Priority Evacuation from a Disk Using Mobile Robots

(Extended Abstract)
  • Jurek Czyzowicz
  • Konstantinos GeorgiouEmail author
  • Ryan Killick
  • Evangelos Kranakis
  • Danny Krizanc
  • Lata Narayanan
  • Jaroslav Opatrny
  • Sunil Shende
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11085)


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. Namely, we propose an algorithm specifying the trajectories of the robots which guarantees evacuation of the queen in time always better than \(2 + 4(\sqrt{2}-1) \frac{\pi }{n}\) for \(n \ge 4\) servants. We also demonstrate that for \(n \ge 4\) servants the queen cannot be evacuated in time less than \(2+\frac{\pi }{n}+\frac{2}{n^2}\).


Mobile robots Priority Evacuation Exit Group search Disk Wireless communication Queen Servants 


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Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  • Jurek Czyzowicz
    • 1
  • Konstantinos Georgiou
    • 2
    Email author
  • Ryan Killick
    • 3
  • Evangelos Kranakis
    • 3
  • Danny Krizanc
    • 4
  • Lata Narayanan
    • 5
  • Jaroslav Opatrny
    • 5
  • Sunil Shende
    • 6
  1. 1.Départemant d’informatiqueUniversité du Québec en OutaouaisGatineauCanada
  2. 2.Department of MathematicsRyerson UniversityTorontoCanada
  3. 3.School of Computer ScienceCarleton UniversityOttawaCanada
  4. 4.Department of Mathematics and Computer ScienceWesleyan UniversityMiddletownUSA
  5. 5.Department of Computer Science and Software EngineeringConcordia UniversityMontrealCanada
  6. 6.Department of Computer ScienceRutgers UniversityCamdenUSA

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