GeomRDF: A Geodata Converter with a Fine-Grained Structured Representation of Geometry in the Web

In recent years, with the advent of the web of data, a growing number of national mapping agencies tend to publish their geospatial data as Linked Data. However, differences between traditional GIS data models and Linked Data model can make the publication process more complicated. Besides, it may require, to be done, the setting of several parameters and some expertise in the semantic web technologies. In addition, the use of standards like GeoSPARQL (or ad hoc predicates) is mandatory to perform spatial queries on published geospatial data. In this paper, we present GeomRDF, a tool that helps users to convert spatial data from traditional GIS formats to RDF model easily. It generates geometries represented as GeoSPARQL WKT literal but also as structured geometries that can be exploited by using only the RDF query language, SPARQL. GeomRDF was implemented as a module in the RDF publication platform Datalift. A validation of GeomRDF has been realized against the French administrative units dataset (provided by IGN France).Comment: 12 pages, 2 figures, the 1st International Workshop on Geospatial Linked Data (GeoLD 2014) - SEMANTiCS 201

Dynamical large deviations for long-range interacting inhomogeneous systems without collective effects

We consider the long-term evolution of an inhomogeneous long-range interacting $N$-body system. Placing ourselves in the dynamically hot limit, i.e. neglecting collective effects, we derive a large deviation principle for the system's empirical angle-averaged distribution function. This result extends the classical ensemble-averaged kinetic theory given by the so-called inhomogeneous Landau equation, as it specifies the probability of typical and large dynamical fluctuations. We detail the main properties of the associated large deviation Hamiltonian, in particular how it complies with the system's conservation laws and possesses a gradient structure.Comment: 13 pages, 0 figures, submitted to AP

An Adaptive Approach for Interlinking Georeferenced Data

International audienceThe resources published on the Web of data are often described by spatial references such as coordinates. The common data linking approaches are mainly based on the hypothesis that spatially close resources are more likely to represent the same thing. However, this assumption is valid only when the spatial references that are compared have been produced with the same positional accuracy, and when they actually represent the same spatial characteristic of the resources captured in an unambiguous way. Otherwise, spatial distance-based matching algorithms may produce erroneous links. In this article, we first suggest to formalize and acquire the knowledge about the spatial references, namely their positional accuracy, their geometric modeling, their level of detail, and the vagueness of the spatial entities they represent. We then propose an interlinking approach that dynamically adapts the way spatial references are compared, based on this knowledge

New designs systems for induction cooking devices for heating performances improving

In order to give a temperature distribution at the bottom of the induction cooking, and moderate reduction the temperature outside the useless areas of these systems. This paper is dedicated to the study of the induction heating systems, which involves coupled electromagnetic and thermal phenomena and where new topologies are proposed. The modelling of the problem is based on the Maxwell's equations and the heat diffusion equation. We present a numerical simulation method based on parameterization of thermal electromagnetic coupling phenomena taking into account the changing of the physical characteristics of the body during the induction heating process. The purpose of this new optimum perforation topology is based on improving the thermal performances of the system, which allows improved dissipation by heat exchange. The results are obtained from a two-dimensional calculation code developed and implemented on Matlab software where CVM the finite volume method was adopted as a method of solving partial differential equations with partial derivatives characteristics of physical phenomena

Fluctuating kinetic theory and fluctuating hydrodynamics of aligning active particles: the dilute limit

Kinetic and hydrodynamic theories are widely employed for describing the collective behaviour of active matter systems. At the fluctuating level, these have been obtained from explicit coarse-graining procedures in the limit where each particle interacts weakly with many others, so that the total forces and torques exerted on each of them is of order unity at all times. Such limit is however not relevant for dilute systems that mostly interact via alignment; there, collisions are rare and make the self-propulsion direction to change abruptly. We derive a fluctuating kinetic theory, and the corresponding fluctuating hydrodynamics, for aligning self-propelled particles in the limit of dilute systems. We discover that fluctuations at kinetic level are not Gaussian and depend on the interactions among particles, but that only their Gaussian part survives in the hydrodynamic limit. At variance with fluctuating hydrodynamics for weakly interacting particles, we find that the noise variance at hydrodynamic level depends on the interaction rules among particles and is proportional to the square of the density, reflecting the binary nature of the aligning process. The results of this paper, which are derived for polar self-propelled particles with polar alignment, could be straightforwardly extended to polar particles with nematic alignment or to fully nematic systems.Comment: 23 pages, 4 figure

RFI mitigation: cyclostationary criterion

Radio astronomical observations are increasingly corrupted by radio frequency interferences. Thus, real- time ltering algorithms are becoming essential. One approach is to use a speci c time property of the Telecoms signals : the cyclostationarity. This property can be exploited for detection purpose or ltering purpose. In par- ticular, new generations of radio telescopes will be based on antenna arrays providing the possibility of applying spatial ltering techniques. In this paper, we compare the performance between classical approaches based on power statistics and cyclic approaches. This comparison is done through simulations on synthetic data and through simulations on real data acquired with the new generation low frequency array radio telescope, LOFAR