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Related papers: Good Arm Identification via Bandit Feedback

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We study the fixed-confidence best-arm identification problem in unimodal bandits, in which the means of the arms increase with the index of the arm up to their maximum, then decrease. We derive two lower bounds on the stopping time of any…

Machine Learning · Computer Science 2025-05-27 Riccardo Poiani , Marc Jourdan , Emilie Kaufmann , Rémy Degenne

In this work I study the problem of adversarial perturbations to rewards, in a Multi-armed bandit (MAB) setting. Specifically, I focus on an adversarial attack to a UCB type best-arm identification policy applied to a stochastic MAB. The…

Machine Learning · Computer Science 2022-09-14 Varsha Pendyala

Consider the problem of best arm identification with a security constraint. Specifically, assume a setup of stochastic linear bandits with $K$ arms of dimension $d$. In each arm pull, the player receives a reward that is the sum of the dot…

Machine Learning · Computer Science 2025-07-29 Asaf Cohen , Onur Günlü

Motivated by the need to efficiently identify multiple candidates in high trial-and-error cost tasks such as drug discovery, we propose a near-optimal algorithm to identify all {\epsilon}-best arms (i.e., those at most {\epsilon} worse than…

Machine Learning · Statistics 2025-10-02 Zhekai Li , Tianyi Ma , Cheng Hua , Ruihao Zhu

We propose the first fully-adaptive algorithm for pure exploration in linear bandits---the task to find the arm with the largest expected reward, which depends on an unknown parameter linearly. While existing methods partially or entirely…

Machine Learning · Statistics 2017-10-17 Liyuan Xu , Junya Honda , Masashi Sugiyama

Recent advances in bandit tools and techniques for sequential learning are steadily enabling new applications and are promising the resolution of a range of challenging related problems. We study the game tree search problem, where the goal…

Machine Learning · Statistics 2017-11-07 Emilie Kaufmann , Wouter Koolen

We study the multi-fidelity multi-armed bandit (MF-MAB), an extension of the canonical multi-armed bandit (MAB) problem. MF-MAB allows each arm to be pulled with different costs (fidelities) and observation accuracy. We study both the best…

Machine Learning · Computer Science 2023-06-14 Xuchuang Wang , Qingyun Wu , Wei Chen , John C. S. Lui

This study investigates an asymptotically locally minimax optimal algorithm for fixed-budget best-arm identification (BAI). We propose the Generalized Neyman Allocation (GNA) algorithm and demonstrate that its worst-case upper bound on the…

Machine Learning · Computer Science 2025-02-04 Masahiro Kato

We study the best arm identification (BAI) problem with potentially biased offline data in the fixed confidence setting, which commonly arises in real-world scenarios such as clinical trials. We prove an impossibility result for adaptive…

Machine Learning · Computer Science 2025-05-30 Le Yang , Vincent Y. F. Tan , Wang Chi Cheung

We study the problem of best-arm identification (BAI) in the fixed-budget setting with heterogeneous reward variances. We propose two variance-adaptive BAI algorithms for this setting: SHVar for known reward variances and SHAdaVar for…

Machine Learning · Computer Science 2023-06-14 Anusha Lalitha , Kousha Kalantari , Yifei Ma , Anoop Deoras , Branislav Kveton

We propose a bandit algorithm that explores by randomizing its history of rewards. Specifically, it pulls the arm with the highest mean reward in a non-parametric bootstrap sample of its history with pseudo rewards. We design the pseudo…

Machine Learning · Computer Science 2019-06-24 Branislav Kveton , Csaba Szepesvari , Sharan Vaswani , Zheng Wen , Mohammad Ghavamzadeh , Tor Lattimore

We consider a non-stationary formulation of the stochastic multi-armed bandit where the rewards are no longer assumed to be identically distributed. For the best-arm identification task, we introduce a version of Successive Elimination…

Artificial Intelligence · Computer Science 2016-09-09 Robin Allesiardo , Raphaël Féraud , Odalric-Ambrym Maillard

We introduce and study a new class of stochastic bandit problems, referred to as predictive bandits. In each round, the decision maker first decides whether to gather information about the rewards of particular arms (so that their rewards…

Machine Learning · Computer Science 2020-04-03 Simon Lindståhl , Alexandre Proutiere , Andreas Johnsson

We consider a variant of the multi-armed bandit model, which we call multi-armed bandit problem with known trend, where the gambler knows the shape of the reward function of each arm but not its distribution. This new problem is motivated…

Machine Learning · Computer Science 2017-05-15 Djallel Bouneffouf , Raphaël Feraud

The combinatorial stochastic semi-bandit problem is an extension of the classical multi-armed bandit problem in which an algorithm pulls more than one arm at each stage and the rewards of all pulled arms are revealed. One difference with…

Machine Learning · Computer Science 2016-12-07 Rémy Degenne , Vianney Perchet

In this paper, we study the problem of outlier arm detection in multi-armed bandit settings, which finds plenty of applications in many high-impact domains such as finance, healthcare, and online advertising. For this problem, a learner…

Machine Learning · Computer Science 2020-07-16 Yikun Ban , Jingrui He

We propose a multi-agent variant of the classical multi-armed bandit problem, in which there are $N$ agents and $K$ arms, and pulling an arm generates a (possibly different) stochastic reward for each agent. Unlike the classical multi-armed…

Computer Science and Game Theory · Computer Science 2021-02-25 Safwan Hossain , Evi Micha , Nisarg Shah

We study best-arm identification (BAI) in the fixed-budget setting. Adaptive allocations based on upper confidence bounds (UCBs), such as UCBE, are known to work well in BAI. However, it is well-known that its optimal regret is…

Machine Learning · Computer Science 2024-10-24 Rong J. B. Zhu , Yanqi Qiu

We consider the problem of identifying the best arm in stochastic Multi-Armed Bandits (MABs) using a fixed sampling budget. Characterizing the minimal instance-specific error probability for this problem constitutes one of the important…

Machine Learning · Computer Science 2024-02-21 Po-An Wang , Ruo-Chun Tzeng , Alexandre Proutiere

The multi-armed bandit (MAB) model is one of the most classical models to study decision-making in an uncertain environment. In this model, a player chooses one of $K$ possible arms of a bandit machine to play at each time step, where the…

Machine Learning · Computer Science 2023-06-13 Bo Li , Chi Ho Yeung