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1703.07809 2026-05-10 math.NA cs.NA math.ST stat.TH

Empirical Risk Minimization as Parameter Choice Rule for General Linear Regularization Methods

Housen Li, Frank Werner

AI总结 本文研究了在统计反问题中,如何通过最小化预测风险的无偏估计来选择正则化参数,以恢复被高斯白噪声干扰的观测数据中的信号。作者考虑了一类广义线性正则化方法,并证明了相应的参数选择规则在风险上具有最优阶数。研究还通过数值模拟验证了该方法在有限样本情况下的有效性和参数选择的合理性。

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Journal ref
Ann. Inst. H. Poincaré Probab. Statist. 56(1): 405-427 (February 2020)
英文摘要

We consider the statistical inverse problem to recover $f$ from noisy measurements $Y = Tf + σξ$ where $ξ$ is Gaussian white noise and $T$ a compact operator between Hilbert spaces. Considering general reconstruction methods of the form $\hat f_α= q_α\left(T^*T\right)T^*Y$ with an ordered filter $q_α$, we investigate the choice of the regularization parameter $α$ by minimizing an unbiased estimate of the predictive risk $\mathbb E\left[\Vert Tf - T\hat f_α\Vert^2\right]$. The corresponding parameter $α_{\mathrm{pred}}$ and its usage are well-known in the literature, but oracle inequalities and optimality results in this general setting are unknown. We prove a (generalized) oracle inequality, which relates the direct risk $\mathbb E\left[\Vert f - \hat f_{α_{\mathrm{pred}}}\Vert^2\right]$ with the oracle prediction risk $\inf_{α>0}\mathbb E\left[\Vert Tf - T\hat f_α\Vert^2\right]$. From this oracle inequality we are then able to conclude that the investigated parameter choice rule is of optimal order. Finally we also present numerical simulations, which support the order optimality of the method and the quality of the parameter choice in finite sample situations.