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LDScript: a Linked Data Script Language
No full textInternational audienceIn addition to the existing standards dedicated to representation or querying, Semantic Web programmers could really benefit from a dedicated programming language enabling them to directly define functions on RDF terms, RDF graphs or SPARQL results. This is especially the case, for instance, when defining SPARQL extension functions. The ability to capitalize complex SPARQL filter expressions into extension functions or to define and reuse dedicated aggregates are real cases where a dedicated language can support modularity and maintenance of the code. Other families of use cases include the definition of functional properties associated to RDF resources or the definition of procedural attachments as functions assigned to RDFS or OWL classes with the selection of the function to be applied to a resource depending on the type of the resource. To address these needs we define LDScript, a Linked Data script language on top of the SPARQL filter expression language. We provide the formal grammar of the syntax and the Natural Semantics inference rules of the semantics of the language. We also provide a benchmark and perform an evaluation using real test bases from W3C with different implementations and approaches comparing, in particular, script interpretation and Java compilation
Les SCI et le droit des régimes matrimoniaux. Présentation générale.
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Temporal dynamic of malaria in a suburban area along the Niger River
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Multi-epoch VLTI-PIONIER imaging of the supergiant V766 Cen
No full text4 pages, 2 figures plus 4 pages appendix. Accepted for publication in Astronomy and Astrophysics (A&A) as a letterInternational audienceThe star V766 Cen (=HR 5171A) was originally classified as a yellow hypergiant but lately found to more likely be a 27-36 Msun red supergiant (RSG). Recent observations indicated a close eclipsing companion in the contact or common-envelope phase. Here, we aim at imaging observations of V766 Cen to confirm the presence of the close companion. We used near-infrared H -band aperture synthesis imaging at three epochs in 2014, 2016, and 2017, employing the PIONIER instrument at the Very Large Telescope Interferometer (VLTI). The visibility data indicate a mean Rosseland angular diameter of 4.1+/-0.8 mas, corresponding to a radius of 1575+/-400 Rsun. The data show an extended shell (MOLsphere) of about 2.5 times the Rosseland diameter, which contributes about 30% of the H-band flux. The reconstructed images at the 2014 epoch show a complex elongated structure within the photospheric disk with a contrast of about 10%. The second and third epochs show qualitatively and quantitatively different structures with a single very bright and narrow feature and high contrasts of 20-30%. This feature is located toward the south-western limb of the photospheric stellar disk. We estimate an angular size of the feature of 1.7+/-0.3 mas, corresponding to a radius of 650+/-150 Rsun, and giving a radius ratio of 0.42+0.35/-0.10} compared to the primary stellar disk. We interpret the images at the 2016 and 2017 epochs as showing the close companion, or a common envelope toward the companion, in front of the primary. At the 2014 epoch, the close companion is behind the primary and not visible. Instead, the structure and contrast at the 2014 epoch are typical of a single RSG harboring giant photospheric convection cells. The companion is most likely a cool giant or supergiant star with a mass of 5+15/-3 Msun
At the origins of learning: Absorbing knowledge flows from within the team
No full textInternational audienceEmpirical studies document a positive effect of collaboration on team productivity. However, little has been done to assess how knowledge flows among team members. Our study addresses this issue by exploring unique rich data on a Swiss funding program promoting research team collaboration. We find that being involved in an established collaboration and team size foster the probability of an individual learning from the other team members. We also find that team members with limited experience are more likely to learn from experienced peers. Moreover, there is an inverted U-shaped effect of cognitive distance on the probability of learning from other team members
A Proof of the Barát–Thomassen Conjecture
No full textInternational audienceThe Barát-Thomassen conjecture asserts that for every tree T on m edges, there exists a constant k T such that every k T-edge-connected graph with size divisible by m can be edge-decomposed into copies of T. So far this conjecture has only been verified when T is a path or when T has diameter at most 4. Here we prove the full statement of the conjecture
Explicit Complementary Observer Design on Special Linear Group SL(3) for Homography Estimation using Conic Correspondences
No full textInternational audienceThis paper presents a new observer on the Special Linear group SL(3). The proposed solution is oriented towards online homography estimation from video sequences obtained from robotic vehicles equipped with a monocular camera. The originality of this paper relies on the extension of our prior works based on linear features to nonlinear features and more particularly to conics. A comprehensive observability analysis is provided. Performance and robustness of the proposed observer are evaluated in both simulations and experiments
A Survey of Active Object Languages
No full textInternational audienceTo program parallel systems efficiently and easily, a wide range of programming models have been proposed, each with different choices concerning synchronization and communication between parallel entities. Among them, the actor model is based on loosely coupled parallel entities that communicate by means of asynchronous messages and mailboxes. Some actor languages provide a strong integration with object-oriented concepts; these are often called active object languages. This paper reviews four major actor and active object languages and compares them according to carefully chosen dimensions that cover central aspects of the programming paradigms and their implementation
3D Simulations of Spatial Dispersive Metals with a Finite Element Time Domain Method
No full textInternational audienceWe present recent advances in the development of a Finite Element Time Domain (Discontinuous Galerkin) solver for computational nanophotonics, focusing on metallic nano structures irradiated by laser pulses. Metallic nano structures of sizes between 2 nm and 25 nm are well known to show spatial dispersion which is modeled by a nonlocal dispersion model for the electron gas [1, 2]. We briefly review and classify the dispersion model used in this work and then step to the numerical modeling of the resulting linear hydrodynamic equations when coupled to the 3D Maxwell's equations in time-domain. The considered 3D finite element time domain method combines the advantage of high order polynomial solutions on very flexible unstructured tetrahedral meshes and a broad band frequency solution due to short pulses [3]. We assess the performance of the numerical method on multiple setups. Among them, we considered a spherical dimer system. Such systems are well known for high field enhancements in the gap and are well suited for single molecule detection [4]. Our numerical simulations investigate the influence of spatial dispersion on the scattering cross-section of spherical dimers with a diameter of 20 nm and 2 nm gap size. Figure 1 compares the scattering cross-section for an incident polarization of the electric field along the dimer