Search results for "electronics"
showing 10 items of 4340 documents
Effect and optimization of burst assembly algorithms for video traffic transmissions over OBS networks
2008
Optical burst switching (OBS) has been proposed to be a technology for implementing the next generation optical Internet. In this architecture, burst assembly algorithms have an important influence in the traffic pattern that characterizes this sort of optical networks. On the other hand, traffic coming from new applications (such as video on demand, Voice over IP, online gaming or Grid services) that have real time and bandwidth constraints has been experimented a rapid increment. Consequently, we consider important to evaluate the performance of the real time traffic over OBS networks. In this paper, we evaluate the video transmissions performance (MPEG4/RTP/UDP) over OBS networks, for bo…
Numerical and experimental study of hydrostatic displacement machine
2012
This paper presents a simulation tool to determine the structural deflections and corresponding leakage flow in a hydrostatic displacement motor. The simulation tool is applied to a new motor principle that is categorized as an extreme low-speed high-torque motor with dimensions that calls for attention to the volumetric efficiency. To counteract structural deflections the motor is equipped with compensation pressure volumes that may be used to limit the leakage flow across the end faces of the circular rotor. This leakage flow is investigated by solving Reynolds equation for the pressure distribution across both end faces. The fluid pressure is combined with structural calculations in a fl…
A Spatial Pyramidal Decomposition Method for ear representation using local dual cross patterns
2019
International audience; In recent years, several scientific works are oriented to develop optimal ear representation, for ear recognition, which is discriminant, compact, and easyto-implement to ensure the best performance in terms of accuracy, computation cost, and storage requirement. In this manner, this paper presents a novel ear representation based on texture analysis framework, which relies mainly on Dual Cross Pattern (DCP) descriptor and Spatial Pyramid Histogram (SPH) method. The features are extracted using DCP descriptor to capture the textural structure then, the SPH of horizontal ear decomposition is applied to obtain the local information. The feature vector representations o…
Warm white LED light by frequency down-conversion of mixed yellow and red Lumogen®
2013
This work reports on the benefits and promising opportunities offered by white LED hybrid technology, based on a mixing perylene-based dyes in order to obtain a warm white light for frequency-down conversion. In a standard Ce:YAG-based white LED, the white light appears cold due to the weakness of red wavelength components in the emission spectrum. In order to obtain a warmer white, one possible solution is to add a red phosphor to the yellow one to move the chromatic coordinates properly, though the luminous efficiency drastically decreases due to the increased light absorption of the coating layer. It is generally believed that the low efficiency of warm white LEDs is the main issue today…
Low-temperature atomic layer deposition of SiO2/Al2O3 multilayer structures constructed on self-standing films of cellulose nanofibrils
2018
In this paper, we have optimized a low-temperature atomic layer deposition (ALD) of SiO 2 using AP-LTO® 330 and ozone (O 3 ) as precursors, and demonstrated its suitability to surface-modify temperature-sensitive bio-based films of cellulose nanofibrils (CNFs). The lowest temperature for the thermal ALD process was 80°C when the silicon precursor residence time was increased by the stop-flow mode. The SiO 2 film deposition rate was dependent on the temperature varying within 1.5–2.2 Å cycle −1 in the temperature range of 80–350°C, respectively. The low-temperature SiO 2 process that resulted was combined with the conventional trimethyl aluminium + H 2 O process in order to prepare thin mul…
A Permanent Magnet Linear Generator for the Enhancement of the Reliability of a Wave Energy Conversion System
2019
In this paper, a linear generator for a highly reliable Wave Energy Conversion system is designed and tested. In order to store energy, the system is able to produce hydrogen The Wave Energy Conversion System consists of an electrical linear generator, a power conversion system and a sea-water electrolyzer. A small scale prototype of the system has been designed and built. The design is oriented to the enhancement of the system robustness and reliability and a Failure Mode and Effects and Criticality Analysis (FMECA) has been used. In order to guarantee an easy extension of the power capability of the marine plant, a modular architecture of the system has been adopted. The design strategy i…
Guidelines proposal for a good and durable WEC design
2017
In this paper, preliminarily a proposal for design guidelines for a “good” design of wave energy converter is presented and successively a small scale prototype of a wave energy converter including the buoyant electrical generator, the power electronics equipment and a sea water electrolyzer is designed on the basis of these guidelines and presented.
Integrated plasmonic waveguides: A mode solver based on density of states formulation
2009
International audience; We express the density of states (DOS) near guided resonances of plasmonic waveguides by using multiple-scattering theory. In direct analogy with the case of localized electronic defect states in condensed matter, we demonstrate that optical DOS variations follow a lorentzian profile near guided modes resonances. The lorentzian shape gives quantitative information on the guided modes (effective index, propagation length, and polarization state). We numerically investigate both leaky and bound (lossy) modes supported by dielectric-loaded surface-plasmon-polariton waveguides.
Spatio-temporal Characteristics of THz Emission at the Subwavelength Scale via Optical Rectification
2011
Highly localized THz emission via optical rectification in thin nonlinear crystals is a promising method for subwavelength microscopy. We present here the peculiar THz spatio-temporal characteristics induced by the non-paraxial generation regime.
Dynamic wavefront sensing and correction with low-cost twisted nematic spatial light modulators
2010
Off-the-shelf spatial light modulators (SLMs), like twisted nematic liquid crystal displays (TNLCDs) used in projection systems, show some interesting features such as high spatial resolution, easy handling, wide availability, and low cost. We describe a compact adaptive optical system using just one TNLCD to measure and compensate optical aberrations. The current system operates at a frame rate of the order of 10 Hz with a four-level codification scheme. Wavefront estimation is performed through conventional Hartmann–Shack sensing architecture. The system has proved to work properly with a maximum rms aberration of 0. 76 μm and wavefront gradient of 50 rad/mm at a wavelength of 514 nm. The…