English
Related papers

Related papers: Conditionally Risk-Averse Contextual Bandits

200 papers

In stochastic contextual bandits, an agent sequentially makes actions from a time-dependent action set based on past experience to minimize the cumulative regret. Like many other machine learning algorithms, the performance of bandits…

Machine Learning · Computer Science 2024-04-09 Yue Kang , Cho-Jui Hsieh , Thomas C. M. Lee

In this paper we propose a novel experimental design-based algorithm to minimize regret in online stochastic linear and combinatorial bandits. While existing literature tends to focus on optimism-based algorithms--which have been shown to…

Machine Learning · Computer Science 2021-03-02 Andrew Wagenmaker , Julian Katz-Samuels , Kevin Jamieson

We present the first high-probability optimal regret bound for a policy optimization technique applied to the problem of stochastic contextual multi-armed bandit (CMAB) with general offline function approximation. Our algorithm is both…

Machine Learning · Computer Science 2026-02-17 Orin Levy , Yishay Mansour

Mobile Context-Aware Recommender Systems can be naturally modelled as an exploration/exploitation trade-off (exr/exp) problem, where the system has to choose between maximizing its expected rewards dealing with its current knowledge…

Information Retrieval · Computer Science 2014-08-12 Djallel Bouneffouf

We introduce a novel online learning framework that unifies and generalizes pre-established models, such as delayed and corrupted feedback, to encompass adversarial environments where action feedback evolves over time. In this setting, the…

Machine Learning · Computer Science 2024-05-28 Yogev Bar-On , Yishay Mansour

We study the stochastic contextual bandit problem, where the reward is generated from an unknown function with additive noise. No assumption is made about the reward function other than boundedness. We propose a new algorithm, NeuralUCB,…

Machine Learning · Computer Science 2020-07-03 Dongruo Zhou , Lihong Li , Quanquan Gu

Contextual bandits have become popular as they offer a middle ground between very simple approaches based on multi-armed bandits and very complex approaches using the full power of reinforcement learning. They have demonstrated success in…

Methodology · Statistics 2017-11-13 Kristjan Greenewald , Ambuj Tewari , Predrag Klasnja , Susan Murphy

Motivated by modern applications, such as online advertisement and recommender systems, we study the top-$k$ extreme contextual bandits problem, where the total number of arms can be enormous, and the learner is allowed to select $k$ arms…

Machine Learning · Statistics 2021-02-17 Rajat Sen , Alexander Rakhlin , Lexing Ying , Rahul Kidambi , Dean Foster , Daniel Hill , Inderjit Dhillon

We study the linear contextual bandit problem in the presence of adversarial corruption, where the interaction between the player and a possibly infinite decision set is contaminated by an adversary that can corrupt the reward up to a…

Machine Learning · Computer Science 2021-10-26 Heyang Zhao , Dongruo Zhou , Quanquan Gu

We consider the problem of stochastic $K$-armed dueling bandit in the contextual setting, where at each round the learner is presented with a context set of $K$ items, each represented by a $d$-dimensional feature vector, and the goal of…

Machine Learning · Computer Science 2021-05-11 Aadirupa Saha , Aditya Gopalan

Many sequential decision-making problems in communication networks can be modeled as contextual bandit problems, which are natural extensions of the well-known multi-armed bandit problem. In contextual bandit problems, at each time, an…

Machine Learning · Computer Science 2016-05-10 Pranav Sakulkar , Bhaskar Krishnamachari

We study a generalization of the problem of online learning in adversarial linear contextual bandits by incorporating loss functions that belong to a reproducing kernel Hilbert space, which allows for a more flexible modeling of complex…

Machine Learning · Statistics 2023-10-04 Gergely Neu , Julia Olkhovskaya , Sattar Vakili

Most off-policy evaluation methods for contextual bandits have focused on the expected outcome of a policy, which is estimated via methods that at best provide only asymptotic guarantees. However, in many applications, the expectation may…

Machine Learning · Statistics 2022-10-27 Muhammad Faaiz Taufiq , Jean-Francois Ton , Rob Cornish , Yee Whye Teh , Arnaud Doucet

The problem of multi-armed bandits (MAB) asks to make sequential decisions while balancing between exploitation and exploration, and have been successfully applied to a wide range of practical scenarios. Various algorithms have been…

Machine Learning · Computer Science 2022-02-24 Xiaojin Zhang , Shuai Li , Weiwen Liu , Shengyu Zhang

This paper considers a contextual bandit problem involving multiple agents, where a learner sequentially observes the contexts and the agent's reported arms, and then selects the arm that maximizes the system's overall reward. Existing work…

Machine Learning · Computer Science 2025-05-30 Arun Verma , Indrajit Saha , Makoto Yokoo , Bryan Kian Hsiang Low

Contextual bandit algorithms are extremely popular and widely used in recommendation systems to provide online personalised recommendations. A recurrent assumption is the stationarity of the reward function, which is rather unrealistic in…

Machine Learning · Statistics 2020-04-29 Giuseppe Di Benedetto , Vito Bellini , Giovanni Zappella

In safety-critical decision-making, the environment may evolve over time, and the learner adjusts its risk level accordingly. This work investigates risk-averse online optimization in dynamic environments with varying risk levels, employing…

Optimization and Control · Mathematics 2025-12-30 Siyi Wang , Zifan Wang , Karl H. Johansson

We study an online decision making problem where on each round a learner chooses a list of items based on some side information, receives a scalar feedback value for each individual item, and a reward that is linearly related to this…

Machine Learning · Computer Science 2016-11-07 Akshay Krishnamurthy , Alekh Agarwal , Miroslav Dudik

We study the problem of meta-learning several contextual stochastic bandits tasks by leveraging their concentration around a low-dimensional affine subspace, which we learn via online principal component analysis to reduce the expected…

Machine Learning · Computer Science 2024-04-02 Steven Bilaj , Sofien Dhouib , Setareh Maghsudi

We consider the kernelized contextual bandit problem with a large feature space. This problem involves $K$ arms, and the goal of the forecaster is to maximize the cumulative rewards through learning the relationship between the contexts and…

Machine Learning · Statistics 2025-05-21 Shogo Iwazaki , Junpei Komiyama , Masaaki Imaizumi