مقـــــــــالات 2010-2015

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Stable indirect fuzzy adaptive control
(Elsevier, 2003) Goléa, N.; Goléa, A.; Benmahammed, K.
This paper investigates new fuzzy model-based observer adaptive control for multi-input multi-output continuous-time nonlinear systems. The proposed adaptive scheme uses Takagi–Seguno (TS) fuzzy models to estimate the plant states and dynamics. Using stability arguments, it is shown that the proposed scheme is globally asymptotically stable. The observation and tracking errors are shown to converge asymptotically to zero, despite the presence ofexternal disturbances and approximation errors. The performance ofthe developed approach is illustrated, by simulation, on two-link robot model.
Solar drying of wastewater sludge
(Elsevier, 2011) Bennamoun, Lyes
Drying constitutes an important process for wastewater sludge management, as it can reduce the mass and the volume of the product and consequently the cost of storage, handling and transport. During constant operating conditions, the drying kinetic of the sludge has shown mainly: a constant drying rate, one or two falling rate periods and a final short period with variations along the process of the physical properties of the product with the appearance of shrinkage and cracks phenomena. Solar drying was benefit as using free solar energy can reduce the cost of the operation. On the other hand, it plays an important role for the pathogen reduction until Environmental protection Agency (EPA) recommendations. In some studied cases, the value of 1000 CFU g−1 DS, which represents the EPA Class A pathogen requirement, for fecal coliform was attained. The general design of used solar dryers was constituted of: a greenhouse made with transparent material and a floor, where the product is speared in thick layers. Furthermore, fans and ventilations can be used in order to have homogeneous distribution of the air inside the greenhouse with replacement of humidified air with fresh one. Automatic or handle mix of the product was used once or for several times a day. In order to increase the performances of the drying system, other ways such as heating the floor using solar water heater, infrared lamps, using heat pumps or adding thermal energy storage systems were also tested. Covered solar drying has given better results than open solar drying. However, the origin of the wastewater sludge affects the obtained results. Alternatively, modeling drying systems was effectuated using heat and mass balances, applied for the air and the dried product. Solar drying of wastewater sludge has given satisfactory results.
Reviewing the experience of solar drying in Algeria with presentation of the different design aspects of solar dryers
(Springer, 2011) Bennamoun, Lyes
Solar drying is one of the processes that have found application in Algeria, because of the important quantities of solar irradiations that can be exploited in this country. Nevertheless, the experience of Algeria in solar drying is recent and limited to drying of fruits, vegetables, medicinal and aromatic herbs. The effectuated review has given an idea about the existing functional dryers in this country with presentation of their different design aspects and in some cases the mathematical modeling for well describing and predicting their behaviours. The solar dryers were classified into two classes according to their operation mode and without taking into account if the dryers are using auxiliary sources of energy. The two classes are: passive dryers and active dryers. On the other hand, each class was divided into subclasses representing the type. We have found the direct and indirect types for the passive dryers, but only indirect types for the active dryers. Mixed types were not developed. The solar dryers were developed and tested in two different climatic regions which are the north of the country and the Sahara. In the most studied cases, one or multiple auxiliary sources of energy were used in order to increase the performances of the dryer or to decrease drying time. Consequently, we register the utilization of pebbles as a heat storage system, resistances as electrical heater, gas-ring and photovoltaic cells in order to give independency against the use of the traditional electrical energy. In the case of the active dryers, adding fans and temperature and flow controllers has permitted the control of the drying conditions. Depending on the dryers, the dried quantities vary from 200 g to 36 kg. Comparison between many studied cases for different modes and types and with open sun drying method was furthermore done. With a few exceptions to some solar dryers which present problems of complexity and was not practical and easy for manipulation to the agricultural producer, the majority of the developed solar dryers have presented satisfactory results
A Detailed Chemical Kinetic Mechanism for Methanol Combustion in Laminar Flames1
(Pleiades Publishing, 2011) Hamdane, S; Rezgui, Y; Guemini, M
On the basis of existing detailed kinetic schemes a general and consistent mechanism of the oxi dation of methanol was compiled for computational studies covering a wide range of lean to rich flames. The proposed model, featuring 21 species and 115 reactions, has been validated using three data sets and the com puted reactants, products and intermediates mole fractions. This scheme was compared to those by Held⎯Dryer, Egolfopolous and Pauwels under the same conditions. The developed mechanism predicts well the concentrations of the major reactants, intermediates, and products at all the studied equivalence ratios and it gives the best calculated values, as compared to the other used models, as well. The production rates analysis of selected species allowed the identification of the major formation and depletion pathways. A reac tion path analysis snowed that the main channels in methanol consumption involved H, OH and O attack and the resulting radicals CH2OH and CH3O produced formaldehyde.
Recursive prediction error identification of fractional order models
(Springer, 2011) Djouambi, Abdelbaki; Voda, Alina; Charef, Abdelfatah
This paper deals with time domain identification of fractional order systems. A new identification technique is developed providing recursive parameters estimation of fractional order models. The identification model is defined by a generalized ARX structure obtained by discretization of a continuous fractional order differential equation. The parameters are then estimated using the recursive least squares and the recursive instrumental variable algorithms extended to fractional order cases. Finally, the quality of the proposed technic is illustrated and compared through the identification of simulated fractional order systems.
An observer based backstepping control for a greenhouse
(2011) Belhani, Ahmed; M’sirdi, Nacer Kouider
In this paper we use the backstepping approach to control climate parameters of greenhouse. To get realistic simulation, we use real weather data collected in the south region of Algeria (Biskra). We control temperature, relative humidity and CO2 concentration by acting on four variables such as heating, ventilation, CO2 injection and water injection. However as the CO2 sensors is not available, we use an nonlinear observer based on temperature and steam density measurements, To get an optimal controller, the multi- objective genetic algorithms based on Non dominated Sorting Genetic Algorithms (NSGA) techniques and Multi-Criteria Decision Analysis (MCDA) approach are introduced.
Combining neural networks for arabic handwriting recognition
(IEEE, 2011) Chergui, Leila; Kef, Maâmar; Chikhi, Salim
Combining classifiers is an approach that has been shown to be useful on numerous occasions when striving for further improvement over the performance of individual classifiers. In this paper we present an off-line Multiple Classifier System (MCS) for Arabic handwriting recognition. The MCS combine two individual recognition systems based on Fuzzy ART network used for the first time in Arabic OCR, and Radial Basis Functions. We use various feature sets based on Hu and Zernike Invariant moments. For deriving the final decision, different combining schemes are applied. The best combination ensemble has a recognition rate of 90,1 %, which is significantly higher than the 84,31% achieved by the best individual classifier. To demonstrate the high performance of the classification system, the results are compared with three research using IFN/ENIT database.
Nonlinear integral backstepping control for induction motors
(İstanbul - Turkey, 2011) Mehazzem, F.; Nemmour, A.L; Benalla, H.
A novel structure of nonlinear integral backstepping control has been proposed for induction motors. We can see clearly that the structure of the controller generated by the classical version of backstepping is composed of a proportional action, which was added a derivative action on errors. Such a structure makes the system sensitive to measurement noise. The lack of integration means also the appearance of a constant static error, caused mainly by non-zero mean disturbances. The solution t o this p roblem i s to d esign a n ew v ersion of the backstepping with integral action. By using the proposed integral backstepping controller, the system has a better load disturbance rejection capability. The effectiveness of this proposed control structure is verified by simulation as well as by experiment under critical disturbance conditions.
LLE for the extraction of alcohol from aqueous solutions with diethyl ether and dichloromethane at 293.15 K, parameter estimation using a hybrid genetic based approach
(Elsevier, 2011) Merzougui, A; Hasseine, A; Kabouche, A; Korichi, M
Experimental liquid–liquid equilibrium (LLE) data for the extraction of methanol, ethanol and 1-propanol from water by diethyl ether and dichloromethane at 293.15 K and at ambient pressure were investigated. Data for the binodal curves have been determined by cloud-point titration method and conjugate points on tie-line were obtained by correlating the refractive index of the binodal curves as a function of composition. The experimental ternary (liquid + liquid) equilibrium data have been estimated using the NRTL and UNIQUAC activity coefficient models to obtain the binary interaction parameters of these components by a combination of Levenberg–Marquardt method and the genetic algorithm based method. Thedistribution coefficients and the selectivity factor of the solvent used were calculated and presented. From our experimental and calculated results, we conclude that for the extraction of alcohol from aqueous solutions with dichloromethane solvent has a higher selectivity factor than the diethyl ether solvent.
Chemical constituents of the roots of Algerian Bunium incrassatum and evaluation of its antimicrobial activity
(Elsevier, 2011) Bousetla, Ahlem; Zellagui, Amar; Derouiche, Kamel; Rhouati, Salah
In this study we investigated the chemical composition of the roots of Bunium incrassatum growing in Algeria, two coumarins, b-sitosterol, sucrose and oleic acid were isolated from methylene chloride:methanol (1/1) extract of the roots of this species. Furthermore, antimicrobial activity of the crude extract was evaluated using agar diffusion method. The antimicrobial results showed that the crude extract had a great potential antimicrobial activity against all the test microorganisms especially fungal strains.
International Conference on Education and Educational Psychology (ICEEPSY 2011)
(Elsevier, 2011) Merrouche, Sarah
Though many schools and universities are today connected to the Internet, its technologies are still not adequately integrated into classroom teaching and learning. Many teachers think in rather restricted ways about using online tools and resources in their profession. This paper attempts to shed light on the MOO (Multi-User Domain – Object Oriented) technology, which provides a flexible and rich virtual environment for synchronous communication. Focus is laid on the Da-MOO, or the Educational MOO, and the way it lends itself to collaborative learning, particularly tandem learning, to support teaching in the language classroom. A practical experience with “The Palace” is described. Algerian EFL students find it appealing, motivating and useful.
Structure identification for complex system and inference interpretable rules
(IEEE, 2012) Remache, Cherif; Maamri, Ramdane; Zaidi, Sahnoun
The large and complex systems are characterized by the difficulty of formalizing and the lack of expertise. They are built from data representing instances of the system. The drawback of these structure selection methods is that pay particular attention to the numerical accuracy of the resulting model and little attention to the qualitative and semantic aspect. The use of a large number of input variables results in an introduction of redundant elements, poor transparency and an excessive complexity of the model obtained. To solve these problems, a particular interest should be given for selecting relevant input variables that can provide a reasonable compromise between the quality of approximation, the complexity and the transparency of the model. The proposed approach for structure selection assumes constraints on the number of variables to be selected in the initial combination to describe the model. Relevant inputs are found from input-output data and variables with the highest correlation coefficient with the output variable are selected in the initial combination
Some spectral properties of linear operators on exotic banach spaces
(LOBACHEVSKII JOURNAL OFMATHEMATICS, 2012) Mushtari, H.
In this work, we present some results concerning the operators defined on various classes of exotic Banach spaces, containing in particular those studied respectively by V. Ferenczi [7, 8] and T. Gowers with B.Maurey [14, 15].We show that, on hereditarily indecomposable or quotient hereditarily indecomposable Banach space X, the set of bounded Fredholm operators is dense in L(X), this gives that the boundary of bounded Fredholm operators is nothing else but the ideal of strictly singular operators ifX is hereditarily indecomposable Banach space (resp. the ideal of strictly cosingular operators ifX is quotient hereditarily indecomposable Banach space).On the other hand, a comparison between sufficiently rich and exotic Banach spaces is given via some properties of the two maps spectra andWolf essential spectra.
Projection based permutation of color images
(IEEE, 2012) Nini, Brahim
The encryption of images is based on two main complementary techniques: permutation and substitution of pixels. The strength of any encryption algorithm depends on the strength of both techniques. This paper presents an algorithm for rows and columns permutation of pixels. It introduces a virtual cylinder surrounding the image through which a virtual viewer looks at the image when rotating around it. The key idea is based on the fact that the line of sight of each pixel to the viewer intersects the cylinder surface at a given point. This point should be the same whatever the position of the viewer is. Therefore, it is used to find out the new pixel’s position corresponding to the original image in a new generated image which is viewed from another position. The new created image has then some pixels which stack up and others which become out. They are then reintroduced in the created holes in the new image. This reinsertion of pixels creates the expected permutation. Based on only two main parts of the key which can be reinforced by others and a substitution technique, the algorithm shows a strength transformation of images for the purpose of their encryption.
Vessel development and the importance of lateral flow in water transport within developing bundles of current-year shoots of grapevine (Vitis vinifera L.)
(Springer, 2012) Halis, Youcef; Djehichi, Samah; Senoussi, Mohamed Mourad
In the developing xylem bundles of young stems, the presence of immature living vessel elements can strongly restrict or even block axial hydraulic conductance, especially in newly matured vessels. Lateral connections between vessels may provide an alternative pathway for water movement to bypass these closed, living elements. Using the grapevine as a model system, the present study aimed to demonstrate the effects of living vessel elements on water movement patterns, and the importance of lateral flow for effective water conductivity in the developing bundles. Living vessel elements were detected using dye staining and the pattern of vessel development and maturation was then monitored. The importance of lateral flow was confirmed using several approaches: (1) capacity for lateral flow, (2) effect of increasing the distance of water transport, and (3) effect of ion concentrations. Living vessel elements were found along the developing bundles, they occupied a significant proportion of the distal and peripheral parts of the flow path, forming a substantial barrier to apoplastic water flow. Water in the developing xylem bundles could move easily from vessel to vessel and between secondary and primary xylem. Furthermore, data from increasing the transport length and altering the ion concentrations supported the critical contribution of the lateral flow to the total hydraulic conductance within the developing bundles. The hydraulic architecture of the developing xylem bundles is described. The results are discussed in terms of reliability and efficiency of water transport during shoot growth and development.
Design of a multifunction low power converter with reduced freedom degrees for photovoltaic and mobile applications
(IEEE, 2012) Belkacem, F.; Saidi, A.; Diallo, D.
This paper is an approach to design a new full bridge single-phase multifunction converter. Reduction of freedom degrees is the principal mean to build the converter dedicated mainly to mobile applications fed by photovoltaic cells. The rules of reducing controllable semiconductors are analyzed and simulation and experimental results prove the feasibility of the approach.
New hybrid arabic handwriting recognizer
(IEEE, 2012) Chergui, Leila; Kef, Maâmar; Chikhi, Salim
Recently, there is a popular belief that classifier combination of different architecture could complement each other for improving results performance. In this paper we introduce a framework to combine results of multiple classifiers for offline Arabic handwriting recognition, by introducing a new scheme of combination of Multi Layer Perceptron and ART1 networks. Besides using two different recognition architectures (MLP and ART1 networks), we exploit various feature sets calculated from the contour of image; the Hu moments and features obtained with sliding windows. The implementation results on IFN/ENIT database show a high degree of accuracy by applying the majority vote method.
Preparation and characterization of CdS thin films
(IEEE, 2012) Moualkia, H.; Attaf, N.; Hadjeris, L.; Herissi, L.; Abdelmalek, N.
In this work we report the structural, optical and electrical properties of CdS thin films prepared by chemical bath deposition (CBD) under the effect of solution temperatures. The solution temperatures used vary between 55 and 75 °C. The XRD patterns show that the films have a hexagonal phase with a preferential (002) orientation. The structural parameters such as the grain size, dislocation density and strain are calculated. The transmission spectra, recorded in the UV visible range, reveal a high transmission coefficient (85%) of the prepared films and an optical band gap values of 2 - 2.4 eV. The electrical measurements show that the dark conductivity values increase from 10-7 to 10-4 (Ω.cm)-1 at higher temperature (Ts > 65°C). It is found that the photoconductivity of the deposited films is two to five decades larger than the dark conductivity, and the photoconductivity to the dark conductivity ratio obtained at 3000 Lx vary from 102 to 105. From these results we inferred that the elaborated CdS thin films exhibit good properties intended for solar cell window layers.
Effects of heat treatment and TiO2 content on the optical properties of Eu3+ doped TiO2–SiO2 thin films
(Elsevier, 2012) Berkani, Oualid; Latrous, Khelil; ElHamzaoui, Hicham; Capoen, Bruno; Bouazaoui, Mohamed
The photoluminescence properties of Eu3+- doped TiO2–SiO2 thin films were investigated.The films were deposited on silicon substrates by thesol–gel process using the dip-coatingmethod.Themolar ratio ofTiO2 content was varied from25%to100%,while Europium concentration was fixed to1%.The obtained films were calcinatedatvarioustemperaturesrangingfrom400 1C to1300 1C, whichallowed determiningtheoptimalconditionsfortheEu3þ luminescence.Meanwhile,thestructureofTiO2–SiO2 powders,preparedinthesameconditionsasthefilms,wasalsostudiedbyRamanspectroscopy. It revealedtheroleofEuropiumandSiO2 on thestabilizationoftheanatasephaseandtheimportance of thesilicamatrixinthecontroloftitaniaparticlesize
Interaction parameter estimation in liquid–liquid phase equilibrium modeling using stochastic and hybrid algorithms
(Elsevier, 2012) Kabouchea, A.; Boultif, A.; Abidib, A.; Gherraf, N.
Metaheuristic methods Simulated annealing (SA) and Genetic algorithm (GA) combined with hybrid functions were investigated to estimate interactions parameters in liquid–liquid phase equilibrium systems. The Rastrigin and Rosenbrock functions with high number of variables were used as test functions to compare the performance of each algorithm. The experimental ternary LLE data for extraction of alcohol with dichloromethane (and diethyl ether) were considered in the NRTL and UNIQUAC activity coefficient model. The interaction parameters were carried out taking into account the closure equation. As a main conclusion, Hybrid algorithms have showed the best performance to estimate the interaction parameters comparatively to stochastic and deterministic algorithms

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