Fault-Tolerant ANTS

  • Tobias Langner
  • Jara Uitto
  • David Stolz
  • Roger Wattenhofer
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8784)


In this paper, we study a variant of the Ants Nearby Treasure Search problem, where n mobile agents, controlled by finite automata, search collaboratively for a treasure hidden by an adversary. In our version of the model, the agents may fail at any time during the execution. We provide a distributed protocol that enables the agents to detect failures and recover from them, thereby providing robustness to the protocol. More precisely, we provide a protocol that allows the agents to locate the treasure in time \(\mathcal{O}(D + D^2/n + Df)\) where D is the distance to the treasure and \(f \in \mathcal{O}(n)\) is the maximum number of failures.


Mobile Agent Competitive Ratio Finite Automaton Complete State Segment Size 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Albers, S., Henzinger, M.: Exploring Unknown Environments. SIAM Journal on Computing 29, 1164–1188 (2000)MathSciNetCrossRefzbMATHGoogle Scholar
  2. 2.
    Aleliunas, R., Karp, R.M., Lipton, R.J., Lovasz, L., Rackoff, C.: Random Walks, Universal Traversal Sequences, and the Complexity of Maze Problems. In: Proceedings of the 20th Annual Symposium on Foundations of Computer Science (SFCS), pp. 218–223 (1979)Google Scholar
  3. 3.
    Angluin, D., Aspnes, J., Diamadi, Z., Fischer, M.J., Peralta, R.: Computation in Networks of Passively Mobile Finite-State Sensors. Distributed Computing, 235–253 (March 2006)Google Scholar
  4. 4.
    Aspnes, J., Ruppert, E.: An Introduction to Population Protocols. In: Garbinato, B., Miranda, H., Rodrigues, L. (eds.) Middleware for Network Eccentric and Mobile Applications, pp. 97–120. Springer (2009)Google Scholar
  5. 5.
    Baeza-Yates, R.A., Culberson, J.C., Rawlins, G.J.E.: Searching in the Plane. Information and Computation 106, 234–252 (1993)MathSciNetCrossRefzbMATHGoogle Scholar
  6. 6.
    Deng, X., Papadimitriou, C.: Exploring an Unknown Graph. Journal of Graph Theory 32, 265–297 (1999)MathSciNetCrossRefzbMATHGoogle Scholar
  7. 7.
    Diks, K., Fraigniaud, P., Kranakis, E., Pelc, A.: Tree Exploration with Little Memory. Journal of Algorithms 51, 38–63 (2004)MathSciNetCrossRefzbMATHGoogle Scholar
  8. 8.
    Emek, Y., Langner, T., Uitto, J., Wattenhofer, R.: Solving the ANTS Problem with Asynchronous Finite State Machines. In: Esparza, J., Fraigniaud, P., Husfeldt, T., Koutsoupias, E. (eds.) ICALP 2014, Part II. LNCS, vol. 8573, pp. 471–482. Springer, Heidelberg (2014)CrossRefGoogle Scholar
  9. 9.
    Feinerman, O., Korman, A.: Memory Lower Bounds for Randomized Collaborative Search and Implications for Biology. In: Aguilera, M.K. (ed.) DISC 2012. LNCS, vol. 7611, pp. 61–75. Springer, Heidelberg (2012)CrossRefGoogle Scholar
  10. 10.
    Feinerman, O., Korman, A., Lotker, Z., Sereni, J.S.: Collaborative Search on the Plane Without Communication. In: Proceedings of the 31st ACM Symposium on Principles of Distributed Computing (PODC), pp. 77–86 (2012)Google Scholar
  11. 11.
    Fraigniaud, P., Ilcinkas, D., Peer, G., Pelc, A., Peleg, D.: Graph Exploration by a Finite Automaton. Theoretical Computer Science 345(2-3), 331–344 (2005)MathSciNetCrossRefzbMATHGoogle Scholar
  12. 12.
    Förster, K.-T., Wattenhofer, R.: Directed Graph Exploration. In: Baldoni, R., Flocchini, P., Binoy, R. (eds.) OPODIS 2012. LNCS, vol. 7702, pp. 151–165. Springer, Heidelberg (2012)CrossRefGoogle Scholar
  13. 13.
    Lenzen, C., Lynch, N., Newport, C., Radeva, T.: Trade-offs between Selection Complexity and Performance when Searching the Plane without Communication. In: Proceedings of the 33rd Symposium on Principles of Distributed Computing, PODC (2014)Google Scholar
  14. 14.
    López-Ortiz, A., Sweet, G.: Parallel Searching on a Lattice. In: Proceedings of the 13th Canadian Conference on Computational Geometry (CCCG), pp. 125–128 (2001)Google Scholar
  15. 15.
    Mitzenmacher, M., Upfal, E.: Probability and Computing: Randomized Algorithms and Probabilistic Analysis. Cambridge University Press, New York (2005)CrossRefGoogle Scholar
  16. 16.
    Panaite, P., Pelc, A.: Exploring Unknown Undirected Graphs. In: Proceedings of the 9th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pp. 316–322 (1998)Google Scholar
  17. 17.
    Reingold, O.: Undirected Connectivity in Log-Space. Journal of the ACM (JACM) 55, 17:1–17:24 (2008)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Tobias Langner
    • 1
  • Jara Uitto
    • 1
  • David Stolz
    • 1
  • Roger Wattenhofer
    • 1
  1. 1.ETH ZürichSwitzerland

Personalised recommendations