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Documents authored by Antuori, Valentin


Document
On How Turing and Singleton Arc Consistency Broke the Enigma Code

Authors: Valentin Antuori, Tom Portoleau, Louis Rivière, and Emmanuel Hebrard

Published in: LIPIcs, Volume 210, 27th International Conference on Principles and Practice of Constraint Programming (CP 2021)


Abstract
In this paper, we highlight an intriguing connection between the cryptographic attacks on Enigma’s code and local consistency reasoning in constraint programming. The coding challenge proposed to the students during the 2020 ACP summer school, to be solved by constraint programming, was to decipher a message encoded using the well known Enigma machine, with as only clue a tiny portion of the original message. A number of students quickly crafted a model, thus nicely showcasing CP technology - as well as their own brightness. The detail that is slightly less favorable to CP technology is that solving this model on modern hardware is challenging, whereas the "Bombe", an antique computing device, could solve it eighty years ago. We argue that from a constraint programming point of vue, the key aspects of the techniques designed by Polish and British cryptanalysts can be seen as, respectively, path consistency and singleton arc consistency on some constraint satisfaction problems.

Cite as

Valentin Antuori, Tom Portoleau, Louis Rivière, and Emmanuel Hebrard. On How Turing and Singleton Arc Consistency Broke the Enigma Code. In 27th International Conference on Principles and Practice of Constraint Programming (CP 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 210, pp. 13:1-13:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)


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@InProceedings{antuori_et_al:LIPIcs.CP.2021.13,
  author =	{Antuori, Valentin and Portoleau, Tom and Rivi\`{e}re, Louis and Hebrard, Emmanuel},
  title =	{{On How Turing and Singleton Arc Consistency Broke the Enigma Code}},
  booktitle =	{27th International Conference on Principles and Practice of Constraint Programming (CP 2021)},
  pages =	{13:1--13:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-211-2},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{210},
  editor =	{Michel, Laurent D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2021.13},
  URN =		{urn:nbn:de:0030-drops-153040},
  doi =		{10.4230/LIPIcs.CP.2021.13},
  annote =	{Keywords: Constraint Programming, Cryptography}
}
Document
Combining Monte Carlo Tree Search and Depth First Search Methods for a Car Manufacturing Workshop Scheduling Problem

Authors: Valentin Antuori, Emmanuel Hebrard, Marie-José Huguet, Siham Essodaigui, and Alain Nguyen

Published in: LIPIcs, Volume 210, 27th International Conference on Principles and Practice of Constraint Programming (CP 2021)


Abstract
Many state-of-the-art methods for combinatorial games rely on Monte Carlo Tree Search (MCTS) method, coupled with machine learning techniques, and these techniques have also recently been applied to combinatorial optimization. In this paper, we propose an efficient approach to a Travelling Salesman Problem with time windows and capacity constraints from the automotive industry. This approach combines the principles of MCTS to balance exploration and exploitation of the search space and a backtracking method to explore promising branches, and to collect relevant information on visited subtrees. This is done simply by replacing the Monte-Carlo rollouts by budget-limited runs of a DFS method. Moreover, the evaluation of the promise of a node in the Monte-Carlo search tree is key, and is a major difference with the case of games. For that purpose, we propose to evaluate a node using the marginal increase of a lower bound of the objective function, weighted with an exponential decay on the depth, in previous simulations. Finally, since the number of Monte-Carlo rollouts and hence the confidence on the evaluation is higher towards the root of the search tree, we propose to adjust the balance exploration/exploitation to the length of the branch. Our experiments show that this method clearly outperforms the best known approaches for this problem.

Cite as

Valentin Antuori, Emmanuel Hebrard, Marie-José Huguet, Siham Essodaigui, and Alain Nguyen. Combining Monte Carlo Tree Search and Depth First Search Methods for a Car Manufacturing Workshop Scheduling Problem. In 27th International Conference on Principles and Practice of Constraint Programming (CP 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 210, pp. 14:1-14:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)


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@InProceedings{antuori_et_al:LIPIcs.CP.2021.14,
  author =	{Antuori, Valentin and Hebrard, Emmanuel and Huguet, Marie-Jos\'{e} and Essodaigui, Siham and Nguyen, Alain},
  title =	{{Combining Monte Carlo Tree Search and Depth First Search Methods for a Car Manufacturing Workshop Scheduling Problem}},
  booktitle =	{27th International Conference on Principles and Practice of Constraint Programming (CP 2021)},
  pages =	{14:1--14:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-211-2},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{210},
  editor =	{Michel, Laurent D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2021.14},
  URN =		{urn:nbn:de:0030-drops-153052},
  doi =		{10.4230/LIPIcs.CP.2021.14},
  annote =	{Keywords: Monte-Carlo Tree Search, Travelling Salesman Problem, Scheduling}
}
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