Search Results for author: Ethan X. Fang

Found 15 papers, 0 papers with code

Stochastic Compositional Gradient Descent: Algorithms for Minimizing Compositions of Expected-Value Functions

no code implementations14 Nov 2014 Mengdi Wang, Ethan X. Fang, Han Liu

For smooth convex problems, the SCGD can be accelerated to converge at a rate of $O(k^{-2/7})$ in the general case and $O(k^{-4/5})$ in the strongly convex case.

Testing and Confidence Intervals for High Dimensional Proportional Hazards Model

no code implementations16 Dec 2014 Ethan X. Fang, Yang Ning, Han Liu

This paper proposes a decorrelation-based approach to test hypotheses and construct confidence intervals for the low dimensional component of high dimensional proportional hazards models.

Model Selection Vocal Bursts Intensity Prediction

Accelerating Stochastic Composition Optimization

no code implementations NeurIPS 2016 Mengdi Wang, Ji Liu, Ethan X. Fang

The ASC-PG is the first proximal gradient method for the stochastic composition problem that can deal with nonsmooth regularization penalty.

reinforcement-learning Reinforcement Learning (RL)

Max-Norm Optimization for Robust Matrix Recovery

no code implementations24 Sep 2016 Ethan X. Fang, Han Liu, Kim-Chuan Toh, Wen-Xin Zhou

This paper studies the matrix completion problem under arbitrary sampling schemes.

Matrix Completion

Misspecified Nonconvex Statistical Optimization for Phase Retrieval

no code implementations18 Dec 2017 Zhuoran Yang, Lin F. Yang, Ethan X. Fang, Tuo Zhao, Zhaoran Wang, Matey Neykov

Existing nonconvex statistical optimization theory and methods crucially rely on the correct specification of the underlying "true" statistical models.

Retrieval

Inductive Bias of Gradient Descent based Adversarial Training on Separable Data

no code implementations7 Jun 2019 Yan Li, Ethan X. Fang, Huan Xu, Tuo Zhao

Specifically, we show that when the adversarial perturbation during training has bounded $\ell_2$-norm, the classifier learned by gradient descent based adversarial training converges in direction to the maximum $\ell_2$-norm margin classifier at the rate of $\tilde{\mathcal{O}}(1/\sqrt{T})$, significantly faster than the rate $\mathcal{O}(1/\log T)$ of training with clean data.

Binary Classification Inductive Bias

Implicit Bias of Gradient Descent based Adversarial Training on Separable Data

no code implementations ICLR 2020 Yan Li, Ethan X. Fang, Huan Xu, Tuo Zhao

Specifically, we show that for any fixed iteration $T$, when the adversarial perturbation during training has proper bounded L2 norm, the classifier learned by gradient descent based adversarial training converges in direction to the maximum L2 norm margin classifier at the rate of $O(1/\sqrt{T})$, significantly faster than the rate $O(1/\log T}$ of training with clean data.

Binary Classification

Risk-Sensitive Deep RL: Variance-Constrained Actor-Critic Provably Finds Globally Optimal Policy

no code implementations28 Dec 2020 Han Zhong, Xun Deng, Ethan X. Fang, Zhuoran Yang, Zhaoran Wang, Runze Li

In particular, we focus on a variance-constrained policy optimization problem where the goal is to find a policy that maximizes the expected value of the long-run average reward, subject to a constraint that the long-run variance of the average reward is upper bounded by a threshold.

reinforcement-learning Reinforcement Learning (RL)

Implicit Regularization of Bregman Proximal Point Algorithm and Mirror Descent on Separable Data

no code implementations15 Aug 2021 Yan Li, Caleb Ju, Ethan X. Fang, Tuo Zhao

For any BPPA instantiated with a fixed Bregman divergence, we provide a lower bound of the margin obtained by BPPA with respect to an arbitrarily chosen norm.

Lagrangian Inference for Ranking Problems

no code implementations1 Oct 2021 Yue Liu, Ethan X. Fang, Junwei Lu

Our proposed method aims to infer general ranking properties of the BTL model.

Uncertainty Quantification

Stochastic Compositional Optimization with Compositional Constraints

no code implementations9 Sep 2022 Shuoguang Yang, Zhe Zhang, Ethan X. Fang

Stochastic compositional optimization (SCO) has attracted considerable attention because of its broad applicability to important real-world problems.

Management

PASTA: Pessimistic Assortment Optimization

no code implementations8 Feb 2023 Juncheng Dong, Weibin Mo, Zhengling Qi, Cong Shi, Ethan X. Fang, Vahid Tarokh

The objective is to use the offline dataset to find an optimal assortment.

Pivotal Estimation of Linear Discriminant Analysis in High Dimensions

no code implementations18 Sep 2023 Ethan X. Fang, Yajun Mei, Yuyang Shi, Qunzhi Xu, Tuo Zhao

We consider the linear discriminant analysis problem in the high-dimensional settings.

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