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International audience; Les communications sans contact sont omniprésentes dans notre quotidien, allant des badges de contrôle d'accès au passeport électronique. Ces systèmes sont sensibles aux attaques par relais, dans lesquelles un adversaire transfère simplement les messages entre le prouveur et le vérifieur pour usurper l'identité du prouveur. Les protocoles délimiteurs de distance (distance-bounding) ont été ont ntroduits pour contrer ces attaques en assurant une borne sur la distance entre le prouveur et le vérifieur grâcè a la mesure du temps des communications. Par la suite de nombreux travaux ont amélioré la sécurité de ces protocoles, mais ont aussi cherché à assurer le respect de la vie privée face à des adversaires actifs et également face à des vérifieurs malicieux. En particulier, une menace difficile à prévenir est la fraude terroriste, où un prouveur lointain coopère avec un complice proche pour tromper le vérifieur. La contre-mesure usuelle pour cette menace est de rendre impossible l'action du complice sans l'aide du prouveur lointain, à moins que le prouveur ne lui donne suffisamment d'information pour qu'il retrouve sa clef privée et puisse ainsi toujours se faire passer pour le prouveur. Dans cet article, nous proposons une nouvelle approche où le prouveur ne révèle pas sa clef privée mais utilise une clef de session avec une signature de groupe, la rendant ainsi utilisable plusieurs fois. Ceci permet à un adversaire d'usurper l'identité du prouveur sans même connaître sa clef de signature. Grâce à cette approche nous proposons SPADE le premier protocole de délimiteur de distance qui est anonyme, révocable et formellement prouvé sûr. Mots-clefs : Protocole délimiteur de distance (Distance Bounding), Sécurité, résitance à la fraude terroriste.

International audience; This paper describes the process and outcomes of a project focused on community centred reclamation of plant-based knowledge in the Kwak̓wala language from previously published materials as well as new documentation with Kwak̓wala speaking Elders. The paper describes our research process resulting in the documentation of 300 plant word names and phrases, starting with 135 plants with names and words in Kwak̓wala that had been documented between the late 19th and early 20th century by Franz Boas and George Hunt, subsequently added to and enriched by community members and academics. An audio-visual dictionary of these plant names and associated phrases is now available through the FirstVoices web portal (http://bit.ly/LDC_FirstVoices). The corresponding author initiated the work and then further developed the research in collaboration with Kwakwa̱ka̱’wakw fluent speakers, linguists, biologists, and the U’mista Cultural Society. The project has stimulated interest among community members who provided valuable feedback on the different ways in which this research can be further accessed and then delivered. The paper concludes with some structured reflections on how to proceed in community-led research projects such as this. The authors see further opportunity for continued cross-disciplinary and community-based research.

International audience; In the visualization community, it is often assumed that visual data storytelling increases memorability and engagement, making it more effective at communicating information. However, many assumptions about the efficacy of storytelling in visualization lack empirical evaluation. Contributing to an emerging body of work, we study whether selected techniques commonly used in visual data storytelling influence people's attitudes towards immigration. We compare (a) personal visual narratives designed to generate empathy; (b) structured visual narratives of aggregates of people; and (c) an exploratory visualization without narrative acting as a control condition. We conducted two crowdsourced between-subject studies comparing the three conditions, each with 300 participants. To assess the differences in attitudes between conditions, we adopted established scales from the social sciences used in the European Social Survey (ESS). Although we found some differences between conditions, the effects on people's attitudes are smaller than we expected. Our findings suggest that we need to be more careful when it comes to our expectations about the effects visual data storytelling can have on attitudes. Additional material: https://flowstory.github.io/attitudes/.

International audience; Software-Defined Networking is a new approach to the design and management of networks. It decouples the software-based control plane from the hardware-based data plane while abstracting the underlying network infrastructure and moving the network intelligence to a centralized software-based controller where network services are deployed. The challenge is then to efficiently provision the service chain requests, while finding the best compromise between the bandwidth requirements, the number of locations for hosting Virtual Network Functions (VNFs), and the number of chain occurrences. We propose two ILP (Integer Linear Programming) models for routing service chain requests, one of them with a decomposition modeling. We conduct extensive numerical experiments, and show we can solve exactly the routing of service chain requests in a few minutes for networks with up to 50 nodes, and traffic requests between all pairs of nodes. We investigate the best compromise between the bandwidth requirements and the number of VNF nodes.

Abstract Fatigue modifies the kinematics of various sports-related movements. Basketball induces fatigue, however, the effects of fatigue on the kinematics of shooting have never been studied. This study analysed the effects of fatigue induced by repeated sprints on the kinematics of 3-point shooting (3PS) in young, elite basketball players (U18 level). 3D joint angles were calculated at the maximum and minimum heights of the centre of mass during 3PS, using inertial measurement units (Biomech system, Xsens Technologies BV, Enschede, The Netherlands). Height, velocity and the angle of the ball at the time of release were extrapolated from the wrist joint angles. All players performed four 3PS actions in dynamic conditions before and after a fatigue protocol at 70% of their maximal exercise capacity. The fatigue protocol consisted of a shuttle test with repeated 20-m sprints interspersed with sets of 5 jumps. There was no change in the kinematics of 3PS (p > 0.05), or the ball release variables (p > 0.05) following the fatigue protocol. This suggests that elite basketball players are able to cope with physical fatigue while performing coordinated movements such as 3PS.

Pour tout type Dynkin fini, nous construisons un associaèdre universel dont l’éventail normal contient tous les éventails de g-vecteurs de ce type comme sections. For any finite Dynkin type, we construct a universal associahedron whose normal fan contains all g-vector fans of that type as sections.

Cette contribution propose une analyse des dynamiques d’autorite a l’œuvre dans la production collaborative d’un corpus litteraire original. Diffusee sur Internet et dans les medias par France Televisions, l’experience transmedia Anarchy.fr a genere une œuvre litteraire collective constituant un materiau privilegie pour etudier les transformations des mecanismes de la visibilite, de la notoriete et de l’autorite en environnement numerique. Les producteurs de l’experience ont ainsi mis en place un univers fictif : la sortie de la France de l’Euro, point de depart d’une intense production narrative par un millier d’auteurs-joueurs en ligne, generant pendant sept semaines plus de 10 000 contributions en reseau.Notre etude sur ce corpus tres specifique adopte une triple approche quantitative, qualitative et dispositive mettant au jour trois manifestations complementaires de l’autorite : topologique, narrative et dispositive. Nous montrons dans le present article que l’autorite narrative se construit a la fois sur les strategiques classiques de l’autorite litteraire et des strategies propres a l’environnement numerique, et que l’autorite dispositive resulte quant a elle de la nature bienveillante du dispositif d’ecriture numerique.

Inferring a decision tree from a given dataset is one of the classic problems in machine learning. This problem consists of buildings , from a labelled dataset, a tree such that each node corresponds to a class and a path between the tree root and a leaf corresponds to a conjunction of features to be satisfied in this class. Following the principle of parsimony, we want to infer a minimal tree consistent with the dataset. Unfortunately, inferring an optimal decision tree is known to be NP-complete for several definitions of optimality. Hence, the majority of existing approaches relies on heuristics, and as for the few exact inference approaches, they do not work on large data sets. In this paper, we propose a novel approach for inferring a decision tree of a minimum depth based on the incremental generation of Boolean formula. The experimental results indicate that it scales sufficiently well and the time it takes to run grows slowly with the size of dataset.

We propose to measure the effects of urban riots on the labour market prospects of workers residing in affected areas through the channel of labour market discrimination based on locality. We investigate the case of the French riots of 2007, which were very geographically concentrated. The town of Villiers-le-Bel is selected as the treatment unit because it received a uniquely high degree of unfavourable exposure in the media. Two other towns serve control groups: i) Sarcelles, which is contiguous to Villiers-le-Bel, has a similar socio-economic-demographic profile, and did experience some rioting activity, and ii) Enghien-les-Bains, which is considered to be economically advantaged and did not experience rioting activity. Using the technique of correspondence testing, we are able to discern disparities in call-back rates for fictitious candidates who respond to actual job postings over four dimensions: gender, ethnic origin, locality of residence (advantaged vs. disadvantaged), and the degree of media exposure during the riots. We implement an empirical approach to measure discrimination across several dimensions that integrates a set of relevant parameters into one unified system of equations. We decomposed the probability of receiving a callback for any candidate of given characteristics as a function of several parameters. We find statistically significant negative effects of a pure media exposure effect. All other factors held constant, people residing in the area which received negative publicity were 3.2 percentage points less likely to receive a callback. The group of workers who tend to be the most associated with the riots, i.e. men of North African origin (at least in terms of perceptions), are the least affected by potential discrimination by region of residence, while women of French origin are the most affected.