We present a theoretically grounded approach to train deep neural networks, including recurrent networks, subject to class-dependent label noise. We propose two procedures for loss correction that are agnostic to both application domain and network architecture. They simply amount to at most a matrix inversion and multiplication, provided that we know the probability of each class being corrupted into another. We further show how one can estimate these probabilities, adapting a recent technique for noise estimation to the multi-class setting, and thus providing an end-to-end framework. Extensive experiments on MNIST, IMDB, CIFAR-10, CIFAR-100 and a large scale dataset of clothing images employing a diversity of architectures -stacking dense, convolutional, pooling, dropout, batch normalization, word embedding, LSTM and residual layers -demonstrate the noise robustness of our proposals. Incidentally, we also prove that, when ReLU is the only non-linearity, the loss curvature is immune to class-dependent label noise.

Training accurate deep neural networks (DNNs) in the presence of noisy labels is an important and challenging task. Though a number of approaches have been proposed for learning with noisy labels, many open issues remain. In this paper, we show that DNN learning with Cross Entropy (CE) exhibits overfitting to noisy labels on some classes ("easy" classes), but more surprisingly, it also suffers from significant under learning on some other classes ("hard" classes). Intuitively, CE requires an extra term to facilitate learning of hard classes, and more importantly, this term should be noise tolerant, so as to avoid overfitting to noisy labels. Inspired by the symmetric KL-divergence, we propose the approach of Symmetric cross entropy Learning (SL), boosting CE symmetrically with a noise robust counterpart Reverse Cross Entropy (RCE). Our proposed SL approach simultaneously addresses both the under learning and overfitting problem of CE in the presence of noisy labels. We provide a theoretical analysis of SL and also empirically show, on a range of benchmark and real-world datasets, that SL outperforms state-of-the-art methods. We also show that SL can be easily incorporated into existing methods in order to further enhance their performance.

深度学习在大量大数据的帮助下取得了众多域中的显着成功。然而，由于许多真实情景中缺乏高质量标签，数据标签的质量是一个问题。由于嘈杂的标签严重降低了深度神经网络的泛化表现，从嘈杂的标签（强大的培训）学习是在现代深度学习应用中成为一项重要任务。在本调查中，我们首先从监督的学习角度描述了与标签噪声学习的问题。接下来，我们提供62项最先进的培训方法的全面审查，所有这些培训方法都按照其方法论差异分为五个群体，其次是用于评估其优越性的六种性质的系统比较。随后，我们对噪声速率估计进行深入分析，并总结了通常使用的评估方法，包括公共噪声数据集和评估度量。最后，我们提出了几个有前途的研究方向，可以作为未来研究的指导。所有内容将在https://github.com/songhwanjun/awesome-noisy-labels提供。

最近，与培训样本相比，具有越来越多的网络参数的过度参数深度网络主导了现代机器学习的性能。但是，当培训数据被损坏时，众所周知，过度参数化的网络往往会过度合适并且不会概括。在这项工作中，我们提出了一种有原则的方法，用于在分类任务中对过度参数的深层网络进行强有力的培训，其中一部分培训标签被损坏。主要想法还很简单：标签噪声与从干净的数据中学到的网络稀疏且不一致，因此我们对噪声进行建模并学会将其与数据分开。具体而言，我们通过另一个稀疏的过度参数术语对标签噪声进行建模，并利用隐式算法正规化来恢复和分离基础损坏。值得注意的是，当在实践中使用如此简单的方法培训时，我们证明了针对各种真实数据集上标签噪声的最新测试精度。此外，我们的实验结果通过理论在简化的线性模型上证实，表明在不连贯的条件下稀疏噪声和低级别数据之间的精确分离。这项工作打开了许多有趣的方向，可以使用稀疏的过度参数化和隐式正则化来改善过度参数化模型。

Label noise is a significant obstacle in deep learning model training. It can have a considerable impact on the performance of image classification models, particularly deep neural networks, which are especially susceptible because they have a strong propensity to memorise noisy labels. In this paper, we have examined the fundamental concept underlying related label noise approaches. A transition matrix estimator has been created, and its effectiveness against the actual transition matrix has been demonstrated. In addition, we examined the label noise robustness of two convolutional neural network classifiers with LeNet and AlexNet designs. The two FashionMINIST datasets have revealed the robustness of both models. We are not efficiently able to demonstrate the influence of the transition matrix noise correction on robustness enhancements due to our inability to correctly tune the complex convolutional neural network model due to time and computing resource constraints. There is a need for additional effort to fine-tune the neural network model and explore the precision of the estimated transition model in future research.

In the presence of noisy labels, designing robust loss functions is critical for securing the generalization performance of deep neural networks. Cross Entropy (CE) loss has been shown to be not robust to noisy labels due to its unboundedness. To alleviate this issue, existing works typically design specialized robust losses with the symmetric condition, which usually lead to the underfitting issue. In this paper, our key idea is to induce a loss bound at the logit level, thus universally enhancing the noise robustness of existing losses. Specifically, we propose logit clipping (LogitClip), which clamps the norm of the logit vector to ensure that it is upper bounded by a constant. In this manner, CE loss equipped with our LogitClip method is effectively bounded, mitigating the overfitting to examples with noisy labels. Moreover, we present theoretical analyses to certify the noise-tolerant ability of LogitClip. Extensive experiments show that LogitClip not only significantly improves the noise robustness of CE loss, but also broadly enhances the generalization performance of popular robust losses.

最近关于使用嘈杂标签的学习的研究通过利用小型干净数据集来显示出色的性能。特别是，基于模型不可知的元学习的标签校正方法进一步提高了性能，通过纠正了嘈杂的标签。但是，标签错误矫予没有保障措施，导致不可避免的性能下降。此外，每个训练步骤都需要至少三个背部传播，显着减慢训练速度。为了缓解这些问题，我们提出了一种强大而有效的方法，可以在飞行中学习标签转换矩阵。采用转换矩阵使分类器对所有校正样本持怀疑态度，这减轻了错误的错误问题。我们还介绍了一个双头架构，以便在单个反向传播中有效地估计标签转换矩阵，使得估计的矩阵紧密地遵循由标签校正引起的移位噪声分布。广泛的实验表明，我们的方法在训练效率方面表现出比现有方法相当或更好的准确性。

In many applications of classifier learning, training data suffers from label noise. Deep networks are learned using huge training data where the problem of noisy labels is particularly relevant. The current techniques proposed for learning deep networks under label noise focus on modifying the network architecture and on algorithms for estimating true labels from noisy labels. An alternate approach would be to look for loss functions that are inherently noise-tolerant. For binary classification there exist theoretical results on loss functions that are robust to label noise. In this paper, we provide some sufficient conditions on a loss function so that risk minimization under that loss function would be inherently tolerant to label noise for multiclass classification problems. These results generalize the existing results on noise-tolerant loss functions for binary classification. We study some of the widely used loss functions in deep networks and show that the loss function based on mean absolute value of error is inherently robust to label noise. Thus standard back propagation is enough to learn the true classifier even under label noise. Through experiments, we illustrate the robustness of risk minimization with such loss functions for learning neural networks.

Deep neural networks (DNNs) have achieved tremendous success in a variety of applications across many disciplines. Yet, their superior performance comes with the expensive cost of requiring correctly annotated large-scale datasets. Moreover, due to DNNs' rich capacity, errors in training labels can hamper performance. To combat this problem, mean absolute error (MAE) has recently been proposed as a noise-robust alternative to the commonly-used categorical cross entropy (CCE) loss. However, as we show in this paper, MAE can perform poorly with DNNs and challenging datasets. Here, we present a theoretically grounded set of noise-robust loss functions that can be seen as a generalization of MAE and CCE. Proposed loss functions can be readily applied with any existing DNN architecture and algorithm, while yielding good performance in a wide range of noisy label scenarios. We report results from experiments conducted with CIFAR-10, CIFAR-100 and FASHION-MNIST datasets and synthetically generated noisy labels.

对标签噪声的学习是一个至关重要的话题，可以保证深度神经网络的可靠表现。最近的研究通常是指具有模型输出概率和损失值的动态噪声建模，然后分离清洁和嘈杂的样本。这些方法取得了显着的成功。但是，与樱桃挑选的数据不同，现有方法在面对不平衡数据集时通常无法表现良好，这是现实世界中常见的情况。我们彻底研究了这一现象，并指出了两个主要问题，这些问题阻碍了性能，即\ emph {类间损耗分布差异}和\ emph {由于不确定性而引起的误导性预测}。第一个问题是现有方法通常执行类不足的噪声建模。然而，损失分布显示在类失衡下的类别之间存在显着差异，并且类不足的噪声建模很容易与少数族裔类别中的嘈杂样本和样本混淆。第二个问题是指该模型可能会因认知不确定性和不确定性而导致的误导性预测，因此仅依靠输出概率的现有方法可能无法区分自信的样本。受我们的观察启发，我们提出了一个不确定性的标签校正框架〜（ULC）来处理不平衡数据集上的标签噪声。首先，我们执行认识不确定性的班级特异性噪声建模，以识别可信赖的干净样本并精炼/丢弃高度自信的真实/损坏的标签。然后，我们在随后的学习过程中介绍了不确定性，以防止标签噪声建模过程中的噪声积累。我们对几个合成和现实世界数据集进行实验。结果证明了提出的方法的有效性，尤其是在数据集中。

The existence of label noise imposes significant challenges (e.g., poor generalization) on the training process of deep neural networks (DNN). As a remedy, this paper introduces a permutation layer learning approach termed PermLL to dynamically calibrate the training process of the DNN subject to instance-dependent and instance-independent label noise. The proposed method augments the architecture of a conventional DNN by an instance-dependent permutation layer. This layer is essentially a convex combination of permutation matrices that is dynamically calibrated for each sample. The primary objective of the permutation layer is to correct the loss of noisy samples mitigating the effect of label noise. We provide two variants of PermLL in this paper: one applies the permutation layer to the model's prediction, while the other applies it directly to the given noisy label. In addition, we provide a theoretical comparison between the two variants and show that previous methods can be seen as one of the variants. Finally, we validate PermLL experimentally and show that it achieves state-of-the-art performance on both real and synthetic datasets.

嘈杂的标签损坏了深网络的性能。为了稳健的学习，突出的两级管道在消除可能的不正确标签和半监督培训之间交替。然而，丢弃观察到的标签的部分可能导致信息丢失，尤其是当腐败不是完全随机的时，例如依赖类或实例依赖。此外，从代表性两级方法Dividemix的训练动态，我们确定了确认偏置的统治：伪标签未能纠正相当大量的嘈杂标签，因此累积误差。为了充分利用观察到的标签和减轻错误的校正，我们提出了强大的标签翻新（鲁棒LR）-a新的混合方法，该方法集成了伪标签和置信度估计技术来翻新嘈杂的标签。我们表明我们的方法成功减轻了标签噪声和确认偏差的损害。结果，它跨数据集和噪声类型实现最先进的结果。例如，强大的LR在真实世界嘈杂的数据集网络VIVION上以前最好的绝对高度提高了4.5％的绝对顶级精度改进。

可以将监督学习视为将相关信息从输入数据中提取到特征表示形式。当监督嘈杂时，此过程变得困难，因为蒸馏信息可能无关紧要。实际上，最近的研究表明，网络可以轻松地过度贴合所有标签，包括损坏的标签，因此几乎无法概括以清洁数据集。在本文中，我们专注于使用嘈杂的标签学习的问题，并将压缩归纳偏置引入网络体系结构以减轻这种过度的问题。更确切地说，我们重新审视一个名为辍学的经典正则化及其变体嵌套辍学。辍学可以作为其功能删除机制的压缩约束，而嵌套辍学进一步学习有序的特征表示W.R.T.特征重要性。此外，具有压缩正则化的训练有素的模型与共同教学相结合，以提高性能。从理论上讲，我们在压缩正则化下对目标函数进行偏置变化分解。我们分析了单个模型和共同教学。该分解提供了三个见解：（i）表明过度合适确实是使用嘈杂标签学习的问题； （ii）通过信息瓶颈配方，它解释了为什么提出的特征压缩有助于对抗标签噪声； （iii）它通过将压缩正规化纳入共同教学而带来的性能提升提供了解释。实验表明，我们的简单方法比具有现实世界标签噪声（包括服装1M和Animal-10N）的基准测试标准的最先进方法具有可比性甚至更好的性能。我们的实施可在https://yingyichen-cyy.github.io/compressfatsfeatnoisylabels/上获得。

Deep neural networks may easily memorize noisy labels present in real-world data, which degrades their ability to generalize. It is therefore important to track and evaluate the robustness of models against noisy label memorization. We propose a metric, called susceptibility, to gauge such memorization for neural networks. Susceptibility is simple and easy to compute during training. Moreover, it does not require access to ground-truth labels and it only uses unlabeled data. We empirically show the effectiveness of our metric in tracking memorization on various architectures and datasets and provide theoretical insights into the design of the susceptibility metric. Finally, we show through extensive experiments on datasets with synthetic and real-world label noise that one can utilize susceptibility and the overall training accuracy to distinguish models that maintain a low memorization on the training set and generalize well to unseen clean data.

作为标签噪声，最受欢迎的分布变化之一，严重降低了深度神经网络的概括性能，具有嘈杂标签的强大训练正在成为现代深度学习中的重要任务。在本文中，我们提出了我们的框架，在子分类器（ALASCA）上创造了自适应标签平滑，该框架提供了具有理论保证和可忽略的其他计算的可靠特征提取器。首先，我们得出标签平滑（LS）会产生隐式Lipschitz正则化（LR）。此外，基于这些推导，我们将自适应LS（ALS）应用于子分类器架构上，以在中间层上的自适应LR的实际应用。我们对ALASCA进行了广泛的实验，并将其与以前的几个数据集上的噪声燃烧方法相结合，并显示我们的框架始终优于相应的基线。

监督学习的关键假设是培训和测试数据遵循相同的概率分布。然而，这种基本假设在实践中并不总是满足，例如，由于不断变化的环境，样本选择偏差，隐私问题或高标签成本。转移学习（TL）放松这种假设，并允许我们在分销班次下学习。通常依赖于重要性加权的经典TL方法 - 基于根据重要性（即测试过度训练密度比率）的训练损失培训预测器。然而，由于现实世界机器学习任务变得越来越复杂，高维和动态，探讨了新的新方法，以应对这些挑战最近。在本文中，在介绍基于重要性加权的TL基础之后，我们根据关节和动态重要预测估计审查最近的进步。此外，我们介绍一种因果机制转移方法，该方法包含T1中的因果结构。最后，我们讨论了TL研究的未来观点。

深神经网络（DNN）的记忆效应在最近的标签噪声学习方法中起关键作用。为了利用这种效果，已经广泛采用了基于模型预测的方法，该方法旨在利用DNN在学习的早期阶段以纠正嘈杂标签的效果。但是，我们观察到该模型在标签预测期间会犯错误，从而导致性能不令人满意。相比之下，在学习早期阶段产生的特征表现出更好的鲁棒性。受到这一观察的启发，在本文中，我们提出了一种基于特征嵌入的新方法，用于用标签噪声，称为标签NoissiLution（Lend）。要具体而言，我们首先根据当前的嵌入式特征计算一个相似性矩阵，以捕获训练数据的局部结构。然后，附近标记的数据（\ textIt {i.e。}，标签噪声稀释）使错误标记的数据携带的嘈杂的监督信号淹没了，其有效性是由特征嵌入的固有鲁棒性保证的。最后，带有稀释标签的培训数据进一步用于培训强大的分类器。从经验上讲，我们通过将我们的贷款与几种代表性的强大学习方法进行比较，对合成和现实世界嘈杂数据集进行了广泛的实验。结果验证了我们贷款的有效性。

We introduce a tunable loss function called $\alpha$-loss, parameterized by $\alpha \in (0,\infty]$, which interpolates between the exponential loss ($\alpha = 1/2$), the log-loss ($\alpha = 1$), and the 0-1 loss ($\alpha = \infty$), for the machine learning setting of classification. Theoretically, we illustrate a fundamental connection between $\alpha$-loss and Arimoto conditional entropy, verify the classification-calibration of $\alpha$-loss in order to demonstrate asymptotic optimality via Rademacher complexity generalization techniques, and build-upon a notion called strictly local quasi-convexity in order to quantitatively characterize the optimization landscape of $\alpha$-loss. Practically, we perform class imbalance, robustness, and classification experiments on benchmark image datasets using convolutional-neural-networks. Our main practical conclusion is that certain tasks may benefit from tuning $\alpha$-loss away from log-loss ($\alpha = 1$), and to this end we provide simple heuristics for the practitioner. In particular, navigating the $\alpha$ hyperparameter can readily provide superior model robustness to label flips ($\alpha > 1$) and sensitivity to imbalanced classes ($\alpha < 1$).

最近已证明自我监督的对比学习（CL）非常有效地防止深网贴上嘈杂的标签。尽管取得了经验成功，但对对比度学习对增强鲁棒性的影响的理论理解非常有限。在这项工作中，我们严格地证明，通过对比度学习学到的表示矩阵可以通过：（i）与数据中每个子类相对应的一个突出的奇异值来增强鲁棒性，并显着较小的剩余奇异值； （ii）{{显着的单数矢量与每个子类的干净标签之间的一个很大的对齐。以上属性使对此类表示的线性层能够有效地学习干净的标签，而不会过度适应噪音。}我们进一步表明，通过对比度学习预先训练的深网的雅各比式的低级别结构使他们能够获得优越的最初的性能是在嘈杂的标签上进行微调时。最后，我们证明了对比度学习提供的最初鲁棒性使鲁棒训练方法能够在极端噪声水平下实现最先进的性能，例如平均27.18 \％\％和15.58 \％\％\％\％\％cifar-10上的提高和80 \％对称嘈杂标签的CIFAR-100，网络视频的准确性提高4.11 \％。

神经崩溃的概念是指在各种规范分类问题中经验观察到的几种新兴现象。在训练深度神经网络的终端阶段，同一类的所有示例的特征嵌入往往会崩溃为单一表示，而不同类别的特征往往会尽可能分开。通常通过简化的模型（称为无约束的特征表示）来研究神经崩溃，其中假定模型具有“无限表达性”，并且可以将每个数据点映射到任何任意表示。在这项工作中，我们提出了不受约束的功能表示的更现实的变体，该变体考虑到了网络的有限表达性。经验证据表明，嘈杂数据点的记忆导致神经崩溃的降解（扩张）。使用记忆 - 稀释（M-D）现象的模型，我们展示了一种机制，通过该机制，不同的损失导致嘈杂数据上受过训练的网络的不同性能。我们的证据揭示了为什么标签平滑性（经验观察到产生正则化效果的跨凝性的修改）导致分类任务的概括改善的原因。