The Beachcombers' Problem: Walking and searching with mobile robots

Czyzowicz, Jurek; Gąsieniec, Leszek; Georgiou, Konstantinos; Kranakis, Evangelos; MacQuarrie, Fraser

doi:10.1016/j.tcs.2015.09.011

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…They also determined the scenarios where either of the two strategies does not provide the optimal idle time. While here each point is visited multiple times by the searcher, Beachcomber's problem [28] deals with scenario when a point is visited at least once and the focus is to have an algorithm for a fastest search considering two-speeds namely walking speed and searching speed. Other variations include the certain number of robots carrying out the search for a treasure or a hider; patrolling a fence [1], [25], [43], [42], [58], [66], [70] or an area; two-speed robots that have a walking speed and a patrolling speed, each of the multiple two-speed robots have speeds specific to them [30], [28], [35]; robots with distinct maximal speed [30]; two robots on a circular path with multiple exit points [27] search-and-fetch with two robots [56] etc.…”

Section: Search Theory and Literature Reviewmentioning

confidence: 99%

Worst-case & average-case Efficiency trade-offs for search problems

Sharma¹

2021

Preprint

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Evacuation problems fall under the vast area of search theory and operations research. Problems of evacuation of two robots on a unit disc have been studied for an efficient evacuation time. Work done so far has focused on improving the ’worst-case’ evacuation time with deterministic algorithms. We study the ’average-case’ evacuation time (randomized algorithms) while considering the efficiency trade-off between worst-case and average-case costs. Our other contribution is to analyze average-case and worst-case costs for the cowpath problem (another search problem) which helped us to set a parallel method for the evacuation problem.

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Section: Search Theory and Literature Reviewmentioning

confidence: 99%

Worst-case & average-case Efficiency trade-offs for search problems

Sharma¹

2021

Preprint

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“…That is, compare the cost of the competitive strategy to the cost of the optimal strategy under full information. For any instance, if there are constants C and A, such that Π ≤ C · Π opt + A holds, the competitive stratCopyright c 2016 The Institute of Electronics, Information and Communication Engineers egy is called C − competitive with a competitive ratio of C. Since then, competitive analysis has been used in many other papers [10]- [12].…”

Section: Preliminariesmentioning

confidence: 99%

Competitive Strategies for Evacuating from an Unknown Affected Area

Wei

Tan

Jiang

2016

IEICE Trans. Inf. & Syst.

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SUMMARYThis article presents efficient strategies for evacuating from an unknown affected area in a plane. Evacuation is the process of movement away from a threat or hazard such as natural disasters. Consider that one or n(n ≥ 3) agents are lost in an unknown convex region P. The agents know neither the boundary information of P nor their positions. We seek competitive strategies that can evacuate the agent from P as quickly as possible. The performance of the strategy is measured by a competitive ratio of the evacuation path over the shortest path. We give a 13.812-competitive spiral strategy for one agent, and prove that it is optimal among all monotone and periodic strategies by showing a matching lower bound. Also, we give a new competitive strategy EES for n(n ≥ 3) agents and adjust it to be more efficient with the analysis of its performance. key words: evacuation problem, computational geometry, path planning, convex region, competitive ratio

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“…There has been recent interest in the study of mobile agent problems such as searching [10], patrolling [11,18] and gathering [5] where the agents have different speeds. However, little research has been carried out for rendezvous with different speeds.…”

Section: Introductionmentioning

confidence: 99%