Fairness and environmental impact are important research directions for the sustainable development of artificial intelligence. However, while each topic is an active research area in natural language processing (NLP), there is a surprising lack of research on the interplay between the two fields. This lacuna is highly problematic, since there is increasing evidence that an exclusive focus on fairness can actually hinder environmental sustainability, and vice versa. In this work, we shed light on this crucial intersection in NLP by (1) investigating the efficiency of current fairness approaches through surveying example methods for reducing unfair stereotypical bias from the literature, and (2) evaluating a common technique to reduce energy consumption (and thus environmental impact) of English NLP models, knowledge distillation (KD), for its impact on fairness. In this case study, we evaluate the effect of important KD factors, including layer and dimensionality reduction, with respect to: (a) performance on the distillation task (natural language inference and semantic similarity prediction), and (b) multiple measures and dimensions of stereotypical bias (e.g., gender bias measured via the Word Embedding Association Test). Our results lead us to clarify current assumptions regarding the effect of KD on unfair bias: contrary to other findings, we show that KD can actually decrease model fairness.

语言可以用作再现和执行有害刻板印象和偏差的手段，并被分析在许多研究中。在本文中，我们对自然语言处理中的性别偏见进行了304篇论文。我们分析了社会科学中性别及其类别的定义，并将其连接到NLP研究中性别偏见的正式定义。我们调查了在对性别偏见的研究中应用的Lexica和数据集，然后比较和对比方法来检测和减轻性别偏见。我们发现对性别偏见的研究遭受了四个核心限制。 1）大多数研究将性别视为忽视其流动性和连续性的二元变量。 2）大部分工作都在单机设置中进行英语或其他高资源语言进行。 3）尽管在NLP方法中对性别偏见进行了无数的论文，但我们发现大多数新开发的算法都没有测试他们的偏见模型，并无视他们的工作的伦理考虑。 4）最后，在这一研究线上发展的方法基本缺陷涵盖性别偏差的非常有限的定义，缺乏评估基线和管道。我们建议建议克服这些限制作为未来研究的指导。

大型的语言模型（PRELMS）正在彻底改变所有基准的自然语言处理。但是，它们的巨大尺寸对于小型实验室或移动设备上的部署而言是过分的。修剪和蒸馏等方法可减少模型尺寸，但通常保留相同的模型体系结构。相反，我们探索了蒸馏预告片中的更有效的架构，单词的持续乘法（CMOW），该构造将每个单词嵌入为矩阵，并使用矩阵乘法来编码序列。我们扩展了CMOW体系结构及其CMOW/CBOW-HYBRID变体，具有双向组件，以提供更具表现力的功能，在预绘制期间进行一般（任务无义的）蒸馏的单次表示，并提供了两种序列编码方案，可促进下游任务。句子对，例如句子相似性和自然语言推断。我们的基于矩阵的双向CMOW/CBOW-HYBRID模型在问题相似性和识别文本范围内的Distilbert具有竞争力，但仅使用参数数量的一半，并且在推理速度方面快三倍。除了情感分析任务SST-2和语言可接受性任务COLA外，我们匹配或超过ELMO的ELMO分数。但是，与以前的跨架结构蒸馏方法相比，我们证明了检测语言可接受性的分数增加了一倍。这表明基于基质的嵌入可用于将大型预赛提炼成竞争模型，并激励朝这个方向进行进一步的研究。

Language model pre-training, such as BERT, has significantly improved the performances of many natural language processing tasks. However, pre-trained language models are usually computationally expensive, so it is difficult to efficiently execute them on resourcerestricted devices. To accelerate inference and reduce model size while maintaining accuracy, we first propose a novel Transformer distillation method that is specially designed for knowledge distillation (KD) of the Transformer-based models. By leveraging this new KD method, the plenty of knowledge encoded in a large "teacher" BERT can be effectively transferred to a small "student" Tiny-BERT. Then, we introduce a new two-stage learning framework for TinyBERT, which performs Transformer distillation at both the pretraining and task-specific learning stages. This framework ensures that TinyBERT can capture the general-domain as well as the task-specific knowledge in BERT. TinyBERT 41 with 4 layers is empirically effective and achieves more than 96.8% the performance of its teacher BERT BASE on GLUE benchmark, while being 7.5x smaller and 9.4x faster on inference. TinyBERT 4 is also significantly better than 4-layer state-of-the-art baselines on BERT distillation, with only ∼28% parameters and ∼31% inference time of them. Moreover, TinyBERT 6 with 6 layers performs on-par with its teacher BERT BASE .

对自然语言处理资源中的偏置模式的提高意识，如BERT，具有许多度量来量化“偏见”和“公平”。但是，如果没有完全不可能，请比较不同指标的结果和评估这些度量的作品仍然困难。我们调查了对预用语言模型的公平度量标准的现有文献，并通过实验评估兼容性，包括语言模型中的偏差，如在其下游任务中。我们通过传统文献调查和相关分析的混合来实现这一目标，以及运行实证评估。我们发现许多指标不兼容，高度依赖于（i）模板，（ii）属性和目标种子和（iii）选择嵌入式。这些结果表明，公平或偏见评估对情境化语言模型仍然具有挑战性，如果不是至少高度主观。为了提高未来的比较和公平评估，我们建议避免嵌入基于的指标并专注于下游任务中的公平评估。

Despite being responsible for state-of-the-art results in several computer vision and natural language processing tasks, neural networks have faced harsh criticism due to some of their current shortcomings. One of them is that neural networks are correlation machines prone to model biases within the data instead of focusing on actual useful causal relationships. This problem is particularly serious in application domains affected by aspects such as race, gender, and age. To prevent models from incurring on unfair decision-making, the AI community has concentrated efforts in correcting algorithmic biases, giving rise to the research area now widely known as fairness in AI. In this survey paper, we provide an in-depth overview of the main debiasing methods for fairness-aware neural networks in the context of vision and language research. We propose a novel taxonomy to better organize the literature on debiasing methods for fairness, and we discuss the current challenges, trends, and important future work directions for the interested researcher and practitioner.

Pre-trained language models (PLMs) have outperformed other NLP models on a wide range of tasks. Opting for a more thorough understanding of their capabilities and inner workings, researchers have established the extend to which they capture lower-level knowledge like grammaticality, and mid-level semantic knowledge like factual understanding. However, there is still little understanding of their knowledge of higher-level aspects of language. In particular, despite the importance of sociodemographic aspects in shaping our language, the questions of whether, where, and how PLMs encode these aspects, e.g., gender or age, is still unexplored. We address this research gap by probing the sociodemographic knowledge of different single-GPU PLMs on multiple English data sets via traditional classifier probing and information-theoretic minimum description length probing. Our results show that PLMs do encode these sociodemographics, and that this knowledge is sometimes spread across the layers of some of the tested PLMs. We further conduct a multilingual analysis and investigate the effect of supplementary training to further explore to what extent, where, and with what amount of pre-training data the knowledge is encoded. Our overall results indicate that sociodemographic knowledge is still a major challenge for NLP. PLMs require large amounts of pre-training data to acquire the knowledge and models that excel in general language understanding do not seem to own more knowledge about these aspects.

由于从大规模预先训练的语言模型的转移学习在自然语言处理中普遍存在，在计算受限环境中运行这些模型仍然是一个具有挑战性的问题。已经提出了包括知识蒸馏，网络量化或网络修剪的几种解决方案;然而，这些方法主要关注英语，从而在考虑低资源语言时扩大差距。在这项工作中，我们为罗马尼亚语推出了三种轻型和快速版本的罗马尼亚语言：Distil-Bert-Base-Ro，Distil-Robert-Base和DistilMulti-Bert-Bas-Ro。前两种模型因单独蒸馏在文献中提供的两个基础版本的罗马尼亚伯爵的知识，而最后一个是通过蒸馏它们的集合来获得的。为了我们的知识，这是第一次尝试创建公开可用的罗马尼亚蒸馏BERT模型，这是在五个任务上进行彻底评估的：语音标记，名为实体识别，情感分析，语义文本相似性和方言识别。这些基准测试的实验结果证明，我们的三种蒸馏模型在与老师的准确性方面保持最大的表现，而GPU的两倍于GPU和〜35 \％较小。此外，我们进一步测试了我们的学生和他们的老师之间的相似性，通过测量其标签和概率忠诚度以及回归忠诚度 - 在这项工作中引入的新指标。

从有限的资源中获得最大收益可以进步自然语言处理（NLP）研究和实践，同时保守资源。这些资源可能是数据，时间，存储或能源。NLP的最新工作从缩放率产生了有趣的结果。但是，仅使用比例来改善结果意味着资源消耗也会扩展。这种关系激发了对有效方法的研究，这些方法需要更少的资源才能获得相似的结果。这项调查涉及NLP效率的方法和发现，旨在指导该领域的新研究人员并激发新方法的发展。

大型的预训练的语言模型成功地用于多种语言的各种任务中。随着这种不断增加的使用，有害副作用的风险也会上升，例如通过再现和加强刻板印象。但是，在解决多种语言或考虑不同的偏见时，发现和缓解这些危害通常很难做到，并且在计算上变得昂贵。为了解决这个问题，我们提出了Fairdistiltation：一种基于知识蒸馏的跨语性方法，可以在控制特定偏见的同时构建较小的语言模型。我们发现，我们的蒸馏方法不会对大多数任务的下游性能产生负面影响，并成功减轻刻板印象和代表性危害。我们证明，与替代方法相比，Fairdistillation可以以低得多的成本创建更公平的语言模型。

Despite achieving state-of-the-art performance on many NLP tasks, the high energy cost and long inference delay prevent Transformer-based pretrained language models (PLMs) from seeing broader adoption including for edge and mobile computing. Efficient NLP research aims to comprehensively consider computation, time and carbon emission for the entire life-cycle of NLP, including data preparation, model training and inference. In this survey, we focus on the inference stage and review the current state of model compression and acceleration for pretrained language models, including benchmarks, metrics and methodology.

基于变压器的NLP模型是使用数亿甚至数十亿个参数训练的，从而限制了其在计算受限环境中的适用性。尽管参数的数量通常与性能相关，但尚不清楚下游任务是否需要整个网络。在最新的修剪和提炼预培训模型的工作中，我们探索了在预训练模型中放下层的策略，并观察修剪对下游胶水任务的影响。我们能够修剪Bert，Roberta和XLNet型号高达40％，同时保持其原始性能的98％。此外，我们证明，在大小和性能方面，您的修剪模型与使用知识蒸馏的型号相提并论。我们的实验产生有趣的观察结果，例如（i）下层对于维持下游任务性能最重要，（ii）某些任务（例如释义检测和句子相似性）对于降低层的降低和（iii）经过训练的模型更强大。使用不同的目标函数表现出不同的学习模式，并且层掉落。

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.

已经证明了对比学习适合学习句子嵌入，可以显着提高语义文本相似性（STS）任务。最近，大型对比学习模型，例如句子T5倾向于学到更强大的句子嵌入。虽然有效，但由于计算资源或时间成本限制，这种大型型号很难在线服务。为了解决这个问题，通常采用知识蒸馏（KD），这可以将大型“教师”模型压缩成一个小的“学生”模型，但通常会遭受一些性能损失。在这里，我们提出了一个增强的KD框架，称为蒸馏 - 对比度（迪斯科）。所提出的迪斯科框架首先利用KD将大句子嵌入模型的能力转移到大型未标记数据的小学生模型，然后在标记的训练数据上具有对比学习的学生模型。对于迪斯科舞厅的KD进程，我们进一步提出了对比的知识蒸馏（CKD），以增强教师模型培训，KD和学生模型的一致性，这可能会提高迅速学习的表现。 7 STS基准测试的广泛实验表明，使用所提出的迪斯科和CKD培训的学生模型很少或甚至没有性能损失，并且始终如一地优于相同参数大小的相应对应物。令人惊讶的是，我们的110米学生模型甚至可以优于最新的最新（SOTA）模型，即句子T5（11B），只有1％的参数。

我们从任务特定的BERT基教师模型执行知识蒸馏（KD）基准到各种学生模型：Bilstm，CNN，Bert-Tiny，Bert-Mini和Bert-small。我们的实验涉及在两个任务中分组的12个数据集：印度尼西亚语言中的文本分类和序列标记。我们还比较蒸馏的各个方面，包括使用Word Embeddings和未标记的数据增强的使用。我们的实验表明，尽管基于变压器的模型的普及程度不断上升，但是使用Bilstm和CNN学生模型，与修剪的BERT模型相比，使用Bilstm和CNN学生模型提供了性能和计算资源（CPU，RAM和存储）之间的最佳权衡。我们进一步提出了一些快速胜利，通过涉及涉及丢失功能，Word Embeddings和未标记的数据准备的简单选择的高效KD培训机制来生产小型NLP模型。

将最新的变压器模型蒸馏成轻量级的学生模型是降低推理时计算成本的有效方法。学生模型通常是紧凑的变压器，参数较少，而昂贵的操作（例如自我发项）持续存在。因此，对于实时或大量用例，提高的推理速度仍然不令人满意。在本文中，我们旨在通过将教师模型提炼成更大，更稀疏的学生模型来进一步推动推理速度的极限 - 更大的是它们扩展到数十亿个参数；稀疏，大多数模型参数是N-gram嵌入。我们对六个单词文本分类任务的实验表明，这些学生模型平均保留了罗伯塔大师教师表现的97％，同时推理时GPU和CPU的加速速度最高为600倍。进一步的调查表明，我们的管道也有助于句子对分类任务和域泛化设置。

我们研究了掩盖语言模型（MLMS）的任务无关内在和特定于任务的外在社会偏见评估措施之间的关系，并发现这两种评估措施之间仅存在弱相关性。此外，我们发现在下游任务进行微调期间，使用不同方法的MLMS DEBIAS进行了重新划分。我们确定两个培训实例中的社会偏见及其分配的标签是内在偏见评估测量值之间差异的原因。总体而言，我们的发现突出了现有的MLM偏见评估措施的局限性，并提出了使用这些措施在下游应用程序中部署MLM的担忧。

量化，知识蒸馏和修剪是NLP中神经网络压缩的最流行方法之一。独立地，这些方法降低了模型的大小并可以加速推断，但是尚未严格研究它们的相对益处和组合相互作用。对于这些技术的八个可能子集中的每一个，我们比较了六个BERT体系结构和八个胶水任务的准确性与模型大小的权衡。我们发现量化和蒸馏始终比修剪更大的好处。出乎意料的是，除了将多种方法一起使用多种修剪和量化之外，很少会产生回报的减少。取而代之的是，我们观察到互补和超级义务减少了模型大小。我们的工作定量表明，结合压缩方法可以协同降低模型大小，并且从业者应优先考虑（1）量化，（2）知识蒸馏，（3）修剪以最大程度地提高准确性与模型大小的权衡。

Pre-trained language models achieve superior performance, but they are computationally expensive due to their large size. Techniques such as pruning and knowledge distillation (KD) have been developed to reduce their size and latency. In most structural pruning methods, the pruning units, such as attention heads and feed-forward hidden dimensions, only span a small model structure space and limit the structures that the pruning algorithm can explore. In this work, we propose Gradient-based Intra-attention pruning (GRAIN), which inspects fine intra-attention structures, and allows different heads to have different sizes. Intra-attention pruning greatly expands the searching space of model structures and yields highly heterogeneous structures. We further propose structure regularization to encourage generating more regular structures, which achieves higher speedups than heterogeneous ones. We also integrate KD into the pruning process with a gradient separation strategy to reduce the interference of KD with the pruning process. GRAIN is evaluated on a variety of tasks. Results show that it notably outperforms other methods at the same or similar model size. Even under extreme compression where only $3\%$ weights in transformers remain, the pruned model is still competitive.

Large transformer models can highly improve Answer Sentence Selection (AS2) tasks, but their high computational costs prevent their use in many real-world applications. In this paper, we explore the following research question: How can we make the AS2 models more accurate without significantly increasing their model complexity? To address the question, we propose a Multiple Heads Student architecture (named CERBERUS), an efficient neural network designed to distill an ensemble of large transformers into a single smaller model. CERBERUS consists of two components: a stack of transformer layers that is used to encode inputs, and a set of ranking heads; unlike traditional distillation technique, each of them is trained by distilling a different large transformer architecture in a way that preserves the diversity of the ensemble members. The resulting model captures the knowledge of heterogeneous transformer models by using just a few extra parameters. We show the effectiveness of CERBERUS on three English datasets for AS2; our proposed approach outperforms all single-model distillations we consider, rivaling the state-of-the-art large AS2 models that have 2.7x more parameters and run 2.5x slower. Code for our model is available at https://github.com/amazon-research/wqa-cerberus