Multivariate time series forecasting with hierarchical structure is pervasive in real-world applications, demanding not only predicting each level of the hierarchy, but also reconciling all forecasts to ensure coherency, i.e., the forecasts should satisfy the hierarchical aggregation constraints. Moreover, the disparities of statistical characteristics between levels can be huge, worsened by non-Gaussian distributions and non-linear correlations. To this extent, we propose a novel end-to-end hierarchical time series forecasting model, based on conditioned normalizing flow-based autoregressive transformer reconciliation, to represent complex data distribution while simultaneously reconciling the forecasts to ensure coherency. Unlike other state-of-the-art methods, we achieve the forecasting and reconciliation simultaneously without requiring any explicit post-processing step. In addition, by harnessing the power of deep model, we do not rely on any assumption such as unbiased estimates or Gaussian distribution. Our evaluation experiments are conducted on four real-world hierarchical datasets from different industrial domains (three public ones and a dataset from the application servers of Alipay's data center) and the preliminary results demonstrate efficacy of our proposed method.
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Pavement Distress Recognition (PDR) is an important step in pavement inspection and can be powered by image-based automation to expedite the process and reduce labor costs. Pavement images are often in high-resolution with a low ratio of distressed to non-distressed areas. Advanced approaches leverage these properties via dividing images into patches and explore discriminative features in the scale space. However, these approaches usually suffer from information loss during image resizing and low efficiency due to complex learning frameworks. In this paper, we propose a novel and efficient method for PDR. A light network named the Kernel Inversed Pyramidal Resizing Network (KIPRN) is introduced for image resizing, and can be flexibly plugged into the image classification network as a pre-network to exploit resolution and scale information. In KIPRN, pyramidal convolution and kernel inversed convolution are specifically designed to mine discriminative information across different feature granularities and scales. The mined information is passed along to the resized images to yield an informative image pyramid to assist the image classification network for PDR. We applied our method to three well-known Convolutional Neural Networks (CNNs), and conducted an evaluation on a large-scale pavement image dataset named CQU-BPDD. Extensive results demonstrate that KIPRN can generally improve the pavement distress recognition of these CNN models and show that the simple combination of KIPRN and EfficientNet-B3 significantly outperforms the state-of-the-art patch-based method in both performance and efficiency.
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Backdoor attacks have emerged as one of the major security threats to deep learning models as they can easily control the model's test-time predictions by pre-injecting a backdoor trigger into the model at training time. While backdoor attacks have been extensively studied on images, few works have investigated the threat of backdoor attacks on time series data. To fill this gap, in this paper we present a novel generative approach for time series backdoor attacks against deep learning based time series classifiers. Backdoor attacks have two main goals: high stealthiness and high attack success rate. We find that, compared to images, it can be more challenging to achieve the two goals on time series. This is because time series have fewer input dimensions and lower degrees of freedom, making it hard to achieve a high attack success rate without compromising stealthiness. Our generative approach addresses this challenge by generating trigger patterns that are as realistic as real-time series patterns while achieving a high attack success rate without causing a significant drop in clean accuracy. We also show that our proposed attack is resistant to potential backdoor defenses. Furthermore, we propose a novel universal generator that can poison any type of time series with a single generator that allows universal attacks without the need to fine-tune the generative model for new time series datasets.
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图形神经网络(GNN)已被广泛用于表示图数据的表示。但是,对图形数据实际上获得多少性能GNN的理解有限。本文介绍了上下文弹出的GNN框架,并提出了两个平滑度指标,以测量从图形数据获得的信息的数量和质量。然后,一种称为CS-GNN的新型GNN模型旨在根据图的平滑度值改善图形信息的使用。证明CS-GNN比不同类型的真实图中现有方法获得更好的性能。
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尽管不变风险最小化(IRM)成功解决了分布式概括问题,但在实践中应用时,IRM仍可以损害最佳性。 IRM的实用变体,例如IRMV1,已被证明与IRM存在显着差距,因此即使在简单的问题中也可能无法捕获不变性。此外,IRMV1中的优化过程涉及两个内在冲突的目标,并且通常需要对客观权重进行仔细的调整。为了纠正上述问题,我们将IRM重新制定为多目标优化问题,并为IRM提出了一种新的优化方案,称为Pareto不变风险最小化(Pair)。对可以在客观冲突下适应优化指导。此外,我们表明对可以赋予实用的IRM变体能够在提供适当的指导时用原始IRM克服障碍。我们对ColoredMnist进行实验,以确认我们的理论和对的有效性。
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尽管最近在欧几里得数据(例如图像)上使用不变性原理(OOD)概括(例如图像),但有关图数据的研究仍然受到限制。与图像不同,图形的复杂性质给采用不变性原理带来了独特的挑战。特别是,图表上的分布变化可以以多种形式出现,例如属性和结构,因此很难识别不变性。此外,在欧几里得数据上通常需要的域或环境分区通常需要的图形可能非常昂贵。为了弥合这一差距,我们提出了一个新的框架,以捕获图形的不变性,以在各种分配变化下进行保证的OOD概括。具体而言,我们表征了具有因果模型的图形上的潜在分布变化,得出结论,当模型仅关注包含有关标签原因最多信息的子图时,可以实现图形上的OOD概括。因此,我们提出了一个信息理论目标,以提取最大地保留不变的阶级信息的所需子图。用这些子图学习不受分配变化的影响。对合成和现实世界数据集进行的广泛实验,包括在AI ADED药物发现中充满挑战的环境,验证了我们方法的上等OOD概括能力。
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改善深度神经网络(DNN)对抗对抗示例的鲁棒性是安全深度学习的重要而挑战性问题。跨越现有的防御技术,具有预计梯度体面(PGD)的对抗培训是最有效的。对手训练通过最大化分类丢失,通过最大限度地减少从内在最大化生成的逆势示例的丢失来解决\ excepitient {内部最大化}生成侵略性示例的初始最大优化问题。 。因此,衡量内部最大化的衡量标准是如何对对抗性培训至关重要的。在本文中,我们提出了这种标准,即限制优化(FOSC)的一阶静止条件,以定量评估内部最大化中发现的对抗性实例的收敛质量。通过FOSC,我们发现,为了确保更好的稳健性,必须在培训的\ Texit {稍后的阶段}中具有更好的收敛质量的对抗性示例。然而,在早期阶段,高收敛质量的对抗例子不是必需的,甚至可能导致稳健性差。基于这些观察,我们提出了一种\ Texit {动态}培训策略,逐步提高产生的对抗性实例的收敛质量,这显着提高了对抗性培训的鲁棒性。我们的理论和经验结果表明了该方法的有效性。
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我们提出了一种叫做SkullEngine的多级粗内CNN框架,可通过协作,集成和可扩展的JSD模型和三个分段和地标检测细化模型进行高分辨率分割和大规模地标检测。我们在临床数据集中评估了由170 CBCT / CT图像组成的临床数据集,用于分割2骨骼(Midface和Mabless)的任务,并在骨骼,牙齿和软组织上检测175个临床普通的地标。
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已知深神经网络(DNN)容易受到对抗性攻击的影响。已经提出了一系列防御方法来培训普遍稳健的DNN,其中对抗性培训已经证明了有希望的结果。然而,尽管对对抗性培训开发的初步理解,但从架构角度来看,它仍然不明确,从架构角度来看,什么配置可以导致更强大的DNN。在本文中,我们通过全面调查网络宽度和深度对前对方培训的DNN的鲁棒性的全面调查来解决这一差距。具体地,我们进行以下关键观察:1)更多参数(更高的模型容量)不一定有助于对抗冒险; 2)网络的最后阶段(最后一组块)降低能力实际上可以改善对抗性的鲁棒性; 3)在相同的参数预算下,存在对抗性鲁棒性的最佳架构配置。我们还提供了一个理论分析,解释了为什么这种网络配置可以帮助鲁棒性。这些架构见解可以帮助设计对抗的强制性DNN。代码可用于\ url {https://github.com/hanxunh/robustwrn}。
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我们总结了使用巨大的自动语音识别(ASR)模型的大量努力的结果,该模型使用包含大约一百万小时音频的大型,多样的未标记数据集进行了预训练。我们发现,即使对于拥有数万个小时的标记数据的非常大的任务,预训练,自我培训和扩大模型大小的组合也大大提高了数据效率。特别是,在具有34K小时标记数据的ASR任务上,通过微调80亿个参数预先训练的构象异构体模型,我们可以匹配最先进的(SOTA)性能(SOTA)的性能,只有3%的培训数据和通过完整的训练集可以显着改善SOTA。我们还报告了从使用大型预训练和自我训练的模型来完成一系列下游任务所获得的普遍利益,这些任务涵盖了广泛的语音域,并涵盖了多个数据集大小的大小,包括在许多人中获得SOTA性能公共基准。此外,我们利用预先训练的网络的学会表示,在非ASR任务上实现SOTA结果。
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