Merging satellite products and ground-based measurements is often required for obtaining precipitation datasets that simultaneously cover large regions with high density and are more accurate than pure satellite precipitation products. Machine and statistical learning regression algorithms are regularly utilized in this endeavour. At the same time, tree-based ensemble algorithms for regression are adopted in various fields for solving algorithmic problems with high accuracy and low computational cost. The latter can constitute a crucial factor for selecting algorithms for satellite precipitation product correction at the daily and finer time scales, where the size of the datasets is particularly large. Still, information on which tree-based ensemble algorithm to select in such a case for the contiguous United States (US) is missing from the literature. In this work, we conduct an extensive comparison between three tree-based ensemble algorithms, specifically random forests, gradient boosting machines (gbm) and extreme gradient boosting (XGBoost), in the context of interest. We use daily data from the PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks) and the IMERG (Integrated Multi-satellitE Retrievals for GPM) gridded datasets. We also use earth-observed precipitation data from the Global Historical Climatology Network daily (GHCNd) database. The experiments refer to the entire contiguous US and additionally include the application of the linear regression algorithm for benchmarking purposes. The results suggest that XGBoost is the best-performing tree-based ensemble algorithm among those compared. They also suggest that IMERG is more useful than PERSIANN in the context investigated.
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糖尿病足溃疡(DFUS)对于糖尿病患者来说是严重的并发症。为了实现现有溃疡的早期诊断,预防溃疡和并发症管理,可以通过自我管理来大大改善DFU患者的护理。在本文中,我们研究了两类图像到图像翻译技术(ITITT),这些技术将支持糖尿病足溃疡的决策和监测:降噪和超分辨率。在前一种情况下,我们调查了消除噪声的功能,用于卷积神经网络堆叠的AutoCoders(CNN-SAE)。在用高斯噪声诱导的RGB图像上测试了CNN-SAE。后一种情况涉及部署四个深度学习超分辨率模型。对于两种情况,所有模型的性能均以执行时间和感知质量进行评估。结果表明,应用技术组成了可行且易于实现的替代方案,该替代方案应由设计用于DFU监视的任何系统使用。
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在文化遗产中,高光谱图像通常使用,因为它们提供了有关材料光学特性的扩展信息。因此,从要应用的机器学习技术的角度来看,这种高维数据的处理变得具有挑战性。在本文中,我们提出了一种基于排名的基于张量的学习模型,以识别和对文化遗产纪念碑的物质缺陷进行分类。与常规的深度学习方法相反,拟议的高阶基于张量的学习表明,具有更高的准确性和鲁棒性,以防止过度拟合。来自联合国教科文组织保护区的现实世界数据的实验结果表明,与常规深度学习模型相比,该计划的优越性。
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非侵入性负载监控(NILM)是将总功率消耗分为单个子组件的任务。多年来,已经合并了信号处理和机器学习算法以实现这一目标。关于最先进的方法,进行了许多出版物和广泛的研究工作,以涉及最先进的方法。科学界最初使用机器学习工具的尼尔姆问题制定和描述的最初兴趣已经转变为更实用的尼尔姆。如今,我们正处于成熟的尼尔姆时期,在现实生活中的应用程序方案中尝试使用尼尔姆。因此,算法的复杂性,可转移性,可靠性,实用性和普遍的信任度是主要的关注问题。这篇评论缩小了早期未成熟的尼尔姆时代与成熟的差距。特别是,本文仅对住宅电器的尼尔姆方法提供了全面的文献综述。本文分析,总结并介绍了大量最近发表的学术文章的结果。此外,本文讨论了这些方法的亮点,并介绍了研究人员应考虑的研究困境,以应用尼尔姆方法。最后,我们表明需要将传统分类模型转移到一个实用且值得信赖的框架中。
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Being able to forecast the popularity of new garment designs is very important in an industry as fast paced as fashion, both in terms of profitability and reducing the problem of unsold inventory. Here, we attempt to address this task in order to provide informative forecasts to fashion designers within a virtual reality designer application that will allow them to fine tune their creations based on current consumer preferences within an interactive and immersive environment. To achieve this we have to deal with the following central challenges: (1) the proposed method should not hinder the creative process and thus it has to rely only on the garment's visual characteristics, (2) the new garment lacks historical data from which to extrapolate their future popularity and (3) fashion trends in general are highly dynamical. To this end, we develop a computer vision pipeline fine tuned on fashion imagery in order to extract relevant visual features along with the category and attributes of the garment. We propose a hierarchical label sharing (HLS) pipeline for automatically capturing hierarchical relations among fashion categories and attributes. Moreover, we propose MuQAR, a Multimodal Quasi-AutoRegressive neural network that forecasts the popularity of new garments by combining their visual features and categorical features while an autoregressive neural network is modelling the popularity time series of the garment's category and attributes. Both the proposed HLS and MuQAR prove capable of surpassing the current state-of-the-art in key benchmark datasets, DeepFashion for image classification and VISUELLE for new garment sales forecasting.
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Although many machine learning methods, especially from the field of deep learning, have been instrumental in addressing challenges within robotic applications, we cannot take full advantage of such methods before these can provide performance and safety guarantees. The lack of trust that impedes the use of these methods mainly stems from a lack of human understanding of what exactly machine learning models have learned, and how robust their behaviour is. This is the problem the field of explainable artificial intelligence aims to solve. Based on insights from the social sciences, we know that humans prefer contrastive explanations, i.e.\ explanations answering the hypothetical question "what if?". In this paper, we show that linear model trees are capable of producing answers to such questions, so-called counterfactual explanations, for robotic systems, including in the case of multiple, continuous inputs and outputs. We demonstrate the use of this method to produce counterfactual explanations for two robotic applications. Additionally, we explore the issue of infeasibility, which is of particular interest in systems governed by the laws of physics.
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The extragradient method has recently gained increasing attention, due to its convergence behavior on smooth games. In $n$-player differentiable games, the eigenvalues of the Jacobian of the vector field are distributed on the complex plane, exhibiting more convoluted dynamics compared to classical (i.e., single player) minimization. In this work, we take a polynomial-based analysis of the extragradient with momentum for optimizing games with \emph{cross-shaped} Jacobian spectrum on the complex plane. We show two results. First, based on the hyperparameter setup, the extragradient with momentum exhibits three different modes of convergence: when the eigenvalues are distributed $i)$ on the real line, $ii)$ both on the real line along with complex conjugates, and $iii)$ only as complex conjugates. Then, we focus on the case $ii)$, i.e., when the eigenvalues of the Jacobian have \emph{cross-shaped} structure, as observed in training generative adversarial networks. For this problem class, we derive the optimal hyperparameters of the momentum extragradient method, and show that it achieves an accelerated convergence rate.
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The ability to dynamically adapt neural networks to newly-available data without performance deterioration would revolutionize deep learning applications. Streaming learning (i.e., learning from one data example at a time) has the potential to enable such real-time adaptation, but current approaches i) freeze a majority of network parameters during streaming and ii) are dependent upon offline, base initialization procedures over large subsets of data, which damages performance and limits applicability. To mitigate these shortcomings, we propose Cold Start Streaming Learning (CSSL), a simple, end-to-end approach for streaming learning with deep networks that uses a combination of replay and data augmentation to avoid catastrophic forgetting. Because CSSL updates all model parameters during streaming, the algorithm is capable of beginning streaming from a random initialization, making base initialization optional. Going further, the algorithm's simplicity allows theoretical convergence guarantees to be derived using analysis of the Neural Tangent Random Feature (NTRF). In experiments, we find that CSSL outperforms existing baselines for streaming learning in experiments on CIFAR100, ImageNet, and Core50 datasets. Additionally, we propose a novel multi-task streaming learning setting and show that CSSL performs favorably in this domain. Put simply, CSSL performs well and demonstrates that the complicated, multi-step training pipelines adopted by most streaming methodologies can be replaced with a simple, end-to-end learning approach without sacrificing performance.
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Graph Neural Networks (GNNs) have achieved great successes in many learning tasks performed on graph structures. Nonetheless, to propagate information GNNs rely on a message passing scheme which can become prohibitively expensive when working with industrial-scale graphs. Inspired by the PPRGo model, we propose the CorePPR model, a scalable solution that utilises a learnable convex combination of the approximate personalised PageRank and the CoreRank to diffuse multi-hop neighbourhood information in GNNs. Additionally, we incorporate a dynamic mechanism to select the most influential neighbours for a particular node which reduces training time while preserving the performance of the model. Overall, we demonstrate that CorePPR outperforms PPRGo, particularly on large graphs where selecting the most influential nodes is particularly relevant for scalability. Our code is publicly available at: https://github.com/arielramos97/CorePPR.
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我们研究保形预测的鲁棒性,这是标记噪声的不确定性定量的强大工具。我们的分析解决了回归和分类问题,表征了何时以及如何构建正确覆盖未观察到的无噪音地面真相标签的不确定性集。通过风格化的理论示例和实际实验,我们认为天真的保形预测涵盖了无噪声的地面真相标签,除非噪声分布是对手设计的。这使我们相信,除了病理数据分布或噪声源外,对标签噪声的纠正是不必要的。在这种情况下,我们还可以在保形预测算法中校正有界大小的噪声,以确保在没有得分或数据规律性的情况下正确覆盖地面真相标签。
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