通常,深度神经网络(DNN)是通过在训练阶段排除的未见数据测量的概括性能评估的。随着DNN的发展,概括性能会收敛到最新的,并且很难仅基于该指标评估DNN。对抗攻击的鲁棒性已被用作通过测量其脆弱性来评估DNN的额外指标。但是,很少有研究通过DNN中的几何形状来分析对抗性鲁棒性。在这项工作中,我们进行了一项实证研究,以分析影响对抗性攻击下模型鲁棒性的DNN的内部特性。特别是,我们提出了人口稠密区域集(PRS)的新颖概念,其中训练样本更频繁地代表在实际环境中DNN的内部特性。从对拟议概念进行的系统实验,我们提供了经验证据,以证明低PRS比与DNNS的对抗鲁棒性具有牢固的关系。我们还设计了PRS正常器利用PRS的特征来改善对抗性鲁棒性,而无需对抗训练。
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对抗性可转移性是一种有趣的性质 - 针对一个模型制作的对抗性扰动也是对另一个模型有效的,而这些模型来自不同的模型家庭或培训过程。为了更好地保护ML系统免受对抗性攻击,提出了几个问题:对抗性转移性的充分条件是什么,以及如何绑定它?有没有办法降低对抗的转移性,以改善合奏ML模型的鲁棒性?为了回答这些问题,在这项工作中,我们首先在理论上分析和概述了模型之间的对抗性可转移的充分条件;然后提出一种实用的算法,以减少集合内基础模型之间的可转换,以提高其鲁棒性。我们的理论分析表明,只有促进基础模型梯度之间的正交性不足以确保低可转移性;与此同时,模型平滑度是控制可转移性的重要因素。我们还在某些条件下提供了对抗性可转移性的下界和上限。灵感来自我们的理论分析,我们提出了一种有效的可转让性,减少了平滑(TRS)集合培训策略,以通过实施基础模型之间的梯度正交性和模型平滑度来培训具有低可转换性的强大集成。我们对TRS进行了广泛的实验,并与6个最先进的集合基线进行比较,防止不同数据集的8个白箱攻击,表明所提出的TRS显着优于所有基线。
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已知深度神经网络(DNN)容易受到用不可察觉的扰动制作的对抗性示例的影响,即,输入图像的微小变化会引起错误的分类,从而威胁着基于深度学习的部署系统的可靠性。经常采用对抗训练(AT)来通过训练损坏和干净的数据的混合物来提高DNN的鲁棒性。但是,大多数基于AT的方法在处理\ textit {转移的对抗示例}方面是无效的,这些方法是生成以欺骗各种防御模型的生成的,因此无法满足现实情况下提出的概括要求。此外,对抗性训练一般的国防模型不能对具有扰动的输入产生可解释的预测,而不同的领域专家则需要一个高度可解释的强大模型才能了解DNN的行为。在这项工作中,我们提出了一种基于Jacobian规范和选择性输入梯度正则化(J-SIGR)的方法,该方法通过Jacobian归一化提出了线性化的鲁棒性,还将基于扰动的显着性图正规化,以模仿模型的可解释预测。因此,我们既可以提高DNN的防御能力和高解释性。最后,我们评估了跨不同体系结构的方法,以针对强大的对抗性攻击。实验表明,提出的J-Sigr赋予了针对转移的对抗攻击的鲁棒性,我们还表明,来自神经网络的预测易于解释。
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作为反对攻击的最有效的防御方法之一,对抗性训练倾向于学习包容性的决策边界,以提高深度学习模型的鲁棒性。但是,由于沿对抗方向的边缘的大幅度和不必要的增加,对抗性训练会在自然实例和对抗性示例之间引起严重的交叉,这不利于平衡稳健性和自然准确性之间的权衡。在本文中,我们提出了一种新颖的对抗训练计划,以在稳健性和自然准确性之间进行更好的权衡。它旨在学习一个中度包容的决策边界,这意味着决策边界下的自然示例的边缘是中等的。我们称此方案为中等边缘的对抗训练(MMAT),该方案生成更细粒度的对抗示例以减轻交叉问题。我们还利用了经过良好培训的教师模型的逻辑来指导我们的模型学习。最后,MMAT在Black-Box和White-Box攻击下都可以实现高自然的精度和鲁棒性。例如,在SVHN上,实现了最新的鲁棒性和自然精度。
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模型归因在深度神经网络中很重要,因为它们可以帮助实践者理解模型,但是最近的研究表明,通过向输入中添加不可察觉的噪声可以轻松扰动归因。非差异性肯德尔的等级相关性是归因保护的关键绩效指数。在本文中,我们首先证明了预期的肯德尔的等级相关性与余弦相似性呈正相关,然后表明归因方向是归因鲁棒性的关键。基于这些发现,我们探索了归因的矢量空间,以使用$ \ ell_p $ norm来解释归因防御方法的缺点,并提出了集成的梯度正常化程序(IGR),从而最大程度地提高了自然和扰动属性之间的余弦相似性。我们的分析进一步公开了IGR鼓励具有相同激活状态的天然样品和相应扰动样品的神经元,这证明可以诱导基于梯度的归因方法的鲁棒性。我们在不同模型和数据集上的实验证实了我们对归因保护的分析,并证明了对抗性鲁棒性的不当改善。
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深度神经网络(DNNS)最近在许多分类任务中取得了巨大的成功。不幸的是,它们容易受到对抗性攻击的影响,这些攻击会产生对抗性示例,这些示例具有很小的扰动,以欺骗DNN模型,尤其是在模型共享方案中。事实证明,对抗性训练是最有效的策略,它将对抗性示例注入模型训练中,以提高DNN模型的稳健性,以对对抗性攻击。但是,基于现有的对抗性示例的对抗训练无法很好地推广到标准,不受干扰的测试数据。为了在标准准确性和对抗性鲁棒性之间取得更好的权衡,我们提出了一个新型的对抗训练框架,称为潜在边界引导的对抗训练(梯子),该训练(梯子)在潜在的边界引导的对抗性示例上对对手进行对手训练DNN模型。与大多数在输入空间中生成对抗示例的现有方法相反,梯子通过增加对潜在特征的扰动而产生了无数的高质量对抗示例。扰动是沿SVM构建的具有注意机制的决策边界的正常情况进行的。我们从边界场的角度和可视化视图分析了生成的边界引导的对抗示例的优点。与Vanilla DNN和竞争性底线相比,对MNIST,SVHN,CELEBA和CIFAR-10的广泛实验和详细分析验证了梯子在标准准确性和对抗性鲁棒性之间取得更好的权衡方面的有效性。
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对抗性的鲁棒性已经成为深度学习的核心目标,无论是在理论和实践中。然而,成功的方法来改善对抗的鲁棒性(如逆势训练)在不受干扰的数据上大大伤害了泛化性能。这可能会对对抗性鲁棒性如何影响现实世界系统的影响(即,如果它可以提高未受干扰的数据的准确性),许多人可能选择放弃鲁棒性)。我们提出内插对抗培训,该培训最近雇用了在对抗培训框架内基于插值的基于插值的培训方法。在CiFar -10上,对抗性训练增加了标准测试错误(当没有对手时)从4.43%到12.32%,而我们的内插对抗培训我们保留了对抗性的鲁棒性,同时实现了仅6.45%的标准测试误差。通过我们的技术,强大模型标准误差的相对增加从178.1%降至仅为45.5%。此外,我们提供内插对抗性培训的数学分析,以确认其效率,并在鲁棒性和泛化方面展示其优势。
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State-of-the-art classifiers have been shown to be largely vulnerable to adversarial perturbations. One of the most effective strategies to improve robustness is adversarial training. In this paper, we investigate the effect of adversarial training on the geometry of the classification landscape and decision boundaries. We show in particular that adversarial training leads to a significant decrease in the curvature of the loss surface with respect to inputs, leading to a drastically more "linear" behaviour of the network. Using a locally quadratic approximation, we provide theoretical evidence on the existence of a strong relation between large robustness and small curvature. To further show the importance of reduced curvature for improving the robustness, we propose a new regularizer that directly minimizes curvature of the loss surface, and leads to adversarial robustness that is on par with adversarial training. Besides being a more efficient and principled alternative to adversarial training, the proposed regularizer confirms our claims on the importance of exhibiting quasi-linear behavior in the vicinity of data points in order to achieve robustness.
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深度学习(DL)系统的安全性是一个极为重要的研究领域,因为它们正在部署在多个应用程序中,因为它们不断改善,以解决具有挑战性的任务。尽管有压倒性的承诺,但深度学习系统容易受到制作的对抗性例子的影响,这可能是人眼无法察觉的,但可能会导致模型错误分类。对基于整体技术的对抗性扰动的保护已被证明很容易受到更强大的对手的影响,或者证明缺乏端到端评估。在本文中,我们试图开发一种新的基于整体的解决方案,该解决方案构建具有不同决策边界的防御者模型相对于原始模型。通过(1)通过一种称为拆分和剃须的方法转换输入的分类器的合奏,以及(2)通过一种称为对比度功能的方法限制重要特征,显示出相对于相对于不同的梯度对抗性攻击,这减少了将对抗性示例从原始示例转移到针对同一类的防御者模型的机会。我们使用标准图像分类数据集(即MNIST,CIFAR-10和CIFAR-100)进行了广泛的实验,以实现最新的对抗攻击,以证明基于合奏的防御的鲁棒性。我们还在存在更强大的对手的情况下评估稳健性,该对手同时靶向合奏中的所有模型。已经提供了整体假阳性和误报的结果,以估计提出的方法的总体性能。
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虽然多步逆势培训被广泛流行作为对抗强烈的对抗攻击的有效防御方法,但其计算成本与标准培训相比,其计算成本是众所周知的。已经提出了几种单步侵权培训方法来减轻上述开销费用;但是,根据优化设置,它们的性能并不能充分可靠。为了克服这些限制,我们偏离了现有的基于输入空间的对抗性培训制度,并提出了一种单步潜在培训方法(SLAT),其利用潜在的代表梯度作为潜在的对抗扰动。我们证明,与所采用的潜伏扰动,恢复局部线性度并确保与现有的单步逆势训练方法相比,恢复局部线性度并确保可靠性的特征梯度的L1规范。因为潜伏的扰动基于可以在输入梯度计算过程中免费获得的潜在表示的梯度,所以所提出的方法与快速梯度标志方法相当成本。实验结果表明,尽管其结构简单,但优于最先进的加速的对抗训练方法。
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Recent work has demonstrated that deep neural networks are vulnerable to adversarial examples-inputs that are almost indistinguishable from natural data and yet classified incorrectly by the network. In fact, some of the latest findings suggest that the existence of adversarial attacks may be an inherent weakness of deep learning models. To address this problem, we study the adversarial robustness of neural networks through the lens of robust optimization. This approach provides us with a broad and unifying view on much of the prior work on this topic. Its principled nature also enables us to identify methods for both training and attacking neural networks that are reliable and, in a certain sense, universal. In particular, they specify a concrete security guarantee that would protect against any adversary. These methods let us train networks with significantly improved resistance to a wide range of adversarial attacks. They also suggest the notion of security against a first-order adversary as a natural and broad security guarantee. We believe that robustness against such well-defined classes of adversaries is an important stepping stone towards fully resistant deep learning models. 1
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最近的一些研究表明,使用额外的分配数据可能会导致高水平的对抗性鲁棒性。但是,不能保证始终可以为所选数据集获得足够的额外数据。在本文中,我们提出了一种有偏见的多域对抗训练(BIAMAT)方法,该方法可以使用公开可用的辅助数据集诱导训练数据放大,而无需在主要和辅助数据集之间进行类分配匹配。提出的方法可以通过多域学习利用辅助数据集来实现主数据集上的对抗性鲁棒性。具体而言,可以通过使用Biamat的应用来实现对鲁棒和非鲁棒特征的数据扩增,如通过理论和经验分析所证明的。此外,我们证明,尽管由于辅助和主要数据之间的分布差异,现有方法容易受到负转移的影响,但提出的方法使神经网络能够通过应用程序通过应用程序来成功处理域差异来灵活地利用各种图像数据集来进行对抗训练基于置信的选择策略。预先训练的模型和代码可在:\ url {https://github.com/saehyung-lee/biamat}中获得。
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基于深度神经网络的医学图像系统容易受到对抗的例子。在文献中提出了许多防御机制,然而,现有的防御者假设被动攻击者对防御系统知之甚少,并没有根据防御改变攻击战略。最近的作品表明,一个强大的自适应攻击,攻击者被认为具有完全了解防御系统的知识,可以轻松绕过现有的防御。在本文中,我们提出了一种名为Medical Aegis的新型对抗性示例防御系统。据我们所知,医疗AEGIS是文献中的第一次防范,成功地解决了对医学图像的强烈适应性的对抗性示例攻击。医疗AEGIS拥有两层保护剂:第一层垫通过去除其高频分量而削弱了攻击的对抗性操纵能力,但对原始图像的分类性能构成了最小的影响;第二层盾牌学习一组每级DNN模型来预测受保护模型的登录。偏离屏蔽的预测表明对抗性示例。盾牌受到在我们的压力测试中的观察中的观察,即在DNN模型的浅层中存在坚固的小径,自适应攻击难以破坏。实验结果表明,建议的防御精确地检测了自适应攻击,模型推理的开销具有可忽略的开销。
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在本文中,引入了偏置分类器,即,作为激活函数的Relu的DNN的偏置部分用作分类器。这项工作是推动偏置部分是具有零梯度的分段常量函数的事实,因此不能直接被基于梯度的方法攻击,以产生诸如FGSM的对手。偏置分类器的存在被证明了提出了一种有效的校准分类方法的训练方法。证明,通过向偏置分类器添加适当的随机第一度部分,在攻击产生对原始方向的意义上获得了针对原始模型梯度的攻击的信息理论上安全分类器。这似乎是第一次提出信息理论上安全分类器的概念。提出了几种用于偏置分类器的攻击方法,并且使用数值实验表明,在大多数情况下,偏置分类器比对这些攻击的DNN更鲁棒。
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Adversarial training based on the minimax formulation is necessary for obtaining adversarial robustness of trained models. However, it is conservative or even pessimistic so that it sometimes hurts the natural generalization. In this paper, we raise a fundamental question-do we have to trade off natural generalization for adversarial robustness? We argue that adversarial training is to employ confident adversarial data for updating the current model. We propose a novel formulation of friendly adversarial training (FAT): rather than employing most adversarial data maximizing the loss, we search for least adversarial data (i.e., friendly adversarial data) minimizing the loss, among the adversarial data that are confidently misclassified. Our novel formulation is easy to implement by just stopping the most adversarial data searching algorithms such as PGD (projected gradient descent) early, which we call early-stopped PGD. Theoretically, FAT is justified by an upper bound of the adversarial risk. Empirically, early-stopped PGD allows us to answer the earlier question negatively-adversarial robustness can indeed be achieved without compromising the natural generalization.* Equal contribution † Preliminary work was done during an internship at RIKEN AIP.
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The study on improving the robustness of deep neural networks against adversarial examples grows rapidly in recent years. Among them, adversarial training is the most promising one, which flattens the input loss landscape (loss change with respect to input) via training on adversarially perturbed examples. However, how the widely used weight loss landscape (loss change with respect to weight) performs in adversarial training is rarely explored. In this paper, we investigate the weight loss landscape from a new perspective, and identify a clear correlation between the flatness of weight loss landscape and robust generalization gap. Several well-recognized adversarial training improvements, such as early stopping, designing new objective functions, or leveraging unlabeled data, all implicitly flatten the weight loss landscape. Based on these observations, we propose a simple yet effective Adversarial Weight Perturbation (AWP) to explicitly regularize the flatness of weight loss landscape, forming a double-perturbation mechanism in the adversarial training framework that adversarially perturbs both inputs and weights. Extensive experiments demonstrate that AWP indeed brings flatter weight loss landscape and can be easily incorporated into various existing adversarial training methods to further boost their adversarial robustness.
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在本文中,我们提出了一种防御策略,以通过合并隐藏的层表示来改善对抗性鲁棒性。这种防御策略的关键旨在压缩或过滤输入信息,包括对抗扰动。而且这种防御策略可以被视为一种激活函数,可以应用于任何类型的神经网络。从理论上讲,我们在某些条件下也证明了这种防御策略的有效性。此外,合并隐藏层表示,我们提出了三种类型的对抗攻击,分别生成三种类型的对抗示例。实验表明,我们的防御方法可以显着改善深神经网络的对抗性鲁棒性,即使我们不采用对抗性训练,也可以实现最新的表现。
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Adversarial training is widely used to improve the robustness of deep neural networks to adversarial attack. However, adversarial training is prone to overfitting, and the cause is far from clear. This work sheds light on the mechanisms underlying overfitting through analyzing the loss landscape w.r.t. the input. We find that robust overfitting results from standard training, specifically the minimization of the clean loss, and can be mitigated by regularization of the loss gradients. Moreover, we find that robust overfitting turns severer during adversarial training partially because the gradient regularization effect of adversarial training becomes weaker due to the increase in the loss landscapes curvature. To improve robust generalization, we propose a new regularizer to smooth the loss landscape by penalizing the weighted logits variation along the adversarial direction. Our method significantly mitigates robust overfitting and achieves the highest robustness and efficiency compared to similar previous methods. Code is available at https://github.com/TreeLLi/Combating-RO-AdvLC.
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尽管机器学习系统的效率和可扩展性,但最近的研究表明,许多分类方法,尤其是深神经网络(DNN),易受对抗的例子;即,仔细制作欺骗训练有素的分类模型的例子,同时无法区分从自然数据到人类。这使得在安全关键区域中应用DNN或相关方法可能不安全。由于这个问题是由Biggio等人确定的。 (2013)和Szegedy等人。(2014年),在这一领域已经完成了很多工作,包括开发攻击方法,以产生对抗的例子和防御技术的构建防范这些例子。本文旨在向统计界介绍这一主题及其最新发展,主要关注对抗性示例的产生和保护。在数值实验中使用的计算代码(在Python和R)公开可用于读者探讨调查的方法。本文希望提交人们将鼓励更多统计学人员在这种重要的令人兴奋的领域的产生和捍卫对抗的例子。
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This study provides a new understanding of the adversarial attack problem by examining the correlation between adversarial attack and visual attention change. In particular, we observed that: (1) images with incomplete attention regions are more vulnerable to adversarial attacks; and (2) successful adversarial attacks lead to deviated and scattered attention map. Accordingly, an attention-based adversarial defense framework is designed to simultaneously rectify the attention map for prediction and preserve the attention area between adversarial and original images. The problem of adding iteratively attacked samples is also discussed in the context of visual attention change. We hope the attention-related data analysis and defense solution in this study will shed some light on the mechanism behind the adversarial attack and also facilitate future adversarial defense/attack model design.
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