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X-WR-CALNAME:GREYC UMR CNRS 6072 - Groupe de Recherche en Informatique, Image, et Instrumentation de Caen
X-ORIGINAL-URL:https://www.greyc.fr
X-WR-CALDESC:évènements pour GREYC UMR CNRS 6072 - Groupe de Recherche en Informatique, Image, et Instrumentation de Caen
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TZID:Europe/Paris
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DTSTART:20250330T010000
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DTSTART:20251026T010000
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251007T104500
DTEND;TZID=Europe/Paris:20251007T114500
DTSTAMP:20260502T145832
CREATED:20250901T144053Z
LAST-MODIFIED:20250924T083853Z
UID:11941-1759833900-1759837500@www.greyc.fr
SUMMARY:Séminaire Algorithmique : Sarah Riva (LIFL\, Univ. Lille) « Control and synthesis of minimal trap spaces in Boolean Network »
DESCRIPTION:Since recent years\, we observe a surge of successful applications of Boolean networks (BNs) in biology and medicine for the modeling and prediction of cellular dynamics in the case of cancer and cellular reprogramming. Such applications face two main challenges: being able to design a qualitative Boolean model which is faithful to the behavior of the biological system and being able to compute predictions to control its (long-term) dynamics. From a computational point of view\, the latter problem mostly depends on the complexity of the dynamical property to enforce\, while the former additionally suffers from the combinatorics of candidate models. \nMinimal trap spaces (MTSs) capture subspaces in which the Boolean dynamics is trapped\, whatever the update mode. They correspond to the attractors of the most permissive mode. Due to their versatility\, the computation of MTSs has recently gained traction\, essentially by focusing on their enumeration. We address the logical reasoning on universal properties of MTSs in the scope of two problems: the reprogramming of Boolean networks for identifying the permanent freeze of Boolean variables that enforce a given property on all the MTSs\, and the synthesis of Boolean networks from universal properties on their MTSs. Both problems reduce to solving the satisfiability of quantified propositional logic formula with 3 levels of quantifiers.
URL:https://www.greyc.fr/event/seminaire-algorithmique-sarah-riva-lifl-univ-lille/
LOCATION:Sciences 3- S3 351
CATEGORIES:Amacc,General,News,Séminaire Algo
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251014T104500
DTEND;TZID=Europe/Paris:20251014T114500
DTSTAMP:20260502T145832
CREATED:20250901T144223Z
LAST-MODIFIED:20250924T083940Z
UID:11943-1760438700-1760442300@www.greyc.fr
SUMMARY:Séminaire Algorithmique : France Gheeraert (LAMFA\, Univ. Picardie) «String attractors\, ou comment capturer la combinatoire d’un texte»
DESCRIPTION:Les string attractors sont des objets combinatoires introduits par Kempa et Prezza dans le but d’unifier différentes mesures de compressibilité de texte provenant de techniques classiques telles que LZ77 ou la transformée de Burrows-Wheeler. Etant donné un texte\, un string attractor est un ensemble de positions permettant de capturer tous les motifs apparaissant dans ce texte. La recherche d’un tel ensemble de positions est un problème NP-complet. Pour contourner cette difficulté\, les recherches se sont rapidement tournées vers des textes possédant des propriétés combinatoires particulières. \nDans cet exposé\, je présenterai les string attractors et les résultats classiques à leur sujet. J’aborderai ensuite le cas particulier des préfixes de la suite (symbolique) de Fibonacci comme une première étape vers l’étude d’autres textes bien connus en combinatoire des mots.
URL:https://www.greyc.fr/event/seminaire-algorithmique-france-gheeraert-lamfa-univ-picardie/
LOCATION:Sciences 3- S3 351
CATEGORIES:Amacc,General,News,Séminaire Algo
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251021T104500
DTEND;TZID=Europe/Paris:20251021T114500
DTSTAMP:20260502T145832
CREATED:20250901T144337Z
LAST-MODIFIED:20251017T093914Z
UID:11945-1761043500-1761047100@www.greyc.fr
SUMMARY:Séminaire Algorithmique : Michel Seck (Ecole Politech. Thiès\, Sénégal) « Towards post-quantum Bitcoin blockchain using Dilithium signature »
DESCRIPTION:Bitcoin is one of the famous cryptocurrencies in the world. It is a permissionless blockchain\, and all transactions are stored in a public decentralized ledger. In its security design\, Bitcoin utilizes various cryptographic primitives\, such as hash functions and signature schemes. In the current version of Bitcoin\, the Elliptic Curve Digital Signature Algorithm (ECDSA) is employed\, which is not considered post-quantum secure due to the Shor’s algorithm. In this talk\, we will analyze the potential replacement of ECDSA with Dilithium\, which is a postquantum digital signature based on lattices and recently standardized by NIST as ML-DSA. Bitcoin operates on a pseudonymous system rather than providing complete anonymity. To enhance privacy protection\, the Bitcoin community has adopted a special type of deterministic wallet as outlined in Bitcoin Improvement Proposal 32 (BIP32). We will show how to construct deterministic wallets from Dilithium by first designing DilithiumRK\, a signature scheme with rerandomizable keys build on top of Dilithium. We will then discuss the unlinkability\, unforgeability and efficiency of DilithiumRK and the resulting wallets.
URL:https://www.greyc.fr/event/seminaire-algorithmique-francois-rioult-et-abdelkader-ouali-greyc-caen/
LOCATION:Sciences 3- S3 351
CATEGORIES:Amacc,General,News,Séminaire Algo
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