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In the last decade after setting decarbonization targets for the energy sector, European countries have witnessed dramatic growth of wind and solar power. Policy makers have often associated renewable integration in power systems with the need for additional back-up or storage which has a cost. The integration cost of Variable Renewable Energy (VRE) is estimated using a cost-based linear piecewise model of country-scale power systems in this analysis. The model is composed of a load, dispatchable power source, VRE, and flexibility option. These elements are then applied to six European countries (Belgium, France, Germany, Italy, Netherlands, United Kingdom and Spain). The model considers an increasing penetration of VRE to reduce the carbon footprint of the system. Initial findings suggest a few key parameters and variables are sufficient to compare the integration cost of increasing VRE shares in European countries electrical systems for studied countries. We find that the integration cost evolves linearly in three main steps depending on the load variation and the capacity factor. The first step shows negative or low integration cost, which slightly increases in the second step before steeply increasing in the last which is consistent with existing literature.

At a water-air interface, the acoustic radiation pressure (ARP), generates a deformation of the interface. In this work, we propose to study the interface deformation for non-continuous excitations. A particular attention is given to the maximum height at the center of the deformation. An experimental setup has been developed to evaluate the height of the deformation for different durations and amplitudes of the transient acoustic radiation pressure. The results are compared to a numerical approach using the Finite-Element Method (FEM). Finally, the numerical and experimental results for a transient excitation have been compared to results obtained for continuous excitation in order to propose a pertinent optimization of the excitation parameters. Results are in good agreement with the theory for a continuous excitation, and encouraging for further improvement on both numerical and experimental methods.

Among the whole experiments using entangled pairs of photons, the famous experiment of two-photon interference known now as Hong-Ou-Mandel (HOM) interference, is probably one of the most fascinating. This ground-breaking experiment paved the way for a multitude of experiments showing the richness of the quantum properties of Spontaneous Parametric Down conversion (SPDC) and their applications to original communication protocols. Most of them use the coherence time property of a bi-photon state and measurement are mainly performed with bucket detectors and coincidence counters. While some studies report the spatial coherence of two-photon state, measurements are always performed in the temporal domain.

International audience; We report experimentally and numerically quantum correlations imaging through thick random media. We demonstrated that spatial correlations between twin photon are still detected but no in form of two-photon speckle-like patterns.

The RICH detector of the NA62 experiment is one of the key detectors to achieve the muon rejection needed in the search for the ${K^ + } \to {\pi ^ + }\nu \bar \nu $ decay, performed by NA62. Since $BR({K^ + } \to {\mu ^ + }\nu )$ is higher than $BR({K^ + } \to {\pi ^ + }\nu \bar \nu )$ by more than 9 orders of magnitude, it represents one of the most relevant background contributions. Its rejection is performed with kinematic reconstruction of the event and identification of the charged particles in the final state (pions against muons). The Ring Imaging Cherenkov detector (RICH) gives a muon rejection higher than a factor 100 in the momentum range 15-35 GeV/c, and measures the track crossing time with a resolution better than 100 ps. It is also exploited to provide trigger for charged particles. In this contribution the RICH detector will be described, together with its basic performance, the mirrors alignment procedure and its usage in ${K^ + } \to {\pi ^ + }\nu \bar \nu $ search.

Surface plasmon polaritons (SPPs) are bosonic quasiparticles. In the last ten years, several groups have reproduced fundamental quantum optics experiments with surface plasmons. Observation of single-plasmon states, waveparticle duality, preservation of entanglement of photons in plasmon-assisted transmission [1,2], and more recently, two-plasmon interference has been reported, revisiting with success the famous Hong-Ou-Mandel (HOM) experiment[3]. Here we report the observation of two-plasmon quantum interference between two freely-propagating, non-guided SPPs interfering on lossy plasmonic beamsplitters. We find that, depending on the beamsplitter features, the reults of the experiment can be very different.

Exploitation of the statistical properties of classical or non-classical light sources is the cause of fascinating new applications. For the two last decades, ghost imaging has emerged as a way to form images of an object with a Single Point Detector (SPD) that does not have spatial resolution [1-5]. By taking into account space-time duality in optics, the extension of the results of spatial ghost imaging to the time domain was investigated [6]. However, the proposed solution used an SPD and many realizations (several thousands) of the same temporal signal, limiting the current applications to the detection of synchronized and reproducible signals. This is in contrast with the original concept of spatial ghost imaging, where the object is unique, but multiplied in the time domain by a random modulation, different from one pixel to another, leading to multiplexing in this time domain.

Binary information encoded within the spin of carriers can be transferred into corresponding right or left-handed circularly polarized photons emitted from an active semiconductor medium via carrier-photon angular momentum conversion. In order to attain maximized spin-injection at out-of-plane magnetic remanence, a number of material systems have been explored as possible solid-state spin injectors. However the electroluminescence circular polarization (P C ) of emitted light was still limited at 3–4% at remanence.

Existing electricity distribution management systems (DMS) have been designed using operational and algorithmic procedures that are highly centralised. As more of the distribution network becomes active, accurately estimating the state of the system becomes essential and therefore DMS must include functions to achieve the required near to real-time state estimation. The objective of this paper is to evaluate and to compare the performances obtained with two different solutions developed by EDF R&D for the Distribution State Estimator (DSE) algorithm for MV networks: classical optimization resolution approach using a Newton resolution algorithm on one side and a Particle Swarm Optimization algorithm on the other side. The performances of these solutions are evaluated in terms of precisions obtained for the estimates related to the primary and secondary variables and of computation times.

The recent developments in the partial and dynamic Reconfigurable Computing (RC) domain demand better ways to manage the simultaneous task execution. In this context, Operating System (OS) services like scheduling, placement, inter-task communication have been developed to make this type of platform more flexible. In order to provide efficient communication scheme between these hardware tasks, a high performance communication infrastructure must be developed and efficient communication services must be proposed. The contribution presented in this paper mainly focuses on the hardware communication service and the communication schemes supported by this new OS service. Performance and implementation cost of our hardware communication service are evaluated and comparisons with the state of the art are given. Compared to related work OS4RS, our proposal is 60× faster to establish communication between hardware tasks.

Exploiting partial reconfiguration of commercial FPGAs allows the construction of dynamic multi-processor system-on-chip (MPSoC). This solution offers many advantages such as: low development costs and maintains flexibility as well as high computation power. However, FPGAs are susceptible to electronic particles which can toggle configuration bit values and hence change the correct function of the design. Moreover, that could be important in critical applications which require safety and security. Hence using FPGA requires to integrate fault-tolerance schemes into the system. The reliable MPSoC system called Re2DA, presented in this paper, guarantee the system operation by the use of dynamic reconfiguration. Nearly no hardware overhead is required to perform fault-tolerant feature in the system while timing overhead is kept relatively low.

Controlling the fluorescence emission from nanoscale quantum emitters such as single molecules is a key element for a wide range of applications, from efficient analytical sensing to quantum information processing. Enhancing the fluorescence intensity and narrowing the emission directivity are both essential features to achieve a full control of fluorescence, yet this is rarely obtained simultaneously with optical nanoantennas.

Spontaneous down conversion (SPDC) occurs in a nonlinear crystal when a pump photon splits in a pair of signal and idler photons. Even if the number of pairs fluctuates, the difference between the signal and idler output photon numbers is zero in an ideal experiment. Jedrkiewicz et al. [1], performed the first experimental demonstration of sub-shot noise behaviour of spatial fluctuations of the signal-idler difference. Recently, we proposed [2], a more direct demonstration without any detector noise subtraction, by detecting single photons in low light level images with an electron multiplying CCD camera (EMCCD). We experimentally demonstrated that opposite spatial fluctuations of SPDC radiation are correlated in the quantum regime. The statistic was performed over 180 angular sectors of 240 pixels for non collinear phase matching. Here, correlations between pixels are presented for collinear phase matching.

Dynamic reconfiguration of FPGAs allows the dynamic management of various tasks that describe an application. This new feature permits, for optimization purpose, to place tasks on line in an available region of the FPGA. Dynamic reconfiguration of tasks leads to some communication problems since tasks are not present in the matrix during all computation time. This dynamicity needs to be supported by the interconnection network. In this paper, we propose the implementation of a flexible interconnection network supporting such dynamicity. The proposed architecture is fully compliant with the present state-of-art dynamically reconfigurable circuits such as Xilinx Virtex family of FPGA.

Selective encryption is a new trend in content protection. It aims at reducing the amount of data to encrypt while achieving a sufficient and inexpensive security. This approach is particularly desirable in constrained communication (real time networking with delay constraints, mobile communication with limited computational power...). In this paper we introduce selective encryption from information theory point of view. We define a set of evaluation criteria for selective encryption algorithms and propose a novel selective encryption algorithm for JPEG2000 compressed images satisfying all these criteria. The main contribution of this proposal consists of reaching the minimum amount of data to encrypt regarding a given level of security and target application requirements. For this purpose, we exploit the R-D optimization performed by JPEG2000 EBCOT algorithm.

A Vlasov-Poisson code is used in this study to model the transition region between the equilibrium plasma and an absorbing wall in the presence of a tilted magnetic field for a weakly collisional plasma. The phase space structure of the plasma-wall transition is analyzed in detail and theoretical estimates of the magnetic presheath width are tested numerically. Simulations show that even for relatively strong magnetic fields, the average angle of incidence of the impinging ions is never as grazing as the angle between the magnetic field and the wall. This is due to the electric field that manages to partially redirect the ions along the direction normal to the surface.

This article illustrates AREVA T&Dpsilas position in terms of their productspsila end of life management. In order to manage the equipments that have reached the end of useful life, this study describes complete dismantling operation diagram, recycling routes and waste management.

This paper proposes a highly flexible streaming video server that is particularly well suited for video-surveillance content. To achieve the required flexibility, the sequences are encoded with the JPEG 2000 coding scheme. To preserve compression efficiency, the temporal redundancy is exploited by a conditional replenishment technique. The main novelty of this paper consists in a post-compression rate allocation, which enables the server to adapt in real-time the content forwarded to heterogeneous clients using a single pre-compressed version of the sequence. An index is pre-calculated offline to reduce the computational load at the server while scheduling the packets in real-time, according to the needs and resources of the clients.

As the penetration level of the distributed generations on distribution network will increase, they must take their share of responsibility in the system security and provide flexibility and controllability necessary to support secure system operation. However, following the occurrence of large disturbances on the network (short-circuits, line outage, voltage dips...) the protective disconnection of large amount of DG (distributed generation) plants results in loss of generation and of support to the network that may lead to significant load shedding or in the worse case even a blackout. This paper presents an investigation about the transient stability and the capacity of DG to withstand disturbances of distributed synchronous generators and wind turbine generators on the distribution network. Two proposed control solutions to avoid the loss of generation are presented.

The image compression standard JPEG 2000 offers a high compression efficiency as well as a great flexibility in the way it accesses the content in terms of spatial location, quality level, and resolution. This paper explores how transmission systems conveying video surveillance sequences can benefit from this flexibility. Rather than transmitting each frame independently as it is generally done in the literature for JPEG 2000 based systems, we adopt a conditional replenishment scheme to exploit the temporal correlation of the video sequence. As a first contribution, we propose a rate-distortion optimal strategy to select the most profitable packets to transmit. As a second contribution, we provide the client with two references, the previous reconstructed frame and an estimation of the current scene background, which improves the transmission system performances.

A high penetration of distributed generation (DG) may influence the operation and control of the distribution system and the transmission system, leading to technical issues that must be identified and analyzed. The distributed generators are small or medium scale units connected to the low or medium voltage networks (LV or MV). Due to their low inertia for small rotating machines, these distributed generators are very sensitive to network disturbances and can cause many technical and operating issues regarding the DG stability. This paper focuses on these stability aspects taking into account the location and the clearing time of the short circuits. Various assumptions about DG coupling mode on LV and MV networks, DG regulation systems, DG rated power and interaction between DG are investigated. Influences of DG with power electronic interface on the stability are discussed. For a large distribution network with a high penetration of DG, a dynamic equivalent reduction technique is used for the study

This work deals with the experimental parametric amplification of optical vortex beams (OVB) in a degenerate type I optical parametric amplifier (OPA). Results show that in a degenerate type I OPA, the amplification gain in the transverse plane depends on the pump beam profile as well as the relative phase between interacting beams. It leads to amplification or de-amplification that reshapes the signal beam in its transverse plane and preserves the orbital angular momentum when an optical vortex is carried by the signal beam. Then, new various patterns are obtained depending on phase matching condition, topological charge of the vortex and wave front of the pump beam.

This study shows that the spatial jitter of the soliton arrays depends on the shot-to-shot degree of correlation of the spatial noise. This correlation degree is strongly dependent on the spatio-temporal coherence of the injected beam.

The trigger detectors for the Muon Forward Spectrometer of the ALICE experiment will be single gap RPCs with low-resistivity bakelite electrodes. The detector will take data for different colliding systems resulting in a wide range of working conditions and requirements, especially concerning position resolution and lifetime. To this aim we have investigated the possibility to operate the RPCs both in streamer and in saturated avalanche mode with the same FE electronics. The study of the detector performance after long irradiation periods has been carried out at the Gamma Irradiation Facility at CERN with different gas mixtures: a quenched streamer gas mixture (51.5% Ar, 41.3% forane, 7.2% C/sub 2/H/sub 10/ and 1% SF/sub 6/) and a saturated avalanche mixture (88% forane, 10% C/sub 2/H/sub 10/ and 2% SF/sub 6/). We present the results of the ageing test of a final RPC in "ALICE-like" irradiation conditions using the streamer gas mixture and the results of the ageing test of a small prototype with the avalanche gas mixture.

ALICE (a large ion collider experiment) is the heavy-ion dedicated experiment at LHC. The resistive plate chamber detector (RPC) with low-resistivity bakelite electrodes was selected for the trigger system of the muon spectrometer. Although the main goal of ALICE is the study of nucleus-nucleus collisions, reference data in p-p interactions will be collected as well. If, on one hand, RPC operation in streamer mode is adequate for data taking with ion beams, on the other hand, the more severe ageing requirements for p-p data taking lead us to explore the possibility of operating the detector in "highly-saturated avalanche" regime. A detailed study of the signal was carried out with cosmic rays to get a more precise view of the intrinsic properties of the gas mixture (among others the streamer fraction vs. HV). The possibility of detecting avalanche signals with our FEE designed for the streamer mode was successfully investigated. Furthermore, tests with muon beam at CERN were carried out with satisfactory results in terms of efficiency, time resolution and cluster size. An analysis of the exhaust gas showed a low HF content: this is an encouraging result in view of long term stability of the detector which is at present under test.

In case of metallic hole arrays we need to establish how structures transmit, reflect and absorb light. We fabricated hole arrays using a focused ion beam etching system (FBI DB235). The period of the array was 430/spl plusmn/5 nm, the hole diameter 250/spl plusmn/5 nm and the thickness of the silver 180/spl plusmn/5 nm. We made arrays with relatively large dimensions, 1 mm/sup 2/ so as to make the measurement of the reflectivity possible with existing facilities. We next performed optical measurements to find the transmittance and the reflectivity as a function of incident angle and incident frequency. In this way we are able to build up a map of the dispersion of the surface plasmon (SP) modes associated with the enhanced transmission.

This paper presents an experimental study of the influence of vapor bubbles on breakdown in liquid nitrogen. Vapor bubbles are initiated by creating a small hot spot at the surface of an electrode. The behavior of vapor bubbles is first investigated by visualization, versus power dissipated by the heater, pressure and electric field. When breakdown occurs in the presence of bubbles, it is due to formation of either a vapor bridge between the electrodes (at low pressure), or a vapor layer on the hot spot (at high pressure). The results are discussed in comparison with gas breakdown fields obtained from the Paschen's law.

A complete framework dealing with power line communication in medium voltage network is proposed. Based on path loss measurements, a complete characterisation of inductive couplers is performed. After a brief recall of inductive coupling techniques, we address the issue of power switching influence on inductive coupler performances. Finally, we show the key role of the medium voltage to low voltage transformer for a phase to ground propagation mode.

Transformers connected to HVDC system using voltage sourced converter (VSC) arrangement are exposed to continuous converter AC voltage waveforms which are typically a rectangular wave shape with a high repetitive frequency. The most commonly encountered is a two-level VSC waveform. Steep voltage steps like these result in high stresses of the insulation due to non-uniform voltage distribution across the windings. The influence of two-level VSC waveforms on the voltage distribution across different winding and gap sections of a typical medium power transformer has been analytically studied. The practical implications of these results on the dielectric stress of transformer insulation is discussed in relation with those stresses generated under power-frequency and standard lightning impulse voltage excitations on which are transformer designs are generally based.