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作者:McElroy, Tucker S.; Roy, Anindya
作者单位:University System of Maryland; University of Maryland Baltimore County
摘要:We study the integral of the Frobenius norm as a measure of the discrepancy between two multivariate spectra. Such a measure can be used to fit time series models, and ensures proximity between model and process at all frequencies of the spectral density-this is more demanding than Kullback-Leibler discrepancy, which is instead related to one-step ahead forecasting performance. We develop new asymptotic results for linear and quadratic functionals of the periodogram, and make two applications ...
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作者:Tan, Kean Ming; Wang, Lan; Zhou, Wen-Xin
作者单位:University of Michigan System; University of Michigan; University of Miami; University of California System; University of California San Diego
摘要:l(1)-penalized quantile regression (QR) is widely used for analysing high-dimensional data with heterogeneity. It is now recognized that the l(1)-penalty introduces non-negligible estimation bias, while a proper use of concave regularization may lead to estimators with refined convergence rates and oracle properties as the signal strengthens. Although folded concave penalized M-estimation with strongly convex loss functions have been well studied, the extant literature on QR is relatively sile...
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作者:Puelz, David; Basse, Guillaume; Feller, Avi; Toulis, Panos
作者单位:University of Texas System; University of Texas Austin; University of Texas System; University of Texas Austin; Stanford University; University of California System; University of California Berkeley; University of Chicago
摘要:Interference exists when a unit's outcome depends on another unit's treatment assignment. For example, intensive policing on one street could have a spillover effect on neighbouring streets. Classical randomization tests typically break down in this setting because many null hypotheses of interest are no longer sharp under interference. A promising alternative is to instead construct a conditional randomization test on a subset of units and assignments for which a given null hypothesis is shar...
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作者:Zhao, Jiwei
作者单位:University of Wisconsin System; University of Wisconsin Madison
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作者:VanderWeele, Tyler J.; Vansteelandt, Stijn
作者单位:Harvard University; Harvard University; Ghent University
摘要:Factor analysis is often used to assess whether a single univariate latent variable is sufficient to explain most of the covariance among a set of indicators for some underlying construct. When evidence suggests that a single factor is adequate, research often proceeds by using a univariate summary of the indicators in subsequent research. Implicit in such practices is the assumption that it is the underlying latent, rather than the indicators, that is causally efficacious. The assumption that...
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作者:Engelke, Sebastian; Volgushev, Stanislav
作者单位:University of Geneva; University of Toronto; University of Geneva
摘要:Extremal graphical models are sparse statistical models for multivariate extreme events. The underlying graph encodes conditional independencies and enables a visual interpretation of the complex extremal dependence structure. For the important case of tree models, we develop a data-driven methodology for learning the graphical structure. We show that sample versions of the extremal correlation and a new summary statistic, which we call the extremal variogram, can be used as weights for a mini...
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作者:Matsubara, Takuo; Knoblauch, Jeremias; Briol, Francois-Xavier; Oates, Chris J.
作者单位:Newcastle University - UK; Alan Turing Institute; University of London; University College London
摘要:Generalised Bayesian inference updates prior beliefs using a loss function, rather than a likelihood, and can therefore be used to confer robustness against possible mis-specification of the likelihood. Here we consider generalised Bayesian inference with a Stein discrepancy as a loss function, motivated by applications in which the likelihood contains an intractable normalisation constant. In this context, the Stein discrepancy circumvents evaluation of the normalisation constant and produces...
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作者:Sun, Yan; Liang, Faming
作者单位:Purdue University System; Purdue University
摘要:The deep neural network suffers from many fundamental issues in machine learning. For example, it often gets trapped into a local minimum in training, and its prediction uncertainty is hard to be assessed. To address these issues, we propose the so-called kernel-expanded stochastic neural network (K-StoNet) model, which incorporates support vector regression as the first hidden layer and reformulates the neural network as a latent variable model. The former maps the input vector into an infini...
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作者:Luo, Wei
作者单位:Zhejiang University
摘要:In this paper, we propose the novel theory and methodologies for dimension reduction with respect to the interaction between two response variables, which is a new research problem that has wide applications in missing data analysis, causal inference, graphical models, etc. We formulate the parameters of interest to be the locally and the globally efficient dimension reduction subspaces, and justify the generality of the corresponding low-dimensional assumption. We then construct estimating eq...
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作者:Wang, Yudong; Tang, Yanlin; Ye, Zhi-Sheng
作者单位:National University of Singapore; East China Normal University
摘要:In paired two-sample tests for mean equality, it is common to encounter unordered samples in which subject identities are not observed or unobservable, and it is impossible to link the measurements before and after treatment. The absence of subject identities masks the correspondence between the two samples, rendering existing methods inapplicable. In this paper, we propose two novel testing approaches. The first splits one of the two unordered samples into blocks and approximates the populati...