Document Open Access Logo

On Asynchrony, Memory, and Communication: Separations and Landscapes

Authors Paola Flocchini , Nicola Santoro , Yuichi Sudo , Koichi Wada



PDF
Thumbnail PDF

File

LIPIcs.OPODIS.2023.28.pdf
  • Filesize: 1.34 MB
  • 23 pages

Document Identifiers

Author Details

Paola Flocchini
  • EECS, University of Ottawa, Canada
Nicola Santoro
  • School of Computer Science, Carleton University, Ottawa, Canada
Yuichi Sudo
  • Faculty of Computer and Information Sciences, Hosei University, Tokyo, Japan
Koichi Wada
  • Faculty of Science and Engineering, Hosei University, Tokyo, Japan

Cite AsGet BibTex

Paola Flocchini, Nicola Santoro, Yuichi Sudo, and Koichi Wada. On Asynchrony, Memory, and Communication: Separations and Landscapes. In 27th International Conference on Principles of Distributed Systems (OPODIS 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 286, pp. 28:1-28:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)
https://doi.org/10.4230/LIPIcs.OPODIS.2023.28

Abstract

Research on distributed computing by a team of identical mobile computational entities, called robots, operating in a Euclidean space in Look-Compute-Move (LCM) cycles, has recently focused on better understanding how the computational power of robots depends on the interplay between their internal capabilities (i.e., persistent memory, communication), captured by the four standard computational models (OBLOT, LUMI, FSTA, and FCOM) and the conditions imposed by the external environment, controlling the activation of the robots and their synchronization of their activities, perceived and modeled as an adversarial scheduler. We consider a set of adversarial asynchronous schedulers ranging from the classical semi-synchronous (Ssynch) and fully asynchronous (Asynch) settings, including schedulers (emerging when studying the atomicity of the combination of operations in the LCM cycles) whose adversarial power is in between those two. We ask the question: what is the computational relationship between a model M₁ under adversarial scheduler K₁ (M₁(K₁)) and a model M₂ under scheduler K₂ (M₂(K₂))? For example, are the robots in M₁(K₁) more powerful (i.e., they can solve more problems) than those in M₂(K₂)? We answer all these questions by providing, through cross-model analysis, a complete characterization of the computational relationship between the power of the four models of robots under the considered asynchronous schedulers. In this process, we also provide qualified answers to several open questions, including the outstanding one on the proper dominance of Ssynch over Asynch in the case of unrestricted visibility.

Subject Classification

ACM Subject Classification
  • Theory of computation → Distributed algorithms
Keywords
  • Look-Compute-Move
  • Oblivious mobile robots
  • Robots with lights
  • Memory versus Communication
  • Moving and Computing
  • Asynchrony

Metrics

  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    0
    PDF Downloads

References

  1. N. Agmon and D. Peleg. Fault-tolerant gathering algorithms for autonomous mobile robots. SIAM Journal on Computing, 36(1):56-82, 2006. URL: https://doi.org/10.1137/050645221.
  2. H. Ando, Y. Osawa, I. Suzuki, and M. Yamashita. A distributed memoryless point convergence algorithm for mobile robots with limited visivility. IEEE Transactions on Robotics and Automation, 15(5):818-828, 1999. Google Scholar
  3. S. Bhagat and K. Mukhopadhyaya. Optimum algorithm for mutual visibility among asynchronous robots with lights. In Proc. 19th Int. Symp. on Stabilization, Safety, and Security of Distributed Systems (SSS), pages 341-355, 2017. URL: https://doi.org/10.1007/978-3-319-69084-1_24.
  4. Z. Bouzid, S. Das, and S. Tixeuil. Gathering of mobile robots tolerating multiple crash faults. In the 33rd Int. Conf. on Distributed Computing Systems, pages 337-346, 2013. URL: https://doi.org/10.1109/ICDCS.2013.27.
  5. K. Buchin, P. Flocchini, I. Kostitsyna, T. Peters, N. Santoro, and K. Wada. Autonomous mobile robots: Refining the computational landscape. In APDCM 2021, pages 576-585, 2021. URL: https://doi.org/10.1109/IPDPSW52791.2021.00091.
  6. K. Buchin, P. Flocchini, I. Kostitsyna, T. Peters, N. Santoro, and K. Wada. On the computational power of energy-constrained mobile robots: Algorithms and cross-model analysis. In Proc. 29th Int. Colloquium on Structural Information and Communication Complexity (SIROCCO), pages 42-61, 2022. URL: https://doi.org/10.1007/978-3-031-09993-9_3.
  7. D. Canepa and M. Potop-Butucaru. Stabilizing flocking via leader election in robot networks. In Proc. 10th Int. Symp. on Stabilization, Safety, and Security of Distributed Systems (SSS), pages 52-66, 2007. URL: https://doi.org/10.1007/978-3-540-76627-8_7.
  8. S. Cicerone, Di Stefano, and A. Navarra. Gathering of robots on meeting-points. Distributed Computing, 31(1):1-50, 2018. URL: https://doi.org/10.1007/S00446-017-0293-3.
  9. M. Cieliebak, P. Flocchini, G. Prencipe, and N. Santoro. Distributed computing by mobile robots: Gathering. SIAM Journal on Computing, 41(4):829-879, 2012. URL: https://doi.org/10.1137/100796534.
  10. R. Cohen and D. Peleg. Convergence properties of the gravitational algorithms in asynchronous robot systems. SIAM J. on Computing, 34(6):1516-1528, 2005. URL: https://doi.org/10.1137/S009753970444647.
  11. S. Das, P. Flocchini, G. Prencipe, N. Santoro, and M. Yamashita. Autonomous mobile robots with lights. Theoretical Computer Science, 609:171-184, 2016. URL: https://doi.org/10.1016/J.TCS.2015.09.018.
  12. G.A. Di Luna, P. Flocchini, S.G. Chaudhuri, F. Poloni, N. Santoro, and G. Viglietta. Mutual visibility by luminous robots without collisions. Information and Computation, 254(3):392-418, 2017. URL: https://doi.org/10.1016/J.IC.2016.09.005.
  13. S. Dolev, S. Kamei, Y. Katayama, F. Ooshita, and K. Wada. Brief announcement: Neighborhood mutual remainder and its self-stabilizing implementation of look-compute-move robots. In 33rd International Symposium on Distributed Computing, pages 43:1-43:3, 2019. URL: https://doi.org/10.4230/LIPICS.DISC.2019.43.
  14. P. Flocchini, G. Prencipe, and N. Santoro (Eds). Distributed Computing by Mobile Entities. Springer, 2019. URL: https://doi.org/10.1007/978-3-030-11072-7.
  15. P. Flocchini, G. Prencipe, and N. Santoro. Distributed Computing by Oblivious Mobile Robots. Morgan & Claypool, 2012. URL: https://doi.org/10.2200/S00440ED1V01Y201208DCT010.
  16. P. Flocchini, G. Prencipe, N. Santoro, and P. Widmayer. Hard tasks for weak robots: the role of common knowledge in pattern formation by autonomous mobile robots. In 10th Int. Symp. on Algorithms and Computation (ISAAC), pages 93-102, 1999. URL: https://doi.org/10.1007/3-540-46632-0_10.
  17. P. Flocchini, G. Prencipe, N. Santoro, and P. Widmayer. Gathering of asynchronous robots with limited visibility. Theoretical Computer Science, 337(1-3):147-169, 2005. URL: https://doi.org/10.1016/J.TCS.2005.01.001.
  18. P. Flocchini, G. Prencipe, N. Santoro, and P. Widmayer. Arbitrary pattern formation by asynchronous oblivious robots. Theoretical Computer Science, 407:412-447, 2008. URL: https://doi.org/10.1016/J.TCS.2008.07.026.
  19. P. Flocchini, N. Santoro, Y. Sudo, and K. Wada. On asynchrony, memory, and communication: Separations and landscapes. CoRR abs/2311.03328, arXiv, 2023. URL: https://arxiv.org/abs/2311.03328.
  20. P. Flocchini, N. Santoro, G. Viglietta, and M. Yamashita. Rendezvous with constant memory. Theoretical Computer Science, 621:57-72, 2016. URL: https://doi.org/10.1016/J.TCS.2016.01.025.
  21. P. Flocchini, N. Santoro, and K. Wada. On memory, communication, and synchronous schedulers when moving and computing. In Proc. 23rd Int. Conference on Principles of Distributed Systems (OPODIS), pages 25:1-25:17, 2019. URL: https://doi.org/10.4230/LIPICS.OPODIS.2019.25.
  22. N. Fujinaga, Y. Yamauchi, H. Ono, S. Kijima, and M. Yamashita. Pattern formation by oblivious asynchronous mobile robots. SIAM Journal on Computing, 44(3):740-785, 2015. URL: https://doi.org/10.1137/140958682.
  23. V. Gervasi and G. Prencipe. Coordination without communication: The case of the flocking problem. Discrete Applied Mathematics, 144(3):324-344, 2004. URL: https://doi.org/10.1016/J.DAM.2003.11.010.
  24. A. Hériban, X. Défago, and S. Tixeuil. Optimally gathering two robots. In Proc. 19th Int. Conference on Distributed Computing and Networking (ICDCN), pages 1-10, 2018. URL: https://doi.org/10.1145/3154273.3154323.
  25. T. Izumi, S. Souissi, Y. Katayama, N. Inuzuka, X. Défago, K. Wada, and M. Yamashita. The gathering problem for two oblivious robots with unreliable compasses. SIAM Journal on Computing, 41(1):26-46, 2012. URL: https://doi.org/10.1137/100797916.
  26. D. Kirkpatrick, I. Kostitsyna, A. Navarra, G. Prencipe, and N. Santoro. Separating bounded and unbounded asynchrony for autonomous robots: Point convergence with limited visibility. In 40th Symposium on Principles of Distributed Computing (PODC). ACM, 2021. URL: https://doi.org/10.1145/3465084.3467910.
  27. T. Okumura, K. Wada, and X. Défago. Optimal rendezvous ℒ-algorithms for asynchronous mobile robots with external-lights. In Proc. 22nd Int. Conference on Principles of Distributed Systems (OPODIS), pages 24:1-24:16, 2018. URL: https://doi.org/10.4230/LIPICS.OPODIS.2018.24.
  28. T. Okumura, K. Wada, and Y. Katayama. Brief announcement: Optimal asynchronous rendezvous for mobile robots with lights. In Proc. 19th Int. Symp. on Stabilization, Safety, and Security of Distributed Systems (SSS), pages 484-488, 2017. URL: https://doi.org/10.1007/978-3-319-69084-1_36.
  29. G. Sharma, R. Alsaedi, C. Bush, and S. Mukhopadyay. The complete visibility problem for fat robots with lights. In Proc. 19th Int. Conference on Distributed Computing and Networking (ICDCN), pages 21:1-21:4, 2018. URL: https://doi.org/10.1145/3154273.3154319.
  30. S. Souissi, T. Izumi, and K. Wada. Oracle-based flocking of mobile robots in crash-recovery model. In Proc. 11th Int. Symp. on Stabilization, Safety, and Security of Distributed Systems (SSS), pages 683-697, 2009. URL: https://doi.org/10.1007/978-3-642-05118-0_47.
  31. I. Suzuki and M. Yamashita. Distributed anonymous mobile robots: Formation of geometric patterns. SIAM Journal on Computing, 28:1347-1363, 1999. URL: https://doi.org/10.1137/S009753979628292X.
  32. S. Terai, K. Wada, and Y. Katayama. Gathering problems for autonomous mobile robots with lights. Theoretical Computer Science, 941(4):241-261, 2023. URL: https://doi.org/10.1016/J.TCS.2022.11.018.
  33. G. Viglietta. Rendezvous of two robots with visible bits. In 10th Int. Symp. on Algorithms and Experiments for Sensor Systems, Wireless Networks and Distributed Robotics (ALGOSENSORS), pages 291-306, 2013. URL: https://doi.org/10.1007/978-3-642-45346-5_21.
  34. M. Yamashita and I. Suzuki. Characterizing geometric patterns formable by oblivious anonymous mobile robots. Theoretical Computer Science, 411(26-28):2433-2453, 2010. URL: https://doi.org/10.1016/J.TCS.2010.01.037.
  35. Y. Yamauchi, T. Uehara, S. Kijima, and M. Yamashita. Plane formation by synchronous mobile robots in the three-dimensional euclidean space. J. ACM, 64:3(16):16:1-16:43, 2017. URL: https://doi.org/10.1145/3060272.
Questions / Remarks / Feedback
X

Feedback for Dagstuhl Publishing


Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail