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Autori principali: Xu, Luyue, Wang, Liming, Xie, Hong, Zhou, Mingqiang
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2408.14432
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author Xu, Luyue
Wang, Liming
Xie, Hong
Zhou, Mingqiang
author_facet Xu, Luyue
Wang, Liming
Xie, Hong
Zhou, Mingqiang
contents Contextual bandits serve as a fundamental algorithmic framework for optimizing recommendation decisions online. Though extensive attention has been paid to tailoring contextual bandits for recommendation applications, the "herding effects" in user feedback have been ignored. These herding effects bias user feedback toward historical ratings, breaking down the assumption of unbiased feedback inherent in contextual bandits. This paper develops a novel variant of the contextual bandit that is tailored to address the feedback bias caused by the herding effects. A user feedback model is formulated to capture this feedback bias. We design the TS-Conf (Thompson Sampling under Conformity) algorithm, which employs posterior sampling to balance the exploration and exploitation tradeoff. We prove an upper bound for the regret of the algorithm, revealing the impact of herding effects on learning speed. Extensive experiments on datasets demonstrate that TS-Conf outperforms four benchmark algorithms. Analysis reveals that TS-Conf effectively mitigates the negative impact of herding effects, resulting in faster learning and improved recommendation accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2408_14432
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Contextual Bandit with Herding Effects: Algorithms and Recommendation Applications
Xu, Luyue
Wang, Liming
Xie, Hong
Zhou, Mingqiang
Machine Learning
Artificial Intelligence
Information Retrieval
Contextual bandits serve as a fundamental algorithmic framework for optimizing recommendation decisions online. Though extensive attention has been paid to tailoring contextual bandits for recommendation applications, the "herding effects" in user feedback have been ignored. These herding effects bias user feedback toward historical ratings, breaking down the assumption of unbiased feedback inherent in contextual bandits. This paper develops a novel variant of the contextual bandit that is tailored to address the feedback bias caused by the herding effects. A user feedback model is formulated to capture this feedback bias. We design the TS-Conf (Thompson Sampling under Conformity) algorithm, which employs posterior sampling to balance the exploration and exploitation tradeoff. We prove an upper bound for the regret of the algorithm, revealing the impact of herding effects on learning speed. Extensive experiments on datasets demonstrate that TS-Conf outperforms four benchmark algorithms. Analysis reveals that TS-Conf effectively mitigates the negative impact of herding effects, resulting in faster learning and improved recommendation accuracy.
title Contextual Bandit with Herding Effects: Algorithms and Recommendation Applications
topic Machine Learning
Artificial Intelligence
Information Retrieval
url https://arxiv.org/abs/2408.14432