Search Results for author: Leonardo Cella

Found 8 papers, 1 papers with code

Group Meritocratic Fairness in Linear Contextual Bandits

1 code implementation7 Jun 2022 Riccardo Grazzi, Arya Akhavan, John Isak Texas Falk, Leonardo Cella, Massimiliano Pontil

This is a very strong notion of fairness, since the relative rank is not directly observed by the agent and depends on the underlying reward model and on the distribution of rewards.

Fairness Multi-Armed Bandits

Meta Representation Learning with Contextual Linear Bandits

no code implementations30 May 2022 Leonardo Cella, Karim Lounici, Massimiliano Pontil

We aim to leverage this information in order to learn a new downstream bandit task, which shares the same representation.

Meta-Learning Representation Learning

Online Model Selection: a Rested Bandit Formulation

no code implementations7 Dec 2020 Leonardo Cella, Claudio Gentile, Massimiliano Pontil

Unlike known model selection efforts in the recent bandit literature, our algorithm exploits the specific structure of the problem to learn the unknown parameters of the expected loss function so as to identify the best arm as quickly as possible.

Model Selection

Meta-learning with Stochastic Linear Bandits

no code implementations ICML 2020 Leonardo Cella, Alessandro Lazaric, Massimiliano Pontil

The goal is to select a learning algorithm which works well on average over a class of bandits tasks, that are sampled from a task-distribution.

Meta-Learning

Validity, consonant plausibility measures, and conformal prediction

no code implementations24 Jan 2020 Leonardo Cella, Ryan Martin

The standard notion of validity, what we refer to here as Type-1 validity, focuses on coverage probability of prediction regions, while a notion of validity relevant to the other prediction-related tasks performed by predictive distributions is lacking.

Conformal Prediction

Stochastic Bandits with Delay-Dependent Payoffs

no code implementations7 Oct 2019 Leonardo Cella, Nicolò Cesa-Bianchi

Motivated by recommendation problems in music streaming platforms, we propose a nonstationary stochastic bandit model in which the expected reward of an arm depends on the number of rounds that have passed since the arm was last pulled.

Efficient Linear Bandits through Matrix Sketching

no code implementations28 Sep 2018 Ilja Kuzborskij, Leonardo Cella, Nicolò Cesa-Bianchi

More precisely, we show that a sketch of size $m$ allows a $\mathcal{O}(md)$ update time for both algorithms, as opposed to $\Omega(d^2)$ required by their non-sketched versions in general (where $d$ is the dimension of context vectors).

Thompson Sampling

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