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Kenitra, Morocco

Lamnii A.,University Hassan First | Mraoui H.,University Mohammed Premier
Computer Aided Geometric Design | Year: 2015

In this paper, we show how to construct a normalized B-spline basis for a special C1 continuous splines of degree 2, defined on Sibson-Thomson refinement. The basis functions have a local support, they are nonnegative, and they form a partition of unity. The dilatation equation can be found by applying the dyadic subdivision scheme directly to the Sibson-Thomson spline basis functions. As an application, a quasi-interpolation method, based on this Sibson-Thomson B-spline representation, is described which can be used for the efficient visualization of gridded surface data. ©2014 Elsevier B.V. All rights reserved. Source

Lamnii A.,University Hassan First | Mraoui H.,University Mohammed Premier
Computer Aided Geometric Design | Year: 2015

The purpose of this article is the construction of a normalized basis for a quadratic condensed Powell-Sabin-12 macro-element space introduced by Alfeld et al. (2010). The basis functions have a local support, they are nonnegative, and they form a partition of unity. The construction of this basis is adopted from Dierckx (1997) and Speleers (2010a), and is based on the determination of a set of triangles that must contain a specific set of points. The proposed basis can only be constructed on triangulations with a maximal angle less than π/2. © 2015 Elsevier B.V. All rights reserved. Source

Touati A.,Hassan 1er University | Abdelmounim E.,1st University | Aboulfatah M.,The Technological Institute of Bordeaux University | Moutabir A.,University Hassan First | Majdoul R.,1 University F
International Review on Modelling and Simulations | Year: 2015

This paper proposes a new adaptive control for Maximum Power Point Tracking (MPPT) in variable-speed wind turbine systems based on a doubly fed induction generator (DFIG). The proposed control does not neglect the dynamic of the drive train, when the conventional strategy considers that the aerodynamic torque is supposed to be equal to the mechanical torque. This assumption is not realistic, especially for turbulent winds. The closed loop control using a high-order sliding mode allows the generator to track the optimal operation points of the wind turbine system under fluctuating wind conditions. This improves the quality of energy, energy efficiency and presents attractive features. To meet at all times the LVRT requirements, a technique using a dynamic voltage restorer system (DVR) is developed to compensate the faulty line voltage, especially for grid disturbances, while the doubly fed induction generator (DFIG) can continue its nominal operation as demanded in actual grid codes. Simulation is carried out in SimPower toolbox of Matlab/Simulink. Simulation results confirm the effectiveness of the proposed control methods and shown that the controllers meet its objectives. © 2015 Praise Worthy Prize S.r.l. - All rights reserved. Source

Gherabi N.,University Hassan First | Gherabi A.,Laval University | Bahaj M.,University Hassan First
International Conference on Multimedia Computing and Systems -Proceedings | Year: 2011

We propose a new method for shape recognition and retrieval based on dynamic programming. Our approach uses the dynamic programming algorithm to compute the optimal score and to find the optimal alignment between two strings. First, each contour of shape is represented by a set of points. After alignment and matching between two shapes, the contours are transformed into a string of symbols and numbers. Finally we find the best alignment of two complete strings and compute the optimal cost of similarity. In general, dynamic programming has two phases - the forward phase and the backward phase. In the forward phase, we compute the optimal cost for each subproblem. In the backward phase, we reconstruct the solution that gives the optimal cost. Our algorithm is tested in a database that contains various shapes such as MPEG-7. © 2011 IEEE. Source

Inaam E.-M.,University Hassan First | Inaam E.-M.,Morocco National Institute of Agronomic Research | Sara H.,University Hassan First | Mohamed E.,University Hassan First | And 2 more authors.
Portugaliae Electrochimica Acta | Year: 2016

The essential oil of Artemisia herba alba has been extracted and tested as an inhibitor of lead corrosion in 0.1 M Na2CO3 medium, using stationary and transient electrochemical techniques. The results obtained show that the essential oil of Artemisia reduces the corrosion rate. The effectiveness of inhibition increases with the oil concentration to reach 77 % with 2000 ppm. The effect of temperature was also studied. © 2016, Sociedade Portuguesa de Electroquimica. All rights reserved. Source

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