本文介绍了一种基于CNN的完全无监督的方法,用于光流量的运动分段。我们假设输入光流可以表示为分段参数运动模型集,通常,仿射或二次运动模型。这项工作的核心思想是利用期望 - 最大化(EM)框架。它使我们能够以良好的方式设计丢失功能和我们运动分割神经网络的培训程序。然而,与经典迭代的EM相比,一旦培训网络,我们就可以为单个推理步骤中的任何看不见的光学流场提供分割,没有对运动模型参数的初始化,因为它们没有估计推断阶段。已经调查了不同的损失功能,包括强大的功能。我们还提出了一种关于光学流场的新型数据增强技术,对性能显着影响。我们在Davis2016数据集上测试了我们的运动分段网络。我们的方法优于相当的无监督方法,非常有效。实际上,它可以在125fps运行,使其可用于实时应用程序。
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Physics-Informed Neural Networks (PINNs) have gained much attention in various fields of engineering thanks to their capability of incorporating physical laws into the models. PINNs integrate the physical constraints by minimizing the partial differential equations (PDEs) residuals on a set of collocation points. The distribution of these collocation points appears to have a huge impact on the performance of PINNs and the assessment of the sampling methods for these points is still an active topic. In this paper, we propose a Fixed-Budget Online Adaptive Mesh Learning (FBOAML) method, which decomposes the domain into sub-domains, for training collocation points based on local maxima and local minima of the PDEs residuals. The stopping criterion is based on a data set of reference, which leads to an adaptive number of iterations for each specific problem. The effectiveness of FBOAML is demonstrated in the context of non-parameterized and parameterized problems. The impact of the hyper-parameters in FBOAML is investigated in this work. The comparison with other adaptive sampling methods is also illustrated. The numerical results demonstrate important gains in terms of accuracy of PINNs with FBOAML over the classical PINNs with non-adaptive collocation points. We also apply FBOAML in a complex industrial application involving coupling between mechanical and thermal fields. We show that FBOAML is able to identify the high-gradient location and even give better prediction for some physical fields than the classical PINNs with collocation points taken on a pre-adapted finite element mesh.
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Deep learning-based object detection is a powerful approach for detecting faulty insulators in power lines. This involves training an object detection model from scratch, or fine tuning a model that is pre-trained on benchmark computer vision datasets. This approach works well with a large number of insulator images, but can result in unreliable models in the low data regime. The current literature mainly focuses on detecting the presence or absence of insulator caps, which is a relatively easy detection task, and does not consider detection of finer faults such as flashed and broken disks. In this article, we formulate three object detection tasks for insulator and asset inspection from aerial images, focusing on incipient faults in disks. We curate a large reference dataset of insulator images that can be used to learn robust features for detecting healthy and faulty insulators. We study the advantage of using this dataset in the low target data regime by pre-training on the reference dataset followed by fine-tuning on the target dataset. The results suggest that object detection models can be used to detect faults in insulators at a much incipient stage, and that transfer learning adds value depending on the type of object detection model. We identify key factors that dictate performance in the low data-regime and outline potential approaches to improve the state-of-the-art.
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Whole slide images (WSI) are microscopy images of stained tissue slides routinely prepared for diagnosis and treatment selection in medical practice. WSI are very large (gigapixel size) and complex (made of up to millions of cells). The current state-of-the-art (SoTA) approach to classify WSI subdivides them into tiles, encodes them by pre-trained networks and applies Multiple Instance Learning (MIL) to train for specific downstream tasks. However, annotated datasets are often small, typically a few hundred to a few thousand WSI, which may cause overfitting and underperforming models. Conversely, the number of unannotated WSI is ever increasing, with datasets of tens of thousands (soon to be millions) of images available. While it has been previously proposed to use these unannotated data to identify suitable tile representations by self-supervised learning (SSL), downstream classification tasks still require full supervision because parts of the MIL architecture is not trained during tile level SSL pre-training. Here, we propose a strategy of slide level SSL to leverage the large number of WSI without annotations to infer powerful slide representations. Applying our method to The Cancer-Genome Atlas, one of the most widely used data resources in cancer research (16 TB image data), we are able to downsize the dataset to 23 MB without any loss in predictive power: we show that a linear classifier trained on top of these embeddings maintains or improves previous SoTA performances on various benchmark WSI classification tasks. Finally, we observe that training a classifier on these representations with tiny datasets (e.g. 50 slides) improved performances over SoTA by an average of +6.3 AUC points over all downstream tasks.
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Reduced order modeling methods are often used as a mean to reduce simulation costs in industrial applications. Despite their computational advantages, reduced order models (ROMs) often fail to accurately reproduce complex dynamics encountered in real life applications. To address this challenge, we leverage NeuralODEs to propose a novel ROM correction approach based on a time-continuous memory formulation. Finally, experimental results show that our proposed method provides a high level of accuracy while retaining the low computational costs inherent to reduced models.
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Due mostly to its application to cognitive radio networks, multiplayer bandits gained a lot of interest in the last decade. A considerable progress has been made on its theoretical aspect. However, the current algorithms are far from applicable and many obstacles remain between these theoretical results and a possible implementation of multiplayer bandits algorithms in real cognitive radio networks. This survey contextualizes and organizes the rich multiplayer bandits literature. In light of the existing works, some clear directions for future research appear. We believe that a further study of these different directions might lead to theoretical algorithms adapted to real-world situations.
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Biological cortical networks are potentially fully recurrent networks without any distinct output layer, where recognition may instead rely on the distribution of activity across its neurons. Because such biological networks can have rich dynamics, they are well-designed to cope with dynamical interactions of the types that occur in nature, while traditional machine learning networks may struggle to make sense of such data. Here we connected a simple model neuronal network (based on the 'linear summation neuron model' featuring biologically realistic dynamics (LSM), consisting of 10 of excitatory and 10 inhibitory neurons, randomly connected) to a robot finger with multiple types of force sensors when interacting with materials of different levels of compliance. Scope: to explore the performance of the network on classification accuracy. Therefore, we compared the performance of the network output with principal component analysis of statistical features of the sensory data as well as its mechanical properties. Remarkably, even though the LSM was a very small and untrained network, and merely designed to provide rich internal network dynamics while the neuron model itself was highly simplified, we found that the LSM outperformed these other statistical approaches in terms of accuracy.
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我们提出了一种新颖的端到端方法,用于在事件流中进行关键点检测和跟踪,该方法比以前的方法提供了更好的精度和更长的关键点轨道。两项贡献共同努力使这成为可能。首先,我们提出了一个简单的过程来生成稳定的关键点标签,我们用来训练复发架构。该培训数据导致检测随着时间的推移非常一致。此外,我们观察到以前的按键检测方法在一段时间内集成事件的表示形式(例如时间表面)。由于需要这种集成,因此我们声称最好预测时间段的关键点的轨迹,而不是单个位置,如先前的方法中所做的那样。我们以一系列热图的形式预测这些轨迹在整合时间段。这可以改善关键点本地化。我们的体系结构也可以保持非常简单,从而导致非常快的推理时间。我们在HVGA ATIS角数据集以及“事件相机数据集和模拟器”数据集上演示了我们的方法,并将其显示为“关键点”轨道的三倍,几乎是最好的先前最佳先前最佳先前的轨道轨迹。 - 艺术方法。我们认为我们的方法可以推广到其他基于事件的相机问题,并发布我们的源代码以鼓励其他作者探索它。
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经典的错误发现率(FDR)控制程序提供了强大而可解释的保证,而它们通常缺乏灵活性。另一方面,最近的机器学习分类算法是基于随机森林(RF)或神经网络(NN)的算法,具有出色的实践表现,但缺乏解释和理论保证。在本文中,我们通过引入新的自适应新颖性检测程序(称为Adadetect)来使这两个相遇。它将多个测试文献的最新作品范围扩展到高维度的范围,尤其是Yang等人的范围。 (2021)。显示AD​​ADETECT既可以强烈控制FDR,又具有在特定意义上模仿甲骨文之一的力量。理论结果,几个基准数据集上的数值实验以及对天体物理数据的应用,我们的方法的兴趣和有效性得到了证明。特别是,虽然可以将AdadEtect与任何分类器结合使用,但它在带有RF的现实世界数据集以及带有NN的图像上特别有效。
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我们解决了条件平均嵌入(CME)的内核脊回归估算的一致性,这是给定$ y $ x $的条件分布的嵌入到目标重现内核hilbert space $ hilbert space $ hilbert Space $ \ Mathcal {H} _y $ $ $ $ 。 CME允许我们对目标RKHS功能的有条件期望,并已在非参数因果和贝叶斯推论中使用。我们解决了错误指定的设置,其中目标CME位于Hilbert-Schmidt操作员的空间中,该操作员从$ \ Mathcal {H} _X _x $和$ L_2 $和$ \ MATHCAL {H} _Y $ $之间的输入插值空间起作用。该操作员的空间被证明是新定义的矢量值插值空间的同构。使用这种同构,我们在未指定的设置下为经验CME估计量提供了一种新颖的自适应统计学习率。我们的分析表明,我们的费率与最佳$ o(\ log n / n)$速率匹配,而无需假设$ \ Mathcal {h} _y $是有限维度。我们进一步建立了学习率的下限,这表明所获得的上限是最佳的。
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