125 research outputs found

    The King’s Jester

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    DOI: 10.7176/JLLL/89-01 Publication date:June 30th 2022   For an epigraph of Le Fou du Roi [1], Binebine chooses,  to quote Victor Hugo who describes the jester’s job as follows:  « Poor red tail! Countless are the pains and numerous the sorrows in a buffoon’s gaiety!  What everlasting and incurable pains, what lugubrious occupation laughter is! ». When reading this, one wonders whether the narrative which is about to unfold, tells the story of the monarch or that of his jester. To this one may only go back to the title of the book which clearly sets the mood and the narrative mode: We are about to read the personal experience of the King’s favorite jester with his master. As a narrator, Lefqih is both a stakeholder and an onlooker. He partakes in, and witnesses, the servility of the courtiers. He, in an attempt to read and sound objective, describes his own «obsequiousness » before his master: « I was, as usual, closely following him with a slightly bent back, a little obsequious as appropriate when one is escorting the king. » The French journalist, Jacques Martin, who used to host the very popular French T.V. program  «l’école des Fans (the School of Fans) » in the late eighties of last century, once asked a kid who was taking part in the program’s broadcast, «What job would you like to have when you grow up? »  The child’s answer was as follows: «Je veux devenir banquier (I would like to become a banker)» and when asked why, the young boy replied, « Dans ce mĂ©tier on gagne beaucoup d’argent! [2] » In the child’s reply one can obviously pinpoint a lot of naĂŻvetĂ©. The question worth asking, however, is whether this gullibility is proper to children only. How about a pastry chef? Does he consume a lot of the cakes he makes? And how about a tailor? Does he dress himself in the best garments of the city? The answer unfortunately may sometimes sound shocking, or (at best) unexpectedly surprising! The reason I have chosen to start the present essay with the mentioning of this case is that the child of Jaques Martin’s program is within every one of us. We all tend to think that a mechanic must be driving the best car; that a cook must inevitably be making the best dishes for himself, and so it goes. But how about a buffoon? Does his job, as a jester, make of him the happiest person on earth? A Moroccan proverb seems to answer the above Question. The proverb  goes as follows: though a butcher, he has turnips for dinner! This may fit perfectly the case of Mahi Binebine’s main character in Le Fou du Roi (The King’s Jester). The opening sentence of the novel illustrates the contrast between appearance and reality and seems to refute the false impression one may have that life behind the palace ramparts can be made  only of joy: « Everything looked normal, but nothing was really so ». This sentence (or rather statement) seems – in the opening page of the novel – to   be used by the narrator as a refrain.  It is used four times to open the first four paragraphs of the first page of the novel. In what reads like a refrain, the repeated sentence, sets the mood and establishes the relation between this first person narrator and the novel’s main character (the King). An actual person who spent nearly forty years in the Royal Palace’s pavilions at the service of  Hassan II, Lefqih* Binebine – from the outset – seems somewhat to legitimize his presence through the intimate bonds which link him to the deceased monarch. From the outset, too, the tone of the narrative seems to herald an impending event which does not say its name: We are here being told about the last hours of the life of a monarch who ruled the country for thirty eight years (1961 - 1999). And when we know that the scene in question is chronicling the Monarch’s last hours, we come to realize that the narrative unfolds in a flashback mode. This last scene of the narrative, with which the novel starts, also portrays to the reader the attachment of the jester to his patron. « I had pains to see him suffer, but I was abstaining from showing it. I was endeavoring to be funny because it was my job to make my master laugh. » The irony of the situation is that the jester has no right to show his pain, since his job consists mainly in making his master laugh. The trouble, however, is that the master is in no mood to laugh. [1] Mahi Binebine, The King’s Jester, translated from the French by M’hammed Benjelloun. [2] Fr . « In this job, one earns a lot of money» * In Arabic the title  Al Faqih, which in the Moroccan dialect is pronounced Fqih, refers to someone who is well versed in theology. It is also a sign of respect shown to anyone called by this titl

    Semi-physical neural modeling for linear signal restoration

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    International audienceThis paper deals with the design methodology of an Inverse Neural Network (INN) model. The basic idea is to carry out a semi-physical model gathering two types of information: the a priori knowledge of the deterministic rules which govern the studied system and the observation of the actual conduct of this system obtained from experimental data. This hybrid model is elaborated by being inspired by the mechanisms of a neuromimetic network whose structure is constrained by the discrete reverse-time state-space equations. In order to validate the approach, some tests are performed on two dynamic models. The first suggested model is a dynamic system characterized by an unspecified r-order Ordinary Differential Equation (ODE). The second one concerns in particular the mass balance equation for a dispersion phenomenon governed by a Partial Differential Equation (PDE) discretized on a basic mesh. The performances are numerically analyzed in terms of generalization, regularization and training effort

    Conception et fabrication d’un transistor de puissance Ă  architecture verticale de type normally˗off Ă  base d’un rĂ©seau de nanofils de GaN

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    Du fait de ses propriĂ©tĂ©s physiques remarquables, le nitrure de gallium (GaN) est un matĂ©riau trĂšs attrayant pour la fabrication de composants pour l’électronique de puissance en commutation et Ă  haute tempĂ©rature. En outre, les transistors HEMT Ă  base de GaN sont les dispositifs les plus utilisĂ©s pour ces applications, dĂ» Ă  leur densitĂ© de courant Ă©levĂ©e et leur faible rĂ©sistance Ă  l’état passant. Cependant, en raison de la conduction latĂ©rale dans ces structures et Ă  l’absence d’un substrat accordĂ© en paramĂštre de maille, le mode normally-off constitue toujours un dĂ©fi. Les contraintes Ă  ce dĂ©veloppement sont principalement liĂ©es aux courants de fuite au niveau de la grille, de la couche tampon, ou Ă  l’interface avec le substrat, ainsi que la dĂ©gradation des propriĂ©tĂ©s de transport causĂ©e par les effets d’auto-Ă©chauffement. C’est pourquoi, nous proposons une nouvelle approche d’un transistor MOSFET de puissance Ă  conduction verticale basĂ©e sur une structure Ă  nanofils Ă  base de GaN. Ce concept permet non seulement une dissipation thermique optimale mais aussi une commande parfaite du canal conducteur via une grille enrobante et isolĂ©e. L’objectif Ă©tant de les rĂ©aliser sur substrat de silicium afin d’assurer un bas coĂ»t, reproductible, fiable et capable de fonctionner dans des environnements hostiles. Pour relever ces dĂ©fis, une simulation numĂ©rique d’un transistor vertical Ă  base d’un nanofil de GaN est rĂ©alisĂ©e au moyen de l’outil TCAD-Sentaurus afin d’optimiser les paramĂštres gĂ©omĂ©triques et physiques du dispositif afin d’obtenir un mode normally-off, stable Ă  fort champ. Pour cela, la structure a Ă©tĂ© optimisĂ©e en prenant en compte certains Ă©tats de surface, de maniĂšre Ă  minimiser les courants de fuite Ă  l’état bloquant et la rĂ©sistance Ă  l’état passant RON, de façon Ă  maximiser la tension de claquage. Deux approches diffĂ©rentes peuvent ĂȘtre mises en Ɠuvre pour Ă©laborer ces nanostructures. La premiĂšre est l’approche descendante (top-down), faisant appel Ă  la gravure de la surface de l’homo-structure, permet de contrĂŽler Ă  la fois le diamĂštre, la longueur (hauteur) et la densitĂ© des nanofils. Cette approche est particuliĂšrement adaptĂ©e pour rĂ©vĂ©ler les plans rĂ©ticulaires verticaux par voie chimique et donc minimiser les Ă©tats Ă©lectroniques de surface du MOSFET. La seconde approche dite ascendante (bottom-up) correspond Ă  rĂ©aliser une croissance Ă©pitaxiale compliante de nanofils de GaN au travers un masque de nano/micro-trous dans un diĂ©lectrique, sur un substrat de silicium. La technique de croissance utilisĂ©e dans cette Ă©tude est l’épitaxie par jets molĂ©culaires (MBE) assistĂ©e par plasma, laquelle assure dans cette configuration une croissance de nanofils exempt de dislocations traversantes. Ces procĂ©dĂ©s laissent entrevoir une amĂ©lioration drastique des performances Ă©lectroniques de ces composants. Les diffĂ©rentes Ă©tapes de la microfabrication du transistor par l’approche descendante ont Ă©tĂ© dĂ©veloppĂ©es (dĂ©pĂŽt de l’oxyde de grille, des couches de sĂ©paration, de la mĂ©tallisation de grille et des contacts de source/drain, etc.).Abstract: Due to its outstanding physical properties, gallium nitride (GaN) is an attractive material to lead the industry of power devices and high temperature switching. Furthermore, GaN-based HEMTs are the most widely used devices for these applications due to their high current density and low on-state resistance. However, because of the lateral conduction in these structures as well as the absence of lattice-matched substrate, the normally-off mode is still difficult to achieve. The obstacles to this development are mainly related to the leakage currents at the gate, the buffer layer, or at the interface with the substrate, as well as the degradation of the transport properties caused by self-heating effects. Therefore, we propose a new vertical conduction power MOSFET approach based on a GaN-based nanowire structure. This concept allows optimal thermal dissipation and perfect control of the conductive channel via a surrounding and isolated gate (GAA). The objective is to realize them on silicon substrate ensuring a low cost, reproducible, reliable, and able to operate in hostile environments. To meet these challenges, a numerical simulation of a vertical power transistor based on a single GaN nanowire is performed using the TCAD-Sentaurus simulator in order to optimize the geometrical and physical parameters of the device, to achieve a stable normally-off mode at high electric field. For this purpose, the structure has been optimized by considering surface states so as to minimize the leakage currents in the off-state and the on-state resistance (RON), then to maximize the breakdown voltage. Two technical approaches are used to elaborate these nanostructures. The first one is the top-down approach, which involved the etching of the homo-structure surface, allowing to control the diameter, the length (height) and the density of the nanowires. This approach is particularly suitable to reveal the vertical reticular planes by chemical process and thus minimizing the electronic surface states of the MOSFET. The second approach, called bottom-up, involves a compliant epitaxial growth of GaN nanowires through a mask of nano/micro-holes in a dielectric on a Si substrate. The technique used in this study is plasma-assisted molecular beam epitaxy (MBE), which ensures the growth of threading dislocation free nanowires. These processes promise a drastic improvement of the electronic performances of these components. The different steps of the microfabrication of the transistor by the top-down approach have been developed (deposition of gate oxide, separation layers, gate metallization and source/drain contacts, etc.)

    DU CHEVALET AU CHAPITRE: ÉCRITURE, PEINTURE ET FOLIE DANS BLEU INDIGO D'ANNE BRAGANCE

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    A Framework of Vertebra Segmentation Using the Active Shape Model-Based Approach

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    We propose a medical image segmentation approach based on the Active Shape Model theory. We apply this method for cervical vertebra detection. The main advantage of this approach is the application of a statistical model created after a training stage. Thus, the knowledge and interaction of the domain expert intervene in this approach. Our application allows the use of two different models, that is, a global one (with several vertebrae) and a local one (with a single vertebra). Two modes of segmentation are also proposed: manual and semiautomatic. For the manual mode, only two points are selected by the user on a given image. The first point needs to be close to the lower anterior corner of the last vertebra and the second near the upper anterior corner of the first vertebra. These two points are required to initialize the segmentation process. We propose to use the Harris corner detector combined with three successive filters to carry out the semiautomatic process. The results obtained on a large set of X-ray images are very promising

    Estimation of a semi-physical GLBE model using dual EnKF learning algorithm coupled with a sensor network design strategy: application to air field monitoring

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    International audienceIn this paper, we present the fusion of two complementary approaches for modeling and monitoring the spatio-temporal behavior of a fluid flow system. We also propose a mobile sensor deployment strategy to produce the most accurate estimate of the true system state. For this purpose, deterministic and statistical information was used. We adopted a filtering method based on a semi-physical model which derives from a fluid flow numerical model known as lattice Boltzmann model (LBM). The a priori physical knowledge was introduced by the Navier-Stokes equations which were discretized by the lattice Boltzmann approach. Moreover, its multiple-relaxation-time (MRT) variant not only improved the stability, but also enabled the introduction of additional degrees of freedom to be estimated like the synaptic weights of a neural network. The statistical knowledge was then introduced into the model by performing a sequential learning of these parameters and an estimation of the speed field of the fluid flow starting from measurements. The low spatial density of measurements, the large amount of data inherent to environmental issues and the nonlinearity of the generalized lattice Boltzmann equations (GLBE) enjoined us to use the ensemble Kalman filter (EnKF) for the recursive estimation procedure. A dual state-parameter estimation which results in a significantly reduced computation time was used by combining two filters consecutively activated in the same iteration. Finally, we proposed to complete the lack of spatial information of the sparse-observation network by adding a mobile sensor, which was routed to the location where the cell-by-cell output estimation error was the highest. Experimental results in the context of the standard lid-driven cavity problem revealed the presence of few zones of interest, where fixed sensors can be deployed to increase performances in terms of convergence speed and estimation quality. Finally, the study showed the feasibility of introducing some additional parameters which act as degrees of freedom, to perform large-eddy simulation of turbulent flows without numerical instabilities

    Apport De La Stratigraphie Sequentielle Dans L’evolution Jurassique Du Moyen Atlas Central (Maroc)

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    The Jurassic evolution of the central Middle Atlas is governed by various factors (climate and eustatism). The use of the concepts of sequential stratigraphy in the regions of Tagnamas and Boulemane allowed to interpret the geometry and the vertical sequence of sedimentary sets. Twelve sequences are identified and delimited by sedimentary discontinuities. The lithostratigraphic division adopted in this study is synchronous with the coastal aggradation charter of Haq & al. (1987 & 1988) and Rioult & al. (1991). The correlations on a regional scale, between different Jurassic lithostratigraphic units is possible, whose the major factors controlling the evolution of intraplate basins are climate and eustatism
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