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Contextual bandits are widely used in Internet services from news recommendation to advertising, and to Web search. Generalized linear models (logistical regression in particular) have demonstrated stronger performance than linear models in…

Machine Learning · Computer Science 2017-06-20 Lihong Li , Yu Lu , Dengyong Zhou

This paper presents a finite-time analysis of the KL-UCB algorithm, an online, horizon-free index policy for stochastic bandit problems. We prove two distinct results: first, for arbitrary bounded rewards, the KL-UCB algorithm satisfies a…

Statistics Theory · Mathematics 2013-08-30 Aurélien Garivier , Olivier Cappé

We study the stochastic bandit problem with ReLU neural network structure. We show that a $\tilde{O}(\sqrt{T})$ regret guarantee is achievable by considering bandits with one-layer ReLU neural networks; to the best of our knowledge, our…

Machine Learning · Computer Science 2024-05-14 Kan Xu , Hamsa Bastani , Surbhi Goel , Osbert Bastani

We consider a multi-armed bandit problem where payoffs are a linear function of an observed stochastic contextual variable. In the scenario where there exists a gap between optimal and suboptimal rewards, several algorithms have been…

Data Structures and Algorithms · Computer Science 2014-07-08 José Bento , Stratis Ioannidis , S. Muthukrishnan , Jinyun Yan

We investigate the high-dimensional sparse linear bandits problem in a data-poor regime where the time horizon is much smaller than the ambient dimension and number of arms. We study the setting under the additional blocking constraint…

Machine Learning · Computer Science 2025-05-30 Adit Jain , Soumyabrata Pal , Sunav Choudhary , Ramasuri Narayanam , Harshita Chopra , Vikram Krishnamurthy

In the contextual linear bandit setting, algorithms built on the optimism principle fail to exploit the structure of the problem and have been shown to be asymptotically suboptimal. In this paper, we follow recent approaches of deriving…

Machine Learning · Computer Science 2020-11-23 Andrea Tirinzoni , Matteo Pirotta , Marcello Restelli , Alessandro Lazaric

We present improved algorithms with worst-case regret guarantees for the stochastic linear bandit problem. The widely used "optimism in the face of uncertainty" principle reduces a stochastic bandit problem to the construction of a…

Machine Learning · Statistics 2024-09-06 Hamish Flynn , David Reeb , Melih Kandemir , Jan Peters

This paper explores a new form of the linear bandit problem in which the algorithm receives the usual stochastic rewards as well as stochastic feedback about which features are relevant to the rewards, the latter feedback being the novel…

Machine Learning · Computer Science 2019-03-13 Urvashi Oswal , Aniruddha Bhargava , Robert Nowak

This paper investigates the problem of generalized linear bandits with heavy-tailed rewards, whose $(1+\epsilon)$-th moment is bounded for some $\epsilon\in (0,1]$. Although there exist methods for generalized linear bandits, most of them…

Machine Learning · Computer Science 2023-10-31 Bo Xue , Yimu Wang , Yuanyu Wan , Jinfeng Yi , Lijun Zhang

We develop the first general semi-bandit algorithm that simultaneously achieves $\mathcal{O}(\log T)$ regret for stochastic environments and $\mathcal{O}(\sqrt{T})$ regret for adversarial environments without knowledge of the regime or the…

Machine Learning · Computer Science 2019-09-27 Julian Zimmert , Haipeng Luo , Chen-Yu Wei

We study reward maximisation in a wide class of structured stochastic multi-armed bandit problems, where the mean rewards of arms satisfy some given structural constraints, e.g. linear, unimodal, sparse, etc. Our aim is to develop methods…

Machine Learning · Statistics 2020-07-03 Rémy Degenne , Han Shao , Wouter M. Koolen

In this paper, we study the stochastic combinatorial multi-armed bandit (CMAB) framework that allows a general nonlinear reward function, whose expected value may not depend only on the means of the input random variables but possibly on…

Machine Learning · Computer Science 2018-07-23 Wei Chen , Wei Hu , Fu Li , Jian Li , Yu Liu , Pinyan Lu

I present the first algorithm for stochastic finite-armed bandits that simultaneously enjoys order-optimal problem-dependent regret and worst-case regret. Besides the theoretical results, the new algorithm is simple, efficient and…

Machine Learning · Computer Science 2016-02-25 Tor Lattimore

This paper investigates stochastic multi-armed bandit algorithms that are robust to adversarial attacks, where an attacker can first observe the learner's action and {then} alter their reward observation. We study two cases of this model,…

Machine Learning · Computer Science 2024-08-19 Xuchuang Wang , Jinhang Zuo , Xutong Liu , John C. S. Lui , Mohammad Hajiesmaili

We provide a simple method to combine stochastic bandit algorithms. Our approach is based on a "meta-UCB" procedure that treats each of $N$ individual bandit algorithms as arms in a higher-level $N$-armed bandit problem that we solve with a…

Machine Learning · Computer Science 2020-12-25 Ashok Cutkosky , Abhimanyu Das , Manish Purohit

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

In this paper, we propose differentially private algorithms for the problem of stochastic linear bandits in the central, local and shuffled models. In the central model, we achieve almost the same regret as the optimal non-private…

Machine Learning · Computer Science 2022-07-08 Osama A. Hanna , Antonious M. Girgis , Christina Fragouli , Suhas Diggavi

This paper studies semiparametric contextual bandits, a generalization of the linear stochastic bandit problem where the reward for an action is modeled as a linear function of known action features confounded by an non-linear…

Machine Learning · Statistics 2018-07-17 Akshay Krishnamurthy , Zhiwei Steven Wu , Vasilis Syrgkanis

This paper studies bandit convex optimization in non-stationary environments with two-point feedback, using dynamic regret as the performance measure. We propose an algorithm based on bandit mirror descent that extends naturally to…

Optimization and Control · Mathematics 2026-05-26 Chang He , Bo Jiang , Shuzhong Zhang

We consider stochastic bandit problems with a continuous set of arms and where the expected reward is a continuous and unimodal function of the arm. No further assumption is made regarding the smoothness and the structure of the expected…

Machine Learning · Computer Science 2015-03-09 Richard Combes , Alexandre Proutiere