Search Results for author: Themis Gouleakis

Found 13 papers, 2 papers with code

Active causal structure learning with advice

1 code implementation31 May 2023 Davin Choo, Themis Gouleakis, Arnab Bhattacharyya

When the advice is a DAG $G$, we design an adaptive search algorithm to recover $G^*$ whose intervention cost is at most $O(\max\{1, \log \psi\})$ times the cost for verifying $G^*$; here, $\psi$ is a distance measure between $G$ and $G^*$ that is upper bounded by the number of variables $n$, and is exactly 0 when $G=G^*$.

Learning-Augmented Algorithms for Online TSP on the Line

no code implementations1 Jun 2022 Themis Gouleakis, Konstantinos Lakis, Golnoosh Shahkarami

Our algorithm for this enhanced setting obtains a 1. 33 competitive ratio with perfect predictions while also being smooth and robust, beating the lower bound of 1. 44 we show for our original prediction setting for the open variant.

Traveling Salesman Problem

Learning Augmented Online Facility Location

1 code implementation17 Jul 2021 Dimitris Fotakis, Evangelia Gergatsouli, Themis Gouleakis, Nikolas Patris

We prove that the competitive ratio decreases smoothly from sublogarithmic in the number of demands to constant, as the error, i. e., the total distance of the predicted locations to the optimal facility locations, decreases towards zero.

Computationally and Statistically Efficient Truncated Regression

no code implementations22 Oct 2020 Constantinos Daskalakis, Themis Gouleakis, Christos Tzamos, Manolis Zampetakis

We provide a computationally and statistically efficient estimator for the classical problem of truncated linear regression, where the dependent variable $y = w^T x + \epsilon$ and its corresponding vector of covariates $x \in R^k$ are only revealed if the dependent variable falls in some subset $S \subseteq R$; otherwise the existence of the pair $(x, y)$ is hidden.

Computational Efficiency regression

Robust Learning under Strong Noise via SQs

no code implementations18 Oct 2020 Ioannis Anagnostides, Themis Gouleakis, Ali Marashian

This work provides several new insights on the robustness of Kearns' statistical query framework against challenging label-noise models.

Optimal Testing of Discrete Distributions with High Probability

no code implementations14 Sep 2020 Ilias Diakonikolas, Themis Gouleakis, Daniel M. Kane, John Peebles, Eric Price

To illustrate the generality of our methods, we give optimal algorithms for testing collections of distributions and testing closeness with unequal sized samples.

Vocal Bursts Intensity Prediction

Towards Testing Monotonicity of Distributions Over General Posets

no code implementations6 Jul 2019 Maryam Aliakbarpour, Themis Gouleakis, John Peebles, Ronitt Rubinfeld, Anak Yodpinyanee

We then build on these lower bounds to give $\Omega(n/\log{n})$ lower bounds for testing monotonicity over a matching poset of size $n$ and significantly improved lower bounds over the hypercube poset.

Distribution-Independent PAC Learning of Halfspaces with Massart Noise

no code implementations NeurIPS 2019 Ilias Diakonikolas, Themis Gouleakis, Christos Tzamos

The goal is to find a hypothesis $h$ that minimizes the misclassification error $\mathbf{Pr}_{(\mathbf{x}, y) \sim \mathcal{D}} \left[ h(\mathbf{x}) \neq y \right]$.

Open-Ended Question Answering PAC learning

Communication and Memory Efficient Testing of Discrete Distributions

no code implementations11 Jun 2019 Ilias Diakonikolas, Themis Gouleakis, Daniel M. Kane, Sankeerth Rao

We study distribution testing with communication and memory constraints in the following computational models: (1) The {\em one-pass streaming model} where the goal is to minimize the sample complexity of the protocol subject to a memory constraint, and (2) A {\em distributed model} where the data samples reside at multiple machines and the goal is to minimize the communication cost of the protocol.

Two-sample testing

Efficient Statistics, in High Dimensions, from Truncated Samples

no code implementations11 Sep 2018 Constantinos Daskalakis, Themis Gouleakis, Christos Tzamos, Manolis Zampetakis

We provide an efficient algorithm for the classical problem, going back to Galton, Pearson, and Fisher, of estimating, with arbitrary accuracy the parameters of a multivariate normal distribution from truncated samples.

Vocal Bursts Intensity Prediction

Optimal Identity Testing with High Probability

no code implementations9 Aug 2017 Ilias Diakonikolas, Themis Gouleakis, John Peebles, Eric Price

Our new upper and lower bounds show that the optimal sample complexity of identity testing is \[ \Theta\left( \frac{1}{\epsilon^2}\left(\sqrt{n \log(1/\delta)} + \log(1/\delta) \right)\right) \] for any $n, \varepsilon$, and $\delta$.

Vocal Bursts Intensity Prediction

Collision-based Testers are Optimal for Uniformity and Closeness

no code implementations11 Nov 2016 Ilias Diakonikolas, Themis Gouleakis, John Peebles, Eric Price

We study the fundamental problems of (i) uniformity testing of a discrete distribution, and (ii) closeness testing between two discrete distributions with bounded $\ell_2$-norm.

Sampling Correctors

no code implementations24 Apr 2015 Clément Canonne, Themis Gouleakis, Ronitt Rubinfeld

We then focus on the question of whether algorithms for sampling correctors can be more efficient in terms of sample complexity than learning algorithms for the analogous families of distributions.

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