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Search Results: 1 - 10 of 13812 matches for " Rachid EL Ayachi "
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Recognition of Tifinaghe Characters Using a Multilayer Neural Network
Rachid EL Ayachi,Mohamed Fakir,Belaid Bouikhalene
International Journal of Image Processing , 2011,
Abstract: In this paper, we present an off line Tifinaghe characters recognition system. Texts are scannedusing a flatbed scanner. Digitized text are normalised, noise is reduced using a median filter,baseline skew is corrected by the use of the Hough transform, and text is segmented into line andlines into words. Features are extracted using the Walsh Transformation. Finally characters arerecognized by a multilayer neural network.
Effect of Sinusoidal Heating on Natural Convection Coupled to Thermal Radiation in a Square Cavity Subjected to Cross Temperature Gradients  [PDF]
Rachid El Ayachi, Abdelghani Raji, Mohamed Na?mi, Hassan Elharfi, Mohammed Hasnaoui
Journal of Electronics Cooling and Thermal Control (JECTC) , 2013, DOI: 10.4236/jectc.2013.31002
Abstract:

Coupled natural convection and surface radiation within a square cavity, filled with air and submitted to discrete heating and cooling from all its walls, is studied numerically. The thermally active elements are centrally located on the walls of the cavity. Two heating modes, called SB and SV, are considered. They correspond to bottom and vertical left elements sinusoidally heated in time, respectively, while the top and vertical right ones are constantly cooled. The remaining portions of all the walls are considered adiabatic. The parameters governing the problem are the amplitude \"\" and the period \"\" of the temporally sinusoidal temperature, the emissivity of the walls \"\", the relative lengths of the active elements \"\" and the Rayleigh number \"\". The effect of such parameters on flow and thermal fields and the resulting heat transfer is examined. It is shown that, during a flow cycle, the flow structure can present complex behavior, depending on the emissivity and the amplitude and period of the exciting temperature. The rate of heat transfer is generally enhanced in the case of sinusoidal heating. Also, the resonance phenomenon existence, characterized by maximum fluctuations in flow intensity and heat transfer, is proved in this study.

A Multiresolution Channel Decomposition for H.264/AVC Unequal Error Protection  [PDF]
Rachid Abbadi, Jamal El Abbadi
Journal of Signal and Information Processing (JSIP) , 2012, DOI: 10.4236/jsip.2012.31001
Abstract: The most commonly used transmission channel in nowadays provides the same level of protection for all the information symbols. As the level of protection should be adequate to the importance of the information set, it is justified to use UEP channels in order to protect information of variable importance. Multiresolution channel decomposition has emerged as a strong concept and when combined with H.264/AVC layered multiresolution source it leads to outstanding results especially for mobile TV applications. Our approach is a double multiresolution scheme with embedded constellation modulations on its baseband channels followed by OFDM time/frequency multiresolution passband modulation. The aim is to protect The NAL units carrying the most valuable information by the coarse constellations into coarse sub-channels, and the NAL units that contain residual data by fined constellations and transposed into the fined OFDM sub-channels. In the multiresolution protection coding, our approach is a multiresolution decomposition of the core convolutional constituent of the PCCC where the NAL units carrying the most valuable information are coded by the rugged coefficient of the multiresolution code and the NAL units that contains residual data are coded by refined less secure coding coefficients.
Numerical Study of Natural Convection in a Two-Dimensional Enclosure with a Sinusoidal Boundary Thermal Condition Utilizing Nanofluid  [PDF]
Ibtissam El Bouihi, Rachid Sehaqui
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.48058
Abstract: Nanofluids are considered to offer important advantages over conventional heat transfer fluids. A model is developed to analyze the behavior of nanofluids taking into account the solid fraction χ. The Navier-Stokes equations are solved numerically with Alternating Direct Implicit method (ADI method) for various Grashof numbers 104 and 105; we have an excellent agreement between our numerical code and previously published works. Copper-Water nanofluid is used with Pr = 6.2 and solid volume fraction χ is varied as 0%; 5%; 10%; 15% and 20%. The problem considered is a two-dimensional heat transfer in a square cavity. The vertical walls are differentially heated, the left is maintained at hot con- dition (sinusoidal) when the right one is cold. The horizontal walls are assumed to be insulated, non conducting and impermeable to mass transfer. The nanofluid in the enclosure is Newtonian, incompressible and laminar. The nanopar- ticles are assumed to have a uniform shape and size. Moreover, it is assumed that both the fluid phase and nanoparticles are in thermal equilibrium state and they flow at the same velocity. The thermophysical properties of the nanofluid are assumed to be constant except for the density variation in the buoyancy force, which is based on the Boussinesq approximation. Different correlations are proposed for predicting heat transfer for uniform and sinusoidal boundary thermal conditions.
Effectiveness of Commercial Organic Acids’ Mixture (AcetolacTM) to Extend the Shelf Life and Enhance the Microbiological Quality of Merguez Sausages
Bouchra El Ayachi,Ahmed Daoudi,Noreddine Benkerroum
American Journal of Food Technology , 2007,
Abstract: The effect of the addition of organic acids on the shelf life and on the hygienic quality of Merguez sausages was studied. A commercial organic acid; AcetolacTM consisting of a mixture of sodium lactate (90%) and sodium acetate (10%) was added at different concentrations (0, 5, 10, 15 or 20 g kg-1) to the butter mixture for sausage making. Microbiological enumerations (total aerobic count, coliforms, fecal streptococci, Staphylococcus aureus and sulfite reducing clostridia) along with the pH and Total Volatile Basic nitrogen (TBV-N) were monitored during storage at refrigeration temperature (~8°C) for 15 days. The results showed that the addition of organic acids reduced significantly (p<0.05) the microbiological counts during the first three days of storage and such an effect increased with the concentration of added AcetolacTM. Thereafter, a significant (p<0.05) increase in the colony forming units (cfus) of all the bacterial groups enumerated was recorded with the exception of S. aureus whose cfus remained practically constant. Concomitantly, the pH and TBV-N content have increased throughout the whole period of storage. As for the shelf life, control samples (without added AcetolacTM) were altered at day 5 of cold storage as judged by a sensory panel on the basis of perceivable sensory attributes. However, such perceivable alterations were delayed at least 5 days in samples treated AcetolacTM at levels ranging between 10 and 20 g kg-1.
Toward Safe and Usable Technologies for Autistic: Risks Identification and Mitigation Guidelines  [PDF]
Nesrine Mezhoudi, Hina Gull, Mohammed A. Alqahtani, Nahla El-Haggar, Moez Ayachi
Open Journal of Applied Sciences (OJAppS) , 2019, DOI: 10.4236/ojapps.2019.91004
Abstract: Recent advances in technology provide countless innovative solutions and applications for supporting children with autism in educational learning and personal development. This result is an increasingly recognized need to deal with new and unexpected risks and issues such as social exclusion. Diverse advanced technologies were aimed to support learning activity from different perspectives with multiple strategies. However, despite the significant amount of work and explored technology, several common risks pop up due to user’s vulnerability to diverse risks such as negative screen effects. Accordingly, there is still plenty of room for improvement in this regard. To address these vulnerabilities and gaps, this paper aims at identifying issues and challenges improving the technology applied for Autism Spectrum Disorders and autistics dedicated applications. It put forward requirements and design decisions supporting safe autistic dedicated interaction with regards to ISO31000 risk management process.
VARIANTES DU PRINCIPE VARIATIONNEL D'EKELAND ET APPLICATIONS
El Amrouss,Abdel Rachid;
Revista Colombiana de Matemáticas , 2006,
Abstract: in this note, we establish a variant of ekeland's variational principle. this result suggests a generalization of the classical palais-smale condition. an example is provided showing how this is used to give the existence of a minimizer for functionals which do not satisfy the palais-smale condition and the one introduced by cerami. we also prove a relation between the coercitivity of functional and the introduced compactness condition.
El cadiazgo en Granada bajo los almorávides: enfrentamiento y negociación
El Hour, Rachid
Al-Qantara : Revista de Estudios Arabes , 2006,
Abstract: This article studies two outstanding aspects of the qadiship of the city of Granada under the Almoravids. First of all, it lays out the list of qadis in Granada based on the data provided by Andalusi biographical sources. Secondly, it analyses the mechanisms of the relationship between Almoravid political power and the local elites of Granada – a relationship which was largely characterised by both negotiation and confrontation. The qadiship of Granada was managed by several Andalusi families, from Granada and outside it. Such management was imposed by the Almoravid authorities rather than by the Granadans themselves. We also find members of Maghrebi families occupying the qadiship in higher numbers than in other Andalusi towns during the some period city (this excludes Algeciras for reasons linked especially to the city′s status). In this way, the Almoravids authorities sought to avoid the monopoly of the judicial functions held by local elites and thereby exercise greater control over the city, which was of particularly great importance given that it was the Andalusi capital. Este artículo estudia dos aspectos primordiales del cadiazgo de la ciudad de granada bajo los almorávides. Por un lado, expone la lista de los cadíes de Granada basándose en los datos proporcionados por las fuentes biográficas andalusíes. Por el otro, analiza los mecanismos de la relación entre el poder político almorávide y la élite local granadina, relación que se caracterizó, en gran medida, por la negociación y el enfrentamiento. El cadiazgo de Granada fue gestionado por varias familias andalusíes, granadinas y no granadinas, y no por voluntad propia de los granadinos, sino por imposición de las autoridades almorávides. También, encontramos miembros de familias magrebíes ocupando el cadiazgo en mayor número del atestiguado al mismo tiempo en otras ciudades
Chlorophylls, Proteins and Fatty Acids Amounts of Arthrospira Platensis Growing under Saline Conditions
Brahim Marzouk,Samah Ayachi,mor El Abed,Wissal Dhifi
Pakistan Journal of Biological Sciences , 2007,
Abstract: Spirulina platensis (Arthrospira platensis) is a Tunisian strain isolated for the first time, in Tunisia, in Oued Essed (Sidi Bou Ali, in Sousse region). Evolution of biomass, proteins, chlorophylls and fatty acids (FA) has been followed during Spirulina growth. Experiments were carried out by varying sodium chloride concentrations in the culture medium in a range from 1 g L-1 (natural environment) to 60 g L-1. Results analysis showed an increase in chlorophyll amounts at 15 g L-1 NaCl in 10 days old cultures but a decrease at high NaCl concentrations. Optimal proteins amounts was observed at 15 g L-1 NaCl in young cultures (5 and 10 days). FA composition was modified by NaCl and depended on culture age. Cultures exposed to high salinity concentrations showed not only a decrease in growth rate but also a loss in total fatty acids TFA quantities. Samples cultured over 15 days at 30 g L-1 NaCl rendered optimal quantities of lipids and γ-linolenic acid.
Al-Pillared Ghassoulite Clay as a New Green Catalyst for the Synthesis of Benzothiazoles and Benzimidazoles: Effect of Amine/CEC Ratio  [PDF]
Rachid Azzallou, Rachid Mamouni, Kimberly Stieglitz, Nabil Saffaj, Mohammadine El Haddad, Said Lazar
International Journal of Organic Chemistry (IJOC) , 2013, DOI: 10.4236/ijoc.2013.32018
Abstract:

The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that substantial portions of the text came from other published papers. The scientific community takes a very strong view on this matter, and the International Journal of Organic Chemistry treats all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.2, 151-157 (pages), 2013, has been removed from this site.

Title: Al-Pillared Ghassoulite Clay as a New Green Catalyst for the Synthesis of Benzothiazoles and Benzimidazoles: Effect of Amine/CEC Ratio

Authors: Rachid Azzallou, Rachid Mamouni, Kimberly Stieglitz, Nabil Saffaj, Mohammadine Said Lazar

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