no code implementations • 15 Nov 2022 • Julien Chhor, Rajarshi Mukherjee, Subhabrata Sen
Given a heterogeneous Gaussian sequence model with unknown mean $\theta \in \mathbb R^d$ and known covariance matrix $\Sigma = \operatorname{diag}(\sigma_1^2,\dots, \sigma_d^2)$, we study the signal detection problem against sparse alternatives, for known sparsity $s$.
no code implementations • 27 Jun 2022 • Julien Chhor, Suzanne Sigalla, Alexandre B. Tsybakov
In the nonparametric regression setting, we construct an estimator which is a continuous function interpolating the data points with high probability, while attaining minimax optimal rates under mean squared risk on the scale of H\"older classes adaptively to the unknown smoothness.
no code implementations • 14 Feb 2022 • Julien Chhor, Flore Sentenac
We consider the problem of estimating a discrete distribution in total variation from $n$ contaminated data batches under a local differential privacy constraint.