最近,通过双段正则化的镜头,基于基于低矩阵完成的无监督学习的兴趣复兴,这显着改善了多学科机器学习任务的性能,例如推荐系统,基因型插图和图像插入。虽然双颗粒正则化贡献了成功的主要部分,但通常涉及计算昂贵的超参数调谐。为了避免这样的缺点并提高完成性能,我们提出了一种新颖的贝叶斯学习算法,该算法会自动学习与双重正规化相关的超参数,同时保证矩阵完成的低级别。值得注意的是,设计出一个小说的先验是为了促进矩阵的低级别并同时编码双电图信息,这比单圈对应物更具挑战性。然后探索所提出的先验和可能性函数之间的非平凡条件偶联性,以使有效算法在变化推理框架下得出。使用合成和现实世界数据集的广泛实验证明了针对各种数据分析任务的拟议学习算法的最先进性能。
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多维时空数据的概率建模对于许多现实世界应用至关重要。然而,现实世界时空数据通常表现出非平稳性的复杂依赖性,即相关结构随位置/时间而变化,并且在空间和时间之间存在不可分割的依赖性,即依赖关系。开发有效和计算有效的统计模型,以适应包含远程和短期变化的非平稳/不可分割的过程,成为一项艰巨的任务,尤其是对于具有各种腐败/缺失结构的大规模数据集。在本文中,我们提出了一个新的统计框架 - 贝叶斯互补内核学习(BCKL),以实现多维时空数据的可扩展概率建模。为了有效地描述复杂的依赖性,BCKL与短距离时空高斯过程(GP)相结合的内核低级分解(GP),其中两个组件相互补充。具体而言,我们使用多线性低级分组组件来捕获数据中的全局/远程相关性,并基于紧凑的核心函数引入加法短尺度GP,以表征其余的局部变异性。我们为模型推断开发了有效的马尔可夫链蒙特卡洛(MCMC)算法,并在合成和现实世界时空数据集上评估了所提出的BCKL框架。我们的结果证实了BCKL在提供准确的后均值和高质量不确定性估计方面的出色表现。
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我们考虑具有某些约束的矩阵分解(MF),在各个领域找到广泛的应用。利用变异推理(VI)和单一近似消息传递(UAMP),我们通过有效的消息传递实现(称为UAMPMF)开发了MF的贝叶斯方法。通过对因子矩阵施加的适当先验,UAMPMF可用于解决许多可以表达为MF的问题,例如非负基质分解,词典学习,具有矩阵不确定性的压缩感,可靠的主成分分析和稀疏矩阵分解。提供了广泛的数值示例,以表明UAMPMF在恢复精度,鲁棒性和计算复杂性方面显着优于最先进的算法。
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Spatiotemporal traffic data imputation is of great significance in intelligent transportation systems and data-driven decision-making processes. To make an accurate reconstruction on partially observed traffic data, we assert the importance of characterizing both global and local trends in traffic time series. In the literature, substantial prior works have demonstrated the effectiveness of utilizing low-rankness property of traffic data by matrix/tensor completion models. In this study, we first introduce a Laplacian kernel to temporal regularization for characterizing local trends in traffic time series, which can be formulated in the form of circular convolution. Then, we develop a low-rank Laplacian convolutional representation (LCR) model by putting the nuclear norm of a circulant matrix and the Laplacian temporal regularization together, which is proved to meet a unified framework that takes a fast Fourier transform solution in a relatively low time complexity. Through extensive experiments on some traffic datasets, we demonstrate the superiority of LCR for imputing traffic time series of various time series behaviors (e.g., data noises and strong/weak periodicity). The proposed LCR model is an efficient and effective solution to large-scale traffic data imputation over the existing baseline models. The adapted datasets and Python implementation are publicly available at https://github.com/xinychen/transdim.
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We propose a message passing algorithm, based on variational Bayesian inference, for low-rank tensor completion with automatic rank determination in the canonical polyadic format when additional side information (SI) is given. The SI comes in the form of lowdimensional subspaces the contain the fiber spans of the tensor (columns, rows, tubes, etc.). We validate the regularization properties induced by SI with extensive numerical experiments on synthetic and real-world data and present the results about tensor recovery and rank determination. The results show that the number of samples required for successful completion is significantly reduced in the presence of SI. We also discuss the origin of a bump in the phase transition curves that exists when the dimensionality of SI is comparable with that of the tensor.
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显式低级正则化,例如核规范的正则化已被广泛用于成像科学。但是,已经发现,在各种图像处理任务中,隐式正规化优于明确的正规化。另一个问题是,固定的显式正则化将适用性限制为广泛图像,因为不同的图像偏爱不同的显式正则化捕获的不同特征。因此,本文提出了一种新的自适应和隐式低级别正则化,从训练数据中动态捕获了较低的先验。我们新的自适应和隐式低级别正则化的核心是在基于Dirichlet Energy的正则化中参数化Laplacian矩阵,我们称之为正则化空气。从理论上讲,我们表明\ retwo {air}的自适应正则化增强了训练结束时的隐式正则化和消失。我们验证了空气对各种基准任务的有效性,表明空气对缺失条目不均匀的情况特别有利。该代码可以在https://github.com/lizhemin15/air-net上找到。
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明确的低级正则化,例如核规范规则,已广泛用于成像科学。但是,已经发现隐式正则化优于各种图像处理任务中的明确正则化。另一个问题是,固定的显式正则化将适用性限制为广泛的图像,因为不同的图像有利于使用不同的显式规则化捕获的不同特征。因此,本文提出了一种新的自适应和隐式低级正则化,其从训练数据动态地捕获低秩。在我们新的自适应和隐式低级正则化的核心,正在使用神经网络参数化Laplacian矩阵,并通过神经网络调用所提出的型号\ Textit {Air-Net}。从理论上讲,我们表明,空气网的自适应正规化增强了隐含的正则化并在培训结束时消失。我们验证了对各种基准任务对各种基准任务的效果,显示空中网对缺失条目不均匀时的情况尤为好评。可以在\ href {https://github.com/lizhemin15/airair-net}} {https://github.com/lizhemin15/airair-net}。
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在本文中,我们提出了一种用于HSI去噪的强大主成分分析的新型非耦合方法,其侧重于分别同时为低级和稀疏组分的等级和列方向稀疏性产生更准确的近似。特别是,新方法采用日志确定级别近似和新颖的$ \ ell_ {2,\ log} $常规,以便分别限制组件矩阵的本地低级或列明智地稀疏属性。对于$ \ ell_ {2,\ log} $ - 正常化的收缩问题,我们开发了一个高效的封闭式解决方案,该解决方案名为$ \ ell_ {2,\ log} $ - 收缩运算符。新的正则化和相应的操作员通常可以用于需要列明显稀疏性的其他问题。此外,我们在基于日志的非凸rpca模型中强加了空间光谱总变化正则化,这增强了从恢复的HSI中的空间和光谱视图中的全局转换平滑度和光谱一致性。关于模拟和实际HSIS的广泛实验证明了所提出的方法在去噪HSIS中的有效性。
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Many existing approaches to collaborative filtering can neither handle very large datasets nor easily deal with users who have very few ratings. In this paper we present the Probabilistic Matrix Factorization (PMF) model which scales linearly with the number of observations and, more importantly, performs well on the large, sparse, and very imbalanced Netflix dataset. We further extend the PMF model to include an adaptive prior on the model parameters and show how the model capacity can be controlled automatically. Finally, we introduce a constrained version of the PMF model that is based on the assumption that users who have rated similar sets of movies are likely to have similar preferences. The resulting model is able to generalize considerably better for users with very few ratings. When the predictions of multiple PMF models are linearly combined with the predictions of Restricted Boltzmann Machines models, we achieve an error rate of 0.8861, that is nearly 7% better than the score of Netflix's own system.
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在本文中,我们介绍了一种用于学习非负矩阵分解(NMF)的概率模型,该模型通常用于预测数据中缺失值并在数据中找到隐藏模式,其中矩阵因子是与每个数据维度相关的潜在变量。通过在非负子空间上支持先验的先验,可以处理潜在因素的非阴性约束。采用基于Gibbs抽样的贝叶斯推理程序。我们在几个现实世界中的数据集上评估了该模型,包括Movielens 100K和Movielens 1M具有不同尺寸和尺寸的Movielens,并表明所提出的贝叶斯NMF GRRN模型可导致更好的预测,并避免与现有的贝叶斯NMF方法相比,避免过度适应。
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张量完成是从部分观察到的条目中估算高阶数据缺失值的问题。由于盛行异常值而引起的数据腐败对传统的张量完成算法提出了重大挑战,这促进了减轻异常值效果的强大算法的发展。但是,现有的强大方法在很大程度上假定腐败很少,这可能在实践中可能不存在。在本文中,我们开发了一种两阶段的稳健张量完成方法,以处理张张量的视觉数据,并具有大量的严重损坏。提出了一个新颖的粗到精细框架,该框架使用全局粗完成结果来指导局部贴剂细化过程。为了有效地减轻大量异常值对张量恢复的影响,我们开发了一种新的基于M估计器的稳健张环回收方法,该方法可以自适应地识别异常值并减轻其在优化中的负面影响。实验结果表明,所提出的方法优于最先进的稳定算法以完成张量。
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Matrix factorization exploits the idea that, in complex high-dimensional data, the actual signal typically lies in lower-dimensional structures. These lower dimensional objects provide useful insight, with interpretability favored by sparse structures. Sparsity, in addition, is beneficial in terms of regularization and, thus, to avoid over-fitting. By exploiting Bayesian shrinkage priors, we devise a computationally convenient approach for high-dimensional matrix factorization. The dependence between row and column entities is modeled by inducing flexible sparse patterns within factors. The availability of external information is accounted for in such a way that structures are allowed while not imposed. Inspired by boosting algorithms, we pair the the proposed approach with a numerical strategy relying on a sequential inclusion and estimation of low-rank contributions, with data-driven stopping rule. Practical advantages of the proposed approach are demonstrated by means of a simulation study and the analysis of soccer heatmaps obtained from new generation tracking data.
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作为估计高维网络的工具,图形模型通常应用于钙成像数据以估计功能性神经元连接,即神经元活动之间的关系。但是,在许多钙成像数据集中,没有同时记录整个神经元的人群,而是部分重叠的块。如(Vinci等人2019年)最初引入的,这导致了图形缝问题,在该问题中,目的是在仅观察到功能的子集时推断完整图的结构。在本文中,我们研究了一种新颖的两步方法来绘制缝的方法,该方法首先使用低级协方差完成技术在估计图结构之前使用低级协方差完成技术划分完整的协方差矩阵。我们介绍了三种解决此问题的方法:阻止奇异价值分解,核标准惩罚和非凸低级别分解。尽管先前的工作已经研究了低级别矩阵的完成,但我们解决了阻碍遗失的挑战,并且是第一个在图形学习背景下研究问题的挑战。我们讨论了两步过程的理论特性,通过证明新颖的l无限 - 基 - 误差界的矩阵完成,以块错失性证明了一种提出的方​​法的图选择一致性。然后,我们研究了所提出的方法在模拟和现实世界数据示例上的经验性能,通过该方法,我们显示了这些方法从钙成像数据中估算功能连通性的功效。
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本文介绍了使用基于补丁的先前分布的图像恢复的新期望传播(EP)框架。虽然Monte Carlo技术典型地用于从难以处理的后分布中进行采样,但它们可以在诸如图像恢复之类的高维推论问题中遭受可扩展性问题。为了解决这个问题,这里使用EP来使用多元高斯密度的产品近似后分布。此外,对这些密度的协方差矩阵施加结构约束允许更大的可扩展性和分布式计算。虽然该方法自然适于处理添加剂高斯观察噪声,但它也可以扩展到非高斯噪声。用于高斯和泊松噪声的去噪,染色和去卷积问题进行的实验说明了这种柔性近似贝叶斯方法的潜在益处,以实现与采样技术相比降低的计算成本。
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我们引入了一个具有隐式规范正规化的概率模型,用于学习非负矩阵分解(NMF),该模型通常用于预测缺失值并在数据中找到隐藏模式,其中矩阵因子是与每个数据维度相关的潜在变量。潜在因素的非负限制是通过选择基于指数函数的指数密度或分布的支持的先验来处理的。采用基于Gibbs抽样的贝叶斯推理程序。我们在几个现实世界数据集上评估了该模型,包括癌症中药物敏感性的基因组学(GDSC $ ic_ {50} $)和具有不同尺寸和尺寸的基因体甲基化,并表明拟议的贝叶斯NMF GL $ _2^2^2 $ and and anGL $ _ \ infty $模型可以对不同的数据值进行强大的预测,并避免与竞争性贝叶斯NMF方法相比过度拟合。
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State-of-the-art causal discovery methods usually assume that the observational data is complete. However, the missing data problem is pervasive in many practical scenarios such as clinical trials, economics, and biology. One straightforward way to address the missing data problem is first to impute the data using off-the-shelf imputation methods and then apply existing causal discovery methods. However, such a two-step method may suffer from suboptimality, as the imputation algorithm may introduce bias for modeling the underlying data distribution. In this paper, we develop a general method, which we call MissDAG, to perform causal discovery from data with incomplete observations. Focusing mainly on the assumptions of ignorable missingness and the identifiable additive noise models (ANMs), MissDAG maximizes the expected likelihood of the visible part of observations under the expectation-maximization (EM) framework. In the E-step, in cases where computing the posterior distributions of parameters in closed-form is not feasible, Monte Carlo EM is leveraged to approximate the likelihood. In the M-step, MissDAG leverages the density transformation to model the noise distributions with simpler and specific formulations by virtue of the ANMs and uses a likelihood-based causal discovery algorithm with directed acyclic graph constraint. We demonstrate the flexibility of MissDAG for incorporating various causal discovery algorithms and its efficacy through extensive simulations and real data experiments.
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Nonnegative Tucker Factorization (NTF) minimizes the euclidean distance or Kullback-Leibler divergence between the original data and its low-rank approximation which often suffers from grossly corruptions or outliers and the neglect of manifold structures of data. In particular, NTF suffers from rotational ambiguity, whose solutions with and without rotation transformations are equally in the sense of yielding the maximum likelihood. In this paper, we propose three Robust Manifold NTF algorithms to handle outliers by incorporating structural knowledge about the outliers. They first applies a half-quadratic optimization algorithm to transform the problem into a general weighted NTF where the weights are influenced by the outliers. Then, we introduce the correntropy induced metric, Huber function and Cauchy function for weights respectively, to handle the outliers. Finally, we introduce a manifold regularization to overcome the rotational ambiguity of NTF. We have compared the proposed method with a number of representative references covering major branches of NTF on a variety of real-world image databases. Experimental results illustrate the effectiveness of the proposed method under two evaluation metrics (accuracy and nmi).
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从高度不足的数据中恢复颜色图像和视频是面部识别和计算机视觉中的一项基本且具有挑战性的任务。通过颜色图像和视频的多维性质,在本文中,我们提出了一种新颖的张量完成方法,该方法能够有效探索离散余弦变换(DCT)下张量数据的稀疏性。具体而言,我们介绍了两个``稀疏 +低升级''张量完成模型,以及两种可实现的算法来找到其解决方案。第一个是基于DCT的稀疏加权核标准诱导低级最小化模型。第二个是基于DCT的稀疏加上$ P $换图映射引起的低秩优化模型。此外,我们因此提出了两种可实施的增强拉格朗日算法,以解决基础优化模型。一系列数值实验在内,包括颜色图像介入和视频数据恢复表明,我们所提出的方法的性能要比许多现有的最新张量完成方法更好,尤其是对于缺少数据比率较高的情况。
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矩阵分解(MF)已广泛应用于建议系统中的协作过滤。它的贝叶斯变体可以得出用户和项目嵌入的后验分布,并且对稀疏评分更强大。但是,贝叶斯方法受到其后验参数的更新规则的限制,这是由于先验和可能性的结合。变量自动编码器(VAE)可以通过捕获后验参数和数据之间的复杂映射来解决此问题。但是,当前对合作过滤的VAE的研究仅根据明确的数据信息考虑映射,而隐含嵌入信息则被忽略了。在本文中,我们首先从两个观点(以用户为导向和面向项目的观点)得出了贝叶斯MF模型的贝叶斯MF模型的较低界限(ELBO)。根据肘部,我们提出了一个基于VAE的贝叶斯MF框架。它不仅利用数据,还利用嵌入信息来近似用户项目联合分布。正如肘部所建议的那样,近似是迭代的,用户和项目嵌入彼此的编码器的交叉反馈。更具体地说,在上一个迭代中采样的用户嵌入被馈送到项目端编码器中,以估计当前迭代处的项目嵌入的后验参数,反之亦然。该估计还可以关注交叉食品的嵌入式,以进一步利用有用的信息。然后,解码器通过当前重新采样的用户和项目嵌入方式通过矩阵分解重建数据。
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我们提出了一种凸锥程序,可推断随机点产品图(RDPG)的潜在概率矩阵。优化问题最大化Bernoulli最大似然函数,增加核规范正则化术语。双重问题具有特别良好的形式,与众所周知的SemideFinite程序放松MaxCut问题有关。使用原始双功率条件,我们绑定了原始和双解决方案的条目和等级。此外,我们在轻微的技术假设下绑定了最佳目标值并证明了略微修改模型的概率估计的渐近一致性。我们对合成RDPG的实验不仅恢复了自然集群,而且还揭示了原始数据的下面的低维几何形状。我们还证明该方法在空手道俱乐部图表和合成美国参议图中恢复潜在结构,并且可以扩展到最多几百个节点的图表。
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