Adversarial Training for Improving the Robustness of Deep Neural Networks

Adversarial Training for Improving the Robustness of Deep Neural Networks PDF Author: Pengyue Hou
Publisher:
ISBN:
Category : Computer vision
Languages : en
Pages : 0

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Book Description
Since 2013, Deep Neural Networks (DNNs) have caught up to a human-level performance at various benchmarks. Meanwhile, it is essential to ensure its safety and reliability. Recently an avenue of study questions the robustness of deep learning models and shows that adversarial samples with human-imperceptible noise can easily fool DNNs. Since then, many strategies have been proposed to improve the robustness of DNNs against such adversarial perturbations. Among many defense strategies, adversarial training (AT) is one of the most recognized methods and constantly yields state-of-the-art performance. It treats adversarial samples as augmented data and uses them in model optimization. Despite its promising results, AT has two problems to be improved: (1) poor generalizability on adversarial data (e.g. large robustness performance gap between training and testing data), and (2) a big drop in model's standard performance. This thesis tackles the above-mentioned drawbacks in AT and introduces two AT strategies. To improve the generalizability of AT-trained models, the first part of the thesis introduces a representation similarity-based AT strategy, namely self-paced adversarial training (SPAT). We investigate the imbalanced semantic similarity among different categories in natural images and discover that DNN models are easily fooled by adversarial samples from their hard-class pairs. With this insight, we propose SPAT to re-weight training samples adaptively during model optimization, enforcing AT to focus on those data from their hard class pairs. To address the second problem in AT, a big performance drop on clean data, the second part of this thesis attempts to answer the question: to what extent the robustness of the model can be improved without sacrificing standard performance? Toward this goal, we propose a simple yet effective transfer learning-based adversarial training strategy that disentangles the negative effects of adversarial samples on model's standard performance. In addition, we introduce a training-friendly adversarial attack algorithm, which boosts adversarial robustness without introducing significant training complexity. Compared to prior arts, extensive experiments demonstrate that the training strategy leads to a more robust model while preserving the model's standard accuracy on clean data.

Adversarial Training for Improving the Robustness of Deep Neural Networks

Adversarial Training for Improving the Robustness of Deep Neural Networks PDF Author: Pengyue Hou
Publisher:
ISBN:
Category : Computer vision
Languages : en
Pages : 0

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Book Description
Since 2013, Deep Neural Networks (DNNs) have caught up to a human-level performance at various benchmarks. Meanwhile, it is essential to ensure its safety and reliability. Recently an avenue of study questions the robustness of deep learning models and shows that adversarial samples with human-imperceptible noise can easily fool DNNs. Since then, many strategies have been proposed to improve the robustness of DNNs against such adversarial perturbations. Among many defense strategies, adversarial training (AT) is one of the most recognized methods and constantly yields state-of-the-art performance. It treats adversarial samples as augmented data and uses them in model optimization. Despite its promising results, AT has two problems to be improved: (1) poor generalizability on adversarial data (e.g. large robustness performance gap between training and testing data), and (2) a big drop in model's standard performance. This thesis tackles the above-mentioned drawbacks in AT and introduces two AT strategies. To improve the generalizability of AT-trained models, the first part of the thesis introduces a representation similarity-based AT strategy, namely self-paced adversarial training (SPAT). We investigate the imbalanced semantic similarity among different categories in natural images and discover that DNN models are easily fooled by adversarial samples from their hard-class pairs. With this insight, we propose SPAT to re-weight training samples adaptively during model optimization, enforcing AT to focus on those data from their hard class pairs. To address the second problem in AT, a big performance drop on clean data, the second part of this thesis attempts to answer the question: to what extent the robustness of the model can be improved without sacrificing standard performance? Toward this goal, we propose a simple yet effective transfer learning-based adversarial training strategy that disentangles the negative effects of adversarial samples on model's standard performance. In addition, we introduce a training-friendly adversarial attack algorithm, which boosts adversarial robustness without introducing significant training complexity. Compared to prior arts, extensive experiments demonstrate that the training strategy leads to a more robust model while preserving the model's standard accuracy on clean data.

Adversarial Robustness of Deep Learning Models

Adversarial Robustness of Deep Learning Models PDF Author: Samarth Gupta (S.M.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 80

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Book Description
Efficient operation and control of modern day urban systems such as transportation networks is now more important than ever due to huge societal benefits. Low cost network-wide sensors generate large amounts of data which needs to processed to extract useful information necessary for operational maintenance and to perform real-time control. Modern Machine Learning (ML) systems, particularly Deep Neural Networks (DNNs), provide a scalable solution to the problem of information retrieval from sensor data. Therefore, Deep Learning systems are increasingly playing an important role in day-to-day operations of our urban systems and hence cannot not be treated as standalone systems anymore. This naturally raises questions from a security viewpoint. Are modern ML systems robust to adversarial attacks for deployment in critical real-world applications? If not, then how can we make progress in securing these systems against such attacks? In this thesis we first demonstrate the vulnerability of modern ML systems on a real world scenario relevant to transportation networks by successfully attacking a commercial ML platform using a traffic-camera image. We review different methods of defense and various challenges associated in training an adversarially robust classifier. In terms of contributions, we propose and investigate a new method of defense to build adversarially robust classifiers using Error-Correcting Codes (ECCs). The idea of using Error-Correcting Codes for multi-class classification has been investigated in the past but only under nominal settings. We build upon this idea in the context of adversarial robustness of Deep Neural Networks. Following the guidelines of code-book design from literature, we formulate a discrete optimization problem to generate codebooks in a systematic manner. This optimization problem maximizes minimum hamming distance between codewords of the codebook while maintaining high column separation. Using the optimal solution of the discrete optimization problem as our codebook, we then build a (robust) multi-class classifier from that codebook. To estimate the adversarial accuracy of ECC based classifiers resulting from different codebooks, we provide methods to generate gradient based white-box attacks. We discuss estimation of class probability estimates (or scores) which are in itself useful for real-world applications along with their use in generating black-box and white-box attacks. We also discuss differentiable decoding methods, which can also be used to generate white-box attacks. We are able to outperform standard all-pairs codebook, providing evidence to the fact that compact codebooks generated using our discrete optimization approach can indeed provide high performance. Most importantly, we show that ECC based classifiers can be partially robust even without any adversarial training. We also show that this robustness is simply not a manifestation of the large network capacity of the overall classifier. Our approach can be seen as the first step towards designing classifiers which are robust by design. These contributions suggest that ECCs based approach can be useful to improve the robustness of modern ML systems and thus making urban systems more resilient to adversarial attacks.

On the Robustness of Neural Network: Attacks and Defenses

On the Robustness of Neural Network: Attacks and Defenses PDF Author: Minhao Cheng
Publisher:
ISBN:
Category :
Languages : en
Pages : 158

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Book Description
Neural networks provide state-of-the-art results for most machine learning tasks. Unfortunately, neural networks are vulnerable to adversarial examples. That is, a slightly modified example could be easily generated and fool a well-trained image classifier based on deep neural networks (DNNs) with high confidence. This makes it difficult to apply neural networks in security-critical areas. To find such examples, we first introduce and define adversarial examples. In the first part, we then discuss how to build adversarial attacks in both image and discrete domains. For image classification, we introduce how to design an adversarial attacker in three different settings. Among them, we focus on the most practical setup for evaluating the adversarial robustness of a machine learning system with limited access: the hard-label black-box attack setting for generating adversarial examples, where limited model queries are allowed and only the decision is provided to a queried data input. For the discrete domain, we first talk about its difficulty and introduce how to conduct the adversarial attack on two applications. While crafting adversarial examples is an important technique to evaluate the robustness of DNNs, there is a huge need for improving the model robustness as well. Enhancing model robustness under new and even adversarial environments is a crucial milestone toward building trustworthy machine learning systems. In the second part, we talk about the methods to strengthen the model's adversarial robustness. We first discuss attack-dependent defense. Specifically, we first discuss one of the most effective methods for improving the robustness of neural networks: adversarial training and its limitations. We introduce a variant to overcome its problem. Then we take a different perspective and introduce attack-independent defense. We summarize the current methods and introduce a framework-based vicinal risk minimization. Inspired by the framework, we introduce self-progressing robust training. Furthermore, we discuss the robustness trade-off problem and introduce a hypothesis and propose a new method to alleviate it.

Strengthening Deep Neural Networks

Strengthening Deep Neural Networks PDF Author: Katy Warr
Publisher: "O'Reilly Media, Inc."
ISBN: 1492044903
Category : Computers
Languages : en
Pages : 246

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Book Description
As deep neural networks (DNNs) become increasingly common in real-world applications, the potential to deliberately "fool" them with data that wouldn’t trick a human presents a new attack vector. This practical book examines real-world scenarios where DNNs—the algorithms intrinsic to much of AI—are used daily to process image, audio, and video data. Author Katy Warr considers attack motivations, the risks posed by this adversarial input, and methods for increasing AI robustness to these attacks. If you’re a data scientist developing DNN algorithms, a security architect interested in how to make AI systems more resilient to attack, or someone fascinated by the differences between artificial and biological perception, this book is for you. Delve into DNNs and discover how they could be tricked by adversarial input Investigate methods used to generate adversarial input capable of fooling DNNs Explore real-world scenarios and model the adversarial threat Evaluate neural network robustness; learn methods to increase resilience of AI systems to adversarial data Examine some ways in which AI might become better at mimicking human perception in years to come

Enhancing Adversarial Robustness of Deep Neural Networks

Enhancing Adversarial Robustness of Deep Neural Networks PDF Author: Jeffrey Zhang (M. Eng.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 58

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Book Description
Logit-based regularization and pretrain-then-tune are two approaches that have recently been shown to enhance adversarial robustness of machine learning models. In the realm of regularization, Zhang et al. (2019) proposed TRADES, a logit-based regularization optimization function that has been shown to improve upon the robust optimization framework developed by Madry et al. (2018) [14, 9]. They were able to achieve state-of-the-art adversarial accuracy on CIFAR10. In the realm of pretrain- then-tune models, Hendrycks el al. (2019) demonstrated that adversarially pretraining a model on ImageNet then adversarially tuning on CIFAR10 greatly improves the adversarial robustness of machine learning models. In this work, we propose Adversarial Regularization, another logit-based regularization optimization framework that surpasses TRADES in adversarial generalization. Furthermore, we explore the impact of trying different types of adversarial training on the pretrain-then-tune paradigm.

Security, Privacy, and Anonymity in Computation, Communication, and Storage

Security, Privacy, and Anonymity in Computation, Communication, and Storage PDF Author: Guojun Wang
Publisher: Springer Nature
ISBN: 3030688518
Category : Computers
Languages : en
Pages : 436

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Book Description
This book constitutes the refereed proceedings of the 13th International Conference on Security, Privacy, and Anonymity in Computation, Communication, and Storage, SpaCCS 2020, held in Nanjing, China, in December 2020. The 30 full papers were carefully reviewed and selected from 88 submissions. The papers cover many dimensions including security algorithms and architectures, privacy-aware policies, regulations and techniques, anonymous computation and communication, encompassing fundamental theoretical approaches, practical experimental projects, and commercial application systems for computation, communication and storage. SpaCCS 2020 is held jointly with the 11th International Workshop on Trust, Security and Privacy for Big Data (TrustData 2020), the 10th International Symposium on Trust, Security and Privacy for Emerging Applications (TSP 2020), the 9th International Symposium on Security and Privacy on Internet of Things (SPIoT 2020), the 6th International Symposium on Sensor-Cloud Systems (SCS 2020), the 2nd International Workshop on Communication, Computing, Informatics and Security (CCIS 2020), the First International Workshop on Intelligence and Security in Next Generation Networks (ISNGN 2020), the First International Symposium on Emerging Information Security and Applications (EISA 2020).

Adversarial Training to Improve Robustness of Adversarial Deep Neural Classifiers in the NOvA Experiment

Adversarial Training to Improve Robustness of Adversarial Deep Neural Classifiers in the NOvA Experiment PDF Author: Kevin Mulder
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description


Shape, Contour and Grouping in Computer Vision

Shape, Contour and Grouping in Computer Vision PDF Author: David A. Forsyth
Publisher: Springer Science & Business Media
ISBN: 3540667229
Category : Computers
Languages : en
Pages : 340

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Book Description
Computer vision has been successful in several important applications recently. Vision techniques can now be used to build very good models of buildings from pictures quickly and easily, to overlay operation planning data on a neuros- geon’s view of a patient, and to recognise some of the gestures a user makes to a computer. Object recognition remains a very di cult problem, however. The key questions to understand in recognition seem to be: (1) how objects should be represented and (2) how to manage the line of reasoning that stretches from image data to object identity. An important part of the process of recognition { perhaps, almost all of it { involves assembling bits of image information into helpful groups. There is a wide variety of possible criteria by which these groups could be established { a set of edge points that has a symmetry could be one useful group; others might be a collection of pixels shaded in a particular way, or a set of pixels with coherent colour or texture. Discussing this process of grouping requires a detailed understanding of the relationship between what is seen in the image and what is actually out there in the world.

Improved Methodology for Evaluating Adversarial Robustness in Deep Neural Networks

Improved Methodology for Evaluating Adversarial Robustness in Deep Neural Networks PDF Author: Kyungmi Lee (S. M.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 93

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Book Description
Deep neural networks are known to be vulnerable to adversarial perturbations, which are often imperceptible to humans but can alter predictions of machine learning systems. Since the exact value of adversarial robustness is difficult to obtain for complex deep neural networks, accuracy of the models against perturbed examples generated by attack methods is empirically used as a proxy to adversarial robustness. However, failure of attack methods to find adversarial perturbations cannot be equated with being robust. In this work, we identify three common cases that lead to overestimation of accuracy against perturbed examples generated by bounded first-order attack methods: 1) the value of cross-entropy loss numerically becoming zero when using standard floating point representation, resulting in non-useful gradients; 2) innately non-differentiable functions in deep neural networks, such as Rectified Linear Unit (ReLU) activation and MaxPool operation, incurring “gradient masking” [2]; and 3) certain regularization methods used during training inducing the model to be less amenable to first-order approximation. We show that these phenomena exist in a wide range of deep neural networks, and that these phenomena are not limited to specific defense methods they have been previously investigated for. For each case, we propose compensation methods that either address sources of inaccurate gradient computation, such as numerical saturation for near zero values and non-differentiability, or reduce the total number of back-propagations for iterative attacks by approximating second-order information. These compensation methods can be combined with existing attack methods for a more precise empirical evaluation metric. We illustrate the impact of these three phenomena with examples of practical interest, such as benchmarking model capacity and regularization techniques for robustness. Furthermore, we show that the gap between adversarial accuracy and the guaranteed lower bound of robustness can be partially explained by these phenomena. Overall, our work shows that overestimated adversarial accuracy that is not indicative of robustness is prevalent even for conventionally trained deep neural networks, and highlights cautions of using empirical evaluation without guaranteed bounds.

Adversarial Machine Learning

Adversarial Machine Learning PDF Author: Yevgeniy Vorobeychik
Publisher: Morgan & Claypool Publishers
ISBN: 168173396X
Category : Computers
Languages : en
Pages : 172

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Book Description
This is a technical overview of the field of adversarial machine learning which has emerged to study vulnerabilities of machine learning approaches in adversarial settings and to develop techniques to make learning robust to adversarial manipulation. After reviewing machine learning concepts and approaches, as well as common use cases of these in adversarial settings, we present a general categorization of attacks on machine learning. We then address two major categories of attacks and associated defenses: decision-time attacks, in which an adversary changes the nature of instances seen by a learned model at the time of prediction in order to cause errors, and poisoning or training time attacks, in which the actual training dataset is maliciously modified. In our final chapter devoted to technical content, we discuss recent techniques for attacks on deep learning, as well as approaches for improving robustness of deep neural networks. We conclude with a discussion of several important issues in the area of adversarial learning that in our view warrant further research. The increasing abundance of large high-quality datasets, combined with significant technical advances over the last several decades have made machine learning into a major tool employed across a broad array of tasks including vision, language, finance, and security. However, success has been accompanied with important new challenges: many applications of machine learning are adversarial in nature. Some are adversarial because they are safety critical, such as autonomous driving. An adversary in these applications can be a malicious party aimed at causing congestion or accidents, or may even model unusual situations that expose vulnerabilities in the prediction engine. Other applications are adversarial because their task and/or the data they use are. For example, an important class of problems in security involves detection, such as malware, spam, and intrusion detection. The use of machine learning for detecting malicious entities creates an incentive among adversaries to evade detection by changing their behavior or the content of malicious objects they develop. Given the increasing interest in the area of adversarial machine learning, we hope this book provides readers with the tools necessary to successfully engage in research and practice of machine learning in adversarial settings.