Adaptive Frontier Exploration on Graphs with Applications to Network-Based Disease Testing

Fuente: arXiv
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Hauptverfasser: Choo, Davin, Pan, Yuqi, Wang, Tonghan, Tambe, Milind, van Heerden, Alastair, Johnson, Cheryl
Format: Preprint
Veröffentlicht: 2025
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author Choo, Davin
Pan, Yuqi
Wang, Tonghan
Tambe, Milind
van Heerden, Alastair
Johnson, Cheryl
author_facet Choo, Davin
Pan, Yuqi
Wang, Tonghan
Tambe, Milind
van Heerden, Alastair
Johnson, Cheryl
contents We study a sequential decision-making problem on a $n$-node graph $\mathcal{G}$ where each node has an unknown label from a finite set $\mathbfΩ$, drawn from a joint distribution $\mathcal{P}$ that is Markov with respect to $\mathcal{G}$. At each step, selecting a node reveals its label and yields a label-dependent reward. The goal is to adaptively choose nodes to maximize expected accumulated discounted rewards. We impose a frontier exploration constraint, where actions are limited to neighbors of previously selected nodes, reflecting practical constraints in settings such as contact tracing and robotic exploration. We design a Gittins index-based policy that applies to general graphs and is provably optimal when $\mathcal{G}$ is a forest. Our implementation runs in $\mathcal{O}(n^2 \cdot |\mathbfΩ|^2)$ time while using $\mathcal{O}(n \cdot |\mathbfΩ|^2)$ oracle calls to $\mathcal{P}$ and $\mathcal{O}(n^2 \cdot |\mathbfΩ|)$ space. Experiments on synthetic and real-world graphs show that our method consistently outperforms natural baselines, including in non-tree, budget-limited, and undiscounted settings. For example, in HIV testing simulations on real-world sexual interaction networks, our policy detects nearly all positive cases with only half the population tested, substantially outperforming other baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2505_21671
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Adaptive Frontier Exploration on Graphs with Applications to Network-Based Disease Testing
Choo, Davin
Pan, Yuqi
Wang, Tonghan
Tambe, Milind
van Heerden, Alastair
Johnson, Cheryl
Artificial Intelligence
Data Structures and Algorithms
Machine Learning
Optimization and Control
We study a sequential decision-making problem on a $n$-node graph $\mathcal{G}$ where each node has an unknown label from a finite set $\mathbfΩ$, drawn from a joint distribution $\mathcal{P}$ that is Markov with respect to $\mathcal{G}$. At each step, selecting a node reveals its label and yields a label-dependent reward. The goal is to adaptively choose nodes to maximize expected accumulated discounted rewards. We impose a frontier exploration constraint, where actions are limited to neighbors of previously selected nodes, reflecting practical constraints in settings such as contact tracing and robotic exploration. We design a Gittins index-based policy that applies to general graphs and is provably optimal when $\mathcal{G}$ is a forest. Our implementation runs in $\mathcal{O}(n^2 \cdot |\mathbfΩ|^2)$ time while using $\mathcal{O}(n \cdot |\mathbfΩ|^2)$ oracle calls to $\mathcal{P}$ and $\mathcal{O}(n^2 \cdot |\mathbfΩ|)$ space. Experiments on synthetic and real-world graphs show that our method consistently outperforms natural baselines, including in non-tree, budget-limited, and undiscounted settings. For example, in HIV testing simulations on real-world sexual interaction networks, our policy detects nearly all positive cases with only half the population tested, substantially outperforming other baselines.
title Adaptive Frontier Exploration on Graphs with Applications to Network-Based Disease Testing
topic Artificial Intelligence
Data Structures and Algorithms
Machine Learning
Optimization and Control
url https://arxiv.org/abs/2505.21671