Search on a line by byzantine robots

Jurek Czyzowicz, Konstantinos Georgiou, Evangelos Kranakis, Danny Krizanc, Lata Narayanan, Jaroslav Opatrny, Sunil Shende

Research output: Chapter in Book/Report/Conference proceedingConference contribution

11 Scopus citations


We consider the problem of fault-tolerant parallel search on an infinite line by n robots. Starting from the origin, the robots are required to find a target at an unknown location. The robots can move with maximum speed 1 and can communicate in wireless mode among themselves. However, among the n robots, there are f robots that exhibit byzantine faults. A faulty robot can fail to report the target even after reaching it, or it can make malicious claims about having found the target when in fact it has not. Given the presence of such faulty robots, the search for the target can only be concluded when the non-faulty robots have sufficient verification that the target has been found. We aim to design algorithms that minimize the value of Sd (n, f), the time to find a target at a distance d from the origin by n robots among which f are faulty. We give several different algorithms whose running time depends on the ratio f/n, the density of faulty robots, and also prove lower bounds. Our algorithms are optimal for some densities of faulty robots.

Original languageEnglish (US)
Title of host publication27th International Symposium on Algorithms and Computation, ISAAC 2016
EditorsSeok-Hee Hong
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959770262
StatePublished - Dec 1 2016
Event27th International Symposium on Algorithms and Computation, ISAAC 2016 - Sydney, Australia
Duration: Dec 12 2016Dec 14 2016

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs


Other27th International Symposium on Algorithms and Computation, ISAAC 2016

ASJC Scopus subject areas

  • Software


  • Byzantine faults
  • Cow path problem
  • Mobile robots
  • Parallel search
  • Wireless communication


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