Saint-Sauveur-en-Rue, France

Graduate School of Electronics of the West

www.eseo.fr
Saint-Sauveur-en-Rue, France
SEARCH FILTERS
Time filter
Source Type

Amorim R.,Federal University of Bahia | Claro D.B.,Federal University of Bahia | Lopes D.,Federal University of Maranhão | Albers P.,Graduate School of Electronics of the West | Andrade A.,Federal University of Bahia
Proceedings - 2011 IEEE 9th International Conference on Web Services, ICWS 2011 | Year: 2011

Service oriented Architecture (SOA) has been widely used in service computing applications and this fact has been encouraged the publication over the Web in a Web Service format. Whereas the number of Web services published on the Web is growing up, discovery techniques must be improved so as to retrieve more desirable services. Nowadays, the most commonly used technique is semantic filters based on ontological concepts. However, such mechanisms can leave out some important Web services of the matching process, because of their structural relationship not mentioned in an ontology. In order to overcome such problems, some authors have proposed a hybrid approach to combine traditional syntactic and semantic approaches. These proposals remain restricted especially with respect to complexity, precision and time of execution, thus making such solutions in most of cases unfeasible. In this paper, we combine semantic filters based on functional properties with a structural approach, analyzing each neighbor relationship in an ontology. The results showed a considerable improvement in terms of performance and a complexity reduction with respect to other existing techniques. Furthermore, we implement a tool called OWLS-S Discovery in order to simplify the use of our approach by developers. © 2011 IEEE.


Moreau S.,CNRS Acoustic Lab of Du Maine University | Plantier G.,Graduate School of Electronics of the West | Valiere J.-C.,University of Poitiers | Bailliet H.,University of Poitiers | Simon L.,CNRS Acoustic Lab of Du Maine University
Experiments in Fluids | Year: 2011

Spectral estimation of irregularly sampled velocity data issued from Laser Doppler Anemometry measurements is considered in this paper. A new method is proposed based on linear interpolation followed by a deconvolution procedure. In this method, the analytic expression of the autocorrelation function of the interpolated data is expressed as a linear function of the autocorrelation function of the data to be estimated. For the analysis of both simulated and experimental data, the results of the proposed method is compared with the one of the reference methods in LDA: refinement of autocorrelation function of sample-and-hold interpolated signal method given by Nobach et al. (Exp Fluids 24:499-509, 1998), refinement of power spectral density of sample-and-hold interpolated signal method given by Simon and Fitzpatrick (Exp Fluids 37:272-280, 2004) and fuzzy slotting technique with local normalization and weighting algorithm given by Nobach (Exp Fluids 32:337-345, 2002). Based on these results, it is concluded that the performances of the proposed method are better than the one of the other methods, especially for what concerns bias and variance. © 2010 Springer-Verlag.


Signolet I.,University of Angers | Henni S.,University of Angers | Colas-Ribas C.,University of Angers | Feuilloy M.,Graduate School of Electronics of the West | And 2 more authors.
European Journal of Vascular and Endovascular Surgery | Year: 2016

Objective In patients with claudication, an ankle brachial index (ABI) under 0.90 is considered to be abnormal and a sufficient argument for the arterial origin of exercise induced pain. Exercise transcutaneous oxygen pressure (Ex-tcpO2) can provide evidence of exercise induced regional blood flow impairment (RBFI) and confirm the arterial origin of walking induced pain. The frequency with which calf Ex-tcpO2 remains apparently normal in patients with claudication and abnormal ABI is unknown. Causes of these discrepant results have yet to be analysed. Methods A retrospective analysis of 4575 Ex-tcpO2 tests performed on 3,281 patients was conducted. The focus was on patients with a history of calf claudication and ABI under 0.90. Duplicate or non-standard tests were excluded, as were patients with no pain or those able to walk more than 15 minutes (on a treadmill). Searches were conducted for possible explanations of normal calf Ex-tcpO2 in the selected patients. Results Cardiorespiratory limitation was identified in 50 patients and isolated non-calf ischemia in 36 of the 106 patients selected. There was no obvious explanation during Ex-tcpO2, but clinical improvement after non-vascular treatment or total absence of improvement after a technically successful revascularisation was noted in 12 patients. Four patients were lost on follow up. Four patients improved after revascularisation, which suggests that the Ex-tcpO2 result was false negative. Conclusions Ex-tcpO2 is negative in more than 20% of tests performed in patients with an ABI under 0.90 and a history of calf claudication. In most cases, when excluding re-tests and non-limiting or non-calf claudication on the treadmill, non-calf ischemia or a non-vascular limitation occurring during the test were observed. This observation supports both the value of treadmill testing in patients with calf claudication assumed to be of arterial origin (ABI<0.90) and the use of Ex-tcpO2 to detect non-calf ischemia. © 2015 European Society for Vascular Surgery.


PubMed | University of Angers and Graduate School of Electronics of the West
Type: Comparative Study | Journal: European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery | Year: 2016

In patients with claudication, an ankle brachial index (ABI) under 0.90 is considered to be abnormal and a sufficient argument for the arterial origin of exercise induced pain. Exercise transcutaneous oxygen pressure (Ex-tcpO2) can provide evidence of exercise induced regional blood flow impairment (RBFI) and confirm the arterial origin of walking induced pain. The frequency with which calf Ex-tcpO2 remains apparently normal in patients with claudication and abnormal ABI is unknown. Causes of these discrepant results have yet to be analysed.A retrospective analysis of 4575 Ex-tcpO2 tests performed on 3,281 patients was conducted. The focus was on patients with a history of calf claudication and ABI under 0.90. Duplicate or non-standard tests were excluded, as were patients with no pain or those able to walk more than 15 minutes (on a treadmill). Searches were conducted for possible explanations of normal calf Ex-tcpO2 in the selected patients.Cardiorespiratory limitation was identified in 50 patients and isolated non-calf ischemia in 36 of the 106 patients selected. There was no obvious explanation during Ex-tcpO2, but clinical improvement after non-vascular treatment or total absence of improvement after a technically successful revascularisation was noted in 12 patients. Four patients were lost on follow up. Four patients improved after revascularisation, which suggests that the Ex-tcpO2 result was false negative.Ex-tcpO2 is negative in more than 20% of tests performed in patients with an ABI under 0.90 and a history of calf claudication. In most cases, when excluding re-tests and non-limiting or non-calf claudication on the treadmill, non-calf ischemia or a non-vascular limitation occurring during the test were observed. This observation supports both the value of treadmill testing in patients with calf claudication assumed to be of arterial origin (ABI<0.90) and the use of Ex-tcpO2 to detect non-calf ischemia.


Daraban S.,Technical University of Cluj Napoca | Petreus D.,Technical University of Cluj Napoca | Morel C.,Graduate School of Electronics of the West
Energy | Year: 2014

This article presents a novel MPPT (maximum power point tracking) algorithm, based on a modified GA (genetic algorithm). When photovoltaic systems are affected by partial shading, a GMPPT (global maximum power point tracking) algorithm is required to increase the energy harvesting capability of the system. A new GMPPT algorithm is proposed in this article: a P&O (perturb and observe) algorithm is integrated inside the GA function and creates a single algorithm. By embedding a simple MPPT algorithm (P&O) inside the structure of the GA, the population size and the number of iterations are decreased, thus finding the MPP (maximum power point) in a shorter time. The algorithm parameters (population size, number of genes, and number of iterations) are optimized and the final solution is provided. A macromodel is used to average the real DC-DC converter and reduce the computation burden of the simulator, thus reducing the simulation time. The control part and the GMPPT algorithm were implemented on a DSP (digital signal processor) and tested on an experimental small scale photovoltaic system. A description of this algorithm and its performances are detailed in this article, verified through simulation and experimental results. © 2014 Elsevier Ltd.


Petreus D.,Technical University of Cluj Napoca | Daraban S.,Technical University of Cluj Napoca | Ciocan I.,Technical University of Cluj Napoca | Patarau T.,Technical University of Cluj Napoca | And 2 more authors.
Solar Energy | Year: 2013

This paper presents a novel control and modulation technique applied to a low cost single stage solar micro-inverter. Multiple modulation strategies are analysed and finally an optimal one is proposed and implemented in order to obtain a low total harmonic distortion factor and a power factor close to unity of the current supplied to the grid. The luminosity step time response of the system is improved using two analog control loops: a hysteresis current mode control loop and a voltage loop on the input solar panel voltage. A MPPT power loop is also implemented in order to harvest maximum energy from the solar panel. The simulation times of the entire system is improved by implementing an average model for the inverter. In this way multiple control strategies and MPPT algorithms can be tested and compared in a shorter time. The experimental results validate the theoretical and simulated ones. © 2013 Elsevier Ltd.


Morel C.,Graduate School of Electronics of the West | Vlad R.,Graduate School of Electronics of the West | Chauveau E.,Technical University of Cluj Napoca
Nonlinear Dynamics | Year: 2010

This paper proposes a method to generate several independent periodic attractors, in continuoustime nonchaotic systems (with an equilibrium point or a limit cycle), based on a switching piecewise-constant controller. We demonstrate here that the state space equidistant repartition of these attractors is on a precise zone of a precise curve that depends on the parameters of the system. We determine the state space domains where the attractors are generated from different initial conditions. A mathematical formula giving their maximal number in function of the controller piecewise-constant values is then deduced. Throughout this study, the proposed methodology is illustrated with several examples. Copyright © 2009 Springer Science+Business Media B.V.


Petreus D.,Technical University of Cluj Napoca | Patarau T.,Technical University of Cluj Napoca | Daraban S.,Technical University of Cluj Napoca | Morel C.,Graduate School of Electronics of the West | Morley B.,AnaCores Ltd.
Solar Energy | Year: 2011

In this paper, a new maximum power point tracking (MPPT) system for photovoltaic applications is presented. The proposed system consists of two analog loops, a current and a voltage loop, built around a boost converter and a digital loop for the computation of the maximum power point. The analog loops provide a fast response to sudden changes of irradiance conditions while the digital loop, enhancing the accuracy, allows the implementation of various MPPT algorithms and facilitates the integration of additional control and monitoring features. Different existing systems are simulated and compared. A small signal model for the proposed system is developed and a novel compensation method is found. The compensation is designed in such a way that it makes the system independent of the input panel used and also of the load connected at the output. In order to have fast simulation results, a macromodel is developed allowing comparison between different algorithms. Furthermore the " perturb and observe" (P&O) algorithm is improved to obtain a better response for changing irradiance conditions. © 2011 Elsevier Ltd.


Bouchouicha D.,National Engineering School of Tunis | Latrach M.,Graduate School of Electronics of the West | Sakli H.,National Engineering School of Tunis
International Journal on Communications Antenna and Propagation | Year: 2012

A new design of Ultra Wide-Band circular slots antenna fed by Co-Planar Waveguide (CPW) is presented in this paper. Antenna impedance and bandwidth are studied as function of the radius and the centers positions of two circular slots. Consequently, the broadband operation is achieved by adjusting, a shape of the ended CPW-fed. The obtained impedance bandwidth, assuming a limit of-10 dB return loss, is from 2.3 GHz to 20 GHz (about 159% fractional bandwidth). The peak gain increases from 4 dBi to 8 dBi according to the use frequency. The proposed antenna is characterized by the simplicity in design and feeding, a very low cost and by a relatively stable radiation pattern over larger part of the bandwidth. © 2012 Praise Worthy Prize S.r.l.-All rights reserved.


Bouchouicha D.,STMicroelectronics | Latrach M.,Graduate School of Electronics of the West | Dupont F.,STMicroelectronics | Ventura L.,University of Tours
European Microwave Week 2010, EuMW2010: Connecting the World, Conference Proceedings - European Microwave Conference, EuMC 2010 | Year: 2010

In this paper, we present a study of RF energy harvesting devices. The surrounding RF power density was measured. The average of the total radiation power density in broadband (1GHz-3.5GHz) is in the order of -12dBm/m 2 (63μW/m 2). The maximum of the RF density power is measured in 1.8GHz-1.9GHz frequency band, it is around -14dBm/m 2. Two rectifiers have been designed and simulated at 1.85GHz and 2.45 GHz. The choice of the load to optimize the recovered DC power is studied, and the various antennas were optimized and evaluated. Multiple rectennas have been designed to recover the ambient RF energy. The best performance is obtained with a spiral antenna. © 2010 EuMA.

Loading Graduate School of Electronics of the West collaborators
Loading Graduate School of Electronics of the West collaborators