Search Results for author: Weihao Kong

Found 28 papers, 4 papers with code

Insufficient Statistics Perturbation: Stable Estimators for Private Least Squares

no code implementations23 Apr 2024 Gavin Brown, Jonathan Hayase, Samuel Hopkins, Weihao Kong, Xiyang Liu, Sewoong Oh, Juan C. Perdomo, Adam Smith

We present a sample- and time-efficient differentially private algorithm for ordinary least squares, with error that depends linearly on the dimension and is independent of the condition number of $X^\top X$, where $X$ is the design matrix.

A Combinatorial Approach to Robust PCA

no code implementations28 Nov 2023 Weihao Kong, Mingda Qiao, Rajat Sen

We study the problem of recovering Gaussian data under adversarial corruptions when the noises are low-rank and the corruptions are on the coordinate level.

Transformers can optimally learn regression mixture models

no code implementations14 Nov 2023 Reese Pathak, Rajat Sen, Weihao Kong, Abhimanyu Das

In this work, we investigate the hypothesis that transformers can learn an optimal predictor for mixtures of regressions.

regression

A decoder-only foundation model for time-series forecasting

no code implementations14 Oct 2023 Abhimanyu Das, Weihao Kong, Rajat Sen, Yichen Zhou

Motivated by recent advances in large language models for Natural Language Processing (NLP), we design a time-series foundation model for forecasting whose out-of-the-box zero-shot performance on a variety of public datasets comes close to the accuracy of state-of-the-art supervised forecasting models for each individual dataset.

Decoder Time Series +1

Linear Regression using Heterogeneous Data Batches

no code implementations5 Sep 2023 Ayush Jain, Rajat Sen, Weihao Kong, Abhimanyu Das, Alon Orlitsky

A common approach assumes that the sources fall in one of several unknown subgroups, each with an unknown input distribution and input-output relationship.

regression

Long-term Forecasting with TiDE: Time-series Dense Encoder

2 code implementations17 Apr 2023 Abhimanyu Das, Weihao Kong, Andrew Leach, Shaan Mathur, Rajat Sen, Rose Yu

Recent work has shown that simple linear models can outperform several Transformer based approaches in long term time-series forecasting.

Anomaly Detection Decoder +2

Estimating Optimal Policy Value in General Linear Contextual Bandits

no code implementations19 Feb 2023 Jonathan N. Lee, Weihao Kong, Aldo Pacchiano, Vidya Muthukumar, Emma Brunskill

Whether this is possible for more realistic context distributions has remained an open and important question for tasks such as model selection.

Model Selection Multi-Armed Bandits

Near Optimal Private and Robust Linear Regression

no code implementations30 Jan 2023 Xiyang Liu, Prateek Jain, Weihao Kong, Sewoong Oh, Arun Sai Suggala

Under label-corruption, this is the first efficient linear regression algorithm to guarantee both $(\varepsilon,\delta)$-DP and robustness.

regression

Efficient List-Decodable Regression using Batches

no code implementations23 Nov 2022 Abhimanyu Das, Ayush Jain, Weihao Kong, Rajat Sen

We begin the study of list-decodable linear regression using batches.

regression

DP-PCA: Statistically Optimal and Differentially Private PCA

no code implementations27 May 2022 Xiyang Liu, Weihao Kong, Prateek Jain, Sewoong Oh

For sub-Gaussian data, we provide nearly optimal statistical error rates even for $n=\tilde O(d)$.

Dirichlet Proportions Model for Hierarchically Coherent Probabilistic Forecasting

no code implementations21 Apr 2022 Abhimanyu Das, Weihao Kong, Biswajit Paria, Rajat Sen

Probabilistic, hierarchically coherent forecasting is a key problem in many practical forecasting applications -- the goal is to obtain coherent probabilistic predictions for a large number of time series arranged in a pre-specified tree hierarchy.

STS Time Series +1

Differential privacy and robust statistics in high dimensions

no code implementations12 Nov 2021 Xiyang Liu, Weihao Kong, Sewoong Oh

The key insight is that if we design an exponential mechanism that accesses the data only via one-dimensional robust statistics, then the resulting local sensitivity can be dramatically reduced.

Vocal Bursts Intensity Prediction

Fisher-Pitman permutation tests based on nonparametric Poisson mixtures with application to single cell genomics

no code implementations6 Jun 2021 Zhen Miao, Weihao Kong, Ramya Korlakai Vinayak, Wei Sun, Fang Han

This paper investigates the theoretical and empirical performance of Fisher-Pitman-type permutation tests for assessing the equality of unknown Poisson mixture distributions.

SPECTRE: Defending Against Backdoor Attacks Using Robust Statistics

1 code implementation22 Apr 2021 Jonathan Hayase, Weihao Kong, Raghav Somani, Sewoong Oh

There have been promising attempts to use the intermediate representations of such a model to separate corrupted examples from clean ones.

Robust and Differentially Private Mean Estimation

1 code implementation NeurIPS 2021 Xiyang Liu, Weihao Kong, Sham Kakade, Sewoong Oh

In statistical learning and analysis from shared data, which is increasingly widely adopted in platforms such as federated learning and meta-learning, there are two major concerns: privacy and robustness.

Federated Learning Meta-Learning

Online Model Selection for Reinforcement Learning with Function Approximation

no code implementations19 Nov 2020 Jonathan N. Lee, Aldo Pacchiano, Vidya Muthukumar, Weihao Kong, Emma Brunskill

Towards this end, we consider the problem of model selection in RL with function approximation, given a set of candidate RL algorithms with known regret guarantees.

Model Selection reinforcement-learning +1

Robust Meta-learning for Mixed Linear Regression with Small Batches

no code implementations NeurIPS 2020 Weihao Kong, Raghav Somani, Sham Kakade, Sewoong Oh

Together, this approach is robust against outliers and achieves a graceful statistical trade-off; the lack of $\Omega(k^{1/2})$-size tasks can be compensated for with smaller tasks, which can now be as small as $O(\log k)$.

Meta-Learning regression

Meta-learning for mixed linear regression

no code implementations ICML 2020 Weihao Kong, Raghav Somani, Zhao Song, Sham Kakade, Sewoong Oh

In modern supervised learning, there are a large number of tasks, but many of them are associated with only a small amount of labeled data.

Meta-Learning regression +1

Sublinear Optimal Policy Value Estimation in Contextual Bandits

no code implementations12 Dec 2019 Weihao Kong, Gregory Valiant, Emma Brunskill

We study the problem of estimating the expected reward of the optimal policy in the stochastic disjoint linear bandit setting.

Multi-Armed Bandits

Optimal Estimation of Change in a Population of Parameters

no code implementations28 Nov 2019 Ramya Korlakai Vinayak, Weihao Kong, Sham M. Kakade

Provided these paired observations, $\{(X_i, Y_i) \}_{i=1}^N$, our goal is to accurately estimate the \emph{distribution of the change in parameters}, $\delta_i := q_i - p_i$, over the population and properties of interest like the \emph{$\ell_1$-magnitude of the change} with sparse observations ($t\ll N$).

Epidemiology

Maximum Likelihood Estimation for Learning Populations of Parameters

no code implementations12 Feb 2019 Ramya Korlakai Vinayak, Weihao Kong, Gregory Valiant, Sham M. Kakade

Precisely, for sufficiently large $N$, the MLE achieves the information theoretic optimal error bound of $\mathcal{O}(\frac{1}{t})$ for $t < c\log{N}$, with regards to the earth mover's distance (between the estimated and true distributions).

Efficient Algorithms and Lower Bounds for Robust Linear Regression

no code implementations31 May 2018 Ilias Diakonikolas, Weihao Kong, Alistair Stewart

An error of $\Omega (\epsilon \sigma)$ is information-theoretically necessary, even with infinite sample size.

regression

Estimating Learnability in the Sublinear Data Regime

no code implementations NeurIPS 2018 Weihao Kong, Gregory Valiant

In this setting, we show that with $O(\sqrt{d})$ samples, one can accurately estimate the fraction of the variance of the label that can be explained via the best linear function of the data.

Binary Classification

Learning Populations of Parameters

no code implementations NeurIPS 2017 Kevin Tian, Weihao Kong, Gregory Valiant

Consider the following estimation problem: there are $n$ entities, each with an unknown parameter $p_i \in [0, 1]$, and we observe $n$ independent random variables, $X_1,\ldots, X_n$, with $X_i \sim $ Binomial$(t, p_i)$.

Sports Analytics

Spectrum Estimation from Samples

1 code implementation30 Jan 2016 Weihao Kong, Gregory Valiant

We consider this fundamental recovery problem in the regime where the number of samples is comparable, or even sublinear in the dimensionality of the distribution in question.

Isotropic Hashing

no code implementations NeurIPS 2012 Weihao Kong, Wu-Jun Li

Most existing hashing methods adopt some projection functions to project the original data into several dimensions of real values, and then each of these projected dimensions is quantized into one bit (zero or one) by thresholding.

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