Search Results for author: Pranjal Awasthi

Found 53 papers, 7 papers with code

Congested Bandits: Optimal Routing via Short-term Resets

no code implementations23 Jan 2023 Pranjal Awasthi, Kush Bhatia, Sreenivas Gollapudi, Kostas Kollias

For the linear contextual bandit setup, our algorithm, based on an iterative least squares planner, achieves policy regret $\tilde{O}(\sqrt{dT} + \Delta)$.

On the Adversarial Robustness of Mixture of Experts

no code implementations19 Oct 2022 Joan Puigcerver, Rodolphe Jenatton, Carlos Riquelme, Pranjal Awasthi, Srinadh Bhojanapalli

We next empirically evaluate the robustness of MoEs on ImageNet using adversarial attacks and show they are indeed more robust than dense models with the same computational cost.

Adversarial Robustness

Agnostic Learning of General ReLU Activation Using Gradient Descent

no code implementations4 Aug 2022 Pranjal Awasthi, Alex Tang, Aravindan Vijayaraghavan

We provide a convergence analysis of gradient descent for the problem of agnostically learning a single ReLU function under Gaussian distributions.

Individual Preference Stability for Clustering

1 code implementation7 Jul 2022 Saba Ahmadi, Pranjal Awasthi, Samir Khuller, Matthäus Kleindessner, Jamie Morgenstern, Pattara Sukprasert, Ali Vakilian

In this paper, we propose a natural notion of individual preference (IP) stability for clustering, which asks that every data point, on average, is closer to the points in its own cluster than to the points in any other cluster.


$\mathscr{H}$-Consistency Estimation Error of Surrogate Loss Minimizers

no code implementations16 May 2022 Pranjal Awasthi, Anqi Mao, Mehryar Mohri, Yutao Zhong

We also show that previous excess error bounds can be recovered as special cases of our general results.

Do More Negative Samples Necessarily Hurt in Contrastive Learning?

no code implementations3 May 2022 Pranjal Awasthi, Nishanth Dikkala, Pritish Kamath

Recent investigations in noise contrastive estimation suggest, both empirically as well as theoretically, that while having more "negative samples" in the contrastive loss improves downstream classification performance initially, beyond a threshold, it hurts downstream performance due to a "collision-coverage" trade-off.

Contrastive Learning

Distributionally Robust Data Join

1 code implementation11 Feb 2022 Pranjal Awasthi, Christopher Jung, Jamie Morgenstern

Suppose we are given two datasets: a labeled dataset and unlabeled dataset which also has additional auxiliary features not present in the first dataset.

Agnostic Learnability of Halfspaces via Logistic Loss

no code implementations31 Jan 2022 Ziwei Ji, Kwangjun Ahn, Pranjal Awasthi, Satyen Kale, Stefani Karp

In this paper, we close this gap by constructing a well-behaved distribution such that the global minimizer of the logistic risk over this distribution only achieves $\Omega(\sqrt{\textrm{OPT}})$ misclassification risk, matching the upper bound in (Frei et al., 2021).


On the Existence of the Adversarial Bayes Classifier (Extended Version)

no code implementations3 Dec 2021 Pranjal Awasthi, Natalie S. Frank, Mehryar Mohri

In this work, we study a fundamental question regarding Bayes optimality for adversarial robustness.

Adversarial Robustness

A Convergence Analysis of Gradient Descent on Graph Neural Networks

no code implementations NeurIPS 2021 Pranjal Awasthi, Abhimanyu Das, Sreenivas Gollapudi

Graph Neural Networks~(GNNs) are a powerful class of architectures for solving learning problems on graphs.

Efficient Algorithms for Learning Depth-2 Neural Networks with General ReLU Activations

no code implementations NeurIPS 2021 Pranjal Awasthi, Alex Tang, Aravindan Vijayaraghavan

We present polynomial time and sample efficient algorithms for learning an unknown depth-2 feedforward neural network with general ReLU activations, under mild non-degeneracy assumptions.

On the benefits of maximum likelihood estimation for Regression and Forecasting

no code implementations ICLR 2022 Pranjal Awasthi, Abhimanyu Das, Rajat Sen, Ananda Theertha Suresh

We also demonstrate empirically that our method instantiated with a well-designed general purpose mixture likelihood family can obtain superior performance for a variety of tasks across time-series forecasting and regression datasets with different data distributions.

regression Time Series Forecasting

Semi-supervised Active Regression

no code implementations12 Jun 2021 Fnu Devvrit, Nived Rajaraman, Pranjal Awasthi

In this setting, the learner has access to a dataset $X \in \mathbb{R}^{(n_1+n_2) \times d}$ which is composed of $n_1$ unlabelled examples that an algorithm can actively query, and $n_2$ examples labelled a-priori.

Active Learning regression

Neural Active Learning with Performance Guarantees

no code implementations NeurIPS 2021 Pranjal Awasthi, Christoph Dann, Claudio Gentile, Ayush Sekhari, Zhilei Wang

We investigate the problem of active learning in the streaming setting in non-parametric regimes, where the labels are stochastically generated from a class of functions on which we make no assumptions whatsoever.

Active Learning Model Selection

A Finer Calibration Analysis for Adversarial Robustness

no code implementations4 May 2021 Pranjal Awasthi, Anqi Mao, Mehryar Mohri, Yutao Zhong

Moreover, our calibration results, combined with the previous study of consistency by Awasthi et al. (2021), also lead to more general $H$-consistency results covering common hypothesis sets.

Adversarial Robustness BIG-bench Machine Learning +1

Calibration and Consistency of Adversarial Surrogate Losses

no code implementations NeurIPS 2021 Pranjal Awasthi, Natalie Frank, Anqi Mao, Mehryar Mohri, Yutao Zhong

We then give a characterization of H-calibration and prove that some surrogate losses are indeed H-calibrated for the adversarial loss, with these hypothesis sets.

Adversarial Robustness

A Multiclass Boosting Framework for Achieving Fast and Provable Adversarial Robustness

no code implementations1 Mar 2021 Jacob Abernethy, Pranjal Awasthi, Satyen Kale

This apparent lack of robustness has led researchers to propose methods that can help to prevent an adversary from having such capabilities.

Adversarial Robustness Object Recognition

Evaluating Fairness of Machine Learning Models Under Uncertain and Incomplete Information

no code implementations16 Feb 2021 Pranjal Awasthi, Alex Beutel, Matthaeus Kleindessner, Jamie Morgenstern, Xuezhi Wang

An alternate approach that is commonly used is to separately train an attribute classifier on data with sensitive attribute information, and then use it later in the ML pipeline to evaluate the bias of a given classifier.

BIG-bench Machine Learning Fairness +1

Online Learning under Adversarial Corruptions

no code implementations1 Jan 2021 Pranjal Awasthi, Sreenivas Gollapudi, Kostas Kollias, Apaar Sadhwani

We study the design of efficient online learning algorithms tolerant to adversarially corrupted rewards.

Multi-Armed Bandits

Beyond GNNs: A Sample Efficient Architecture for Graph Problems

no code implementations1 Jan 2021 Pranjal Awasthi, Abhimanyu Das, Sreenivas Gollapudi

Finally, we empirically demonstrate the effectiveness of our proposed architecture for a variety of graph problems.

Generalization Bounds

Adversarial Robustness Across Representation Spaces

no code implementations CVPR 2021 Pranjal Awasthi, George Yu, Chun-Sung Ferng, Andrew Tomkins, Da-Cheng Juan

In this work we extend the above setting to consider the problem of training of deep neural networks that can be made simultaneously robust to perturbations applied in multiple natural representation spaces.

Adversarial Robustness Image Classification

PAC-Bayes Learning Bounds for Sample-Dependent Priors

no code implementations NeurIPS 2020 Pranjal Awasthi, Satyen Kale, Stefani Karp, Mehryar Mohri

We present a series of new PAC-Bayes learning guarantees for randomized algorithms with sample-dependent priors.

Beyond Individual and Group Fairness

no code implementations21 Aug 2020 Pranjal Awasthi, Corinna Cortes, Yishay Mansour, Mehryar Mohri

In the adversarial setting, we design efficient algorithms with competitive ratio guarantees.


On the Rademacher Complexity of Linear Hypothesis Sets

no code implementations21 Jul 2020 Pranjal Awasthi, Natalie Frank, Mehryar Mohri

Linear predictors form a rich class of hypotheses used in a variety of learning algorithms.

Adversarial robustness via robust low rank representations

no code implementations NeurIPS 2020 Pranjal Awasthi, Himanshu Jain, Ankit Singh Rawat, Aravindan Vijayaraghavan

Adversarial robustness measures the susceptibility of a classifier to imperceptible perturbations made to the inputs at test time.

Adversarial Robustness

Active Sampling for Min-Max Fairness

1 code implementation11 Jun 2020 Jacob Abernethy, Pranjal Awasthi, Matthäus Kleindessner, Jamie Morgenstern, Chris Russell, Jie Zhang

We propose simple active sampling and reweighting strategies for optimizing min-max fairness that can be applied to any classification or regression model learned via loss minimization.

Fairness regression

A Notion of Individual Fairness for Clustering

no code implementations8 Jun 2020 Matthäus Kleindessner, Pranjal Awasthi, Jamie Morgenstern

A common distinction in fair machine learning, in particular in fair classification, is between group fairness and individual fairness.


Estimating Principal Components under Adversarial Perturbations

no code implementations31 May 2020 Pranjal Awasthi, Xue Chen, Aravindan Vijayaraghavan

We design a computationally efficient algorithm that given corrupted data, recovers an estimate of the top-$r$ principal subspace with error that depends on a robustness parameter $\kappa$ that we identify.

BIG-bench Machine Learning

Adversarial Learning Guarantees for Linear Hypotheses and Neural Networks

no code implementations ICML 2020 Pranjal Awasthi, Natalie Frank, Mehryar Mohri

We give upper and lower bounds for the adversarial empirical Rademacher complexity of linear hypotheses with adversarial perturbations measured in $l_r$-norm for an arbitrary $r \geq 1$.

Adversarial Robustness

Efficient active learning of sparse halfspaces with arbitrary bounded noise

no code implementations NeurIPS 2020 Chicheng Zhang, Jie Shen, Pranjal Awasthi

Even in the presence of mild label noise, i. e. $\eta$ is a small constant, this is a challenging problem and only recently have label complexity bounds of the form $\tilde{O}\big(s \cdot \mathrm{polylog}(d, \frac{1}{\epsilon})\big)$ been established in [Zhang, 2018] for computationally efficient algorithms.

Active Learning

A Deep Conditioning Treatment of Neural Networks

no code implementations4 Feb 2020 Naman Agarwal, Pranjal Awasthi, Satyen Kale

We study the role of depth in training randomly initialized overparameterized neural networks.

Adversarially Robust Low Dimensional Representations

no code implementations29 Nov 2019 Pranjal Awasthi, Vaggos Chatziafratis, Xue Chen, Aravindan Vijayaraghavan

In particular, our adversarially robust PCA primitive leads to computationally efficient and robust algorithms for both unsupervised and supervised learning problems such as clustering and learning adversarially robust classifiers.

BIG-bench Machine Learning

On Robustness to Adversarial Examples and Polynomial Optimization

1 code implementation NeurIPS 2019 Pranjal Awasthi, Abhratanu Dutta, Aravindan Vijayaraghavan

In particular, we leverage this connection to (a) design computationally efficient robust algorithms with provable guarantees for a large class of hypothesis, namely linear classifiers and degree-2 polynomial threshold functions (PTFs), (b) give a precise characterization of the price of achieving robustness in a computationally efficient manner for these classes, (c) design efficient algorithms to certify robustness and generate adversarial attacks in a principled manner for 2-layer neural networks.

Equalized odds postprocessing under imperfect group information

2 code implementations7 Jun 2019 Pranjal Awasthi, Matthäus Kleindessner, Jamie Morgenstern

We identify conditions on the perturbation that guarantee that the bias of a classifier is reduced even by running equalized odds with the perturbed attribute.

Fairness General Classification

Guarantees for Spectral Clustering with Fairness Constraints

1 code implementation24 Jan 2019 Matthäus Kleindessner, Samira Samadi, Pranjal Awasthi, Jamie Morgenstern

Given the widespread popularity of spectral clustering (SC) for partitioning graph data, we study a version of constrained SC in which we try to incorporate the fairness notion proposed by Chierichetti et al. (2017).

Fairness Stochastic Block Model

Fair k-Center Clustering for Data Summarization

1 code implementation24 Jan 2019 Matthäus Kleindessner, Pranjal Awasthi, Jamie Morgenstern

In data summarization we want to choose $k$ prototypes in order to summarize a data set.

Data Summarization Fairness

Crowdsourcing with Arbitrary Adversaries

no code implementations ICML 2018 Matthaeus Kleindessner, Pranjal Awasthi

Most existing works on crowdsourcing assume that the workers follow the Dawid-Skene model, or the one-coin model as its special case, where every worker makes mistakes independently of other workers and with the same error probability for every task.

Towards Learning Sparsely Used Dictionaries with Arbitrary Supports

no code implementations23 Apr 2018 Pranjal Awasthi, Aravindan Vijayaraghavan

To address this question while circumventing the issue of non-identifiability, we study a natural semirandom model for dictionary learning where there are a large number of samples $y=Ax$ with arbitrary k-sparse supports for x, along with a few samples where the sparse supports are chosen uniformly at random.

Dictionary Learning

Clustering Semi-Random Mixtures of Gaussians

no code implementations ICML 2018 Pranjal Awasthi, Aravindan Vijayaraghavan

Gaussian mixture models (GMM) are the most widely used statistical model for the $k$-means clustering problem and form a popular framework for clustering in machine learning and data analysis.

Efficient PAC Learning from the Crowd

no code implementations21 Mar 2017 Pranjal Awasthi, Avrim Blum, Nika Haghtalab, Yishay Mansour

When a noticeable fraction of the labelers are perfect, and the rest behave arbitrarily, we show that any $\mathcal{F}$ that can be efficiently learned in the traditional realizable PAC model can be learned in a computationally efficient manner by querying the crowd, despite high amounts of noise in the responses.

PAC learning

Robust Communication-Optimal Distributed Clustering Algorithms

no code implementations2 Mar 2017 Pranjal Awasthi, Ainesh Bakshi, Maria-Florina Balcan, Colin White, David Woodruff

In this work, we study the $k$-median and $k$-means clustering problems when the data is distributed across many servers and can contain outliers.

On some provably correct cases of variational inference for topic models

no code implementations NeurIPS 2015 Pranjal Awasthi, Andrej Risteski

The assumptions on the topic priors are related to the well known Dirichlet prior, introduced to the area of topic modeling by (Blei et al., 2003).

Dictionary Learning Topic Models +1

Efficient Learning of Linear Separators under Bounded Noise

no code implementations12 Mar 2015 Pranjal Awasthi, Maria-Florina Balcan, Nika Haghtalab, Ruth Urner

We provide the first polynomial time algorithm that can learn linear separators to arbitrarily small excess error in this noise model under the uniform distribution over the unit ball in $\Re^d$, for some constant value of $\eta$.

Active Learning Learning Theory

Label optimal regret bounds for online local learning

no code implementations7 Mar 2015 Pranjal Awasthi, Moses Charikar, Kevin A. Lai, Andrej Risteski

We resolve an open question from (Christiano, 2014b) posed in COLT'14 regarding the optimal dependency of the regret achievable for online local learning on the size of the label set.

Collaborative Filtering

Learning Mixtures of Ranking Models

no code implementations NeurIPS 2014 Pranjal Awasthi, Avrim Blum, Or Sheffet, Aravindan Vijayaraghavan

We present the first polynomial time algorithm which provably learns the parameters of a mixture of two Mallows models.

Tensor Decomposition

Relax, no need to round: integrality of clustering formulations

no code implementations18 Aug 2014 Pranjal Awasthi, Afonso S. Bandeira, Moses Charikar, Ravishankar Krishnaswamy, Soledad Villar, Rachel Ward

Under the same distributional model, the $k$-means LP relaxation fails to recover such clusters at separation as large as $\Delta = 4$.

Local algorithms for interactive clustering

no code implementations24 Dec 2013 Pranjal Awasthi, Maria-Florina Balcan, Konstantin Voevodski

We study the design of interactive clustering algorithms for data sets satisfying natural stability assumptions.

The Power of Localization for Efficiently Learning Linear Separators with Noise

no code implementations31 Jul 2013 Pranjal Awasthi, Maria Florina Balcan, Philip M. Long

For malicious noise, where the adversary can corrupt both the label and the features, we provide a polynomial-time algorithm for learning linear separators in $\Re^d$ under isotropic log-concave distributions that can tolerate a nearly information-theoretically optimal noise rate of $\eta = \Omega(\epsilon)$.

Active Learning

Learning using Local Membership Queries

no code implementations5 Nov 2012 Pranjal Awasthi, Vitaly Feldman, Varun Kanade

We introduce a new model of membership query (MQ) learning, where the learning algorithm is restricted to query points that are \emph{close} to random examples drawn from the underlying distribution.

Supervised Clustering

no code implementations NeurIPS 2010 Pranjal Awasthi, Reza B. Zadeh

We also propose a dynamic model where the teacher sees a random subset of the points.

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