Search Results for author: Kaiwen Wang

Found 17 papers, 6 papers with code

Provable Benefits of Representational Transfer in Reinforcement Learning

1 code implementation29 May 2022 Alekh Agarwal, Yuda Song, Wen Sun, Kaiwen Wang, Mengdi Wang, Xuezhou Zhang

We study the problem of representational transfer in RL, where an agent first pretrains in a number of source tasks to discover a shared representation, which is subsequently used to learn a good policy in a \emph{target task}.

reinforcement-learning Reinforcement Learning (RL) +1

Learning Bellman Complete Representations for Offline Policy Evaluation

1 code implementation12 Jul 2022 Jonathan D. Chang, Kaiwen Wang, Nathan Kallus, Wen Sun

We study representation learning for Offline Reinforcement Learning (RL), focusing on the important task of Offline Policy Evaluation (OPE).

Continuous Control Reinforcement Learning (RL) +1

Doubly Robust Distributionally Robust Off-Policy Evaluation and Learning

1 code implementation19 Feb 2022 Nathan Kallus, Xiaojie Mao, Kaiwen Wang, Zhengyuan Zhou

Thanks to a localization technique, LDR$^2$OPE only requires fitting a small number of regressions, just like DR methods for standard OPE.

Off-policy evaluation

JoinGym: An Efficient Query Optimization Environment for Reinforcement Learning

1 code implementation21 Jul 2023 Kaiwen Wang, Junxiong Wang, Yueying Li, Nathan Kallus, Immanuel Trummer, Wen Sun

Join order selection (JOS) is the problem of ordering join operations to minimize total query execution cost and it is the core NP-hard combinatorial optimization problem of query optimization.

Benchmarking Combinatorial Optimization +3

Scalable and Provably Accurate Algorithms for Differentially Private Distributed Decision Tree Learning

1 code implementation19 Dec 2020 Kaiwen Wang, Travis Dick, Maria-Florina Balcan

We provide the first utility guarantees for differentially private top-down decision tree learning in both the single machine and distributed settings.

Privacy Preserving

Respond-CAM: Analyzing Deep Models for 3D Imaging Data by Visualizations

no code implementations31 May 2018 Guannan Zhao, Bo Zhou, Kaiwen Wang, Rui Jiang, Min Xu

The weighted feature maps are combined to produce a heatmap that highlights the important regions in the image for predicting the target concept.

Multi-task Learning for Macromolecule Classification, Segmentation and Coarse Structural Recovery in Cryo-Tomography

no code implementations16 May 2018 Chang Liu, Xiangrui Zeng, Kaiwen Wang, Qiang Guo, Min Xu

Cellular Electron Cryo-Tomography (CECT) is a powerful 3D imaging tool for studying the native structure and organization of macromolecules inside single cells.

Classification General Classification +3

Partitioned Active Learning for Heterogeneous Systems

no code implementations14 May 2021 Cheolhei Lee, Kaiwen Wang, Jianguo Wu, Wenjun Cai, Xiaowei Yue

Active learning is a subfield of machine learning that focuses on improving the data collection efficiency of expensive-to-evaluate systems.

Active Learning Computational Efficiency

Deep Multi-Modal Structural Equations For Causal Effect Estimation With Unstructured Proxies

no code implementations18 Mar 2022 Shachi Deshpande, Kaiwen Wang, Dhruv Sreenivas, Zheng Li, Volodymyr Kuleshov

Oftentimes, the confounders are unobserved, but we have access to large amounts of additional unstructured data (images, text) that contain valuable proxy signal about the missing confounders.

Causal Inference Time Series Analysis

Near-Minimax-Optimal Risk-Sensitive Reinforcement Learning with CVaR

no code implementations7 Feb 2023 Kaiwen Wang, Nathan Kallus, Wen Sun

In this paper, we study risk-sensitive Reinforcement Learning (RL), focusing on the objective of Conditional Value at Risk (CVaR) with risk tolerance $\tau$.

reinforcement-learning Reinforcement Learning (RL)

More Benefits of Being Distributional: Second-Order Bounds for Reinforcement Learning

no code implementations11 Feb 2024 Kaiwen Wang, Owen Oertell, Alekh Agarwal, Nathan Kallus, Wen Sun

Second-order bounds are instance-dependent bounds that scale with the variance of return, which we prove are tighter than the previously known small-loss bounds of distributional RL.

Distributional Reinforcement Learning Multi-Armed Bandits +1

Risk-Sensitive RL with Optimized Certainty Equivalents via Reduction to Standard RL

no code implementations10 Mar 2024 Kaiwen Wang, Dawen Liang, Nathan Kallus, Wen Sun

We study Risk-Sensitive Reinforcement Learning (RSRL) with the Optimized Certainty Equivalent (OCE) risk, which generalizes Conditional Value-at-risk (CVaR), entropic risk and Markowitz's mean-variance.

Adversarial Defense Teacher for Cross-Domain Object Detection under Poor Visibility Conditions

no code implementations23 Mar 2024 Kaiwen Wang, Yinzhe Shen, Martin Lauer

Existing object detectors encounter challenges in handling domain shifts between training and real-world data, particularly under poor visibility conditions like fog and night.

Adversarial Defense object-detection +1

Efficient and Sharp Off-Policy Evaluation in Robust Markov Decision Processes

no code implementations29 Mar 2024 Andrew Bennett, Nathan Kallus, Miruna Oprescu, Wen Sun, Kaiwen Wang

We characterize the sharp bounds on policy value under this model, that is, the tightest possible bounds given by the transition observations from the original MDP, and we study the estimation of these bounds from such transition observations.

Off-policy evaluation

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