4.Faculty of exact science_Seminars
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Item 2-Orthogonal Polynomials and Darboux Transforms(University of Eloued جامعة الوادي, 2019-04-23) Faghmous, Chadia; Bouras, Mohamed Cherif; Ali Khelil, KarimaIn this work we present a new interpretation of Darboux transforms in the context of 2-orthogonal polynomials and nd condi- tions in order for any Darboux transform to yield a new set of 2- orthog- onal polynomials. We also introduce the LU and UL factorizations of the monic Jacobi matrix associated with a quasi-de nite linear functional de ned on the linear space of polynomials with real coe¢ cients.Item 3rd International Conference in Operator Theory, PDE and Applications(University of Eloued جامعة الوادي, 2019-03-12) Mathematics DepartmentItem Abstracts of 1st international conference on optoelectronics, Materials & renewable energy(University of Eloued جامعة الوادي, 2022-12-12) Faculty of Exact SciencesItem Abstracts of 4th International Conference in Operator Theory, PDE and Application(University Of Eloued جامعة الوادي, 2022-12-07) Faculty of Exact SciencesItem Abstracts of The Second Internationl Conference on: Materials, Energy and Environment (MEE'2023). October 23-24, 2023.(University of Eloued جامعة الوادي, 2023-10-23) Faculty of Exact Scienceshe Second International Conference on Materials, Energy and Environment will be held at El Oued University on October 23-24, 2023. It goal is to bring together researchers, professors and industrialists concerned by technological and scientific advances in the Materials, Energy and Environment sciences. This first international edition is intended to be open to industrial concerns and the transfer of technology between universities and industries. This is why applied themes are programmed to better meet the needs of the industrial community. TItem ANALYTICAL STUDY OF ELECTRONIC AND OPTICAL PROPERTIES OF InAs / InGaAs QUANTUM DOT LASER(University of Eloued جامعة الوادي, 2018-02-05) TALEB, Soufyane; SOUDINI, Belabbéss; LAGRAA, IbrahimAs part of improving the properties of optoelectronic components, by a better quantum confinement of electrons and holes, we carried out an analytical study of carrier dynamics in quantum dots lasers (QDL). Our calculations are performed on the set of five rate equations for carriers and photons in two energy states. The results of the curriers density, photon density, output power, and the in /out scattering rates between the quantum dot (QD) and quantum well (QW) versus the time and the injection current. Our results are in agreement with others work and then a confirmation of the validity of this numerical model to reproduce the electronic and the optical properties of quantum dot laser.Item Applying Artificial intelligence techniques for predicting amount of CO2 emissions from calcined cement raw materials(University of Eloued جامعة الوادي, 2022-01-24)This paper aims to predict the amount of carbon dioxide CO2 emissions from raw material used in cement clinker production during calcination process. The amount of CO2 emissions is mainly from the decarbonisation thermal process that is directly related to chemical composition, distribution of particle size and time exposed at high temperature. These influencing factors interact with each other, making the calculation of the amount of CO2 emissions with conventional techniques more difficult. For this reason, several artificial intelligence techniques are applied to predict the amount of CO2 emissions. The key advantage of the proposed techniques is its ability to learn and to generalise without any prior knowledge of an explicit relationship between target and its influencing parameters. The intelligence techniques applied are deep neural network (DNN), artificial neural networks (ANN) optimised using ant colony optimization (ACO-ANN) and genetic algorithm (GA-ANN). The results obtained are promising and show that all intelligence techniques can provide excellent accuracy with high R2 and low error. DNN predicts the amount of CO2 emissions very accurately when comparing to other techniques. Overall, the performance accuracy of ACO-ANN technique is higher than the GA-ANN. According to R2 values, there are more than 99%, 98.5% and 98% of experimental data in testing phases can be explained by DNN, ACO-ANN and GA-ANN respectively with average relative error less than 1.04%. As conclusion, all intelligence techniques can be employed as an excellent alternative to predict the amount of CO2 emissions.Item Approximate method for oxygen diffusion and absorption in sick cell(University of Eloued جامعة الوادي, 2019-04-23) Djellab, Nadjate; Boureghda, A.we consider the oxygen di usion problem where the injection of oxygen into a sick cell and di usion of the injected oxygen inside the cell. The problem mathematically formulated through two di erent steps. At the rst stage, the stable case having no oxygen transition in the isolated cell is searched while at the second stage the moving boundary of oxygen absorbed by the tissues in the cell is searched. In this study, trace of moving boundary of the oxygen di usion problem is determined using constrained integral method, the pro le of moving boundary is determined by third order polynomial.Item Artificial intelligent in upstream oil and gas industry: a review of applications, challenges and perspectives(University of Eloued جامعة الوادي, 2022-01-24) Kenioua, Abdelhamid; Touati Brahim, Ammar; Kenioua, LaidIn the last two decades, oil and gas (O&G) industries are facing several challenges and issues in different levels; from the decrease in commodity prices to the dynamic and unexpected environment. There has been a constant urge to maximize benefits and attain values from limited resources. Traditional empirical and numerical simulation techniques have failed to provide comprehensive optimized solutions in little time due to the Immense amount of data generated on daily basis with various formats, techniques and process. The proper technical analysis of this “explosion of data” is to be carried out to improve performance of O&G industries. Artificial intelligence (AI) has found extensive usage in simplifying complex decision-making procedures in practically every competitive market field, and O&G industry is not an exception. This paper provides a comprehensive stateof- art review in the field of machine learning and artificial intelligence to solve O&G industry problems. We focus on the upstream segment as the most capital- intensive part of oil and gas and the segment of enormous uncertainties to tackle. Based on a summary of various researchers work on machine learning and AI applications, we outline the most recent trends in developing AI-based tools and identify their effects on accelerating the process in the industry. This paper discusses also the main challenges related to non-technical factors that prevent the intensive application of AI in the upstream O&G industry.Item Assessing Combinations of Artificial Neural Networks Input Meteorological Parameters to Improve Daily Runoff Simulation(University of Eloued جامعة الوادي, 2022-01-24) Aoulmi, Yamina; Marouf, Nadir; Amireche, MohamedHydrological models are one of the tools used for reconstruction or simulation, forecasting for the anticipation of future changes in the flow of a river, which allows better management of water resources during low flow periods and anticipation of flood risks during high water periods. Using artificial neural network (ANN) in the fields of hydrology and water resources, became advocated due to its capability of tackling, modeling and forecasting the problems that are nonlinear or stochastic within the Rainfall-Runoff (R-R) system. This research aims to test the practicability of using ANNs with two input configurations; to model the R-R relationship in two stations Mirebek and Ain Berda located in the Seybouse basin in Algeria. The 1st (ANN IP) considers only precipitation as an input variable for the daily flow simulation. The 2nd (ANN IIP,T,Hu) considers a combination of the Temperature and Humidity with precipitation at the model input. The results of the two models were compared through performance metrics, viz., Root Mean Square Error (RMSE),mean absolute error (MAE), Pearson's correlation coefficient (R), Nash Sutcliffe Efficiency coefficient (NSE), and through graphical interpretation (scatter plots and time series). Better flow simulations were provided by the three-input model for the two stations; where R=0.90, NSE=80.5% for Mirebek station and R=0.85, NSE=72% for Ain Berda. This result has confirmed that as much input variables are numerous, as more the model of ANN is efficient. The finding of this study indicates that the developed ANN models could be considered as a powerful tool for predicting Runoff.Item ASYMPTOTIC STABILITY OF A PROBLEM WITH KELVIN-VOIGT TERM AND BALAKRISHNAN-TAYLOR DAMPING.(University of Eloued جامعة الوادي, 2019-04-23) TOUALBIA, SARRAThe purpose of this work is to study the energy Decay of solutions for a nonlinear equation of the kelving voigt type with balakrishnan taylor damping and acoustic boundary in a bounded domain in Rn.Item Automation of the reading and interpretation of the OTDR plot(University of Eloued جامعة الوادي, 2022-01-24) MAZOUZI, Amine; ABOUN ABID, MiloudUnlike conventional networks, optical fiber transmission systems allow optical signals to be transported from the transmitter to the receiver. They have become the adaptable solution for transmissions of all types of data. By taking into account the problems and the external constraints which degrade the quality of the transmitted signal, the monitoring of the optical fibers is carried out by measurement tools making it possible to detect the various events and the defects along the fiber and this in order to do the maintenance. Necessary to provide better transmission on the medium. Currently the operation of monitoring an optical transmission link is carried out by an agent who constantly monitors the various changes in events that have occurred in the layout of the transmission line using OTDR equipments.Item Ball bearing monitoring using decision-tree and adaptive neuro-fuzzy inference system(University of Eloued جامعة الوادي, 2022-01-24) Euldji, Riadh; Boumahdi, Mouloud; Bachene, Mourad; Euldji, RafikThis study aims to provide a methodology that relies on the combination of the following approaches: the decision tree, the neural network, and the fuzzy logic to monitor the evolution of bearing degradation. Data collected from the vibratory signals generated from the tests carried out on ball bearings mounted in an experimental fatigue platform, are used. The decision tree method is applied to select the most relevant monitoring indicator, which will be used to develop an Adaptive Neuro-Fuzzy Inference System (ANFIS). The training and test data required for model development have been classified according to the following states: normal, abnormal, and dangerous. These were defined from two thresholds: alert threshold and danger threshold. Then, the ANFIS model is trained from the indicators selected by the decision tree to predict the behaviour of the bearing in operation. The results confirm the effectiveness of the proposed approach for monitoring the health of ball bearingItem Big Data Veracity: Methods and challenges(University of Eloued جامعة الوادي, 2022-01-24) benabderrahmane, MOUTASSEM; laouni, DJAFRI; GAAFOUR, Abdel-KaderToday, the Internet has become the main source of information, a place where there are no restrictions on who can share information .This latter can play an important role in prediction, estimation and decision making processes. But, this role will not only be achieved through abundance, it will also be the result of data quality. Veracity refers to the assurance of quality or credibility of the data collected. The data can be incomplete, biased, vague or wrong. For this reason, automatic filtering mechanism has been developed. Moreover, due to the increasing velocity of information spread, manual assessment of information veracity became hard, a time consuming process and even the already existing automatic filtering mechanisms has to be improved to cope with the speed of information spread. In this paper, a literature review is established to highlight the recent methods and techniques which are exploited in computerized veracity assessment. The challenges and limitations of existing works will be discussed, and future research directions will be proposed to address critical issues of data veracity in the era of big data.Item Book Of Abstracts Of The 1st Study day on applied chemistry and environmental engineering SDACEE-2024. April, 22, 2024(University Of Eloued جامعة الوادي, 2024-04-22) Dpartment of ChemistryThe SDACEE-2024 is part of the program of activities realized by the Department of Chemistry in cooperation with the research laboratory “LACE” in order to motivate researchers, especially PhD students, to present the results of their works and to discuss them with various categories of researchers. The book of abstracts of SDACEE-2024 presents a summary of 2 plenary conferences with 4 oral and 31 poster presentations. This book includes recent and original works realized in the field of Applied Chemistry and Environmental Engineering. The huge part of this book was devoted to the researches of Chemical depollution and environmental protection topic because of its importance in the subject of the event. It also covers an important topic in Applied Chemistry like organic synthesis according the ecofriendly methods. Two others topic are devoted to the pharmaceutical chemistry and drug discovery with phytochemistry and medicinal plants.Item BRESSE-TIMOSHENKO SYSTEM : WELL-POSSEDNESS AND STABILITY RESULTS(University of Eloued جامعة الوادي, 2019-04-23) YAZID, F.; OUCHENANE, D.In this paper, we consider a Bresse-Timoshenko type system with distributed delay term. Under suitable assumptions, we establish the global well-posedness of the initial and boundary value problem by using the Faedo- Galerkin approximations and some energy estimates. By using the energy method, we show the exponential stability results for the system with delay in vertical displacement.Item CARACTERISATION PAR DIFFRACTION DES RAYONS X DE LA SOLUTION SOLIDE Ca0.5Sr0.5FeO2.5+δ(University of Eloued جامعة الوادي, 2018-02-05) MAHBOUB, Mohammed Sadok; ZEROUAL, Soria; BOUDJADA, AliL'échantillon du composé Ca0.5Sr0.5FeO2.5+δ a été synthétisé par solution solide à 1200°C. Le résultat final de l’affinement Le Bail du diffractogramme des rayons X sur poudres dans le groupe d’espace orthorhombique Imma nous a donné des valeurs correspondant aux trois phases ce qui signifie l'existence de la « miscibility gap ». La première phase Ca0.65Sr0.35FeO2.5+δ est enrichie en Ca avec les paramètres de mailles a=5.46799(18)Å, b=15.05175(62) Å et c=5.62380(18) Å, la deuxième Ca0.4Sr0.6FeO2.5+ est enrichie en Sr avec a=5.49090(53) Å, b=15.26665(126) Å et c=5.63900(84) Å, et la troisième Ca0.25Sr0.75FeO2.5+δ enrichie en Sr avec a=5.51623(68) Å, b=15.38207(186) Å et c=5.65523(61) Å, avec une valeur d'affinement final χ2=1.38.Item CARACTERISATION PAR DRX DES MATERIAUX COMPOSITES A MATRICE THERMOPLASTIQUE (PEHD) RENFORCEE PAR DE FIBRES DE PALMIER DATTIER (FD)(University of Eloued جامعة الوادي, 2018-02-05) HACHAICHI, Amina; NEKAA, SoryaL’objectif de ce travail est d’élaborer et de caractériser un nouveau matériau composite à base de polyéthylène haute densité (PEHD) renforcé par des de palmier dattier (FD). L’inconvénient majeur que l’on rencontre pour ce type de système est l’incompatibilité avec la matrice PEHD. Pour pallier à cet inconvénient, la fibre de palmier dattier a été traitée par le permanganate de Potassium (KMnO4) pour améliorer la liaison à l'interface fibre/polymère. La méthode de diffraction des rayons X est l’une des méthodes les plus intéressantes pour caractériser les structures cristallines. D’après les résultats de ces analyses, on a observé que le taux de cristallinité des composites PEHD/FD à 30% de fibres non traitées et traitées a augmenté par rapport la matrice PEHD. D’autre part, nous remarquons que le traitement n’a pas d’influence importante sur le taux de cristallinitéItem CARACTÉRISATIONS OPTIQUES ET OPTO-ÉLECTRONIQUES DE COUCHES MINCES DE SILICIUM AMORPHE HYDROGÉNÉ(University of Eloued جامعة الوادي, 2018-02-05) Tata, S.; Laidoudi, L.; Cherfi1, R.; Chabane, L.; Rahal, A.Notre travail rentre dans le cadre des caractérisations optiques et opto-électroniques des couches minces à base de silicium amorphe hydrogéné (a-Si:H). Les couches ont été déposées à une température de porte substrat égale à 300 °C, par pulvérisation DC assistée d’un magnétron, sur plusieurs types de substrats compatibles avec les techniques de caractérisations utilisées. La spectrophotométrie UV-visible-IR a permis de déterminer l’épaisseur des couches, leur gap optique ainsi que leur indice de réfraction statique. Les jonctions Schottky (Au/a-Si :H) ont été caractérisées par la technique surface Photo-Voltage (SPV), qui permet d’estimer la longueur de diffusion des porteurs minoritaires, paramètre clé pour des applications photovoltaïques. Les résultats obtenus ont montré que les films élaborés sont photoconductreurs, et que les paramètres obtenus sont du même ordre que ceux rencontrés dans la littératureItem A CBR approach based on ontology to supplier selection(University of Eloued جامعة الوادي, 2022-01-24) BEKKAOUI, Mokhtaria; KARRAY, Mohamed Hedi; MELIANI, Sidi MohammedMost previous research categorizes supply chain management (SCM) into the following three major parts: purchasing, manufacturing, and distribution. In the purchasing process, supplier selection represents a crucial step for enhancing firms’ competitiveness.An increasing number of researches have been devoted to the development of different methodologies to cope with this problem.The majority of research explores the difference in the set of criteria for supplier selection. They used famous methods for selection such as AHP (Analytic Hierarchy Process); ANP (Analytic Network Process); DEA (Data Envelopment Analysis);TOPSIS (Technique for Order Preference by Similarity to Ideal Solution). Thus, this paper presents a CBR (Case Based Reasoning) approach in the context of supplier selection decision making.