Interoperability between Heterogeneous Federation Architectures: Illustration with SAML and WS-Federation

International audienceDigital identity management intra and inter information systems, and, service oriented architectures, are the roots of identity federation. This kind of security architectures aims at enabling information system interoperability. Existing architectures, however, do not consider interoperability of heterogeneous federation architectures, which rely on different federation protocols.In this paper, we try to initiate an in-depth reflection on this issue, through the comparison of two main federation architecture specifications: SAML and WS-Federation. We firstly propose an overall outline of identity federation. We furthermore address the issue of interoperability for federation architectures using a different federation protocol. Afterwards, we compare SAML and WS-Federation. Eventually, we define the ways of convergence, and therefore, of interoperability

Jet photonique simple ou double pour la détection d'objets sub-longueur d'onde

National audienceOn appelle « jet photonique » un faisceau électromagnétique ayant une grande concentration de puissance en champ proche. Ce jet photonique possède des propriétés comme une faible divergence et une faible largeur à mi-hauteur. Il peut être appliqué pour la détection d'objet de taille sub-longueur d'onde. Les jets photoniques peuvent être observés pour des longueurs d'onde optiques dans le voisinage d'une sphère diélectrique micrométrique. Ils peuvent être obtenus également dans la gamme des microondes. Dans cet article, nous montrons la réalisation et la mise en évidence de ces jets photoniques dans la gamme microondes. La modélisation développée a permis de mettre en oeuvre des systèmes produisant des jets simples ou doubles. L'expérimentation et ses résultats sont présentés et la détection facile d'objets de faible taille devant la longueur d'onde est mise en évidence ainsi que la mise en évidence de leur mouvement

Electromagnetic jet for characterization applications

This comparative study allows to evaluate the performance of an electromagnetic jet to determine the electromagnetic response of materials, without being in usual far field conditions. In this work, the reflection coefficient of a substrate with ground plane, calculated analytically, is compared with that determined in simulation by the electromagnetic jet. The results show a satisfactory agreement after calibrating the simulated reflection coefficient at the focal point of the jet. Thus, we were able to find, by a local measurement, data consistent with a classical free space type measurement.Comment: in French language. 17{\`e}mes Journ{\'e}es de Caract{\'e}risation Microondes et Mat{\'e}riaux, Laboratoire GREMAIN; CEA Le Ripault, Apr 2023, TOURS, Franc

Rectangular empty waveguide transition for realizing an electromagnetic jet based measuring device

Spheres, cylinders, cones, cuboids have been used in the literature to generate photonic jets at the back of these structures when illuminated by plane waves. We are working on the generalization (which we call electromagnetic jet) of this concept in guided structures in the microwave domain. The electromagnetic jet can be obtained from a rectangular waveguide loaded with dielectric. In order to use the electromagnetic jet as a localized measurement tool, it is therefore necessary to address the adaptation between an empty rectangular waveguide and a loaded guide. This is the object of the work presented here, where two solutions are compared.Comment: in French language, 17{\`e}mes Journ{\'e}es de Caract{\'e}risation Microondes et Mat{\'e}riaux, Laboratoire GREMAN; CEA Le Ripault, Apr 2023, TOURS, Franc

Regulatory Response to Carbon Starvation in Caulobacter crescentus

Bacteria adapt to shifts from rapid to slow growth, and have developed strategies for long-term survival during prolonged starvation and stress conditions. We report the regulatory response of C. crescentus to carbon starvation, based on combined high-throughput proteome and transcriptome analyses. Our results identify cell cycle changes in gene expression in response to carbon starvation that involve the prominent role of the FixK FNR/CAP family transcription factor and the CtrA cell cycle regulator. Notably, the SigT ECF sigma factor mediates the carbon starvation-induced degradation of CtrA, while activating a core set of general starvation-stress genes that respond to carbon starvation, osmotic stress, and exposure to heavy metals. Comparison of the response of swarmer cells and stalked cells to carbon starvation revealed four groups of genes that exhibit different expression profiles. Also, cell pole morphogenesis and initiation of chromosome replication normally occurring at the swarmer-to-stalked cell transition are uncoupled in carbon-starved cells

MetaLines: Transmission Line Approach for the Design of Metamaterial Devices

International audienceAs presented in the chapter1, applications of left-handed materials (LHMs) are characterized by simultaneous negative permittivity and permeability in various microwave applications. This concept was extended to the field of transmission lines by UCLA group [CAL 2002]. An equivalent circuit approach was also developed by Eleftheriades and al [ELE 2002]. As a result the concept of Left-Handed Transmission Line (line with a negative phase velocity) was proposed. For practical applications the parasitic Right-Handed (RH) effects naturally occurring in a Left-Handed (LH) structure must be taken into account. Thus, the various proposals have led to the concept of composite right left handed line (CRLH). The CRLH notation is now the usual designation of these artificial lines since the name clearly describes the fundamentally right-handed and left-handed nature of metamaterial lines [CAL 2006]

On the bulk averaging approach for obtaining the effective parameters of thin magnetic granular films

An analytical model for the effective magnetic properties of a thin film consisting of a few layers of particles with arbitrary permeability and the stochastical initial magnetization is presented. The model is magnetostatic and implies the explicit averaging of the true field. It is shown that it works for all possible thicknesses of the film (arbitrary number of particles across the film) and there is no need for surface-to-bulk transition. The surface effect leading to the change of the reflective properties of the thin film compared to the prediction of the traditional theory is significant for a sparse arrangement of the grains and vanishes when these are touching. The method is verified by comparison with the model of the lattice of magnetic scattering centers

Metamaterials for non-radiative microwave functions and antennas, in Metamaterials and wave control

International audienceCurrent and future wireless communications systems have to be smart while proposing an acceptable quality of service for given applications and optimized resource management in terms of energy consumption and spectral occupation. Moreover, the demand for nomadic devices is growing, thus requiring light, low profile and miniaturized microwave components which can easily integrate into complex systems. All these requirements can be contradictory for the conventional microwave engineer since for instance, miniaturization is usually achieved with a non-negligible impact on overall performances. Since metamaterials can be tailored to present required electromagnetic properties, it should definitely provide a higher degree of freedom in the design of both radiative and non-radiative components for wireless systems. The potential of metamaterial to improve the performances of microwave devices should also be considered. This chapter is divided in two main parts: the first one deals with metamaterial applications for non-radiative microwave components and the second one describes the potential and applications of metamaterials to microwave antennas

Role of wave interaction of wires and split-ring resonators for the losses in a left-handed composite

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Double split-ring resonators: analytical and numerical modelling

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