbations are applied to the model. This raises the interest and concern in the stability of post-hoc explanations. However, the remaining question is: is the instability caused by the neural network model or the post-hoc explanation method? This work explores the potential source that leads to unstable post-hoc explanations. To separate the influence from the model, we propose a simple output probability perturbation method. Compared to prior input side perturbation methods, the output probability perturbation method can circumvent the neural model's potential effect on the explanations and allow the analysis on the explanation method. We evaluate the proposed method with three widely-used post-hoc explanation methods (LIME (Ribeiro et al., 2016), Kernel Shapley (Lundberg and Lee, 2017a), and Sample Shapley (Strumbelj and Kononenko, 2010)). The results demonstrate that the post-hoc methods are stable, barely producing discrepant explanations under output probability perturbations. The observation suggests that neural network models may be the primary source of fragile explanations.
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