علوم وتكنولوجيا
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Item A cellular automaton based approach for real time(Springer, 2015) Boutekkouk, FatehReal Time Embedded Systems are becoming ubiquitous. Since these systems have autonomous batteries, their design must minimize power consumption in order to extend batteries life time. On the other hand, Cellular Automaton (CA) appears a good choice to simulate the future behavior of complex dynamic and parallel systems. Due to some intrinsic characteristics such as neighborhood and local transitions, CA can exhibit some complex behaviors. In this work, we apply CA to model the well known problem of Real time scheduling and eventually to optimize the power consumption of a Real time multicores embedded system with periodic tasks. CA algorithm is focused on the so-called technique: Dynamic Voltage Scaling (DVS). The proposed CA is a 2D grid.Item A common fixed point theorem for weakly compatible mappings in symmetric spaces satisfying a contractive condition of integral type(2006) Aliouche, A; Jungck, GIn this paper, we proved a common fixed point theorem for weakly compatible mappings in symmetric spaces satisfying a contractive condition of integral type and a property (E.A) introduced in [M. Aamri, D. El Moutawakil, Some new common fixed point theorems under strict contractive conditions, J. Math. Anal. Appl. 270 (2002) 181–188]. Our theorem generalizes Theorem 2.2 of [M. Aamri, D. El Moutawakil, Common fixed points under contractive conditions in symmetric spaces, Appl. Math. E-Notes 3 (2003) 156–162] and Theorem 2 of [M. Aamri, D. El Moutawakil, Some new common fixed point theorems under strict contractive conditions, J. Math. Anal. Appl. 270 (2002) 181–188Item A Comparative study on scaling sapabilities of Si and SiGe Nanoscale double date dunneling FETs(Springer, 2019) Dibi, Zohir; Bentrcia, Toufik; Djeffa, Fayçal; Ferhati, HichemIn the last few years, an accelerated trend towards the miniaturization of nanoscale circuits has been recorded. In this context, the Tunneling Field-Effect Transistors (TFETs) are gaining attention because of their good subthreshold characteristics, high scalability and low leakage current. However, they suffer from low values of the ON-state current and severe ambipolar transport mechanism. The aim of this work is to investigate the performance of SiGe nanoscale Double Gate TFET device including low doped drain region. The electrical performance of the considered device is investigated numerically using ATLAS 2D simulator, where both scaling and reliability aspects of the proposed design are reported. In this context, we address the impact of the channel length, traps density and drain doping parameters on the variation of some figures of merit of the device namely the swing factor and the ION/IOFF ratio. The obtained results indicate the superior immunity of the proposed design against traps induced degradation in comparison to the conventional TFET structure. Therefore, this work can offer more insights regarding the benefit of adopting channel materials and drain doping engineering techniques for future reliable low-power nanoscale electronic applications.Item A Detailed Chemical Kinetic Mechanism for Methanol Combustion in Laminar Flames1(Pleiades Publishing, 2011) Hamdane, S; Rezgui, Y; Guemini, MOn 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.Item A hybrid approach to extend the life time of heterogeneous wireless sensor networks(Elsevier, 2015) boutekkouk, Fateh; Taibi, Fatima; Meziani, KhawlaIn this work, we propose to use two optimization meta-heuristics that are: firefly and simulated annealing to extend the life time of a heterogeneous wireless sensors network (WSN) with a fixed base station by reducing the communication energy consumption. The proposed approach combines between the clustering and the chain approaches. Our optimization algorithm tries at first time to find the optimal clustering over the network nodes using the firefly algorithm then inside each cluster it attempts to find the best chain using simulated annealing. A particularity in our algorithm is the dynamic adjustment of clusters number over rounds.Item A loss minimization DTC scheme for EV induction motors(IEEE, 2007) Haddoun, Abdelhakim; Benbouzid, Mohamed El Hachemi; Abdessemed, Rachid; Ghouili, Jamel; Srairi, KamelThis paper proposes a strategy to minimize the losses of an induction motor propelling an electric vehicle (EV). The proposed control strategy, which is based on a direct flux and torque control scheme, utilizes the stator flux as a control variable, and the flux level is selected in accordance with the torque demand of the EV to achieve the efficiency-optimized drive performance. Moreover, among EV’s motor electric propulsion features, the energy efficiency is a basic characteristic that is influenced by vehicle dynamics and system architecture. For this reason, the EV dynamics are taken into account. Simulation tests have been carried out on a 1.1-kW EV induction motor drive to evaluate the consistency and the performance of the proposed control approach.Item A Method of solution for integro-differential parabolic equation with purely integral conditions(2015) Merad, Ahcene; Bouziani, AbdelfatahThe objective of this paper is to prove existence, uniqueness, and continuous dependence upon the data of solution to integro-differential parabolic equation with purely integral conditions. The proofs are based on a priory estimates and Laplace transform method. Finally, we obtain the solution by using a numerical technique for inverting the Laplace transforms. 20.1 IntroductionItem A neural network-based approach to motion estimation with discontinuities(IEEE, 2008) Berkane, Mohamed; Clarysse, PatrickA new neural network-based approach is proposed to estimate motion hierarchy in image sequences taking into consideration motion discontinuities. The network consists in an input layer, an intermediate layer and an output layer. In order to estimate the most likely displacement at each pixel, we have transposed the block matching approach into the neural network approach and add mechanisms to detect motion discontinuities. Information redundancy allows for parallel processing in view of real-time complex motion estimation tasks. Preliminary tests on synthetic and real images are very promising.Item A Novel conformance testing technique for agent interaction protocols(London, UK, 2013) Mokhati, Farid; Badri, Mourad; Zerrougui, SalimAgent Interaction Protocols (AIP) play a crucial role in multi-agent systems development. AIP allow specifying interactions (sequences of messages) between agents. As agent-oriented development emerges, testing agent-based software is receiving increased research attention. We present, in this paper, a novel conformance testing technique for agent interaction protocols. The approach supports an incremental testing strategy that considers both agent and society testing of Multi-Agent Systems. It uses aspect-oriented technology to support and monitor the testing process. The proposed technique consists in two main phases: (1) Generating adequate test cases from a formal description of Multi-Agent Systems’ behavior, and (2) Verifying the execution of test cases. The technique is supported by a visual tool (AIPTE: Agent Interaction Protocols Testing Environment). A case study is presented to illustrate the approach.Item A novel fuzzy approach for handwritten arabic character recognition(Springer, 2015) Kef, Maamar; Chergui, Leila; Chikhi, SalimThe aim of our work is to present a new method based on structural characteristics and a fuzzy classifier for off-line recognition of handwritten Arabic characters in all their forms (beginning, end, middle and isolated). The proposed method can be integrated in any handwritten Arabic words recognition system based on an explicit segmentation process. First, three preprocessing operations are applied on character images: thinning, contour tracing and connected components detection. These operations extract structural characteristics used to divide the set of characters into five subsets. Next, features are extracted using invariant pseudo-Zernike moments. Classification was done using the Fuzzy ARTMAP neural network, which is very fast in training and supports incremental learning. Five Fuzzy ARTMAP neural networks were employed; each one is designed to recognize one subset of characters. The recognition process is achieved in two steps: in the first one, a clustering method affects characters to one of the five character subsets. In the second one, the pseudo-Zernike features are used by the appropriate Fuzzy ARTMAP classifier to identify the character. Training process and tests were performed on a set of character images manually extracted from the IFN/ENIT database. A height recognition rate was reported.Item A property of the spectra of non-Pisot numbers Une propriété du spectre des réels autres que les nombres de Pisot(ELSEVIER, 2010) Zaimi, ToufikItem A reduced maximality labeled transition system generation for recursive Petri nets(Elsevier, 2015) Bouneb, Messaouda; Saidouni, Djamel Eddine; Ilie, Jean MichelIn Saidouni et al. (Maximality semantic for recursive Petri net. Europeen conference on modelling and simulation (ECMS’13) pp 544–550, 2013) a maximality operational semantics has been defined for the recursive Petri net model. This operational semantics generates a true concurrency structure named maximality-based labeled transition systems (MLTS). This paper proposes an approach that generates an on-the-fly reducedMLTS modulo a maximality bisimulation relation. The interest of the approach is shown using an example concerning the woodshop cutting systemItem A Serial combination of neural network for arabic OCR(Springer, 2014) Chergui, Leila; Kef, MaamarToday, handwriting recognition is one of the most challenging tasks and exciting areas of search in computer science. Indeed, despite the growing interest in this field, no satisfactory solution is available. For this reason Multiple Classifier Systems (MCS) based on the combination of outputs of a set of different classifiers have been proposed as a method for the developing of high performance classifier system. In this paper we describe a serial combination scheme of an Arabic Optical Character Recognition System. The classification engine is based on Adaptive Resonance Theory and Radial Basic Function, where an RBF network acting as the first classifier is properly combined with a set of ART1 network (one for each group) trained to classify the word image. The experiments applied on the IFN/ENIT database show that the proposed architecture exhibits best performanceItem An efficient small size electromagnetic energyharvesting sensor for low-DC-powerapplications(IET, 2017) Dibi, Zohir; Meddour, FayçalAn efficient small size electromagnetic energy harvesting sensor for low-DC-power applications is proposed. Thesensor consists of two main parts: a dual polarisation square patch antenna used to collect the RF energy at a central frequencyof 2.45 GHz, and two voltage doublers rectifier circuit for the RF-to-DC conversion. The overall size of the design is 50 × 50 × 6.2 mm3. Firstly, the antenna is designed using high-frequency structure simulator software; followed by the design of therectifier circuit in advanced design system. After simulations, a sensor prototype is fabricated using F4B as the antennasubstrate. Measurements show that the sensor achieves a comparatively high maximum measured efficiency of 41% for apower level of −10 dBm. The sensor has a simple structure, it is compact sized, light weight, and presents a high RF-to-DCconversion efficiency for low-RF-power levels which can be used to charge different low-DC-power devicesItem An experimental approach to improve the basin type solar still using an integrated natural circulation loop(Elsevier, 2015) Rahmani, Ahmed; Boutriaa, Abdelouahab; Hadef, AmarIn this paper, a new experimental approach is proposed to enhance the performances of the conventional solar still using the natural circulation effect inside the still. The idea consists in generating air flow by a rectangular natural circulation loop appended to the rear side of the still. The proposed still was tested during summer period and the experimental data presented in this paper concerns four typical days. The convective heat transfer coefficient is evaluated and compared with Dunkle’s model. The comparison shows that convective heat transfer is considerably improved by the air convection created inside the still. The natural circulation phenomenon in the still is studied and a good agreement between the experimental data and Vijajan’s laminar correlation is found. Therefore, natural circulation phenomenon is found to have a good effect on the still performances where the still daily productivity is of 3.72 kg/m2 and the maximum efficiency is of 45.15%.Item An observer based backstepping control for a greenhouse(2011) Belhani, Ahmed; M’sirdi, Nacer KouiderIn 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.Item Approximation by polynomials with bounded coefficients(ELSEVIER, 2007) Zaimi, ToufikLet θ be a real number satisfying 1 <θ< 2, and let A(θ ) be the set of polynomials with coefficients in {0, 1}, evaluated at θ. Using a result of Bugeaud, we prove by elementary methods that θ is a Pisot number when the set (A(θ ) − A(θ ) − A(θ )) is discrete; the problem whether Pisot numbers are the only numbers θ such that 0 is not a limit point of (A(θ ) − A(θ )) is still unsolved. We also determine the three greatest limit points of the quantities inf{c, c > 0, c ∈ C(θ )}, where C(θ ) is the set of polynomials with coefficients in {−1, 1}, evaluated at θ, and we find in particular infinitely many Perron numbers θ such that the sets C(θ ) are discrete.Item Benzene Combustion: A Detailed Chemical Kinetic Modeling in Laminar Flames Conditions1(Pleiades Publishing, 2014) Rezgui, Y; Guemini, MModels resulting from the merging of validated kinetic schemes were used to compile a new detailed mechanism for benzene combustion in laminar flames. The proposed model, featuring 215 species and 1313 reactions, has been validated using fuelrich, lowpressure, premixed benzene–oxygen–argon flames available in the literature. Good agreement between simulated and experimental data is achieved for the major reactants, intermediates, and products. However, computed maxima for some polyaromatic hydro carbons were lower than experimental ones.Item Bonding Analysis of Square-Antiprismatic and Fused Square-Antiprismatic Copper(I)-Selenium Clusters(Journal of Cluster Science, 2004) Zouchoune, Bachir; Fransois Halet, Jean; Yves Saillard, JeanThe electronic structure of the Cu2(4n+2)Se4n+2(PH3)8 (n = 1–4) D4h series of model clusters has been analyzed by means of density functional theory calculations. The fused square antiprismatic structure of the metal framework is found to be always preferred over the fused cuboctahedral one because it reinforces the Cu-P bonds. Thus, the presence of the terminal phosphine ligands tends to strengthen the Cu…Cu (d10… d10) bonding by mixing bonding combinations of the vacant Cu 4s and 4p orbitals into the occupied 3d combinations. The calculations indicate that the compounds corresponding to n = 3 and 4 should be easily two-electron-reduced, leading to stable dianionic specieItem Boundary conditions for one-dimensional Feshbach–Villars equation(ELSEVIER, 2000) Merad, M; Chetouani, L; Bounames, AWe solve the one-dimensional Feshbach–Villars equation for spinless particle subjected to a scalar smooth potential. The wave function is given in terms of the hypergeometric function and via a limiting procedure, the wave functions of the step potential are deduced. Then, the appropriate boundary conditions for the step potential are deduced using the two-component form.