Imposed Switching Frequency Direct Torque Control of Induction Machine Using Five Level Flying Capacitors Inverter

The paper proposes a new control structure for sensorless induction motor drive based on a five-level voltage source inverter (VSI). The output voltages of the five-level VSI can be represented by nine groups. Then, the amplitude and the rotating velocity of the flux vector can be controlled freely. Both fast torque and optimal switching logic can be obtained. The selection is based on the value of the stator flux and the torque. This paper investigates a new control structure focused on controlling switching frequency and torque harmonics contents. These strategies, called ISFDTC, indeed combines harmoniously both these factors, without compromising the excellence of the dynamical performances typically conferred to standard DTC strategies. The validity of the proposed control technique is verified by Matlab/Simulink. Simulation results presented in this paper confirm the validity and feasibility of the proposed control approach and can be tested on experimental setup.Peer reviewe

Fast, Efficient and Environmentally Friendly Extraction of Cu(II) and Zn(II) by Hybrid Silicas Impregnated with Acidic Organic Extractants

The extraction of copper and zinc by mesostructured silicas impregnated with organic acidic chelators, an acylisoxazolone 3-phenyl-4-benzoyl-5-isoxazolone (HPBI), an acylpyrazolone 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP) and an organophosphoric acid di-(2-ethylhexyl)-phosphoric acid (DEHPA) was performed in a sulfate medium. Various factors such as the pH of the aqueous phase, the chelators concentration in the silica matrix, the extraction equilibrium time and the extraction capacity of the two cations on silica were studied. The cations were extracted at very acidic pH with very high extraction rates. The stripping of cations was achieved at pHs that were more acidic than those utilized for the extraction by maintaining the structure intact. Finally, their separation was successfully conducted in the cases of the three chelators

Controlling the Trade-Off between Resource Efficiency and User Satisfaction in NDNs Based on Naïve Bayes Data Classification and Lagrange Method

[EN] This paper addresses the fundamental problem of the trade-off between resource efficiency and user satisfaction in the limited environments of Named Data Networks (NDNs). The proposed strategy is named RADC (Resource Allocation based Data Classification), which aims at managing such trade-off by controlling the system's fairness index. To this end, a machine learning technique based on Multinomial Naive Bayes is used to classify the received contents. Then, an adaptive resource allocation strategy based on the Lagrange utility function is proposed. To cache the received content, an adequate content placement and a replacement mechanism are enforced. Simulation at the system level shows that this strategy could be a powerful tool for administrators to manage the trade-off between efficiency and user satisfaction.This work is derived from R&D project RTI2018-096384-B-I00, funded by MCIN/AEI/ 10.13039/501100011033 and "ERDF A way of making Europe".Herouala, AT.; Kerrache, CA.; Ziani, B.; Tavares De Araujo Cesariny Calafate, CM.; Lagraa, N.; Tahari, AEK. (2022). Controlling the Trade-Off between Resource Efficiency and User Satisfaction in NDNs Based on Naïve Bayes Data Classification and Lagrange Method. Future Internet. 14(2):1-14. https://doi.org/10.3390/fi1402004811414

Magnetic field evaluation around 400 kv underground power cable under harmonics effects

Power lines or underground power cables generate electromagnetic interaction with other objects near to them. This study evaluates the magnetic field emitted by underground extra high voltage cables. The presented work aims to show a numerical simulation of the magnetic field of a buried 400 kV underground power line, which is used as a novel prototype in several countries at a short distance. The underground power cable study, in the presence of the current harmonics at different positions, with time variation by finite element resolution, using Comsol Multiphysics with Matlab software in two dimensions. The simulation results illustrate the magnetic flux density variation-in terms of amplitude and distribution as a function of different actual harmonics rates. The underground cable performance and magnetic field have affected by the harmonics effects. The maximum magnetic induction levels generated by significant harmonics are superior to the limits recommended by the international standard norms. In this paper, shielding has been used as an appropriate remedy to attenuate the magnetic field

Utilisation de la télédétection pour la cartographie de l’occupation du sol : cas des monts de Beni-Chougrane (Mascara-Algerie Nord Occidentale)

La cartographie rapide de l’occupation du sol permet d’appréhender la dynamique des formations végétales et contribuera à mieux aménager les espaces. La télédétection constitue un outil permettant de répondre à cette préoccupation. La carte d’occupation du sol obtenue par la méthodes universelle (Corine Land cover ) est répartie en unités et en classes d’occupation dans la zone étudiée. La classification supervisée a permis de regrouper et de classer les différents objets au sol en fonction des finalités que nous nous étions fixées au départ. Ainsi il a été obtenu 9 classes d’occupation du sol : eau, verger, matorral, pelouse, végétation clairsemée, sol nu, oléo-lentisque et forêts. Cette distribution permet de suivre la dynamique de ces entités et de cartographier leur évolution. La cartographie obtenue permettra de mettre en place par entité les principales recommandations d’aménagement. Une synthèse cartographique assistée par l’ordinateur constitue donc un outil permettant d’appréhender dans de meilleures conditions toute approche d’aménagement

De la culture cultivée à l’enseignement de la culture en Algérie dans un contexte plurilingue

International audienceEn classe de langue vivante ou étrangère, la langue est le moyen par lequel les professeurs enseignent et c'est par ce même code que les élèves démontrent ce qu'ils ont appris. L'acquisition de cette langue est l'objectif pédagogique de l'enseignement-apprentissage des langues vivantes ou étrangères. C'est ainsi que le comportement verbal et non-verbal de l'apprenant en classe de langue étrangère prend une forme complexe. Il existe alors un écart entre son modèle de communication acquis dans la culture d'appartenance et celui qui s'établit en classe de français langue étrangère. L'enseignement-apprentissage du français, en tant que langue étrangère, en Algérie est situé dans une culture étrangère. L'apprenant algérien est l'héritier de sa culture d'origine. Sa vision du monde est formatée par sa culture d'origine. Il interprète la réalité à travers la grammaire de sa culture. En effet, l'enseignement des langues s'opère toujours dans un contexte de contacts entre deux ou plusieurs cultures. Chacune d'elles possède une dignité et une valeur qui doivent être respectées et préservées : « Toute culture est liée à une culture d'ensemble, qui la caractérise et qui est elle-même le résultat de très nombreuses cultures plus petites, plus sectorisées. Une culture est un ensemble de pratiques communes, de manières de voir, de penser, et de faire, qui contribuent à définir les appartenances des individus, c'est-à-dire les héritages partagés dont ceux-ci sont les produits et qui constituent une partie de leur identité.» (L.Porcher, 1995 : 55). L'approche d'une autre culture, voire l'intériorisation de certains de ces aspects, a donc une visée externe, mais permet, bien entendu, en la modifiant partiellement, d'affirmer une identité individuelle. Par ailleurs, dans un contexte algérien où coexistent plusieurs langues qui entrent en conflit, au gré des référents des discours actualisés, un travail sur les représentations permet de situer le même par rapport à l'Autre et inversement. À la suite de Richard (1990 : 70) nous soutenons qu'« En parlant de la différence de l'autre, le sujet affirme sa propre différence ». Nous saisissons pleinement ce processus dans l'acte de dénomination. Dénommer l'autre, c'est avant tout se dénommer soi-même dans un flux/reflux d'éloignement ou de rapprochement des protagonistes de l'échange fictif que suscite l'enseignement –apprentissage du FLE (Benali & Guehria 2013)

Chemical composition and biological activity of Salvia ofcinalis L. essential oil against Aphis fabae Scopoli (Hemiptera: Aphididae)

This study investigated chemical composition, repellent and biocidal activities of Salvia ofcinalis essential oil against Aphis fabae. In total, 19 major components were identifed by gas chromatography/mass spectrometry. The major constituents in S. ofcinalis essential oil were determined as 1,8 cineole (11.40%), β- Selinene (11.26%), Camphor (9.50%),α-Thujone (8.80%), and Caryophyllene (8.19%). The efect of the diferent concentrations (0.01, 0.02, 0.04, 0.08 and 1.16 μl/cm2 ) of the S. ofcinalis essential oil were tested on the apterous adult of A. fabae under laboratory conditions. Bioassays were conducted using the area preference and the flter paper methods for testing repellency and insecticidal activities. The S. ofcinalis essential oil showed strong repellent activity (95.0±5.77%) against A. fabae when used the highest concentration (0.16 μl/cm2 ) for 24 h. The average percent repellency (PR) was of 75.50±15.38%. Furthermore, S. ofcinalis essential oil resulted in high mortality, even when applied at low concentrations. LC50 was 0.027 µl/cm2 at 24 h while the LT50 ranged from 49.615 to 5.666 h at the lowest (0.01 μl/cm2 ) and the highest (0.16 μl/cm2 ) concentrations, respectively. This is the frst study on the biological activity of S. ofcinalis essential oil against A. fabae

Relative-Identity Management Based on Context

International audienceMobile devices nowadays are equipped with sensors and technologies that enable context evaluation. Those devices are not expensive in such a way that everyone can buy a smart phone easily. So, developing mobile context-awareness applications for helping dependent persons to deal with their everyday tasks is crucial. This paper aims to develop a new identities manage-ment system that runs on the dependent person's mobile device. This agent will assist dependent persons by giving them information, advices, instructions and helps regarding their activities of daily living. The main idea is to use a simple communication way to identify objects and subjects in the surrounding context of the assisted person. In this paper we propose efficient identification mecha-nisms that take benefit from our well understanding of the context. Our ap-proach simplifies the use of the interaction between dependent persons and the agent. Hence, unlike usual approaches, the identity of a given entity will not be universal by widely tailored to the current person’s context. In the case where the context is shared by many entities with the risk of identification ambiguity, our identification could use different means such as colors or locations towards others for identification of entities

Cu (II) Extraction from Sulfate Media by Functionalized Algerian Bentonites

International audienc