The arts of fighting and of scholastic dispute: two types of duels at the end of the Middle Ages and during the Renaissance

Fencing and the art of combat in general can bring you to think of an argument, a serious conversation between two individuals or two groups. Conversely, intellectual disputes and discursive exchanges can be compared to actual duels with the difference that questions, answers, and reasoning replace gestures, defences, and attacks. This rather simplistic vision deserves to be questioned in regard to the medieval and Renaissance periods, in particular from the written productions resulting from the theorisation and the inscription of these two forms of interaction: the scholastic dispute and the art of fencing. This article aims to make the link between the mechanism of the scholastic dispute, which has existed since the Middle Ages and which persists in the Renaissance, and the world of the art of medieval and early modern combat, which is materialised through the treatises of fencing and wrestling written by educated masters-at-arms as well as the practice of public fencing competitions

Computer-aided proofs for multiparty computation with active security

Secure multi-party computation (MPC) is a general cryptographic technique that allows distrusting parties to compute a function of their individual inputs, while only revealing the output of the function. It has found applications in areas such as auctioning, email filtering, and secure teleconference. Given its importance, it is crucial that the protocols are specified and implemented correctly. In the programming language community it has become good practice to use computer proof assistants to verify correctness proofs. In the field of cryptography, EasyCrypt is the state of the art proof assistant. It provides an embedded language for probabilistic programming, together with a specialized logic, embedded into an ambient general purpose higher-order logic. It allows us to conveniently express cryptographic properties. EasyCrypt has been used successfully on many applications, including public-key encryption, signatures, garbled circuits and differential privacy. Here we show for the first time that it can also be used to prove security of MPC against a malicious adversary. We formalize additive and replicated secret sharing schemes and apply them to Maurer's MPC protocol for secure addition and multiplication. Our method extends to general polynomial functions. We follow the insights from EasyCrypt that security proofs can be often be reduced to proofs about program equivalence, a topic that is well understood in the verification of programming languages. In particular, we show that in the passive case the non-interference-based definition is equivalent to a standard game-based security definition. For the active case we provide a new NI definition, which we call input independence

Quantification adaptative pour la stéganalyse d'images texturées

National audienceNous cherchons à améliorer les performances d'un schéma de stéganalyse (i.e. la détection de messages cachées) pour des images texturées. Le schéma de stéganographie étudié consiste à modifier certains pixels de l'image par une perturbation +/-1, et le schéma de stéganalyse utilise les caractéristiques construites à partir de la probabilité conditionnelle empirique de différences de 4 pixels voisins. Dans sa version originale, la stéganalyse n'est pas trés efficace sur des images texturées et ce travail vise à† explorer plusieurs techniques de quantification en utilisant d'abord un pas de quantification plus important puis une quantification adaptative scalaire ou vectorielle. Les cellules de la quantification adaptative sont générées en utilisant un K-means ou un K-means ''équilibré'' de manière à ce chaque cellule quantifie approximativement le même nombre d'échantillon. Nous obtenons un gain maximal de classification de 3% pour un pas de quantification uniforme de 3. En utilisant l'algorithme K-means équilibré sur [-18,18], le gain par rapport à la version de base est de 4.7\%

On the possibility of a long subglacial river under the north Greenland ice sheet

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / 2F Auditorium, National Institute of Polar Researc

Entre mouvements intuitifs et gestes techniques : « Poignarder » un homme (xve-xvie siècles)

Les dagues et les couteaux sont des armes courantes à la fin du Moyen Âge et à la Renaissance. Elles sont présentes aussi bien dans les sources judiciaires, comme les lettres de rémission, que dans les documents normatifs, à l’exemple des ordonnances légiférant le port d’armes. L’expérimentation gestuelle nous permet d’analyser les techniques martiales issues des livres de combat et de comprendre quels sont les paramètres déterminant la bonne exécution d’un coup. Cependant, l’étude des lettres de rémission, en particulier des combats réels qui y sont exposés, montrent qu’utiliser techniquement et efficacement une arme afin d’atteindre et de blesser un adversaire n’est pas simple. En effet, différents facteurs sont à prendre en considération lors d’un duel, comme par exemple le contexte sérieux ou ludique du combat, les armes à disposition (de guerres ou simulatrices), et enfin le profil de chaque adversaire.Daggers and knives were common weapons towards the end of the Middle Ages and during the Renaissance. They were equally present in judiciary sources, such as letters of remission, as in normative documents such as rulings that legislated the carrying of weapons. Gestural experimentation allows one to analyze the martial techniques from combat manuals and to understand what were the determining factors in the correct execution of a strike. The study of letters of remission, however, in particular those that concerned real combat, demonstrates that the efficient and technical use of an arm with the aim of touching and wounding an adversary was not easy. In fact, different factors were to be taken into consideration during a duel, such as, for example, the serious or playful context of the combat, the available weapons (real or artificial), and, finally, each combatant's profile

Introduction

Le son produit par l’appel des arts de guerre et de grâce a été pour certains chercheurs l’occasion de réveiller en eux leur âme cavalière, celle des bretteurs, danseurs ou autres joueurs de fifre. Ce colloque a pris pour objectif de rassembler historiens, archéologues, littéraires et sociologues s’intéressant à la codification des gestes historiques et à leur restitution. L’idée était de mettre en avant les liens étroits qu’unissaient sur une longue période (xive-xviiie siècle) deux grands d..

Coupling biophysical and micro-economic models to assess the effect of mitigation measures on greenhouse gas emissions from agriculture

International audienceAgricultural soils are a major source of atmospheric nitrous oxide (N2O), a potent greenhouse gas (GHG). Because N2O emissions strongly depend on soil type, climate, and crop management, their inventory requires the combination of biophysical and economic modeling, to simulate farmers' behavior. Here, we coupled a biophysical soil-crop model, CERES-EGS, with an economic farm type supply model, AROPAj, at the regional scale in northern France. Response curves of N2O emissions to fertilizer nitrogen (Nf) inputs were generated with CERES-EGC, and linearized to obtain emission factors. The latter ranged from 0.001 to 0.0225 kg N2O-N kg-1 Nf, depending on soil and crop type, compared to the fixed 0.0125 value of the IPCC guidelines. The modeled emission factors were fed into the economic model AROPAj which relates farm-level GHG emissions to production factors. This resulted in a N2O efflux 20% lower than with the default IPCC method. The costs of abating GHG emissions from agriculture were calculated using a first-best tax on GHG emissions, and a second-best tax on their presumed factors (livestock size and fertilizer inputs). The first-best taxation was relatively efficient, achieving an 8\% reduction with a tax of 11 euro/t-CO2-equivalent, compared to 68 euro/t-CO2eq for the same target with the second-best scheme

Coupling biophysical and micro-economic models to assess the effect of mitigation measures on greenhouse gas emissions from agriculture

Agricultural soils are a major source of atmospheric nitrous oxide (N2O), a potent greenhouse gas (GHG). Because N2O emissions strongly depend on soil type, climate, and crop management, their inventory requires the combination of biophysical and economic modeling, to simulate farmers' behavior. Here, we coupled a biophysical soil-crop model, CERES-EGS, with an economic farm type supply model, AROPAj, at the regional scale in northern France. Response curves of N2O emissions to fertilizer nitrogen (Nf) inputs were generated with CERES-EGC, and linearized to obtain emission factors. The latter ranged from 0.001 to 0.0225 kg N2O-N kg-1 Nf, depending on soil and crop type, compared to the fixed 0.0125 value of the IPCC guidelines. The modeled emission factors were fed into the economic model AROPAj which relates farm-level GHG emissions to production factors. This resulted in a N2O efflux 20% lower than with the default IPCC method. The costs of abating GHG emissions from agriculture were calculated using a first-best tax on GHG emissions, and a second-best tax on their presumed factors (livestock size and fertilizer inputs). The first-best taxation was relatively efficient, achieving an 8\% reduction with a tax of 11 euro/t-CO2-equivalent, compared to 68 euro/t-CO2eq for the same target with the second-best scheme.nitrous oxide; agro-ecosystem model; economic modeling; greenhouse gas; mitigation measures