Linear Search for an Escaping Target with Unknown Speed

Fuente: arXiv
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Main Authors: Coleman, Jared, Ivanov, Dmitry, Kranakis, Evangelos, Krizanc, Danny, Morales-Ponce, Oscar
Format: Preprint
Published: 2024
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_version_ 1866917647910699008
author Coleman, Jared
Ivanov, Dmitry
Kranakis, Evangelos
Krizanc, Danny
Morales-Ponce, Oscar
author_facet Coleman, Jared
Ivanov, Dmitry
Kranakis, Evangelos
Krizanc, Danny
Morales-Ponce, Oscar
contents We consider linear search for an escaping target whose speed and initial position are unknown to the searcher. A searcher (an autonomous mobile agent) is initially placed at the origin of the real line and can move with maximum speed $1$ in either direction along the line. An oblivious mobile target that is moving away from the origin with an unknown constant speed $v<1$ is initially placed by an adversary on the infinite line at distance $d$ from the origin in an unknown direction. We consider two cases, depending on whether $d$ is known or unknown. The main contribution of this paper is to prove a new lower bound and give algorithms leading to new upper bounds for search in these settings. This results in an optimal (up to lower order terms in the exponent) competitive ratio in the case where $d$ is known and improved upper and lower bounds for the case where $d$ is unknown. Our results solve an open problem proposed in [Coleman et al., Proc. OPODIS 2022].
format Preprint
id arxiv_https___arxiv_org_abs_2404_14300
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Linear Search for an Escaping Target with Unknown Speed
Coleman, Jared
Ivanov, Dmitry
Kranakis, Evangelos
Krizanc, Danny
Morales-Ponce, Oscar
Discrete Mathematics
We consider linear search for an escaping target whose speed and initial position are unknown to the searcher. A searcher (an autonomous mobile agent) is initially placed at the origin of the real line and can move with maximum speed $1$ in either direction along the line. An oblivious mobile target that is moving away from the origin with an unknown constant speed $v<1$ is initially placed by an adversary on the infinite line at distance $d$ from the origin in an unknown direction. We consider two cases, depending on whether $d$ is known or unknown. The main contribution of this paper is to prove a new lower bound and give algorithms leading to new upper bounds for search in these settings. This results in an optimal (up to lower order terms in the exponent) competitive ratio in the case where $d$ is known and improved upper and lower bounds for the case where $d$ is unknown. Our results solve an open problem proposed in [Coleman et al., Proc. OPODIS 2022].
title Linear Search for an Escaping Target with Unknown Speed
topic Discrete Mathematics
url https://arxiv.org/abs/2404.14300