Torque estimator using MPPT method for wind turbines

In this work, we presents a control scheme of the interface of a grid connected Variable Speed Wind Energy Generation System based on Doubly Fed Induction Generator (DFIG). The vectorial strategy for oriented stator flux GADA has been developed To extract the maximum power MPPT from the wind turbine. It uses a second order sliding mode controller and Kalman observer, using the super twisting algorithm. The simulation describes the effectiveness of the control strategy adopted.For A step and random profiles of the wind speed, reveals better tracking and perfect convergence of electromagnetic torque and concellation of reactive power to the stator. This control limits the mechanical stress on the tansmission shaft, improves the quality of the currents generated on the grid and optimizes the efficiency of the conversion chain

Interference model and evaluation in LTE networks

International audienceThe purpose of this paper is to evaluate the impact of frequency parameter settings while evaluating interference model in LTE (Long Term Evolution); the work is applied on a network. We develop and validate the interference model based on SINR which is used by 3GPP (3rd Group Partnership Project) to estimate the quality of signal received by UE (User Equipment) and issued from eNB (enhanced Node Base). For this aim, two frequency schemes have been compared: the frequency reuse 1 scheme whereby the whole available bandwidth is used in each cell/sector and the frequency reuse 3 scheme in which the entire bandwidth is divided into 3 non-overlapping groups and assigned to 3 co-site sectors within each cell

Optimisation robuste dans les réseaux de radiocommunications

National audienceLes réseaux de communication mobile doivent écouler un trafic de plus en plus important. Pour ce faire, les réseaux auto-organisés SON (Self Organizing Networks) proposent des solutions qui visent à augmenter leur capacité en s'adaptant le mieux possible à la demande des clients. Dans ce cadre, la future norme de téléphonie mobile LTE [1] inclut des fonctions d'auto-organisation dont le but de réduire à la fois la complexité du paramétrage, les coûts d'investissements et les coûts d'exploitation. Notre étude porte sur l'optimisation du paramétrage de réseaux de communication mobile. Les données d'entrée du modèle sont les demandes en trafic des clients. Elles proviennent de prévisions et sont donc incertaines. Nous présentons alors une optimisation robuste qui permet de trouver de bons paramètrages, peu sensibles aux variations de trafic

A new model for indoor WLAN positioning system

National audienceIn this paper we attempt to answer the following question : how to deploy a WLAN in order to guarantee the requested Quality of Service (QoS) while reducing the location error ? Such a problem includes two aspects : WLAN planning and positioning error reduction. To provide users an optimal wireless access to their local network, WLAN planning not only consists in selecting a location for each transmitter and setting the parameters of all sites, but also acts on allocating one of the available frequencies to each Access Point (AP) configuration [1]. And toward the indoor positioning system, once the Received Signal Strengths (RSSs) from all visible APs are measured and inputted, the location is estimated and outputted using the RSS distribution and machine learning technique [2]. We propose a new approach where WLAN planning and positioning error reduction are modeled as an optimization problem and tackled together during WLAN planning process

iPedagogique : une application d'apprentissage multi-usages intégrant une pédagogie de projets tutorés basée sur la synchronisation de fragments de procédés coopératifs.

International audienceL'enseignement d'unités de valeurs scientifiques ou techniques est largement fondé sur l'acquisition de connaissances conceptuelles et la validation d'un savoir-faire. Au cours d'une formation, l'apprenant et l'enseignant doivent être efficaces tant du point de vue quantitatif que qualitatif, tout spécialement en surmontant des difficultés organisationnelles, en introduisant (ou acquérant selon) des compétences implicites à la conduite ou la gestion de projet, en bénéficiant d'une aide à la synchronisation. Nous présentons les grandes lignes d'une application auteur en expérimentation dans une école d'ingénieurs généralistes et dans deux formations Multimédia (IUT, IUP). Tout particulièrement nous rapportons l'intégration expérimentale réussie de la pédagogie par projets. Nous présentons un méta modèle de procédés coopératifs de gestion de projet d'une entreprise pédagogique éphémère. Nous l'illustrons expérimentalement et nous poursuivons l'étude par la présentation des prémisses d'un système d'aide multi-usages

Interference model and antenna parameters setting effects on 4G-LTE networks coverage

International audienceThe currently emerging Long Term Evolution 4G-LTE cellular networks are based on new technique of transmission called the Orthogonal Frequency Division Multiple Access (OFDMA). This paper shows the interest of robust approach due to the uncertainty of traffic distribution. First, we develop and validate the interference model based on SINR metric for the deployment of the LTE network, and then we use greedy algorithms to show how frequency and tilt parameter settings can impact the coverage performance metric. Two frequency schemes have been compared to validate our model: the frequency reuse 1 scheme whereby the whole available bandwidth is used in each cell/sector and the frequency reuse 3 scheme in which the entire bandwidth is divided into 3 non-overlapping groups and assigned to 3 co-site sectors within each cell

Impact des paramètres antennaires sur la couverture dans les réseaux LTE

National audienceLa demande en trafic dans les réseaux de radiocommunication a augmenté d'une manière vertigineuse ces dernières années [3]. Dans les réseaux LTE (Long Term Evolution), plusieurs recherches sur le paramétrage des antennes [1, 2] ont été effectuées pour répondre aux besoins des utilisateurs et augmenter les performances du système. Diverses combinaisons de paramètres d'antenne ont été étudiées en termes de performance en SINR (Signal to Interference plus Noise Ratio) et en débit [1, 2]. Nous proposons d'évaluer à la fois le SINR et le débit pour différents schémas de fréquence dans le cas d'un réseau LTE. Ce dernier est construit sur la base d'un réseau GSM/UMTS réel tri-secteurs (Territoire de Belfort), pour lequel le trafic est translaté sur le mode LTE. Ce travail permet d'analyser finement les stations mobiles (position, signal reçu, débit offert...) durant toute une journée de trafic. Nous proposons une méthodologie pour modifier automatiquement certains paramètres antennaires (tilt, fréquence d'émission) afin que le réseau réponde au mieux aux variations de trafic et d'environnement

Les incidences du contexte sociolinguistique sur l’enseignement-apprentissage du français dans le Sud algérien

Cette contribution, issue de ma thèse, cherche à cerner le statut de la langue française dans une région située dans le Sud-Est algérien, le Souf. Le présent texte tente de comprendre les caractéristiques des représentations d’enseignants du primaire concernant les incidences du contexte sociolinguistique sur l’enseignement-apprentissage du français dans cette région et d’en tirer quelques interprétations. L’étude s’appuie sur des données recueillies par questionnaires et complétées par une série d’entretiens semi-directifs.This contribution is part of a doctoral research which aims at studying the impact of the sociolinguistic context in which French is taught and learnt in the Souf region in South-Eastern Algeria. It will aim at identifying the status of French in this region and at studying its influence on French teaching and learning. The status of French in the Souf is determined by three parameters, as shown by data collected through questionnaires and semi-directive interviews : attitudes towards French, the influence of society and family in its teaching and learning and representations of its use in Sufi society

Distributed Maintenance of Anytime Available Spanning Trees in Dynamic Networks

We address the problem of building and maintaining distributed spanning trees in highly dynamic networks, in which topological events can occur at any time and any rate, and no stable periods can be assumed. In these harsh environments, we strive to preserve some properties such as cycle-freeness or the existence of a root in each tree, in order to make it possible to keep using the trees uninterruptedly (to a possible extent). Our algorithm operates at a coarse-grain level, using atomic pairwise interactions in a way akin to recent population protocol models. The algorithm relies on a perpetual alternation of \emph{topology-induced splittings} and \emph{computation-induced mergings} of a forest of spanning trees. Each tree in the forest hosts exactly one token (also called root) that performs a random walk {\em inside} the tree, switching parent-child relationships as it crosses edges. When two tokens are located on both sides of a same edge, their trees are merged upon this edge and one token disappears. Whenever an edge that belongs to a tree disappears, its child endpoint regenerates a new token instantly. The main features of this approach is that both \emph{merging} and \emph{splitting} are purely localized phenomenons. In this paper, we present and motivate the algorithm, and we prove its correctness in arbitrary dynamic networks. Then we discuss several implementation choices around this general principle. Preliminary results regarding its analysis are also discussed, in particular an analytical expression of the expected merging time for two given trees in a static context.Comment: Distributed Maintenance of Anytime Available Spanning Trees in Dynamic Networks, Poland (2013

Optimization of the Deployment of Wireless Sensor Networks Dedicated to Fire Detection in Smart Car Parks using Chaos Whale Optimization Algorithm

Smart Car Parks (SCPs) based on Wireless Sensor Networks (WSNs) are one of the most interesting Internet of Things applications. This paper addresses the deployment optimization problem of two-tiered WSNs dedicated to fire monitoring in SCPs. Networks deployed inside the SCP consist of three types of nodes: Sensor Nodes (SNs) which cover the spots within the parking area, Relay Nodes (RNs) which forward alert messages generated by SNs, and the Sink node which is connected to the outside world (e.g, firefighters), through a high bandwidth connection. We propose an algorithm based on chaos theory and Whale Optimization Algorithm (WOA), which minimizes simultaneously the deployed number of SNs, RNs, and network diameter while ensuring coverage and connectivity. To evaluate the effectiveness of our proposal, we have conducted extensive tests. The results show that the Chaos WOA (CWOA) outperforms the original WOA in terms of solution quality and computation time and by comparison with an exact method, CWOA provides results very close to the optimal in terms of fitness value and is efficient in terms of computational time when the problem becomes more complex