Training adversarially robust discriminative (i.e., softmax) classifier has been the dominant approach to robust classification. Building on recent work on adversarial training (AT)-based generative models, we investigate using AT to learn unnormalized class-conditional density models and then performing generative robust classification. Our result shows that, under the condition of similar model capacities, the generative robust classifier achieves comparable performance to a baseline softmax robust classifier when the test data is clean or when the test perturbation is of limited size, and much better performance when the test perturbation size exceeds the training perturbation size. The generative classifier is also able to generate samples or counterfactuals that more closely resemble the training data, suggesting that the generative classifier can better capture the class-conditional distributions. In contrast to standard discriminative adversarial training where advanced data augmentation techniques are only effective when combined with weight averaging, we find it straightforward to apply advanced data augmentation to achieve better robustness in our approach. Our result suggests that the generative classifier is a competitive alternative to robust classification, especially for problems with limited number of classes.
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本文使用签名的累积分布变换(SCDT)提出了一种新的端到端信号分类方法。我们采用基于运输的生成模型来定义分类问题。然后,我们利用SCDT的数学属性来使问题更容易在变换域中,并使用SCDT域中的最接近局部子空间(NLS)搜索算法求解未知样本的类。实验表明,所提出的方法提供了高精度的分类结果,同时又有数据效率,对分布样本的强大稳定性以及相对于深度学习端到端分类方法的计算复杂性而具有竞争力。在Python语言中的实现将其作为软件包Pytranskit(https://github.com/rohdelab/pytranskit)的一部分集成。
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深度卷积神经网络(CNNS)广泛地被认为是最先进的通用端到端图像分类系统。然而,当训练数据受到限制时,它们众所周知,他们需要渲染方法计算得昂贵并且并不总是有效的数据增强策略。而不是使用数据增强策略来编码在机器学习中通常在机器学习中进行的修正,而我们建议通过利用氡累积分配变换(R-CDT)的某些数学属性来数学上增强切片 - Wasserstein空间中最近的子空间分类模型。最近引入的图像变换。我们证明,对于特定类型的学习问题,我们的数学解决方案在分类精度和计算复杂性方面具有深度CNN的数据增强,并且在有限的训练数据设置下特别有效。该方法简单,有效,计算高效,不迭代,不需要调整参数。实现我们的方法的Python代码可在https://github.com/rohdelab/mathemation_augmentation中获得。我们的方法是作为软件包Pytranskit的一部分,可在https://github.com/rohdelab/pytranskit中获得。
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我们研究了一种基于对抗性训练(AT)的学习基于能量的模型(EBM)的新方法。我们表明(二进制)学习一种特殊的能量功能,可以模拟数据分布的支持,并且学习过程与基于MCMC的EBM的最大似然学习密切相关。我们进一步提出了改进的与AT生成建模的技术,并证明这种新方法能够产生多样化和现实的图像。除了具有竞争性的图像生成性能到明确的EBM外,研究的方法还可以稳定训练,非常适合图像翻译任务,并且表现出强大的分布外对抗性鲁棒性。我们的结果证明了AT生成建模方法的生存能力,表明AT是学习EBM的竞争性替代方法。
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深度神经网络针对对抗性例子的脆弱性已成为将这些模型部署在敏感领域中的重要问题。事实证明,针对这种攻击的明确防御是具有挑战性的,依赖于检测对抗样本的方法只有在攻击者忽略检测机制时才有效。在本文中,我们提出了一种原则性的对抗示例检测方法,该方法可以承受规范受限的白色框攻击。受K类分类问题的启发,我们训练K二进制分类器,其中I-th二进制分类器用于区分I类的清洁数据和其他类的对抗性样本。在测试时,我们首先使用训练有素的分类器获取输入的预测标签(例如k),然后使用k-th二进制分类器来确定输入是否为干净的样本(k类)或对抗的扰动示例(其他类)。我们进一步设计了一种生成方法来通过将每个二进制分类器解释为类别条件数据的无标准密度模型来检测/分类对抗示例。我们提供上述对抗性示例检测/分类方法的全面评估,并证明其竞争性能和引人注目的特性。
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We introduce a new tool for stochastic convex optimization (SCO): a Reweighted Stochastic Query (ReSQue) estimator for the gradient of a function convolved with a (Gaussian) probability density. Combining ReSQue with recent advances in ball oracle acceleration [CJJJLST20, ACJJS21], we develop algorithms achieving state-of-the-art complexities for SCO in parallel and private settings. For a SCO objective constrained to the unit ball in $\mathbb{R}^d$, we obtain the following results (up to polylogarithmic factors). We give a parallel algorithm obtaining optimization error $\epsilon_{\text{opt}}$ with $d^{1/3}\epsilon_{\text{opt}}^{-2/3}$ gradient oracle query depth and $d^{1/3}\epsilon_{\text{opt}}^{-2/3} + \epsilon_{\text{opt}}^{-2}$ gradient queries in total, assuming access to a bounded-variance stochastic gradient estimator. For $\epsilon_{\text{opt}} \in [d^{-1}, d^{-1/4}]$, our algorithm matches the state-of-the-art oracle depth of [BJLLS19] while maintaining the optimal total work of stochastic gradient descent. We give an $(\epsilon_{\text{dp}}, \delta)$-differentially private algorithm which, given $n$ samples of Lipschitz loss functions, obtains near-optimal optimization error and makes $\min(n, n^2\epsilon_{\text{dp}}^2 d^{-1}) + \min(n^{4/3}\epsilon_{\text{dp}}^{1/3}, (nd)^{2/3}\epsilon_{\text{dp}}^{-1})$ queries to the gradients of these functions. In the regime $d \le n \epsilon_{\text{dp}}^{2}$, where privacy comes at no cost in terms of the optimal loss up to constants, our algorithm uses $n + (nd)^{2/3}\epsilon_{\text{dp}}^{-1}$ queries and improves recent advancements of [KLL21, AFKT21]. In the moderately low-dimensional setting $d \le \sqrt n \epsilon_{\text{dp}}^{3/2}$, our query complexity is near-linear.
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New architecture GPUs like A100 are now equipped with multi-instance GPU (MIG) technology, which allows the GPU to be partitioned into multiple small, isolated instances. This technology provides more flexibility for users to support both deep learning training and inference workloads, but efficiently utilizing it can still be challenging. The vision of this paper is to provide a more comprehensive and practical benchmark study for MIG in order to eliminate the need for tedious manual benchmarking and tuning efforts. To achieve this vision, the paper presents MIGPerf, an open-source tool that streamlines the benchmark study for MIG. Using MIGPerf, the authors conduct a series of experiments, including deep learning training and inference characterization on MIG, GPU sharing characterization, and framework compatibility with MIG. The results of these experiments provide new insights and guidance for users to effectively employ MIG, and lay the foundation for further research on the orchestration of hybrid training and inference workloads on MIGs. The code and results are released on https://github.com/MLSysOps/MIGProfiler. This work is still in progress and more results will be published soon.
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In the scenario of black-box adversarial attack, the target model's parameters are unknown, and the attacker aims to find a successful adversarial perturbation based on query feedback under a query budget. Due to the limited feedback information, existing query-based black-box attack methods often require many queries for attacking each benign example. To reduce query cost, we propose to utilize the feedback information across historical attacks, dubbed example-level adversarial transferability. Specifically, by treating the attack on each benign example as one task, we develop a meta-learning framework by training a meta-generator to produce perturbations conditioned on benign examples. When attacking a new benign example, the meta generator can be quickly fine-tuned based on the feedback information of the new task as well as a few historical attacks to produce effective perturbations. Moreover, since the meta-train procedure consumes many queries to learn a generalizable generator, we utilize model-level adversarial transferability to train the meta-generator on a white-box surrogate model, then transfer it to help the attack against the target model. The proposed framework with the two types of adversarial transferability can be naturally combined with any off-the-shelf query-based attack methods to boost their performance, which is verified by extensive experiments.
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Cashews are grown by over 3 million smallholders in more than 40 countries worldwide as a principal source of income. As the third largest cashew producer in Africa, Benin has nearly 200,000 smallholder cashew growers contributing 15% of the country's national export earnings. However, a lack of information on where and how cashew trees grow across the country hinders decision-making that could support increased cashew production and poverty alleviation. By leveraging 2.4-m Planet Basemaps and 0.5-m aerial imagery, newly developed deep learning algorithms, and large-scale ground truth datasets, we successfully produced the first national map of cashew in Benin and characterized the expansion of cashew plantations between 2015 and 2021. In particular, we developed a SpatioTemporal Classification with Attention (STCA) model to map the distribution of cashew plantations, which can fully capture texture information from discriminative time steps during a growing season. We further developed a Clustering Augmented Self-supervised Temporal Classification (CASTC) model to distinguish high-density versus low-density cashew plantations by automatic feature extraction and optimized clustering. Results show that the STCA model has an overall accuracy of 80% and the CASTC model achieved an overall accuracy of 77.9%. We found that the cashew area in Benin has doubled from 2015 to 2021 with 60% of new plantation development coming from cropland or fallow land, while encroachment of cashew plantations into protected areas has increased by 70%. Only half of cashew plantations were high-density in 2021, suggesting high potential for intensification. Our study illustrates the power of combining high-resolution remote sensing imagery and state-of-the-art deep learning algorithms to better understand tree crops in the heterogeneous smallholder landscape.
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In this paper, we develop an efficient multi-scale network to predict action classes in partial videos in an end-to-end manner. Unlike most existing methods with offline feature generation, our method directly takes frames as input and further models motion evolution on two different temporal scales.Therefore, we solve the complexity problems of the two stages of modeling and the problem of insufficient temporal and spatial information of a single scale. Our proposed End-to-End MultiScale Network (E2EMSNet) is composed of two scales which are named segment scale and observed global scale. The segment scale leverages temporal difference over consecutive frames for finer motion patterns by supplying 2D convolutions. For observed global scale, a Long Short-Term Memory (LSTM) is incorporated to capture motion features of observed frames. Our model provides a simple and efficient modeling framework with a small computational cost. Our E2EMSNet is evaluated on three challenging datasets: BIT, HMDB51, and UCF101. The extensive experiments demonstrate the effectiveness of our method for action prediction in videos.
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