Neural networks trained with ERM (empirical risk minimization) sometimes learn unintended decision rules, in particular when their training data is biased, i.e., when training labels are strongly correlated with undesirable features. To prevent a network from learning such features, recent methods augment training data such that examples displaying spurious correlations (i.e., bias-aligned examples) become a minority, whereas the other, bias-conflicting examples become prevalent. However, these approaches are sometimes difficult to train and scale to real-world data because they rely on generative models or disentangled representations. We propose an alternative based on mixup, a popular augmentation that creates convex combinations of training examples. Our method, coined SelecMix, applies mixup to contradicting pairs of examples, defined as showing either (i) the same label but dissimilar biased features, or (ii) different labels but similar biased features. Identifying such pairs requires comparing examples with respect to unknown biased features. For this, we utilize an auxiliary contrastive model with the popular heuristic that biased features are learned preferentially during training. Experiments on standard benchmarks demonstrate the effectiveness of the method, in particular when label noise complicates the identification of bias-conflicting examples.

几项研究在经验上比较了各种模型的分布（ID）和分布（OOD）性能。他们报告了计算机视觉和NLP中基准的频繁正相关。令人惊讶的是，他们从未观察到反相关性表明必要的权衡。这重要的是确定ID性能是否可以作为OOD概括的代理。这篇简短的论文表明，ID和OOD性能之间的逆相关性确实在现实基准中发生。由于模型的选择有偏见，因此在过去的研究中可能被错过。我们使用来自多个训练时期和随机种子的模型展示了Wilds-Amelyon17数据集上模式的示例。我们的观察结果尤其引人注目，对经过正规化器训练的模型，将解决方案多样化为ERM目标。我们在过去的研究中得出了细微的建议和结论。 （1）高OOD性能有时确实需要交易ID性能。 （2）仅专注于ID性能可能不会导致最佳OOD性能：它可能导致OOD性能的减少并最终带来负面回报。 （3）我们的示例提醒人们，实证研究仅按照现有方法来制定制度：在提出规定的建议时有必要进行护理。

机器学习（ML）模型通常是针对给定数据集的精度进行优化的。但是，此预测标准很少捕获模型的所有理想属性，特别是它与域专家对任务的理解的匹配程度。指定的是指多种模型的存在，这些模型在其内域准确性上是无法区分的，即使它们在其他期望的属性（例如分布（OOD）性能）上有所不同。确定这些情况对于评估ML模型的可靠性至关重要。我们正式化了指定的概念，并提出了一种识别和部分解决它的方法。我们训练多个模型具有独立约束，迫使他们实施不同的功能。他们发现了预测性特征，否则标准经验风险最小化（ERM）忽略了这些特征，然后我们将其提炼成具有出色OOD性能的全球模型。重要的是，我们限制了模型以与数据歧管保持一致，以确保它们发现有意义的功能。我们在计算机视觉（拼贴，wild-camelyon17，gqa）中演示了多个数据集的方法，并讨论了指定规定的一般含义。最值得注意的是，没有其他假设，内域性能无法用于OOD模型选择。

清洁和不同标记的数据的可用性是培训复杂任务（例如视觉问答（VQA））的培训模型的主要障碍。大型视觉和语言模型的广泛工作表明，自我监督的学习对预处理多模式相互作用有效。在此技术报告中，我们专注于视觉表示。我们审查和评估自我监督的方法，以利用未标记的图像并预处理模型，然后我们对其进行了自定义VQA任务，该任务允许进行控制的评估和诊断。我们将基于能量的模型（EBM）与对比度学习（CL）进行比较。尽管EBM越来越受欢迎，但他们缺乏对下游任务的评估。我们发现，EBM和CL都可以从未标记的图像中学习表示形式，这些图像能够在很少的注释数据上训练VQA模型。在类似于CLEVR的简单设置中，我们发现CL表示还可以改善系统的概括，甚至匹配来自较大，监督，预测模型的表示的性能。但是，我们发现EBM由于不稳定性和结果差异很高而难以训练。尽管EBMS被证明对OOD检测有用，但基于监督的基于能量的训练和不确定性校准的其他结果在很大程度上是负面的。总体而言，CL当前似乎比EBM的选项更为可取。

最近证明，接受SGD训练的神经网络优先依赖线性预测的特征，并且可以忽略复杂的，同样可预测的功能。这种简单性偏见可以解释他们缺乏分布（OOD）的鲁棒性。学习任务越复杂，统计工件（即选择偏见，虚假相关性）的可能性就越大比学习的机制更简单。我们证明可以减轻简单性偏差并改善了OOD的概括。我们使用对其输入梯度对齐的惩罚来训练一组类似的模型以不同的方式拟合数据。我们从理论和经验上展示了这会导致学习更复杂的预测模式的学习。 OOD的概括从根本上需要超出I.I.D.示例，例如多个培训环境，反事实示例或其他侧面信息。我们的方法表明，我们可以将此要求推迟到独立的模型选择阶段。我们获得了SOTA的结果，可以在视觉域偏置数据和概括方面进行视觉识别。该方法 - 第一个逃避简单性偏见的方法 - 突出了需要更好地理解和控制深度学习中的归纳偏见。

我们介绍了视觉问题应答（VQA）的评估方法，以更好地诊断捷径学习案例。当模型利用虚假统计规则产生正确答案但实际上没有部署所需的行为时，会发生这些情况。需要在数据集中识别可能的快捷方式，并在部署现实世界中的模型之前评估它们的使用。 VQA的研究界专注于基于问题的快捷方式，其中模型可能是通过依赖于先前的问题条件培训并提供重量的问题条件培训来回答“天空的颜色”。视觉证据。我们进一步逐步，考虑涉及两个问题和图像的多模式捷径。我们首先通过挖掘琐碎的预测规则，例如诸如单词和视觉元素的共同发生的琐碎的预测规则来确定流行的VQA V2培训中的潜在捷径。然后，我们将介绍VQA-Consterexamples（VQA-CE），一个评估协议，基于我们的反例等的子集i.e.图像 - 问题答案三胞胎，我们的规则导致错误的答案。我们在大规模研究VQA现有方法中使用这一新评估。我们表明即使是最先进的模型也表现不佳，并且在这种情况下，降低偏差的现有技术在很大程度上无效。我们的研究结果表明，过去的vqa中的基于问题的偏差的工作仅签署了一个复杂问题的一个方面。我们方法的代码可在https://github.com/cdancette/detect-shortcut中获得。

A robot that can carry out a natural-language instruction has been a dream since before the Jetsons cartoon series imagined a life of leisure mediated by a fleet of attentive robot helpers. It is a dream that remains stubbornly distant. However, recent advances in vision and language methods have made incredible progress in closely related areas. This is significant because a robot interpreting a naturallanguage navigation instruction on the basis of what it sees is carrying out a vision and language process that is similar to Visual Question Answering. Both tasks can be interpreted as visually grounded sequence-to-sequence translation problems, and many of the same methods are applicable. To enable and encourage the application of vision and language methods to the problem of interpreting visuallygrounded navigation instructions, we present the Matter-port3D Simulator -a large-scale reinforcement learning environment based on real imagery [11]. Using this simulator, which can in future support a range of embodied vision and language tasks, we provide the first benchmark dataset for visually-grounded natural language navigation in real buildings -the Room-to-Room (R2R) dataset 1 .1 https://bringmeaspoon.org Instruction: Head upstairs and walk past the piano through an archway directly in front. Turn right when the hallway ends at pictures and table. Wait by the moose antlers hanging on the wall.

Top-down visual attention mechanisms have been used extensively in image captioning and visual question answering (VQA) to enable deeper image understanding through fine-grained analysis and even multiple steps of reasoning. In this work, we propose a combined bottom-up and topdown attention mechanism that enables attention to be calculated at the level of objects and other salient image regions. This is the natural basis for attention to be considered. Within our approach, the bottom-up mechanism (based on Faster R-CNN) proposes image regions, each with an associated feature vector, while the top-down mechanism determines feature weightings. Applying this approach to image captioning, our results on the MSCOCO test server establish a new state-of-the-art for the task, achieving CIDEr / SPICE / BLEU-4 scores of 117.9, 21.5 and 36.9, respectively. Demonstrating the broad applicability of the method, applying the same approach to VQA we obtain first place in the 2017 VQA Challenge.

Classical reinforcement learning (RL) techniques are generally concerned with the design of decision-making policies driven by the maximisation of the expected outcome. Nevertheless, this approach does not take into consideration the potential risk associated with the actions taken, which may be critical in certain applications. To address that issue, the present research work introduces a novel methodology based on distributional RL to derive sequential decision-making policies that are sensitive to the risk, the latter being modelled by the tail of the return probability distribution. The core idea is to replace the $Q$ function generally standing at the core of learning schemes in RL by another function taking into account both the expected return and the risk. Named the risk-based utility function $U$, it can be extracted from the random return distribution $Z$ naturally learnt by any distributional RL algorithm. This enables to span the complete potential trade-off between risk minimisation and expected return maximisation, in contrast to fully risk-averse methodologies. Fundamentally, this research yields a truly practical and accessible solution for learning risk-sensitive policies with minimal modification to the distributional RL algorithm, and with an emphasis on the interpretability of the resulting decision-making process.

Deep learning models are being increasingly applied to imbalanced data in high stakes fields such as medicine, autonomous driving, and intelligence analysis. Imbalanced data compounds the black-box nature of deep networks because the relationships between classes may be highly skewed and unclear. This can reduce trust by model users and hamper the progress of developers of imbalanced learning algorithms. Existing methods that investigate imbalanced data complexity are geared toward binary classification, shallow learning models and low dimensional data. In addition, current eXplainable Artificial Intelligence (XAI) techniques mainly focus on converting opaque deep learning models into simpler models (e.g., decision trees) or mapping predictions for specific instances to inputs, instead of examining global data properties and complexities. Therefore, there is a need for a framework that is tailored to modern deep networks, that incorporates large, high dimensional, multi-class datasets, and uncovers data complexities commonly found in imbalanced data (e.g., class overlap, sub-concepts, and outlier instances). We propose a set of techniques that can be used by both deep learning model users to identify, visualize and understand class prototypes, sub-concepts and outlier instances; and by imbalanced learning algorithm developers to detect features and class exemplars that are key to model performance. Our framework also identifies instances that reside on the border of class decision boundaries, which can carry highly discriminative information. Unlike many existing XAI techniques which map model decisions to gray-scale pixel locations, we use saliency through back-propagation to identify and aggregate image color bands across entire classes. Our framework is publicly available at \url{https://github.com/dd1github/XAI_for_Imbalanced_Learning}