随着神经网络的不断扩展,对其财产的完整和合理验证的需求变得至关重要。近年来,确定二进制神经网络(BNN)在布尔逻辑中具有等效的表示,并且可以使用诸如SAT求解器之类的逻辑推理工具进行正式分析。但是,迄今为止,只能将BNN转换为SAT公式。在这项工作中,我们介绍了真实表深卷积神经网络(TTNETS),这是一个新的sat-odsody型号,首次是现实价值的重量。此外,它通过构造承认,在稳健性验证设置中,包括调节后和拖延性,包括后调整功能。后一种属性导致比BNN更紧凑的SAT符号编码。这使使用一般SAT求解器的使用使属性验证更加容易。我们证明了TTNET关于形式鲁棒性属性的值:TTNET在具有可比的计算时间的所有BNN的验证精度上优于验证的准确性。更普遍地,它们代表了所有已知的完整验证方法之间的相关权衡:TTNET在快速验证时间内实现了高验证的精度,并且没有超时。在这里,我们正在探索TTNET的概念证明,以实现非常重要的应用(稳健性的完整验证),我们相信这个新颖的实现的网络构成了对功能正式验证需求不断增长的实际响应。我们假设TTNET可以应用于各种基于CNN的架构,并将其扩展到其他属性,例如公平性,故障攻击和精确规则提取。
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在过去的十年中,神经网络(NNS)已被广泛用于许多应用程序,包括安全系统,例如自主系统。尽管采用了新兴的采用,但众所周知,NNS容易受到对抗攻击的影响。因此,提供确保此类系统正常工作的保证非常重要。为了解决这些问题,我们介绍了一个修复不安全NNS W.R.T.的框架。安全规范,即利用可满足的模型理论(SMT)求解器。我们的方法能够通过仅修改其重量值的一些重量值来搜索新的,安全的NN表示形式。此外,我们的技术试图最大程度地提高与原始网络在其决策边界方面的相似性。我们进行了广泛的实验,以证明我们提出的框架能够产生安全NNS W.R.T.的能力。对抗性的鲁棒性特性,只有轻度的准确性损失(就相似性而言)。此外,我们将我们的方法与天真的基线进行比较,以证明其有效性。总而言之,我们提供了一种算法以自动修复具有安全性的算法,并建议一些启发式方法以提高其计算性能。当前,通过遵循这种方法,我们能够产生由分段线性relu激活函数组成的小型(即具有多达数百个参数)的小型(即具有多达数百个参数)。然而,我们的框架是可以合成NNS W.R.T.的一般框架。一阶逻辑规范的任何可决定片段。
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This report summarizes the 3rd International Verification of Neural Networks Competition (VNN-COMP 2022), held as a part of the 5th Workshop on Formal Methods for ML-Enabled Autonomous Systems (FoMLAS), which was collocated with the 34th International Conference on Computer-Aided Verification (CAV). VNN-COMP is held annually to facilitate the fair and objective comparison of state-of-the-art neural network verification tools, encourage the standardization of tool interfaces, and bring together the neural network verification community. To this end, standardized formats for networks (ONNX) and specification (VNN-LIB) were defined, tools were evaluated on equal-cost hardware (using an automatic evaluation pipeline based on AWS instances), and tool parameters were chosen by the participants before the final test sets were made public. In the 2022 iteration, 11 teams participated on a diverse set of 12 scored benchmarks. This report summarizes the rules, benchmarks, participating tools, results, and lessons learned from this iteration of this competition.
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神经网络已广泛应用于垃圾邮件和网络钓鱼检测,入侵预防和恶意软件检测等安全应用程序。但是,这种黑盒方法通常在应用中具有不确定性和不良的解释性。此外,神经网络本身通常容易受到对抗攻击的影响。由于这些原因,人们对可信赖和严格的方法有很高的需求来验证神经网络模型的鲁棒性。对抗性的鲁棒性在处理恶意操纵输入时涉及神经网络的可靠性,是安全和机器学习中最热门的主题之一。在这项工作中,我们在神经网络的对抗性鲁棒性验证中调查了现有文献,并在机器学习,安全和软件工程领域收集了39项多元化研究工作。我们系统地分析了它们的方法,包括如何制定鲁棒性,使用哪种验证技术以及每种技术的优势和局限性。我们从正式验证的角度提供分类学,以全面理解该主题。我们根据财产规范,减少问题和推理策略对现有技术进行分类。我们还展示了使用样本模型在现有研究中应用的代表性技术。最后,我们讨论了未来研究的开放问题。
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已知深神经网络(DNN)容易受到对抗性攻击的影响。已经提出了一系列防御方法来培训普遍稳健的DNN,其中对抗性培训已经证明了有希望的结果。然而,尽管对对抗性培训开发的初步理解,但从架构角度来看,它仍然不明确,从架构角度来看,什么配置可以导致更强大的DNN。在本文中,我们通过全面调查网络宽度和深度对前对方培训的DNN的鲁棒性的全面调查来解决这一差距。具体地,我们进行以下关键观察:1)更多参数(更高的模型容量)不一定有助于对抗冒险; 2)网络的最后阶段(最后一组块)降低能力实际上可以改善对抗性的鲁棒性; 3)在相同的参数预算下,存在对抗性鲁棒性的最佳架构配置。我们还提供了一个理论分析,解释了为什么这种网络配置可以帮助鲁棒性。这些架构见解可以帮助设计对抗的强制性DNN。代码可用于\ url {https://github.com/hanxunh/robustwrn}。
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Adversarial examples that fool machine learning models, particularly deep neural networks, have been a topic of intense research interest, with attacks and defenses being developed in a tight back-and-forth. Most past defenses are best effort and have been shown to be vulnerable to sophisticated attacks. Recently a set of certified defenses have been introduced, which provide guarantees of robustness to normbounded attacks. However these defenses either do not scale to large datasets or are limited in the types of models they can support. This paper presents the first certified defense that both scales to large networks and datasets (such as Google's Inception network for ImageNet) and applies broadly to arbitrary model types. Our defense, called PixelDP, is based on a novel connection between robustness against adversarial examples and differential privacy, a cryptographically-inspired privacy formalism, that provides a rigorous, generic, and flexible foundation for defense.
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We study the problem of training and certifying adversarially robust quantized neural networks (QNNs). Quantization is a technique for making neural networks more efficient by running them using low-bit integer arithmetic and is therefore commonly adopted in industry. Recent work has shown that floating-point neural networks that have been verified to be robust can become vulnerable to adversarial attacks after quantization, and certification of the quantized representation is necessary to guarantee robustness. In this work, we present quantization-aware interval bound propagation (QA-IBP), a novel method for training robust QNNs. Inspired by advances in robust learning of non-quantized networks, our training algorithm computes the gradient of an abstract representation of the actual network. Unlike existing approaches, our method can handle the discrete semantics of QNNs. Based on QA-IBP, we also develop a complete verification procedure for verifying the adversarial robustness of QNNs, which is guaranteed to terminate and produce a correct answer. Compared to existing approaches, the key advantage of our verification procedure is that it runs entirely on GPU or other accelerator devices. We demonstrate experimentally that our approach significantly outperforms existing methods and establish the new state-of-the-art for training and certifying the robustness of QNNs.
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深度神经网络(DNN)的巨大进步导致了各种任务的最先进的性能。然而,最近的研究表明,DNNS容易受到对抗的攻击,这在将这些模型部署到自动驾驶等安全关键型应用时,这使得非常关注。已经提出了不同的防御方法,包括:a)经验防御,通常可以在不提供稳健性认证的情况下再次再次攻击; b)可认真的稳健方法,由稳健性验证组成,提供了在某些条件下的任何攻击和相应的强大培训方法中的稳健准确性的下限。在本文中,我们系统化了可认真的稳健方法和相关的实用和理论意义和调查结果。我们还提供了在不同数据集上现有的稳健验证和培训方法的第一个全面基准。特别是,我们1)为稳健性验证和培训方法提供分类,以及总结代表性算法的方法,2)揭示这些方法中的特征,优势,局限性和基本联系,3)讨论当前的研究进展情况TNN和4的可信稳健方法的理论障碍,主要挑战和未来方向提供了一个开放的统一平台,以评估超过20种代表可认真的稳健方法,用于各种DNN。
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While deep neural networks (DNNs) have demonstrated impressive performance in solving many challenging tasks, they are limited to resource-constrained devices owing to their demand for computation power and storage space. Quantization is one of the most promising techniques to address this issue by quantizing the weights and/or activation tensors of a DNN into lower bit-width fixed-point numbers. While quantization has been empirically shown to introduce minor accuracy loss, it lacks formal guarantees on that, especially when the resulting quantized neural networks (QNNs) are deployed in safety-critical applications. A majority of existing verification methods focus exclusively on individual neural networks, either DNNs or QNNs. While promising attempts have been made to verify the quantization error bound between DNNs and their quantized counterparts, they are not complete and more importantly do not support fully quantified neural networks, namely, only weights are quantized. To fill this gap, in this work, we propose a quantization error bound verification method (QEBVerif), where both weights and activation tensors are quantized. QEBVerif consists of two analyses: a differential reachability analysis (DRA) and a mixed-integer linear programming (MILP) based verification method. DRA performs difference analysis between the DNN and its quantized counterpart layer-by-layer to efficiently compute a tight quantization error interval. If it fails to prove the error bound, then we encode the verification problem into an equivalent MILP problem which can be solved by off-the-shelf solvers. Thus, QEBVerif is sound, complete, and arguably efficient. We implement QEBVerif in a tool and conduct extensive experiments, showing its effectiveness and efficiency.
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有限的线性时间逻辑($ \ mathsf {ltl} _f $)是一种强大的正式表示,用于建模时间序列。我们解决了学习Compact $ \ Mathsf {ltl} _f $ formul的问题,从标记的系统行为的痕迹。我们提出了一部小说神经网络运营商,并评估结果架构,神经$ \ mathsf {ltl} _f $。我们的方法包括专用复发过滤器,旨在满足$ \ Mathsf {ltl} _f $ temporal运算符,以学习痕迹的高度准确的分类器。然后,它离散地激活并提取由学习权重表示的真相表。此实话表将转换为符号形式并作为学习公式返回。随机生成$ \ Mathsf {LTL} _F $公式显示神经$ \ MATHSF {LTL} _F $尺寸,比现有方法更大,即使在存在噪声时也保持高精度。
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背景信息:在过去几年中,机器学习(ML)一直是许多创新的核心。然而,包括在所谓的“安全关键”系统中,例如汽车或航空的系统已经被证明是非常具有挑战性的,因为ML的范式转变为ML带来完全改变传统认证方法。目的:本文旨在阐明与ML为基础的安全关键系统认证有关的挑战,以及文献中提出的解决方案,以解决它们,回答问题的问题如何证明基于机器学习的安全关键系统?'方法:我们开展2015年至2020年至2020年之间发布的研究论文的系统文献综述(SLR),涵盖了与ML系统认证有关的主题。总共确定了217篇论文涵盖了主题,被认为是ML认证的主要支柱:鲁棒性,不确定性,解释性,验证,安全强化学习和直接认证。我们分析了每个子场的主要趋势和问题,并提取了提取的论文的总结。结果:单反结果突出了社区对该主题的热情,以及在数据集和模型类型方面缺乏多样性。它还强调需要进一步发展学术界和行业之间的联系,以加深域名研究。最后,它还说明了必须在上面提到的主要支柱之间建立连接的必要性,这些主要柱主要主要研究。结论:我们强调了目前部署的努力,以实现ML基于ML的软件系统,并讨论了一些未来的研究方向。
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多项式网络(PNS)最近在面部和图像识别方面表现出了有希望的表现。但是,PNS的鲁棒性尚不清楚,因此获得证书对于使其在现实世界应用中的采用至关重要。基于分支和绑定(BAB)技术的Relu神经网络(NNS)上的现有验证算法不能微不足道地应用于PN验证。在这项工作中,我们设计了一种新的边界方法,该方法配备了BAB,用于全球融合保证,称为VPN。一个关键的见解是,我们获得的边界比间隔结合的传播基线更紧密。这可以通过MNIST,CIFAR10和STL10数据集的经验验证进行声音和完整的PN验证。我们认为我们的方法对NN验证具有自身的兴趣。
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我们提出了一种用于训练深神经网络的新型混合算法,该算法将最先进的梯度下降(GD)方法与混合整数线性编程(MILP)求解器相结合,以准确性以及变体的差异以及变体,以及回归和分类任务的资源和数据效率。我们的GD+求解器混合算法称为GDSolver,工作如下:给定DNN $ d $作为输入,GDSolver召集GD派出部分训练$ d $,直到卡在当地的最小值中,这一点GDSOLVER将Milp Solver召集到一定程度上详尽地搜索损失景观的区域,围绕$ d $的最后一层参数的重量分配,目的是贯穿并逃脱本地的最小值。重复该过程,直到达到所需的准确性。在我们的实验中,我们发现GDSolver不仅可以很好地扩展到其他数据和非常大的模型大小,而且还优于收敛和数据效率率的所有其他竞争方法。对于回归任务,GDOLVER生产的模型平均在48%的时间内降低了31.5%,并且对于MNIST和CIFAR10的分类任务,GDSOLVER仅使用所有竞争方法就能达到最高精度,仅使用50% GD基准需要的培训数据。
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Although deep neural networks (DNNs) have achieved great success in many tasks, they can often be fooled by adversarial examples that are generated by adding small but purposeful distortions to natural examples. Previous studies to defend against adversarial examples mostly focused on refining the DNN models, but have either shown limited success or required expensive computation. We propose a new strategy, feature squeezing, that can be used to harden DNN models by detecting adversarial examples. Feature squeezing reduces the search space available to an adversary by coalescing samples that correspond to many different feature vectors in the original space into a single sample. By comparing a DNN model's prediction on the original input with that on squeezed inputs, feature squeezing detects adversarial examples with high accuracy and few false positives.This paper explores two feature squeezing methods: reducing the color bit depth of each pixel and spatial smoothing. These simple strategies are inexpensive and complementary to other defenses, and can be combined in a joint detection framework to achieve high detection rates against state-of-the-art attacks.
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Efforts to improve the adversarial robustness of convolutional neural networks have primarily focused on developing more effective adversarial training methods. In contrast, little attention was devoted to analyzing the role of architectural elements (such as topology, depth, and width) on adversarial robustness. This paper seeks to bridge this gap and present a holistic study on the impact of architectural design on adversarial robustness. We focus on residual networks and consider architecture design at the block level, i.e., topology, kernel size, activation, and normalization, as well as at the network scaling level, i.e., depth and width of each block in the network. In both cases, we first derive insights through systematic ablative experiments. Then we design a robust residual block, dubbed RobustResBlock, and a compound scaling rule, dubbed RobustScaling, to distribute depth and width at the desired FLOP count. Finally, we combine RobustResBlock and RobustScaling and present a portfolio of adversarially robust residual networks, RobustResNets, spanning a broad spectrum of model capacities. Experimental validation across multiple datasets and adversarial attacks demonstrate that RobustResNets consistently outperform both the standard WRNs and other existing robust architectures, achieving state-of-the-art AutoAttack robust accuracy of 61.1% without additional data and 63.7% with 500K external data while being $2\times$ more compact in terms of parameters. Code is available at \url{ https://github.com/zhichao-lu/robust-residual-network}
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Verifying the robustness property of a general Rectified Linear Unit (ReLU) network is an NPcomplete problem. Although finding the exact minimum adversarial distortion is hard, giving a certified lower bound of the minimum distortion is possible. Current available methods of computing such a bound are either time-consuming or deliver low quality bounds that are too loose to be useful. In this paper, we exploit the special structure of ReLU networks and provide two computationally efficient algorithms (Fast-Lin,Fast-Lip) that are able to certify non-trivial lower bounds of minimum adversarial distortions. Experiments show that (1) our methods deliver bounds close to (the gap is 2-3X) exact minimum distortions found by Reluplex in small networks while our algorithms are more than 10,000 times faster; (2) our methods deliver similar quality of bounds (the gap is within 35% and usually around 10%; sometimes our bounds are even better) for larger networks compared to the methods based on solving linear programming problems but our algorithms are 33-14,000 times faster; (3) our method is capable of solving large MNIST and CIFAR networks up to 7 layers with more than 10,000 neurons within tens of seconds on a single CPU core. In addition, we show that there is no polynomial time algorithm that can approximately find the minimum 1 adversarial distortion of a ReLU network with a 0.99 ln n approximation ratio unless NP=P, where n is the number of neurons in the network.
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我们考虑了认证深神经网络对现实分布变化的鲁棒性的问题。为此,我们通过提出一个新型的神经符号验证框架来弥合手工制作的规格和现实部署设置之间的差距模型。这种环境引起的一个独特的挑战是,现有的验证者不能紧密地近似sigmoid激活,这对于许多最新的生成模型至关重要。为了应对这一挑战,我们提出了一个通用的元算象来处理乙状结肠激活,该乙状结激素利用反示例引导的抽象细化的经典概念。关键思想是“懒惰地”完善Sigmoid函数的抽象,以排除先前抽象中发现的虚假反示例,从而确保验证过程中的进展,同时保持状态空间较小。 MNIST和CIFAR-10数据集的实验表明,我们的框架在一系列具有挑战性的分配变化方面大大优于现有方法。
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基于基于不完整的神经网络验证如冠的绑定传播非常有效,可以显着加速基于神经网络的分支和绑定(BAB)。然而,绑定的传播不能完全处理由昂贵的线性编程(LP)求解器的BAB常规引入的神经元分割限制,导致界限和损伤验证效率。在这项工作中,我们开发了一种基于$ \ beta $ -cra所做的,一种基于新的绑定传播方法,可以通过从原始或双空间构造的可优化参数$ \ beta $完全编码神经元分割。当在中间层中联合优化时,$ \ Beta $ -CROWN通常会产生比具有神经元分裂约束的典型LP验证更好的界限,同时像GPU上的皇冠一样高效且并行化。适用于完全稳健的验证基准,使用BAB的$ \ Beta $ -CROWN比基于LP的BAB方法快三个数量级,并且比所有现有方法更快,同时产生较低的超时率。通过早期终止BAB,我们的方法也可用于有效的不完整验证。与强大的不完整验证者相比,我们始终如一地在许多设置中获得更高的验证准确性,包括基于凸屏障破碎技术的验证技术。与最严重但非常昂贵的Semidefinite编程(SDP)的不完整验证者相比,我们获得了更高的验证精度,验证时间较少三个级。我们的算法授权$ \ alpha,\ \β$ -craft(Alpha-Beta-Crown)验证者,VNN-Comp 2021中的获胜工具。我们的代码可在http://papercode.cc/betacrown提供
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While machine learning is traditionally a resource intensive task, embedded systems, autonomous navigation, and the vision of the Internet of Things fuel the interest in resource-efficient approaches. These approaches aim for a carefully chosen trade-off between performance and resource consumption in terms of computation and energy. The development of such approaches is among the major challenges in current machine learning research and key to ensure a smooth transition of machine learning technology from a scientific environment with virtually unlimited computing resources into everyday's applications. In this article, we provide an overview of the current state of the art of machine learning techniques facilitating these real-world requirements. In particular, we focus on deep neural networks (DNNs), the predominant machine learning models of the past decade. We give a comprehensive overview of the vast literature that can be mainly split into three non-mutually exclusive categories: (i) quantized neural networks, (ii) network pruning, and (iii) structural efficiency. These techniques can be applied during training or as post-processing, and they are widely used to reduce the computational demands in terms of memory footprint, inference speed, and energy efficiency. We also briefly discuss different concepts of embedded hardware for DNNs and their compatibility with machine learning techniques as well as potential for energy and latency reduction. We substantiate our discussion with experiments on well-known benchmark datasets using compression techniques (quantization, pruning) for a set of resource-constrained embedded systems, such as CPUs, GPUs and FPGAs. The obtained results highlight the difficulty of finding good trade-offs between resource efficiency and predictive performance.
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神经网络在检测嘈杂数据中的模式方面非常成功,并且已成为许多领域的首选技术。但是,他们对对抗攻击的敏感性阻碍了它们的有用性。最近,已经提出了许多用于衡量和改善网络对对抗性扰动的鲁棒性的方法,并且这项不断增长的研究体现了许多明确或隐性的鲁棒性观念。这些概念之间的联系通常是微妙的,文献中缺少它们之间的系统比较。在本文中,我们开始解决这一差距,通过在网络的培训阶段,其验证和部署之后设置对网络鲁棒性作为数学属性的经验分析和评估的一般原则。然后,我们应用这些原则并进行案例研究,以展示我们一般方法的实际好处。
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