We propose Hierarchical ProtoPNet: an interpretable network that explains its reasoning process by considering the hierarchical relationship between classes. Different from previous methods that explain their reasoning process by dissecting the input image and finding the prototypical parts responsible for the classification, we propose to explain the reasoning process for video action classification by dissecting the input video frames on multiple levels of the class hierarchy. The explanations leverage the hierarchy to deal with uncertainty, akin to human reasoning: When we observe water and human activity, but no definitive action it can be recognized as the water sports parent class. Only after observing a person swimming can we definitively refine it to the swimming action. Experiments on ActivityNet and UCF-101 show performance improvements while providing multi-level explanations.
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无监督的人重新识别是计算机视觉中的一项具有挑战性且有前途的任务。如今,无监督的人重新识别方法通过使用伪标签培训取得了巨大进步。但是,如何以无监督的方式进行纯化的特征和标签噪声的显式研究。为了净化功能,我们考虑了来自不同本地视图的两种其他功能,以丰富功能表示。所提出的多视图功能仔细地集成到我们的群体对比度学习中,以利用全球功能容易忽略和偏见的更具歧视性线索。为了净化标签噪声,我们建议在离线方案中利用教师模型的知识。具体来说,我们首先从嘈杂的伪标签培训教师模型,然后使用教师模型指导我们的学生模型的学习。在我们的环境中,学生模型可以在教师模型的监督下快速融合,因此,随着教师模型的影响很大,嘈杂标签的干扰。在仔细处理功能学习中的噪音和偏见之后,我们的纯化模块被证明对无监督的人的重新识别非常有效。对三个受欢迎人重新识别数据集进行的广泛实验证明了我们方法的优势。尤其是,我们的方法在具有挑战性的Market-1501基准中,在完全无监督的环境下,在具有挑战性的Market-1501基准中实现了最先进的精度85.8 \%@map和94.5 \% @rank-1。代码将发布。
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天气预报是一项有吸引力的挑战性任务,因为它对人类生活和大气运动的复杂性的影响。在大量历史观察到的时间序列数据的支持下,该任务适用于数据驱动的方法,尤其是深层神经网络。最近,基于图神经网络(GNN)方法在时空预测方面取得了出色的性能。但是,基于规范的GNNS方法仅分别对每个站的气象变量的局部图或整个车站的全局图进行建模,从而缺乏不同站点的气象变量之间的信息相互作用。在本文中,我们提出了一种新型的层次时空图形神经网络(Histgnn),以模拟多个站点气象变量之间的跨区域时空相关性。自适应图学习层和空间图卷积用于构建自学习图,并研究可变级别和站点级别图的节点之间的隐藏依赖性。为了捕获时间模式,扩张的成立为GATE时间卷积的主干旨在对长而各种气象趋势进行建模。此外,提出了动态的交互学习来构建在层次图中传递的双向信息。三个现实世界中的气象数据集的实验结果表明,史基元超过7个基准的卓越性能,并且将误差降低了4.2%至11.6%,尤其是与最先进的天气预测方法相比。
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在这项工作中,我们提出了一种基于深度学习的新方案,用于解决高维非线性后向随机微分方程(BSDES)。这个想法是将问题重新重新制定为包括本地损失功能的全球优化。本质上,我们使用深神网络及其具有自动分化的梯度近似BSDE的未知解。通过在每个时间步骤定义的二次局部损耗函数中最小化近似值来执行近似值,该局部损失函数始终包括终端条件。这种损失函数是通过用终端条件迭代时间积分的Euler离散化来获得的。我们的公式可以促使随机梯度下降算法不仅要考虑到每个时间层的准确性,而且会收敛到良好的局部最小值。为了证明我们的算法的性能,提供了几种高维非线性BSDE,包括金融中的定价问题。
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Sparse principal component analysis (SPCA) has been widely used for dimensionality reduction and feature extraction in high-dimensional data analysis. Despite there are many methodological and theoretical developments in the past two decades, the theoretical guarantees of the popular SPCA algorithm proposed by Zou, Hastie & Tibshirani (2006) based on the elastic net are still unknown. We aim to close this important theoretical gap in this paper. We first revisit the SPCA algorithm of Zou et al. (2006) and present our implementation. Also, we study a computationally more efficient variant of the SPCA algorithm in Zou et al. (2006) that can be considered as the limiting case of SPCA. We provide the guarantees of convergence to a stationary point for both algorithms. We prove that, under a sparse spiked covariance model, both algorithms can recover the principal subspace consistently under mild regularity conditions. We show that their estimation error bounds match the best available bounds of existing works or the minimax rates up to some logarithmic factors. Moreover, we demonstrate the numerical performance of both algorithms in simulation studies.
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Long-term non-prehensile planar manipulation is a challenging task for robot planning and feedback control. It is characterized by underactuation, hybrid control, and contact uncertainty. One main difficulty is to determine contact points and directions, which involves joint logic and geometrical reasoning in the modes of the dynamics model. To tackle this issue, we propose a demonstration-guided hierarchical optimization framework to achieve offline task and motion planning (TAMP). Our work extends the formulation of the dynamics model of the pusher-slider system to include separation mode with face switching cases, and solves a warm-started TAMP problem by exploiting human demonstrations. We show that our approach can cope well with the local minima problems currently present in the state-of-the-art solvers and determine a valid solution to the task. We validate our results in simulation and demonstrate its applicability on a pusher-slider system with real Franka Emika robot in the presence of external disturbances.
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Human modeling and relighting are two fundamental problems in computer vision and graphics, where high-quality datasets can largely facilitate related research. However, most existing human datasets only provide multi-view human images captured under the same illumination. Although valuable for modeling tasks, they are not readily used in relighting problems. To promote research in both fields, in this paper, we present UltraStage, a new 3D human dataset that contains more than 2K high-quality human assets captured under both multi-view and multi-illumination settings. Specifically, for each example, we provide 32 surrounding views illuminated with one white light and two gradient illuminations. In addition to regular multi-view images, gradient illuminations help recover detailed surface normal and spatially-varying material maps, enabling various relighting applications. Inspired by recent advances in neural representation, we further interpret each example into a neural human asset which allows novel view synthesis under arbitrary lighting conditions. We show our neural human assets can achieve extremely high capture performance and are capable of representing fine details such as facial wrinkles and cloth folds. We also validate UltraStage in single image relighting tasks, training neural networks with virtual relighted data from neural assets and demonstrating realistic rendering improvements over prior arts. UltraStage will be publicly available to the community to stimulate significant future developments in various human modeling and rendering tasks.
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Ongoing risks from climate change have impacted the livelihood of global nomadic communities, and are likely to lead to increased migratory movements in coming years. As a result, mobility considerations are becoming increasingly important in energy systems planning, particularly to achieve energy access in developing countries. Advanced Plug and Play control strategies have been recently developed with such a decentralized framework in mind, more easily allowing for the interconnection of nomadic communities, both to each other and to the main grid. In light of the above, the design and planning strategy of a mobile multi-energy supply system for a nomadic community is investigated in this work. Motivated by the scale and dimensionality of the associated uncertainties, impacting all major design and decision variables over the 30-year planning horizon, Deep Reinforcement Learning (DRL) is implemented for the design and planning problem tackled. DRL based solutions are benchmarked against several rigid baseline design options to compare expected performance under uncertainty. The results on a case study for ger communities in Mongolia suggest that mobile nomadic energy systems can be both technically and economically feasible, particularly when considering flexibility, although the degree of spatial dispersion among households is an important limiting factor. Key economic, sustainability and resilience indicators such as Cost, Equivalent Emissions and Total Unmet Load are measured, suggesting potential improvements compared to available baselines of up to 25%, 67% and 76%, respectively. Finally, the decomposition of values of flexibility and plug and play operation is presented using a variation of real options theory, with important implications for both nomadic communities and policymakers focused on enabling their energy access.
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Background and Purpose: Colorectal cancer is a common fatal malignancy, the fourth most common cancer in men, and the third most common cancer in women worldwide. Timely detection of cancer in its early stages is essential for treating the disease. Currently, there is a lack of datasets for histopathological image segmentation of rectal cancer, which often hampers the assessment accuracy when computer technology is used to aid in diagnosis. Methods: This present study provided a new publicly available Enteroscope Biopsy Histopathological Hematoxylin and Eosin Image Dataset for Image Segmentation Tasks (EBHI-Seg). To demonstrate the validity and extensiveness of EBHI-Seg, the experimental results for EBHI-Seg are evaluated using classical machine learning methods and deep learning methods. Results: The experimental results showed that deep learning methods had a better image segmentation performance when utilizing EBHI-Seg. The maximum accuracy of the Dice evaluation metric for the classical machine learning method is 0.948, while the Dice evaluation metric for the deep learning method is 0.965. Conclusion: This publicly available dataset contained 5,170 images of six types of tumor differentiation stages and the corresponding ground truth images. The dataset can provide researchers with new segmentation algorithms for medical diagnosis of colorectal cancer, which can be used in the clinical setting to help doctors and patients.
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Anomaly Detection (AD), as a critical problem, has been widely discussed. In this paper, we specialize in one specific problem, Visual Defect Detection (VDD), in many industrial applications. And in practice, defect image samples are very rare and difficult to collect. Thus, we focus on the unsupervised visual defect detection and localization tasks and propose a novel framework based on the recent score-based generative models, which synthesize the real image by iterative denoising through stochastic differential equations (SDEs). Our work is inspired by the fact that with noise injected into the original image, the defects may be changed into normal cases in the denoising process (i.e., reconstruction). First, based on the assumption that the anomalous data lie in the low probability density region of the normal data distribution, we explain a common phenomenon that occurs when reconstruction-based approaches are applied to VDD: normal pixels also change during the reconstruction process. Second, due to the differences in normal pixels between the reconstructed and original images, a time-dependent gradient value (i.e., score) of normal data distribution is utilized as a metric, rather than reconstruction loss, to gauge the defects. Third, a novel $T$ scales approach is developed to dramatically reduce the required number of iterations, accelerating the inference process. These practices allow our model to generalize VDD in an unsupervised manner while maintaining reasonably good performance. We evaluate our method on several datasets to demonstrate its effectiveness.
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