Priority evacuation from a disk: The case of n ≥ 4

TY - JOUR

T1 - Priority evacuation from a disk

T2 - The case of n ≥ 4

AU - Czyzowicz, J.

AU - Georgiou, K.

AU - Killick, R.

AU - Kranakis, E.

AU - Krizanc, D.

AU - Narayanan, L.

AU - Opatrny, J.

AU - Shende, S.

N1 - Funding Information: Research supported in part by NSERC Discovery grant.Research supported by the Ontario Graduate Scholarship.Research supported in part by NSF grant AF-1813940. Publisher Copyright: © 2020 Elsevier B.V.

PY - 2020/12/18

Y1 - 2020/12/18

N2 - We introduce and study a new search-type problem with (n+1)-robots on a disk. The searchers (robots) all start from the center of the disk, have unit speed, and can communicate wirelessly. The goal is for a distinguished robot (the queen) to reach and evacuate from an exit that is hidden on the perimeter of the disk in as little time as possible. The remaining n robots (servants) are there to facilitate the queen's objective and are not required to reach the hidden exit. We provide upper and lower bounds for the time required to evacuate the queen from a unit disk. Namely, we propose an algorithm specifying the trajectories of the robots which guarantees evacuation of the queen in time always better than [Formula presented] for n≥4 servants. We also demonstrate that for n≥4 servants the queen cannot be evacuated in time less than [Formula presented].

AB - We introduce and study a new search-type problem with (n+1)-robots on a disk. The searchers (robots) all start from the center of the disk, have unit speed, and can communicate wirelessly. The goal is for a distinguished robot (the queen) to reach and evacuate from an exit that is hidden on the perimeter of the disk in as little time as possible. The remaining n robots (servants) are there to facilitate the queen's objective and are not required to reach the hidden exit. We provide upper and lower bounds for the time required to evacuate the queen from a unit disk. Namely, we propose an algorithm specifying the trajectories of the robots which guarantees evacuation of the queen in time always better than [Formula presented] for n≥4 servants. We also demonstrate that for n≥4 servants the queen cannot be evacuated in time less than [Formula presented].

KW - Disk

KW - Evacuation

KW - Exit

KW - Group Search

KW - Mobile Robots

KW - Priority

KW - Queen

KW - Servants

KW - Wireless Communication

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U2 - https://doi.org/10.1016/j.tcs.2020.09.023

DO - https://doi.org/10.1016/j.tcs.2020.09.023

M3 - Article

SN - 0304-3975

VL - 846

SP - 91

EP - 102

JO - Theoretical Computer Science

JF - Theoretical Computer Science

ER -