Search Results for author: Thanasis Pittas

Found 11 papers, 0 papers with code

Robust Sparse Estimation for Gaussians with Optimal Error under Huber Contamination

no code implementations15 Mar 2024 Ilias Diakonikolas, Daniel M. Kane, Sushrut Karmalkar, Ankit Pensia, Thanasis Pittas

Concretely, for Gaussian robust $k$-sparse mean estimation on $\mathbb{R}^d$ with corruption rate $\epsilon>0$, our algorithm has sample complexity $(k^2/\epsilon^2)\mathrm{polylog}(d/\epsilon)$, runs in sample polynomial time, and approximates the target mean within $\ell_2$-error $O(\epsilon)$.

Statistical Query Lower Bounds for Learning Truncated Gaussians

no code implementations4 Mar 2024 Ilias Diakonikolas, Daniel M. Kane, Thanasis Pittas, Nikos Zarifis

We study the problem of estimating the mean of an identity covariance Gaussian in the truncated setting, in the regime when the truncation set comes from a low-complexity family $\mathcal{C}$ of sets.

Clustering Mixtures of Bounded Covariance Distributions Under Optimal Separation

no code implementations19 Dec 2023 Ilias Diakonikolas, Daniel M. Kane, Jasper C. H. Lee, Thanasis Pittas

Furthermore, under a variant of the "no large sub-cluster'' condition from in prior work [BKK22], we show that our algorithm outputs an accurate clustering, not just a refinement, even for general-weight mixtures.

Clustering

Near-Optimal Algorithms for Gaussians with Huber Contamination: Mean Estimation and Linear Regression

no code implementations NeurIPS 2023 Ilias Diakonikolas, Daniel M. Kane, Ankit Pensia, Thanasis Pittas

We study the fundamental problems of Gaussian mean estimation and linear regression with Gaussian covariates in the presence of Huber contamination.

regression

SQ Lower Bounds for Learning Bounded Covariance GMMs

no code implementations22 Jun 2023 Ilias Diakonikolas, Daniel M. Kane, Thanasis Pittas, Nikos Zarifis

In the special case where the separation is on the order of $k^{1/2}$, we additionally obtain fine-grained SQ lower bounds with the correct exponent.

Nearly-Linear Time and Streaming Algorithms for Outlier-Robust PCA

no code implementations4 May 2023 Ilias Diakonikolas, Daniel M. Kane, Ankit Pensia, Thanasis Pittas

Our main contribution is to develop a nearly-linear time algorithm for robust PCA with near-optimal error guarantees.

Robust Sparse Mean Estimation via Sum of Squares

no code implementations7 Jun 2022 Ilias Diakonikolas, Daniel M. Kane, Sushrut Karmalkar, Ankit Pensia, Thanasis Pittas

In this work, we develop the first efficient algorithms for robust sparse mean estimation without a priori knowledge of the covariance.

Streaming Algorithms for High-Dimensional Robust Statistics

no code implementations26 Apr 2022 Ilias Diakonikolas, Daniel M. Kane, Ankit Pensia, Thanasis Pittas

In this work, we develop the first efficient streaming algorithms for high-dimensional robust statistics with near-optimal memory requirements (up to logarithmic factors).

Stochastic Optimization Vocal Bursts Intensity Prediction

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