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H

Harrison H. Zhou

Researcher at Yale University

Publications -  89
Citations -  4911

Harrison H. Zhou is an academic researcher from Yale University. The author has contributed to research in topics: Minimax & Estimator. The author has an hindex of 34, co-authored 88 publications receiving 4283 citations.

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Optimal rates of convergence for covariance matrix estimation

TL;DR: In this article, the optimal rates of convergence for estimating the covariance matrix under both the operator norm and Frobenius norm were established and the minimax upper bound was obtained by constructing a special class of tapering estimators and by studying their risk properties.
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Optimal rates of convergence for sparse covariance matrix estimation

TL;DR: In this paper, a rate sharp minimax lower bound for estimating sparse covariance matrices under a range of matrix operator norm and Bregman divergence losses was derived, and a thresholding estimator was shown to attain the optimal rate of convergence under the spectral norm.
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Estimating structured high-dimensional covariance and precision matrices: Optimal rates and adaptive estimation

TL;DR: Minimax rates of convergence for estimating several classes of structured covariance and precision matrices, including bandable, Toeplitz, and sparse covariance matrices as well as sparse precisionMatrices, are given under the spectral norm loss.
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Asymptotic normality and optimalities in estimation of large Gaussian graphical models

TL;DR: In this article, a regression approach is proposed to obtain asymptotically efficient estimation of each entry of a precision matrix under a sparseness condition relative to the sample size.
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Optimal rates of convergence for sparse covariance matrix estimation

TL;DR: This paper develops a lower bound technique that is particularly well suited for treating “two-directional” problems such as estimating sparse covariance matrices and establishes the optimal rate of convergence under a range of matrix operator norm and Bregman divergence losses.