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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盲目图像超分辨率(SR)的典型方法通过直接估算或学习潜在空间中的降解表示来处理未知的降解。这些方法的一个潜在局限性是,他们假设可以通过整合各种手工降解(例如,比科比克下采样)来模拟未知的降解,这不一定是正确的。现实世界中的降解可能超出了手工降解的模拟范围,这被称为新型降解。在这项工作中,我们建议学习一个潜在的降解空间,可以将其从手工制作的(基本)降解中推广到新的降解。然后将其在此潜在空间中获得的新型降解的表示形式被利用,以生成与新型降解一致的降级图像,以构成SR模型的配对训练数据。此外,我们执行各种推断,以使潜在表示空间中的降解后降解与先前的分布(例如高斯分布)相匹配。因此,我们能够采样更多的高质量表示以进行新的降级,以增加SR模型的训练数据。我们对合成数据集和现实数据集进行了广泛的实验,以验证我们在新型降解中盲目超分辨率的有效性和优势。
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摄像头捕获的文档图像通常会遭受透视和几何变形的影响。在考虑视觉不良美学和OCR系统性能不断恶化时,纠正它们是很大的价值。最近的基于学习的方法将重点放在精确的文档图像上。但是,这可能不足以克服实际挑战,包括具有大边缘区域或没有边缘的文档图像。由于这种不切实际,用户在遇到大边缘区域时努力进行裁剪。同时,没有边距的脱瓦图像仍然是一个无法克服的问题。据我们所知,仍然没有完整有效的管道来纠正野外文档图像。为了解决这个问题,我们提出了一种称为Marior的新方法(删除边缘和\迭代内容纠正)。马里奥(Marior)遵循一种渐进策略,以粗到精细的方式迭代地改善脱水质量和可读性。具体而言,我们将管道分为两个模块:边缘去除模块(MRM)和迭代内容整流模块(ICRM)。首先,我们预测输入图像的分割面膜以删除边缘,从而获得初步结果。然后,我们通过产生密集的位移流以实现内容感知的整流来进一步完善图像。我们可以适应地确定改进的迭代次数。实验证明了我们方法在公共基准测试方面的最先进性能。资源可在https://github.com/zzzhang-jx/marior上获得,以进行进一步比较。
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由于其在隐私保护,文档修复和文本编辑方面的各种应用,因此删除文本引起了越来越多的关注。它显示出深度神经网络的重大进展。但是,大多数现有方法通常会为复杂的背景产生不一致的结果。为了解决此问题,我们提出了一个上下文引导的文本删除网络,称为CTRNET。 Ctrnet探索了低级结构和高级判别上下文特征,作为指导背景恢复过程的先验知识。我们进一步提出了具有CNNS和Transformer-编码器的局部全球含量建模(LGCM)块,以捕获局部特征并在全球像素之间建立长期关系。最后,我们将LGCM与特征建模和解码的上下文指南合并。在基准数据集,Scut-Enstext和Scut-Syn上进行的实验表明,CTRNET显着胜过现有的最新方法。此外,关于考试论文的定性实验也证明了我们方法的概括能力。代码和补充材料可在https://github.com/lcy0604/ctrnet上获得。
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随着人工智能和机器学习的日益普及,文献中已经提出了针对深度学习模型的广泛攻击。逃避攻击和中毒攻击都试图利用对抗性变化的样本来欺骗受害者模型以错误地分类对抗样本。尽管这种攻击声称是隐形的,即对人的眼睛看不见,但很少评估这种说法。在本文中,我们介绍了第一个大规模研究,涉及对深度学习的攻击中使用的对抗样本的隐身性。我们已经对六个流行的基准数据集实施了20种代表性的对抗ML攻击。我们使用两种互补方法评估了攻击样本的隐身性:(1)一项数值研究,采用24个指标用于图像相似性或质量评估; (2)对3组问卷的用户研究,从1,000多个回答中收集了20,000多次注释。我们的结果表明,大多数现有攻击引入了不可忽略的扰动,这些扰动对人的眼睛并不隐秘。我们进一步分析了有助于攻击隐身性的因素。我们进一步研究了数值分析与用户研究之间的相关性,并证明某些图像质量指标可能在攻击设计中提供有用的指导,而评估的图像质量和攻击的视觉隐身性之间仍然存在显着差距。
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Dataset distillation has emerged as a prominent technique to improve data efficiency when training machine learning models. It encapsulates the knowledge from a large dataset into a smaller synthetic dataset. A model trained on this smaller distilled dataset can attain comparable performance to a model trained on the original training dataset. However, the existing dataset distillation techniques mainly aim at achieving the best trade-off between resource usage efficiency and model utility. The security risks stemming from them have not been explored. This study performs the first backdoor attack against the models trained on the data distilled by dataset distillation models in the image domain. Concretely, we inject triggers into the synthetic data during the distillation procedure rather than during the model training stage, where all previous attacks are performed. We propose two types of backdoor attacks, namely NAIVEATTACK and DOORPING. NAIVEATTACK simply adds triggers to the raw data at the initial distillation phase, while DOORPING iteratively updates the triggers during the entire distillation procedure. We conduct extensive evaluations on multiple datasets, architectures, and dataset distillation techniques. Empirical evaluation shows that NAIVEATTACK achieves decent attack success rate (ASR) scores in some cases, while DOORPING reaches higher ASR scores (close to 1.0) in all cases. Furthermore, we conduct a comprehensive ablation study to analyze the factors that may affect the attack performance. Finally, we evaluate multiple defense mechanisms against our backdoor attacks and show that our attacks can practically circumvent these defense mechanisms.
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Blind image quality assessment (BIQA) remains challenging due to the diversity of distortion and image content variation, which complicate the distortion patterns crossing different scales and aggravate the difficulty of the regression problem for BIQA. However, existing BIQA methods often fail to consider multi-scale distortion patterns and image content, and little research has been done on learning strategies to make the regression model produce better performance. In this paper, we propose a simple yet effective Progressive Multi-Task Image Quality Assessment (PMT-IQA) model, which contains a multi-scale feature extraction module (MS) and a progressive multi-task learning module (PMT), to help the model learn complex distortion patterns and better optimize the regression issue to align with the law of human learning process from easy to hard. To verify the effectiveness of the proposed PMT-IQA model, we conduct experiments on four widely used public datasets, and the experimental results indicate that the performance of PMT-IQA is superior to the comparison approaches, and both MS and PMT modules improve the model's performance.
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The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.
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Given the increasingly intricate forms of partial differential equations (PDEs) in physics and related fields, computationally solving PDEs without analytic solutions inevitably suffers from the trade-off between accuracy and efficiency. Recent advances in neural operators, a kind of mesh-independent neural-network-based PDE solvers, have suggested the dawn of overcoming this challenge. In this emerging direction, Koopman neural operator (KNO) is a representative demonstration and outperforms other state-of-the-art alternatives in terms of accuracy and efficiency. Here we present KoopmanLab, a self-contained and user-friendly PyTorch module of the Koopman neural operator family for solving partial differential equations. Beyond the original version of KNO, we develop multiple new variants of KNO based on different neural network architectures to improve the general applicability of our module. These variants are validated by mesh-independent and long-term prediction experiments implemented on representative PDEs (e.g., the Navier-Stokes equation and the Bateman-Burgers equation) and ERA5 (i.e., one of the largest high-resolution data sets of global-scale climate fields). These demonstrations suggest the potential of KoopmanLab to be considered in diverse applications of partial differential equations.
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A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
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