STMLFeb 9, 2015

High dimensional errors-in-variables models with dependent measurements

arXiv:1502.02355v21 citations
Originality Incremental advance
AI Analysis

This addresses a gap in statistical modeling for dependent measurement errors, particularly in neuroscience applications, though it appears incremental as it extends existing methods to a new error structure.

The paper tackles the problem of recovering a sparse vector in high-dimensional errors-in-variables models where measurement errors are dependent across observations, a scenario relevant in neuroscience for modeling neural fluctuations. It establishes consistency and convergence rates for Lasso-type and Dantzig-type estimators, with error bounds approaching those of standard methods as errors diminish.

Suppose that we observe $y \in \mathbb{R}^f$ and $X \in \mathbb{R}^{f \times m}$ in the following errors-in-variables model: \begin{eqnarray*} y & = & X_0 β^* + ε\\ X & = & X_0 + W \end{eqnarray*} where $X_0$ is a $f \times m$ design matrix with independent subgaussian row vectors, $ε\in \mathbb{R}^f$ is a noise vector and $W$ is a mean zero $f \times m$ random noise matrix with independent subgaussian column vectors, independent of $X_0$ and $ε$. This model is significantly different from those analyzed in the literature in the sense that we allow the measurement error for each covariate to be a dependent vector across its $f$ observations. Such error structures appear in the science literature when modeling the trial-to-trial fluctuations in response strength shared across a set of neurons. Under sparsity and restrictive eigenvalue type of conditions, we show that one is able to recover a sparse vector $β^* \in \mathbb{R}^m$ from the model given a single observation matrix $X$ and the response vector $y$. We establish consistency in estimating $β^*$ and obtain the rates of convergence in the $\ell_q$ norm, where $q = 1, 2$ for the Lasso-type estimator, and for $q \in [1, 2]$ for a Dantzig-type conic programming estimator. We show error bounds which approach that of the regular Lasso and the Dantzig selector in case the errors in $W$ are tending to 0.

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