Preferences Evolve And So Should Your Bandits: Bandits with Evolving States for Online Platforms

Fuente: arXiv
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Main Authors: Khosravi, Khashayar, Leme, Renato Paes, Podimata, Chara, Tsorvantzis, Apostolis
Format: Preprint
Published: 2023
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author Khosravi, Khashayar
Leme, Renato Paes
Podimata, Chara
Tsorvantzis, Apostolis
author_facet Khosravi, Khashayar
Leme, Renato Paes
Podimata, Chara
Tsorvantzis, Apostolis
contents We propose a model for learning with bandit feedback while accounting for deterministically evolving and unobservable states that we call Bandits with Deterministically Evolving States ($B$-$DES$). The workhorse applications of our model are learning for recommendation systems and learning for online ads. In both cases, the reward that the algorithm obtains at each round is a function of the short-term reward of the action chosen and how "healthy" the system is (i.e., as measured by its state). For example, in recommendation systems, the reward that the platform obtains from a user's engagement with a particular type of content depends not only on the inherent features of the specific content, but also on how the user's preferences have evolved as a result of interacting with other types of content on the platform. Our general model accounts for the different rate $λ\in [0,1]$ at which the state evolves (e.g., how fast a user's preferences shift as a result of previous content consumption) and encompasses standard multi-armed bandits as a special case. The goal of the algorithm is to minimize a notion of regret against the best-fixed sequence of arms pulled, which is significantly harder to attain compared to standard benchmark of the best-fixed action in hindsight. We present online learning algorithms for any possible value of the evolution rate $λ$ and we show the robustness of our results to various model misspecifications.
format Preprint
id arxiv_https___arxiv_org_abs_2307_11655
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Preferences Evolve And So Should Your Bandits: Bandits with Evolving States for Online Platforms
Khosravi, Khashayar
Leme, Renato Paes
Podimata, Chara
Tsorvantzis, Apostolis
Machine Learning
Artificial Intelligence
Computer Science and Game Theory
We propose a model for learning with bandit feedback while accounting for deterministically evolving and unobservable states that we call Bandits with Deterministically Evolving States ($B$-$DES$). The workhorse applications of our model are learning for recommendation systems and learning for online ads. In both cases, the reward that the algorithm obtains at each round is a function of the short-term reward of the action chosen and how "healthy" the system is (i.e., as measured by its state). For example, in recommendation systems, the reward that the platform obtains from a user's engagement with a particular type of content depends not only on the inherent features of the specific content, but also on how the user's preferences have evolved as a result of interacting with other types of content on the platform. Our general model accounts for the different rate $λ\in [0,1]$ at which the state evolves (e.g., how fast a user's preferences shift as a result of previous content consumption) and encompasses standard multi-armed bandits as a special case. The goal of the algorithm is to minimize a notion of regret against the best-fixed sequence of arms pulled, which is significantly harder to attain compared to standard benchmark of the best-fixed action in hindsight. We present online learning algorithms for any possible value of the evolution rate $λ$ and we show the robustness of our results to various model misspecifications.
title Preferences Evolve And So Should Your Bandits: Bandits with Evolving States for Online Platforms
topic Machine Learning
Artificial Intelligence
Computer Science and Game Theory
url https://arxiv.org/abs/2307.11655