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Geometric freeze-tag problem

delete2026-02-28
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PRE
AI
A
Alipour, Sharareh *
A
Arash Ahadi
K
Kajal Baghestani
S
S. Sahraei
M
Mirzaei, Mahdis
DOI:10.1007/s10458-026-09738-8delete
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Abstract

Abstract

En 中文
The Freeze-Tag Problem (FTP) involves activating a set of initially inactive robots as quickly as possible, starting from a single active robot. Once activated, a robot can assist in activating other robots. Each active robot moves at unit speed. The objective is to minimize the makespan, i.e., the time required to activate the last robot. A key performance measure is the wake-up ratio, defined as the maximum time needed to activate all of the robots in any initial configuration. This work focuses on the geometric (Euclidean) version of FTP in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{\mathbb {R}}<^>{\varvec{d}}$$\end{document} under the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{\ell }_{\varvec{p}}$$\end{document} norm, where the initial distance between each inactive robot and the single active robot is at most \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{1}$$\end{document}. For \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{(\mathbb {R}}<^>{\varvec{2}}\varvec{, \ell }_{\varvec{2}}\varvec{)}$$\end{document}, we improve the previous upper bound of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{4.62}$$\end{document} (Bonichon et al. [1], CCCG 2024) to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{4.31}$$\end{document}. The known lower bound for the wake-up ratio is \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{3.82}$$\end{document}. In \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{\mathbb {R}}<^>{\varvec{3}}$$\end{document}, we propose a new strategy that achieves a wake-up ratio of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{12}$$\end{document} for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{(\mathbb {R}}<^>{\varvec{3}}\varvec{, \ell }_{\varvec{1}}\varvec{)}$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{12.76}$$\end{document} for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{(\mathbb {R}}<^>{\varvec{3}}\varvec{, \ell }_{\varvec{2}}\varvec{)}$$\end{document}. We also explore the FTP in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{(\mathbb {R}}<^>{\varvec{3}}\varvec{, \ell }_{\varvec{2}}\varvec{)}$$\end{document} for specific instances where robots are positioned on the boundary of a sphere, providing further insights into practical scenarios. Finally, we demonstrate the practical efficiency of our \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varvec{(\mathbb {R}}<^>{\varvec{2}}\varvec{, \ell }_{\varvec{2}}\varvec{)}$$\end{document} algorithm through simulations on real-world spatial data.
Keywords:
Freeze-tag problem
Makespan
Approximation algorithms
Robot routing
Scheduling
Distributed computing

Journal

A
Autonomous Agents and Multi-Agent Systems
IF:
2.6
Papers:
31
Citations:
1.2K

Organization

S
sharif university of technology
Scholars:
652
Papers: 330
Citations: 0
U
university of tehran
Scholars:
2.2K
Papers: 1.1K
Citations: 0