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URN: urn:nbn:de:0030-drops-8687
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Eubeler, Andrea ; Fleischer, Rudolf ; Kamphans, Tom ; Klein, Rolf ; Langetepe, Elmar ; Trippen, Gerhard

Competitive Online Searching for a Ray in the Plane

06421.LangetepeElmar.Paper.868.pdf (0.2 MB)


We consider the problem of a searcher that looks, for example, for a lost flashlight in a dusty environment. The searcher finds the flashlight as soon as it crosses the ray emanating from the flashlight. In order to pick it up, the searcher moves to the origin of the light beam. We compare the length of the path of the searcher to the shortest path to the goal. First, we give a search strategy for a special case of the ray search---the window shopper problem---, where the ray we are looking for is perpendicular to a known ray. Our strategy achieves a competitive factor of $1.059ldots$, which is optimal. Then, we consider rays in arbitrary position in the plane. We present an online strategy that achieves a factor of $22.513ldots$, and give a lower bound of $2pi,e=17.079ldots$.

BibTeX - Entry

  author =	{Andrea Eubeler and Rudolf Fleischer and Tom Kamphans and Rolf Klein and Elmar Langetepe and Gerhard Trippen},
  title =	{Competitive Online Searching for a Ray in the Plane},
  booktitle =	{Robot Navigation},
  year =	{2007},
  editor =	{S{\'a}ndor Fekete and Rudolf Fleischer and Rolf Klein and Alejandro Lopez-Ortiz},
  number =	{06421},
  series =	{Dagstuhl Seminar Proceedings},
  ISSN =	{1862-4405},
  publisher =	{Internationales Begegnungs- und Forschungszentrum f{\"u}r Informatik (IBFI), Schloss Dagstuhl, Germany},
  address =	{Dagstuhl, Germany},
  URL =		{},
  annote =	{Keywords: Online motion planning, competitive analysis, ray search}

Keywords: Online motion planning, competitive analysis, ray search
Collection: 06421 - Robot Navigation
Issue Date: 2007
Date of publication: 07.02.2007

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