Ranked Prioritization of Groups in Combinatorial Bandit Allocation


Lily Xu, Arpita Biswas, Fei Fang, and Milind Tambe. 7/23/2022. “Ranked Prioritization of Groups in Combinatorial Bandit Allocation.” International Joint Conference on Artificial Intelligence (IJCAI) 31. Vienna, Austria. arXiv link


Preventing poaching through ranger patrols is critical for protecting endangered wildlife. Combinatorial bandits have been used to allocate limited patrol resources, but existing approaches overlook the fact that each location is home to multiple species in varying proportions, so a patrol benefits each species to differing degrees. When some species are more vulnerable, we ought to offer more protection to these animals; unfortunately, existing combinatorial bandit approaches do not offer a way to prioritize important species. To bridge this gap, (1) We propose a novel combinatorial bandit objective that trades off between reward maximization and also accounts for prioritization over species, which we call ranked prioritization. We show this objective can be expressed as a weighted linear sum of Lipschitz-continuous reward functions. (2) We provide RankedCUCB, an algorithm to select combinatorial actions that optimize our prioritization-based objective, and prove that it achieves asymptotic no-regret. (3) We demonstrate empirically that RankedCUCB leads to up to 38% improvement in outcomes for endangered species using real-world wildlife conservation data. Along with adapting to other challenges such as preventing illegal logging and overfishing, our no-regret algorithm addresses the general combinatorial bandit problem with a weighted linear objective.
See also: Conservation, PAWS, 2022
Last updated on 06/13/2022