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Evacuating Two Robots from a Disk: A Second Cut

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Structural Information and Communication Complexity (SIROCCO 2019)

Part of the book series: Lecture Notes in Computer Science ((LNTCS,volume 11639))

Abstract

We present an improved algorithm for the problem of evacuating two robots from the unit disk via an unknown exit on the boundary. Robots start at the center of the disk, move at unit speed, and can only communicate locally. Our algorithm improves previous results by Brandt et al. [CIAC’17] by introducing a second detour through the interior of the disk. This allows for an improved evacuation time of 5.6234. The best known lower bound of 5.255 was shown by Czyzowicz et al. [CIAC’15].

Yann Disser is supported by the ‘Excellence Initiative’ of the German Federal and State Governments and the Graduate School CE at TU Darmstadt.

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Notes

  1. 1.

    This and all other missing proofs can be found in the full version.

References

  1. Alpern, S.: The rendezvous search problem. SIAM J. Control Optim. 33(3), 673–683 (1995)

    Article  MathSciNet  Google Scholar 

  2. Baezayates, R., Culberson, J., Rawlins, G.: Searching in the plane. Inf. Comput. 106(2), 234–252 (1993)

    Article  MathSciNet  Google Scholar 

  3. Beck, A., Newman, D.J.: Yet more on the linear search problem. Isr. J. Math. 8(4), 419–429 (1970). https://doi.org/10.1007/BF02798690

    Article  MathSciNet  MATH  Google Scholar 

  4. Borowiecki, P., Das, S., Dereniowski, D., Kuszner, Ł.: Distributed evacuation in graphs with multiple exits. In: Suomela, J. (ed.) SIROCCO 2016. LNCS, vol. 9988, pp. 228–241. Springer, Cham (2016). https://doi.org/10.1007/978-3-319-48314-6_15

    Chapter  Google Scholar 

  5. Brandt, S., Laufenberg, F., Lv, Y., Stolz, D., Wattenhofer, R.: Collaboration without communication: evacuating two robots from a disk. In: Fotakis, D., Pagourtzis, A., Paschos, V.T. (eds.) CIAC 2017. LNCS, vol. 10236, pp. 104–115. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-57586-5_10

    Chapter  Google Scholar 

  6. Chalopin, J., Das, S., Disser, Y., Mihalák, M., Widmayer, P.: Mapping simple polygons: how robots benefit from looking back. Algorithmica 65, 43–59 (2013). https://doi.org/10.1007/s00453-011-9572-8

    Article  MathSciNet  MATH  Google Scholar 

  7. Chalopin, J., Das, S., Disser, Y., Mihalák, M., Widmayer, P.: Mapping simple polygons: the power of telling convex from reflex. ACM Trans. Algorithms 11, 1–16 (2015). Article No. 33

    Article  MathSciNet  Google Scholar 

  8. Czyzowicz, J., et al.: Priority evacuation from a disk using mobile robots. In: Lotker, Z., Patt-Shamir, B. (eds.) SIROCCO 2018. LNCS, vol. 11085, pp. 392–407. Springer, Cham (2018). https://doi.org/10.1007/978-3-030-01325-7_32

    Chapter  Google Scholar 

  9. Czyzowicz, J., Georgiou, K., Kranakis, E., Narayanan, L., Opatrny, J., Vogtenhuber, B.: Evacuating robots from a disk using face-to-face communication (extended abstract). In: Paschos, V.T., Widmayer, P. (eds.) CIAC 2015. LNCS, vol. 9079, pp. 140–152. Springer, Cham (2015). https://doi.org/10.1007/978-3-319-18173-8_10

    Chapter  Google Scholar 

  10. Czyzowicz, J., Kranakis, E., Krizanc, D., Narayanan, L., Opatrny, J., Shende, S.: Wireless autonomous robot evacuation from equilateral triangles and squares. In: Papavassiliou, S., Ruehrup, S. (eds.) ADHOC-NOW 2015. LNCS, vol. 9143, pp. 181–194. Springer, Cham (2015). https://doi.org/10.1007/978-3-319-19662-6_13

    Chapter  Google Scholar 

  11. Czyzowicz, J., Dobrev, S., Georgiou, K., Kranakis, E., MacQuarrie, F.: Evacuating two robots from multiple unknown exits in a circle. In: Proceedings of the 17th International Conference on Distributed Computing and Networking (IDCN). p. 8 (2016). Article No. 28

    Google Scholar 

  12. Czyzowicz, J., Gasieniec, L., Gorry, T., Kranakis, E., Martin, R., Pajak, D.: Evacuating robots via unknown exit in a disk. In: Kuhn, F. (ed.) DISC 2014. LNCS, vol. 8784, pp. 122–136. Springer, Heidelberg (2014). https://doi.org/10.1007/978-3-662-45174-8_9

    Chapter  Google Scholar 

  13. Czyzowicz, J., et al.: Evacuation from a disc in the presence of a faulty robot. In: Das, S., Tixeuil, S. (eds.) SIROCCO 2017. LNCS, vol. 10641, pp. 158–173. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-72050-0_10

    Chapter  Google Scholar 

  14. Czyzowicz, J., et al.: God save the queen. In: Proceedings of the 9th International Conference on Fun with Algorithms (FUN), pp. 16:1–16:20 (2018). Article No. 16

    Google Scholar 

  15. Feinerman, O., Korman, A.: The ants problem. Distrib. Comput. 30(3), 149–168 (2017)

    Article  MathSciNet  Google Scholar 

  16. Kao, M.Y., Reif, J.H., Tate, S.R.: Searching in an unknown environment: an optimal randomized algorithm for the cow-path problem. Inf. Comput. 131(1), 63–79 (1996)

    Article  MathSciNet  Google Scholar 

  17. Kranakis, E., Krizanc, D., Rajsbaum, S.: Mobile agent rendezvous: a survey. In: Flocchini, P., Gasieniec, L. (eds.) SIROCCO 2006. LNCS, vol. 4056, pp. 1–9. Springer, Heidelberg (2006). https://doi.org/10.1007/11780823_1

    Chapter  Google Scholar 

  18. Lamprou, I., Martin, R., Schewe, S.: Fast two-robot disk evacuation with wireless communication. In: Gavoille, C., Ilcinkas, D. (eds.) DISC 2016. LNCS, vol. 9888, pp. 1–15. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-53426-7_1

    Chapter  Google Scholar 

  19. Littlewood, J.: A Mathematician’s Miscellany. Methuen & Co. Ltd., London (1953)

    MATH  Google Scholar 

  20. Pattanayak, D., Ramesh, H., Mandal, P.S., Schmid, S.: Evacuating two robots from two unknown exits on the perimeter of a disk with wireless communication. In: Proceedings of the 19th International Conference on Distributed Computing and Networking (ICDCN). p. 4 (2018). Article No. 20

    Google Scholar 

  21. Ta-Shma, A., Zwick, U.: Deterministic rendezvous, treasure hunts, and strongly universal exploration sequences. ACM Trans. Algorithms 10(3), 12:1–12:15 (2014)

    Article  MathSciNet  Google Scholar 

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Correspondence to Yann Disser or Sören Schmitt .

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Disser, Y., Schmitt, S. (2019). Evacuating Two Robots from a Disk: A Second Cut. In: Censor-Hillel, K., Flammini, M. (eds) Structural Information and Communication Complexity. SIROCCO 2019. Lecture Notes in Computer Science(), vol 11639. Springer, Cham. https://doi.org/10.1007/978-3-030-24922-9_14

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  • DOI: https://doi.org/10.1007/978-3-030-24922-9_14

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