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Search Results: 1 - 10 of 401272 matches for " M.Talbi "
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Positive solutions with changing sign energy to a nonhomogeneous elliptic problem of fourth order
Boletim da Sociedade Paranaense de Matemática , 2011,
Abstract: In this paper, we study the existence for two positive solutions toa nonhomogeneous elliptic equation of fourth order with a parameter lambda such tha 0 < lambda < lambda^. The first solution has a negative energy while the energy of the second one is positive for 0 < lambda < lambda_0 and negative for lambda_0 < lambda < lambda^. The values lambda_0 and lambda^ are given under variational form and we show that every corresponding critical point is solution of the nonlinear elliptic problem (with a suitable multiplicative term).
Diouri A.,Khachani N.,Alami Talbi M.
MATEC Web of Conferences , 2012, DOI: 10.1051/matecconf/20120200001
Hydration behavior of iron doped calcium sulfoaluminate phase at room temperature
Idrissi M.,Diouri A.,Alami Talbi M.,Sassi O.
MATEC Web of Conferences , 2012, DOI: 10.1051/matecconf/20120201005
Abstract: Different samples of calcium sulfoaluminate phase doped with iron, (Ca4Al(6-2x)Fe2xSO16) with x = 0, 0.2 and 0.5, were synthesized at 1350°C. The hydration kinetics of the resulted phases was investigated by calorimetric and conductimetric techniques. The hydrated samples were analyzed by X-ray diffraction and scanning electron microscopy. The hydration of calcium sulfoaluminate was slightly modified by inclusion of iron in its structure. Dissolution rate of calcium sulfoaluminate phase doped with iron appeared to be slowed down such as the nucleation rate during the induction period while the percentage of reaction after 1 day was slightly increased. The analysis of hydrates indicated the formation of the same hydrates, ettringite and calcium monosulfoaluminate and the gibbsite, with or without iron replacement. Gibbsite played a major role in the kinetics of the induction period and thus the presence of iron may decrease its nucleation rate forming (A, F)H3 instead of AH3.
A Matlab Implementation of a Speech Recognition System Using HMM Models
A. Cherif,F. Chabane,M. Talbi,F.L. Agha
Journal of Engineering and Applied Sciences , 2012,
Abstract: In this study, we present a speech recognition interface designed for vocal control. The implementation has been realized under the Matlab environment with scripts in C. The program uses the statistical HMM (Hidden Markov Models) for speech modeling, the K-means, Baum-welch algorithms for training and codebook conception and finally the Viterbi decoding algorithm for the recognition process. The recognized word decision is based on the maximal likehood value. The speech database is constituted of 1000 words mono-speaker associated with a denoising module before be applied to the developed interface.
Simulation and Comparison of Noise Concellation Techniques in Speech Processing
Talbi Mourad
Research Journal of Applied Sciences , 2012,
Abstract: In this study we will develop a speech denoising interface which will be used for recognition, synthesis and coding applications. This interface developed under Matlab, uses wavelets transform. The results of this method are applied on several kind of noises then they will be compared with the spectral subtraction method.
Fast Hybrid PSO and Tabu Search Approach for Optimization of a Fuzzy Controller
Nesrine Talbi
International Journal of Computer Science Issues , 2011,
Abstract: In this paper, a fuzzy controller type Takagi_Sugeno zero order is optimized by the method of hybrid Particle Swarm Optimization (PSO) and Tabu Search (TS). The algorithm automatically adjusts the membership functions of fuzzy controller inputs and the conclusions of fuzzy rules. At each iteration of PSO, we calculate the best solution and we seek the best neighbor by Tabu search, this operation minimizes the number of iterations and computation time while maintaining accuracy and minimum response time. We apply this algorithm to optimize a fuzzy controller for a simple inverted pendulum with three rules.
Theoretical approaches for studying Astrochemistry
Talbi D.
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20111802002
Abstract: The most popular ab initio theoretical approaches that are used to study the gas phase astrochemical reactivity are presented. The methods that are needed for the electronic calculation and the statistical approaches that are used for determining the rate coefficients are detailed.
Ajout de phosphogypse à des mortiers à base de cendres volantes et filler calcaire Addition of phosphogypsum to blended mortars based on fly ash and limestone filler
Raoui A.,Diouri A.,Kamali-Bernard S.,Alami Talbi M.
MATEC Web of Conferences , 2012, DOI: 10.1051/matecconf/20120201018
Abstract: L’objectif de ce travail est d’étudier la possibilité de la valorisation du phosphogypse dans les matériaux de construction vue sa grande disponibilité comme sous-produit de l’industrie des phosphates. Nous étudions l’effet de l’ajout du phosphogypse sur un mélange de clinker, cendres volantes et filler calcaire. Les échantillons sont préparés par l’ajout de 10% de phosphogypse et de 30% de cendres volantes aux mélanges constitués du clinker et du filler calcaire. Les mélanges sont hydratés et caractérisés par diffraction des rayons X et spectroscopie infrarouge. Des phases cristallines se développent dès le 3ème jour, et on remarque que les phases les plus fréquentes sont : la Portlandite Ca(OH)2, la Calcite CaCO3, l’ettringite Ca6Al2(SO4)3(OH)12 26H2O, Ca5(SiO4)2(OH)2 et le gypse CaSO4, 2H2O mais leur pourcentages varient selon les mélanges. La mesure de la durée de prise des mortiers montre que le début et la fin de la prise sont généralement retardés proportionnellement à l’ajout des cendres volantes et du phosphogypse. La microstructure des matériaux a également été étudiée par la mesure de la perméabilité apparente, les résultats montrent que l’ajout du phosphogypse a contribué à une diminution de la perméabilité des échantillons par contre les cendres volantes ont un effet contraire. La résistance à la compression des mortiers montre des résultats concordants, les résistances augmentent avec la diminution de la perméabilité. The objective of this paper is to study the possibility of valorization of phosphogypsum in building materials because his large availability as a by-product of the phosphate industry. We study the effect of adding phosphogypsum on a mixture of clinker, fly ash and limestone filler. The samples were prepared by adding 10% of phosphogypsum and 30% of fly ash to mixtures consisting of clinker and limestone filler. The mixtures are hydrated and characterized by X-ray diffraction and Infrared spectroscopy. Crystalline phases grow from the third day, and we note that the most common phases are: Portlandite Ca(OH)2, CaCO3 calcite, ettringite Ca6Al2(SO4)3 (OH)12 26H2O, Ca5(SiO4)2(OH)2 and gypsum CaSO4, 2H2O but their percentages vary depending on the mixtures. Measuring the setting time of mortars shows that the beginning and end of setting are usually delayed in proportion to the addition of fly ash and phosphogypsum. The microstructure of materials was also studied by measuring the apparent permeability; the results show that the addition of phosphogypsum has contributed to a decrease in the permeability of the samples against fly
Quel est l’intérêt des enseignants marocains pour l’épistémologie et l’histoire des sciences ? Le cas des sciences physiques
Sa?d El?Jamali,Mohamed Mrabet?Bader,M’hamed El?Kouali,Mohammed Talbi
Revue Internationale de Pédagogie de l’Enseignement Supérieur , 2009,
Abstract: L’enseignement des sciences au sein de l’école marocaine conna t une situation paradoxale où les enseignants sont tiraillés entre les contraintes liées à l’enseignement et les demandes institutionnelles de changement par rapports aux contenus et aux méthodes. Cet article travaille les liens entre la formation aux didactiques disciplinaires, d’une part, et les dimensions de l’épistémologie et de l’histoire des sciences, d’autre part. Il présente les résultats d’une enquête menée auprès des enseignants pour savoir comment ils intègrent les dimensions épistémologiques et historiques dans la préparation de leurs enseignements. Il plaide pour un renforcement de ces dimensions dans la formation initiale et continue des enseignants. Science teaching in Moroccan schools is in a paradoxical situation where teachers are coping with the constraints of teaching practices while dealing with institutional demands for change in contents and methods. This article discusses the links between disciplinary training of teachers on the one hand and epistemological and historical aspects on the other hand. It presents the results of a survey carried out with teachers in order to understand ho they integrate epistemological and historical dimensions in their teaching practice. It also advocates reinforcing these dimensions in intial and continuing training of teachers.
Modélisation analytique et numérique de structures sandwich de type carton ondulé
S. Allaoui,Z. Aboura,M. L. Benzeggagh,N. Talbi,R. Ayad
Physics , 2011,
Abstract: Corrugated cardboard is a sandwich used generally for packing in the form of case. It's the most used material for packing because it can be recycled as well as biodegradable. It's implementation in form of structure, makes the numerical studies of the product (cases) very heavy. Analytical and numerical models were developed to predict the mechanical behavior of the homogenized material. Following that the studies become more simple and less expensive. An analytical model of homogenisation based on the classical laminate theory has been proposed in a previous studies. It predicts the elastic behavior of the corrugated cardboard. This work purposes an extension of this model. Initially, It will be applied at the case of corrugated cardboard composed of more than three constituents. After that, a numerical study of bending witch take account of the effect of shear is proposed. Finally, the anlytical model will be used to predict the elastic and anelastic behavior of the corrugated cardboard.
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