In recent years, applying deep learning (DL) to assess structural damages has gained growing popularity in vision-based structural health monitoring (SHM). However, both data deficiency and class-imbalance hinder the wide adoption of DL in practical applications of SHM. Common mitigation strategies include transfer learning, over-sampling, and under-sampling, yet these ad-hoc methods only provide limited performance boost that varies from one case to another. In this work, we introduce one variant of the Generative Adversarial Network (GAN), named the balanced semi-supervised GAN (BSS-GAN). It adopts the semi-supervised learning concept and applies balanced-batch sampling in training to resolve low-data and imbalanced-class problems. A series of computer experiments on concrete cracking and spalling classification were conducted under the low-data imbalanced-class regime with limited computing power. The results show that the BSS-GAN is able to achieve better damage detection in terms of recall and $F_\beta$ score than other conventional methods, indicating its state-of-the-art performance.
translated by 谷歌翻译
作为一个严重的问题,近年来已经广泛研究了单图超分辨率(SISR)。 SISR的主要任务是恢复由退化程序引起的信息损失。根据Nyquist抽样理论,降解会导致混叠效应,并使低分辨率(LR)图像的正确纹理很难恢复。实际上,自然图像中相邻斑块之间存在相关性和自相似性。本文考虑了自相似性,并提出了一个分层图像超分辨率网络(HSRNET)来抑制混叠的影响。我们从优化的角度考虑SISR问题,并根据半季节分裂(HQS)方法提出了迭代解决方案模式。为了先验探索本地图像的质地,我们设计了一个分层探索块(HEB)并进行性增加了接受场。此外,设计多级空间注意力(MSA)是为了获得相邻特征的关系并增强了高频信息,这是视觉体验的关键作用。实验结果表明,与其他作品相比,HSRNET实现了更好的定量和视觉性能,并更有效地释放了别名。
translated by 谷歌翻译
As a critical threat to deep neural networks (DNNs), backdoor attacks can be categorized into two types, i.e., source-agnostic backdoor attacks (SABAs) and source-specific backdoor attacks (SSBAs). Compared to traditional SABAs, SSBAs are more advanced in that they have superior stealthier in bypassing mainstream countermeasures that are effective against SABAs. Nonetheless, existing SSBAs suffer from two major limitations. First, they can hardly achieve a good trade-off between ASR (attack success rate) and FPR (false positive rate). Besides, they can be effectively detected by the state-of-the-art (SOTA) countermeasures (e.g., SCAn). To address the limitations above, we propose a new class of viable source-specific backdoor attacks, coined as CASSOCK. Our key insight is that trigger designs when creating poisoned data and cover data in SSBAs play a crucial role in demonstrating a viable source-specific attack, which has not been considered by existing SSBAs. With this insight, we focus on trigger transparency and content when crafting triggers for poisoned dataset where a sample has an attacker-targeted label and cover dataset where a sample has a ground-truth label. Specifically, we implement $CASSOCK_{Trans}$ and $CASSOCK_{Cont}$. While both they are orthogonal, they are complementary to each other, generating a more powerful attack, called $CASSOCK_{Comp}$, with further improved attack performance and stealthiness. We perform a comprehensive evaluation of the three $CASSOCK$-based attacks on four popular datasets and three SOTA defenses. Compared with a representative SSBA as a baseline ($SSBA_{Base}$), $CASSOCK$-based attacks have significantly advanced the attack performance, i.e., higher ASR and lower FPR with comparable CDA (clean data accuracy). Besides, $CASSOCK$-based attacks have effectively bypassed the SOTA defenses, and $SSBA_{Base}$ cannot.
translated by 谷歌翻译
联合学习(FL)在许多分散的用户中训练全球模型,每个用户都有本地数据集。与传统的集中学习相比,FL不需要直接访问本地数据集,因此旨在减轻数据隐私问题。但是,由于推理攻击,包括成员推理,属性推理和数据反演,FL中的数据隐私泄漏仍然存在。在这项工作中,我们提出了一种新型的隐私推理攻击,创造的偏好分析攻击(PPA),它准确地介绍了本地用户的私人偏好,例如,最喜欢(不喜欢)来自客户的在线购物中的(不喜欢)项目和最常见的表达式从用户的自拍照中。通常,PPA可以在本地客户端(用户)的特征上介绍top-k(即,尤其是k = 1、2、3和k = 1)的偏好。我们的关键见解是,本地用户模型的梯度变化对给定类别的样本比例(尤其是大多数(少数)类别的样本比例具有明显的敏感性。通过观察用户模型对类的梯度敏感性,PPA可以介绍用户本地数据集中类的样本比例,从而公开用户对类的偏好。 FL的固有统计异质性进一步促进了PPA。我们使用四个数据集(MNIST,CIFAR10,RAF-DB和PRODUCTS-10K)广泛评估了PPA的有效性。我们的结果表明,PPA分别达到了MNIST和CIFAR10的90%和98%的TOP-1攻击精度。更重要的是,在实际的购物商业商业场景(即产品-10k)和社交网络(即RAF-DB)中,PPA在前一种情况下,PPA获得了78%的TOP-1攻击精度,以推断出最有序的物品(即作为商业竞争对手),在后一种情况下,有88%来推断受害者用户最常见的面部表情,例如恶心。
translated by 谷歌翻译
将低分辨率(LR)图像恢复到超分辨率(SR)图像具有正确和清晰的细节是挑战。现有的深度学习工作几乎忽略了图像的固有结构信息,这是对SR结果的视觉感知的重要作用。在本文中,我们将分层特征开发网络设计为探测并以多尺度特征融合方式保持结构信息。首先,我们提出了在传统边缘探测器上的交叉卷积,以定位和代表边缘特征。然后,交叉卷积块(CCBS)设计有功能归一化和渠道注意,以考虑特征的固有相关性。最后,我们利用多尺度特征融合组(MFFG)来嵌入交叉卷积块,并在层次的层次上开发不同尺度的结构特征的关系,调用名为Cross-SRN的轻量级结构保护网络。实验结果表明,交叉SRN通过准确且清晰的结构细节实现了对最先进的方法的竞争或卓越的恢复性能。此外,我们设置了一个标准,以选择具有丰富的结构纹理的图像。所提出的跨SRN优于所选择的基准测试的最先进的方法,这表明我们的网络在保存边缘具有显着的优势。
translated by 谷歌翻译
神经体系结构搜索(NAS)的主要挑战之一是有效地对体系结构的性能进行排名。绩效排名者的主流评估使用排名相关性(例如,肯德尔的tau),这对整个空间都同样关注。但是,NAS的优化目标是识别顶级体系结构,同时对搜索空间中其他体系结构的关注更少。在本文中,我们从经验和理论上都表明,标准化的累积累积增益(NDCG)对于排名者来说是一个更好的指标。随后,我们提出了一种新算法Acenas,该算法直接通过Lambdarank优化NDCG。它还利用体重共享NAS产生的弱标签来预先培训排名,以便进一步降低搜索成本。对12个NAS基准和大规模搜索空间进行的广泛实验表明,我们的方法始终超过SOTA NAS方法,精度提高了3.67%,搜索成本降低了8倍。
translated by 谷歌翻译
单像超分辨率(SISR),作为传统的不良反对问题,通过最近的卷积神经网络(CNN)的发展得到了极大的振兴。这些基于CNN的方法通常将低分辨率图像映射到其相应的高分辨率版本,具有复杂的网络结构和损耗功能,显示出令人印象深刻的性能。本文对传统的SISR算法提供了新的洞察力,并提出了一种基本上不同的方法,依赖于迭代优化。提出了一种新颖的迭代超分辨率网络(ISRN),顶部是迭代优化。我们首先分析图像SR问题的观察模型,通过以更一般和有效的方式模仿和融合每次迭代来激发可行的解决方案。考虑到批量归一化的缺点,我们提出了一种特征归一化(F-NOM,FN)方法来调节网络中的功能。此外,开发了一种具有FN的新颖块以改善作为FNB称为FNB的网络表示。剩余剩余结构被提出形成一个非常深的网络,其中FNBS与长时间跳过连接,以获得更好的信息传递和稳定训练阶段。对BICUBIC(BI)降解的测试基准的广泛实验结果表明我们的ISRN不仅可以恢复更多的结构信息,而且还可以获得竞争或更好的PSNR / SSIM结果,与其他作品相比,参数更少。除BI之外,我们除了模拟模糊(BD)和低级噪声(DN)的实际降级。 ISRN及其延伸ISRN +两者都比使用BD和DN降级模型的其他产品更好。
translated by 谷歌翻译
In this paper, we study the problem of knowledge-intensive text-to-SQL, in which domain knowledge is necessary to parse expert questions into SQL queries over domain-specific tables. We formalize this scenario by building a new Chinese benchmark KnowSQL consisting of domain-specific questions covering various domains. We then address this problem by presenting formulaic knowledge, rather than by annotating additional data examples. More concretely, we construct a formulaic knowledge bank as a domain knowledge base and propose a framework (ReGrouP) to leverage this formulaic knowledge during parsing. Experiments using ReGrouP demonstrate a significant 28.2% improvement overall on KnowSQL.
translated by 谷歌翻译
Weakly-supervised object localization aims to indicate the category as well as the scope of an object in an image given only the image-level labels. Most of the existing works are based on Class Activation Mapping (CAM) and endeavor to enlarge the discriminative area inside the activation map to perceive the whole object, yet ignore the co-occurrence confounder of the object and context (e.g., fish and water), which makes the model inspection hard to distinguish object boundaries. Besides, the use of CAM also brings a dilemma problem that the classification and localization always suffer from a performance gap and can not reach their highest accuracy simultaneously. In this paper, we propose a casual knowledge distillation method, dubbed KD-CI-CAM, to address these two under-explored issues in one go. More specifically, we tackle the co-occurrence context confounder problem via causal intervention (CI), which explores the causalities among image features, contexts, and categories to eliminate the biased object-context entanglement in the class activation maps. Based on the de-biased object feature, we additionally propose a multi-teacher causal distillation framework to balance the absorption of classification knowledge and localization knowledge during model training. Extensive experiments on several benchmarks demonstrate the effectiveness of KD-CI-CAM in learning clear object boundaries from confounding contexts and addressing the dilemma problem between classification and localization performance.
translated by 谷歌翻译
Dynamic treatment regimes assign personalized treatments to patients sequentially over time based on their baseline information and time-varying covariates. In mobile health applications, these covariates are typically collected at different frequencies over a long time horizon. In this paper, we propose a deep spectral Q-learning algorithm, which integrates principal component analysis (PCA) with deep Q-learning to handle the mixed frequency data. In theory, we prove that the mean return under the estimated optimal policy converges to that under the optimal one and establish its rate of convergence. The usefulness of our proposal is further illustrated via simulations and an application to a diabetes dataset.
translated by 谷歌翻译