Search Results for author: Raef Bassily

Found 28 papers, 1 papers with code

Differentially Private Worst-group Risk Minimization

no code implementations29 Feb 2024 Xinyu Zhou, Raef Bassily

We first present a new algorithm that achieves excess worst-group population risk of $\tilde{O}(\frac{p\sqrt{d}}{K\epsilon} + \sqrt{\frac{p}{K}})$, where $K$ is the total number of samples drawn from all groups and $d$ is the problem dimension.

Differentially Private Non-Convex Optimization under the KL Condition with Optimal Rates

no code implementations22 Nov 2023 Michael Menart, Enayat Ullah, Raman Arora, Raef Bassily, Cristóbal Guzmán

We further show that, without assuming the KL condition, the same gradient descent algorithm can achieve fast convergence to a stationary point when the gradient stays sufficiently large during the run of the algorithm.

Differentially Private Domain Adaptation with Theoretical Guarantees

no code implementations15 Jun 2023 Raef Bassily, Corinna Cortes, Anqi Mao, Mehryar Mohri

This is the modern problem of supervised domain adaptation from a public source to a private target domain.

Domain Adaptation

Differentially Private Algorithms for the Stochastic Saddle Point Problem with Optimal Rates for the Strong Gap

no code implementations24 Feb 2023 Raef Bassily, Cristóbal Guzmán, Michael Menart

We show that convex-concave Lipschitz stochastic saddle point problems (also known as stochastic minimax optimization) can be solved under the constraint of $(\epsilon,\delta)$-differential privacy with \emph{strong (primal-dual) gap} rate of $\tilde O\big(\frac{1}{\sqrt{n}} + \frac{\sqrt{d}}{n\epsilon}\big)$, where $n$ is the dataset size and $d$ is the dimension of the problem.

Stochastic Optimization

Private Domain Adaptation from a Public Source

no code implementations12 Aug 2022 Raef Bassily, Mehryar Mohri, Ananda Theertha Suresh

A key problem in a variety of applications is that of domain adaptation from a public source domain, for which a relatively large amount of labeled data with no privacy constraints is at one's disposal, to a private target domain, for which a private sample is available with very few or no labeled data.

Domain Adaptation

Faster Rates of Convergence to Stationary Points in Differentially Private Optimization

no code implementations2 Jun 2022 Raman Arora, Raef Bassily, Tomás González, Cristóbal Guzmán, Michael Menart, Enayat Ullah

We provide a new efficient algorithm that finds an $\tilde{O}\big(\big[\frac{\sqrt{d}}{n\varepsilon}\big]^{2/3}\big)$-stationary point in the finite-sum setting, where $n$ is the number of samples.

Stochastic Optimization

Differentially Private Generalized Linear Models Revisited

no code implementations6 May 2022 Raman Arora, Raef Bassily, Cristóbal Guzmán, Michael Menart, Enayat Ullah

For this case, we close the gap in the existing work and show that the optimal rate is (up to log factors) $\Theta\left(\frac{\Vert w^*\Vert}{\sqrt{n}} + \min\left\{\frac{\Vert w^*\Vert}{\sqrt{n\epsilon}},\frac{\sqrt{\text{rank}}\Vert w^*\Vert}{n\epsilon}\right\}\right)$, where $\text{rank}$ is the rank of the design matrix.

Model Selection

Differentially Private Learning with Margin Guarantees

no code implementations21 Apr 2022 Raef Bassily, Mehryar Mohri, Ananda Theertha Suresh

For the family of linear hypotheses, we give a pure DP learning algorithm that benefits from relative deviation margin guarantees, as well as an efficient DP learning algorithm with margin guarantees.

Model Selection

Differentially Private Stochastic Optimization: New Results in Convex and Non-Convex Settings

no code implementations NeurIPS 2021 Raef Bassily, Cristóbal Guzmán, Michael Menart

For the $\ell_1$-case with smooth losses and polyhedral constraint, we provide the first nearly dimension independent rate, $\tilde O\big(\frac{\log^{2/3}{d}}{{(n\varepsilon)^{1/3}}}\big)$ in linear time.

Stochastic Optimization

Non-Euclidean Differentially Private Stochastic Convex Optimization: Optimal Rates in Linear Time

no code implementations1 Mar 2021 Raef Bassily, Cristóbal Guzmán, Anupama Nandi

For $2 < p \leq \infty$, we show that existing linear-time constructions for the Euclidean setup attain a nearly optimal excess risk in the low-dimensional regime.

Learning from Mixtures of Private and Public Populations

no code implementations NeurIPS 2020 Raef Bassily, Shay Moran, Anupama Nandi

Inspired by the above example, we consider a model in which the population $\mathcal{D}$ is a mixture of two sub-populations: a private sub-population $\mathcal{D}_{\sf priv}$ of private and sensitive data, and a public sub-population $\mathcal{D}_{\sf pub}$ of data with no privacy concerns.

PAC learning

Private Query Release Assisted by Public Data

no code implementations ICML 2020 Raef Bassily, Albert Cheu, Shay Moran, Aleksandar Nikolov, Jonathan Ullman, Zhiwei Steven Wu

In comparison, with only private samples, this problem cannot be solved even for simple query classes with VC-dimension one, and without any private samples, a larger public sample of size $d/\alpha^2$ is needed.

Limits of Private Learning with Access to Public Data

no code implementations NeurIPS 2019 Noga Alon, Raef Bassily, Shay Moran

We consider learning problems where the training set consists of two types of examples: private and public.

Private Stochastic Convex Optimization with Optimal Rates

no code implementations NeurIPS 2019 Raef Bassily, Vitaly Feldman, Kunal Talwar, Abhradeep Thakurta

A long line of existing work on private convex optimization focuses on the empirical loss and derives asymptotically tight bounds on the excess empirical loss.

Privately Answering Classification Queries in the Agnostic PAC Model

no code implementations31 Jul 2019 Anupama Nandi, Raef Bassily

We formally study this problem in the agnostic PAC model and derive a new upper bound on the private sample complexity.

Classification General Classification

Model-Agnostic Private Learning

no code implementations NeurIPS 2018 Raef Bassily, Abhradeep Guha Thakurta, Om Dipakbhai Thakkar

In the PAC model, we analyze our construction and prove upper bounds on the sample complexity for both the realizable and the non-realizable cases.

General Classification Transfer Learning

On exponential convergence of SGD in non-convex over-parametrized learning

no code implementations6 Nov 2018 Raef Bassily, Mikhail Belkin, Siyuan Ma

Large over-parametrized models learned via stochastic gradient descent (SGD) methods have become a key element in modern machine learning.

BIG-bench Machine Learning

Linear Queries Estimation with Local Differential Privacy

no code implementations5 Oct 2018 Raef Bassily

We study the problem of estimating a set of $d$ linear queries with respect to some unknown distribution $\mathbf{p}$ over a domain $\mathcal{J}=[J]$ based on a sensitive data set of $n$ individuals under the constraint of local differential privacy.

Model-Agnostic Private Learning via Stability

no code implementations14 Mar 2018 Raef Bassily, Om Thakkar, Abhradeep Thakurta

We provide a new technique to boost the average-case stability properties of learning algorithms to strong (worst-case) stability properties, and then exploit them to obtain private classification algorithms.

Binary Classification Classification +2

The Power of Interpolation: Understanding the Effectiveness of SGD in Modern Over-parametrized Learning

no code implementations ICML 2018 Siyuan Ma, Raef Bassily, Mikhail Belkin

We show that there is a critical batch size $m^*$ such that: (a) SGD iteration with mini-batch size $m\leq m^*$ is nearly equivalent to $m$ iterations of mini-batch size $1$ (\emph{linear scaling regime}).

Learners that Use Little Information

no code implementations14 Oct 2017 Raef Bassily, Shay Moran, Ido Nachum, Jonathan Shafer, Amir Yehudayoff

We discuss an approach that allows us to prove upper bounds on the amount of information that algorithms reveal about their inputs, and also provide a lower bound by showing a simple concept class for which every (possibly randomized) empirical risk minimizer must reveal a lot of information.

Typical Stability

no code implementations12 Apr 2016 Raef Bassily, Yoav Freund

We show that typical stability can control generalization error in adaptive data analysis even when the samples in the dataset are not necessarily independent and when queries to be computed are not necessarily of bounded-sensitivity as long as the results of the queries over the dataset (i. e., the computed statistics) follow a distribution with a "light" tail.

Algorithmic Stability for Adaptive Data Analysis

no code implementations8 Nov 2015 Raef Bassily, Kobbi Nissim, Adam Smith, Thomas Steinke, Uri Stemmer, Jonathan Ullman

Specifically, suppose there is an unknown distribution $\mathbf{P}$ and a set of $n$ independent samples $\mathbf{x}$ is drawn from $\mathbf{P}$.

Local, Private, Efficient Protocols for Succinct Histograms

no code implementations18 Apr 2015 Raef Bassily, Adam Smith

Moreover, we show that this much error is necessary, regardless of computational efficiency, and even for the simple setting where only one item appears with significant frequency in the data set.

Computational Efficiency

More General Queries and Less Generalization Error in Adaptive Data Analysis

no code implementations16 Mar 2015 Raef Bassily, Adam Smith, Thomas Steinke, Jonathan Ullman

However, generalization error is typically bounded in a non-adaptive model, where all questions are specified before the dataset is drawn.

Differentially Private Empirical Risk Minimization: Efficient Algorithms and Tight Error Bounds

1 code implementation27 May 2014 Raef Bassily, Adam Smith, Abhradeep Thakurta

We provide a separate set of algorithms and matching lower bounds for the setting in which the loss functions are known to also be strongly convex.

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