糖尿病性视网膜病(DR)和糖尿病黄斑水肿(DME)是全球永久失明的主要原因。在临床实践中设计具有良好泛化能力的自动分级系统至关重要。但是,先前的工作是独立的DR或DME等级,而无需考虑它们之间的内部相关性,或者通过共享特征表示共同对其进行分级,但忽略了由困难的样本和数据偏见引起的潜在概括问题。为了解决这些问题,我们提出了一个与动态难度意识的加权损失(DAW)和双流式分离的学习体系结构(分离)的框架。受课程学习的启发,DAW通过适应性地测量难度从简单的样本学习到困难样本。分离分离分级任务的特征,以避免潜在地强调偏见。通过添加DAW和Decarach,该模型学习了鲁棒的分离特征表示,以探索DR和DME之间的内部相关性并实现更好的分级性能。在三个基准测试的实验显示了我们框架内框架和跨数据库测试的有效性和鲁棒性。
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本文提出了一个改进金字塔变压器(复制器),以进行健壮的面部标志性检测。大多数面部地标探测器都专注于学习代表性图像特征。但是,这些基于CNN的功能表示不足以处理复杂的现实世界情景,因为忽略了地标的内部结构以及地标和环境之间的关系。在这项工作中,我们制定了面部标志性检测任务,作为沿金字塔记忆的提炼里程碑式的查询。具体而言,引入了金字塔变压器头(PTH),以在地标之间建立同源关系,以及地标和跨尺度环境之间的异源关系。此外,动态里程碑改进(DLR)模块旨在将地标回归分解为端到端的细化过程,其中动态聚合的查询被转换为残留坐标预测。对四个面部标志检测基准及其各种子集进行的广泛实验结果表明,我们的框架具有卓越的性能和较高的鲁棒性。
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在现实世界应用中的深度神经网络(DNN)的成功受益于丰富的预训练模型。然而,回溯预训练模型可以对下游DNN的部署构成显着的特洛伊木马威胁。现有的DNN测试方法主要旨在在对抗性设置中找到错误的角壳行为,但未能发现由强大的木马攻击所制作的后门。观察特洛伊木马网络行为表明,它们不仅由先前的工作所提出的单一受损神经元反射,而且归因于在多个神经元的激活强度和频率中的关键神经路径。这项工作制定了DNN后门测试,并提出了录音机框架。通过少量良性示例的关键神经元的差异模糊,我们识别特洛伊木马路径,特别是临界人,并通过模拟所识别的路径中的关键神经元来产生后门测试示例。广泛的实验表明了追索者的优越性,比现有方法更高的检测性能。通过隐秘的混合和自适应攻击来检测到后门的录音机更好,现有方法无法检测到。此外,我们的实验表明,录音所可能会揭示模型动物园中的模型的潜在潜在的背面。
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虽然深入学习模型取得了前所未有的成功,但他们对逆势袭击的脆弱性引起了越来越关注,特别是在部署安全关键域名时。为了解决挑战,已经提出了鲁棒性改善的许多辩护策略,包括反应性和积极主动。从图像特征空间的角度来看,由于特征的偏移,其中一些人无法达到满足结果。此外,模型学习的功能与分类结果无直接相关。与他们不同,我们考虑基本上从模型内部进行防御方法,并在攻击前后调查神经元行为。我们观察到,通过大大改变为正确标签的神经元大大改变神经元来误导模型。受其激励,我们介绍了神经元影响的概念,进一步将神经元分为前,中间和尾部。基于它,我们提出神经元水平逆扰动(NIP),第一神经元水平反应防御方法对抗对抗攻击。通过强化前神经元并削弱尾部中的弱化,辊隙可以消除几乎所有的对抗扰动,同时仍然保持高良好的精度。此外,它可以通过适应性,尤其是更大的扰动来应对不同的扰动。在三个数据集和六种模型上进行的综合实验表明,NIP优于最先进的基线对抗11个对抗性攻击。我们进一步通过神经元激活和可视化提供可解释的证据,以便更好地理解。
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Optical coherence tomography (OCT) captures cross-sectional data and is used for the screening, monitoring, and treatment planning of retinal diseases. Technological developments to increase the speed of acquisition often results in systems with a narrower spectral bandwidth, and hence a lower axial resolution. Traditionally, image-processing-based techniques have been utilized to reconstruct subsampled OCT data and more recently, deep-learning-based methods have been explored. In this study, we simulate reduced axial scan (A-scan) resolution by Gaussian windowing in the spectral domain and investigate the use of a learning-based approach for image feature reconstruction. In anticipation of the reduced resolution that accompanies wide-field OCT systems, we build upon super-resolution techniques to explore methods to better aid clinicians in their decision-making to improve patient outcomes, by reconstructing lost features using a pixel-to-pixel approach with an altered super-resolution generative adversarial network (SRGAN) architecture.
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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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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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There are multiple scales of abstraction from which we can describe the same image, depending on whether we are focusing on fine-grained details or a more global attribute of the image. In brain mapping, learning to automatically parse images to build representations of both small-scale features (e.g., the presence of cells or blood vessels) and global properties of an image (e.g., which brain region the image comes from) is a crucial and open challenge. However, most existing datasets and benchmarks for neuroanatomy consider only a single downstream task at a time. To bridge this gap, we introduce a new dataset, annotations, and multiple downstream tasks that provide diverse ways to readout information about brain structure and architecture from the same image. Our multi-task neuroimaging benchmark (MTNeuro) is built on volumetric, micrometer-resolution X-ray microtomography images spanning a large thalamocortical section of mouse brain, encompassing multiple cortical and subcortical regions. We generated a number of different prediction challenges and evaluated several supervised and self-supervised models for brain-region prediction and pixel-level semantic segmentation of microstructures. Our experiments not only highlight the rich heterogeneity of this dataset, but also provide insights into how self-supervised approaches can be used to learn representations that capture multiple attributes of a single image and perform well on a variety of downstream tasks. Datasets, code, and pre-trained baseline models are provided at: https://mtneuro.github.io/ .
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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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Off-policy evaluation (OPE) is a method for estimating the return of a target policy using some pre-collected observational data generated by a potentially different behavior policy. In some cases, there may be unmeasured variables that can confound the action-reward or action-next-state relationships, rendering many existing OPE approaches ineffective. This paper develops an instrumental variable (IV)-based method for consistent OPE in confounded Markov decision processes (MDPs). Similar to single-stage decision making, we show that IV enables us to correctly identify the target policy's value in infinite horizon settings as well. Furthermore, we propose an efficient and robust value estimator and illustrate its effectiveness through extensive simulations and analysis of real data from a world-leading short-video platform.
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