1 code implementation • 27 Aug 2023 • Shreyas Chaudhari, David Arbour, Georgios Theocharous, Nikos Vlassis
Prior work has developed estimators that leverage the structure in slates to estimate the expected off-policy performance, but the estimation of the entire performance distribution remains elusive.
1 code implementation • 20 Jul 2023 • Ashish Singh, Prateek Agarwal, Zixuan Huang, Arpita Singh, Tong Yu, Sungchul Kim, Victor Bursztyn, Nikos Vlassis, Ryan A. Rossi
Captions are crucial for understanding scientific visualizations and documents.
no code implementations • 22 Dec 2022 • Dawen Liang, Nikos Vlassis
The conventional way to address this problem is through importance sampling correction, but this comes with practical limitations.
1 code implementation • NeurIPS 2021 • Nikos Vlassis, Ashok Chandrashekar, Fernando Amat Gil, Nathan Kallus
We study the problem of off-policy evaluation from batched contextual bandit data with multidimensional actions, often termed slates.
no code implementations • 5 Jan 2021 • Nikos Vlassis, Fernando Amat Gil, Ashok Chandrashekar
We study the problem of off-policy evaluation for slate bandits, for the typical case in which the logging policy factorizes over the slots of the slate.
no code implementations • 13 Dec 2019 • Aurélien F. Bibaut, Ivana Malenica, Nikos Vlassis, Mark J. Van Der Laan
We study the problem of off-policy evaluation (OPE) in Reinforcement Learning (RL), where the aim is to estimate the performance of a new policy given historical data that may have been generated by a different policy, or policies.
no code implementations • NeurIPS 2018 • Georgios Theocharous, Zheng Wen, Yasin Abbasi, Nikos Vlassis
Our algorithm termed deterministic schedule PSRL (DS-PSRL) is efficient in terms of time, sample, and space complexity.
no code implementations • 26 Feb 2018 • Ershad Banijamali, Yasin Abbasi-Yadkori, Mohammad Ghavamzadeh, Nikos Vlassis
However, under a condition that is akin to the occupancy measures of the base policies having large overlap, we show that there exists an efficient algorithm that finds a policy that is almost as good as the best convex combination of the base policies.
no code implementations • 21 Nov 2017 • Georgios Theocharous, Zheng Wen, Yasin Abbasi-Yadkori, Nikos Vlassis
Our algorithm termed deterministic schedule PSRL (DS-PSRL) is efficient in terms of time, sample, and space complexity.
no code implementations • 25 Jan 2017 • Shi Zong, Branislav Kveton, Shlomo Berkovsky, Azin Ashkan, Nikos Vlassis, Zheng Wen
To the best of our knowledge, this is the first large-scale causal study of the impact of weather on TV watching patterns.
no code implementations • NeurIPS 2016 • Nicolo Colombo, Nikos Vlassis
Joint matrix triangularization is often used for estimating the joint eigenstructure of a set M of matrices, with applications in signal processing and machine learning.
no code implementations • 30 Nov 2016 • Ehsan Amid, Nikos Vlassis, Manfred K. Warmuth
We describe a new method called t-ETE for finding a low-dimensional embedding of a set of objects in Euclidean space.
no code implementations • 2 Jul 2016 • Nicolo Colombo, Nikos Vlassis
The a priori bounds are theoretical inequalities that involve functions of the ground-truth matrices and noise matrices, whereas the a posteriori bounds are given in terms of observable quantities that can be computed from the input matrices.