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GENERALIZED LAGUERRE APPROXIMATION AND ITS APPLICATIONS TO EXTERIOR PROBLEMS

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Journal of Computational Mathematics 2005年第2期23卷 113-130页

作者： ben-yuGuo JieShen Cheng-longXu DepartmentofMathematics ShanghaiNormalUniversityandDivisionofComputationalScienceofE-instituteofShanghaiUniversitiesShanghai200233China DepartmentofMathematics PurdueUniversityUSA DepartmentofAppliedMathematics TongjiUniversityShanghai200092China

Approximations using the generalized Laguerre polynomials are investigated in this paper. Error estimates for various orthogonal projections are established. These estimates generalize and improve previously published results on the Laguerre approximations. As an example of applications, a mixed Laguerre-Fourier spectral method for the Helmholtz equation in an exterior domain is analyzed and implemented. The proposed method enjoys optimal error estimates, and with suitable basis functions, leads to a sparse and symmetric linear system.

关键词： Generalized Laguerre polynomials Exterior problems Mixed Laguerre-Fourier spectral method

Doubly-fed induction generator drive based WECS using fuzzy logic controller

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Frontiers in Energy 2015年第3期9卷 272-281页

作者： Abdelhak DIDA Djilani ben ATTOUS Department of Electrical Engineering Biskra University Biskra 07000 Algeria Department of Electrical Engineering El-Oued University El Oued 39000 Algeria

The purpose of this paper is to improve the control performance of the variable speed, constant frequency doubly-fed induction generator in the wind turbine generation system by using fuzzy logic controllers. The control of the rotor-side converter is realized by stator flux oriented control, whereas the control of the grid-side converter is performed by a control strategy based on grid voltage orientation to maintain the DC-link voltage stability. An intelligent fuzzy inference system is proposed as an alternative of the conventional proportional and integral （PI） controller to overcome any disturbance, such as fast wind speed variation, short grid voltage fault, parameter variations and so on. Five fuzzy logic controllers are used in the rotor side converter （RSC） for maximum power point tracking （MPPT） algorithm, active and reactive power control loops, and another two fuzzy logic controllers for direct and quadratic rotor currents components control loops. The performances have been tested on 1.5 MW doubly-fed induction generator （DFIG） in a Matlab/Simulink software environment.

关键词： fuzzy logic wind turbine vector control,doubly-fed induction generator (DFIG)

An Efficient Two-Phase Model for Computing Influential Nodes in Social Networks Using Social Actions

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Journal of Computer Science & Technology 2018年第2期33卷 286-304页

作者： Mehdi Azaouzi Lotfi ben Romdhane Modeling of Automated Reasoning Systems Research Laboratory LR17ES05 Higher Institute of Computer Science and Telecom University of Sousse Sousse 526-~002 Tunisia

The measurement of influence in social networks has received a lot of attention in the data mining community. Influence maximization refers to the process of finding influential users who make the most of information or product adoption. In real settings, the influence of a user in a social network can be modeled by the set of actions （e.g., ＂like＂, ＂share＂, ＂retweet＂, ＂comment＂） performed by other users of the network on his/her publications. To the best of our knowledge, all proposed models in the literature treat these actions equally. However, it is obvious that a ＂like＂ of a publication means less influence than a ＂share＂ of the same publication. This suggests that each action has its own level of influence （or importance）. In this paper, we propose a model （called Social Action-Based Influence Maximization Model, SAIM） for influence maximization in social networks. In SAIM, actions are not considered equally in measuring the ＂influence power＂ of an individual, and it is composed of two major steps. In the first step, we compute the influence power of each individual in the social network. This influence power is computed from user actions using PageRank. At the end of this step, we get a weighted social network in which each node is labeled by its influence power. In the second step of SAIM, we compute an optimal set of influential nodes using a new concept named ＂influence-BFS tree＂. Experiments conducted on large-scale real-world and synthetic social networks reveal the good performance of our model SAIM in computing, in acceptable time scales, a minimal set of influential nodes allowing the maximum spreading of information.

关键词： social network social influence social action personalized PageRank influence-BFS tree

Semi-global leader-following consensus-based formation flight of unmanned aerial vehicles

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Chinese Journal of Aeronautics 2022年第1期35卷 31-43页

作者： Panpan ZHOU ben M.CHEN Department of Mechanical ami Automation Engineering The Chinese University of Hong KongHong KongChina

In this paper,we investigate a formation control problem of multi-agent systems(specifically a group of unmanned aerial vehicles)based on a semi-global leader-following consensus approach with both the leader and the followers subject to input *** the low gain feedback design technique,a distributed static control protocol and a distributed adaptive control protocol are *** former solves the problem under an assumption that the communication network is undirected,and it depends on the global information of the *** the latter,we relax the undirected graph to directed ***,an adaptive updating gain is designed to avoid using the global information of the communication *** is shown that the consensus protocols can solve the semi-global leader-following consensus problem if the leader agent is globally *** results are verified successfully by both simulation and real flight tests.

关键词： Consensus Formation flying Input saturation Low gain feedback Multi-agent systems Unmanned aerial vehicles

Efficacy of Essential Trace Elements Supplementation on Mineral Composition,Sperm Characteristics,Antioxidant Status,and Genotoxicity in Testis of Tebuconazole-treated Rats

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Biomedical and Environmental Sciences 2020年第10期33卷 760-770页

作者： Hajer ben SAAD Fatma ben ABDALLAH Intidhar BKHAIRIA Ons BOUDAWARA Moncef NASRI Ahmed HAKIM Ibtissem ben AMARA Laboratory of Enzyme engineering and Microbiology National Engineering School in SfaxUniversity of SfaxB.P.11733038 SfaxTunisia Laboratory of Human Molecular Genetics Faculty of Medicine ofSfaxUniversity of SfaxTunisia Laboratory of Anatomopathology CHU Habib BourguibaUniversity of Sfax3029 SfaxTunisia Laboratory of Pharmacology Faculty of Medicine3029 SfaxUniversity of SfaxTunisia

Objective This research was performed to evaluate the effect of tebuconazole(TBZ)on reproductive organs of male rats and to assess the protective role of combined essential trace elements in alleviating the detrimental effect of TBZ on male reproductive *** For this purpose,48 rats were exposed to 100 mg/kg TBZ,TBZ supplemented with zinc(Zn),selenium(Se),copper(Cu),and iron(Fe),TBZ+(Se+Zn);TBZ+Cu;or TBZ+*** experiment was conducted for 30 consecutive *** TBZ caused a significant perturbation in mineral levels and reduction in reproductive organs weights,plasma testosterone level,and testicular antioxidant enzyme *** TBZ-treated group also showed a significant increase in sperm abnormalities(count,motility,and viability percent),plasma follicle-stimulating hormone and luteinizing hormone concentrations,lipid peroxidation,protein oxidation,and severe DNA degradation in comparison with the ***,TBZ caused testis ***,treatment with trace elements,in combination or alone,improved the reproductive organ weights,sperm characteristics,TBZ-induced toxicity,and histopathological modifications in *** TBZ exerts significant harmful effects on male reproductive *** concurrent administration of trace elements reduces testis dysfunction,fertility,and toxicity induced by TBZ.

关键词： Zinc Selenium Iron Copper Testicular toxicity

Evaluation of Protein Extraction Methods for Vitis vinifera Leaf and Root Proteome Analysis by Two-Dimensional Electrophoresis

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Journal of Integrative Plant Biology 2010年第10期52卷 933-940页

作者： Neila Jellouli Asma ben Salem Abdelwahed Ghorbel Hatem ben Jouira Laboratoire de Physiologie Moléculaire de la Vigne Centre de Biotechnologie de Borj Cédria

An efficient protein extraction method is crucial to ensure successful separation by two-dimensional electrophoresis （2-DE） for recalcitrant plant species, in particular for grapevine （Vitis vinifera L.）. Trichloroacetic acid-acetone （TCA-acetone） and phenol extraction methods were evaluated for proteome analysis of leaves and roots from the Tunisian cultivar ＇Razegui＇. The phenol-based protocol proved to give a higher protein yield, a greater spot resolution, and a minimal streaking on 2-DE gels for both leaf and root tissues compared with the TCA-based protocol. Furthermore, the highest numbers of detected proteins on 2-DE gels were observed using the phenol extraction from leaves and roots as compared with TCA-acetone extraction.

关键词： Proteins Protein products Extraction Extracts Acetone Tca Separating Methods Colloids Roots

Event-Triggered Adaptive Fuzzy Finite Time Control of Fractional-Order Non-Strict Feedback Nonlinear Systems

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Journal of Systems Science & Complexity 2022年第6期35卷 2166-2180页

作者： XIN Chun LI Yuanxin NIU ben College of Science Liaoning University of TechnologyJinzhou 121001China School of Information Science and Engineering Shandong Normal UniversityJinan 250014China

In this article,the problem of event-triggered adaptive fuzzy finite time control of nonstrict feedback fractional order nonlinear systems is *** using the property of fuzzy basis function,the obstacle caused by algebraic loop problems is successfully ***,a new adaptive event-triggered scheme is designed under the unified framework of backstepping control method,which can largely reduce the amount of *** stability of the closed-loop system is ensured through fractional Lyapunov stability ***,the effectiveness of the proposed scheme is verified by simulation examples.

关键词： Backstepping control event-triggered control(ETC) fractional order nonlinear system(FONS) fuzzy logic system(FLS) non-strict feedback structure

A Holistic View of Polymer Aggregate

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Chinese Journal of Polymer Science 2022年第3期40卷 231-232,I0004页

作者： ben Zhong Tang Shenzhen Institute of Aggregate Science and Technology School of Science and EngineeringThe Chinese University of Hong KongShenzhenChina

Polymers are *** living kingdom is full of natural polymers or biological macromolecules(e.g.,polysaccharides,polynucleotides and proteins),while the modern society is alive with synthetic polymers or manmade macromol... 详细信息

关键词： rubber fibers

Fast and Accurate Thoracic SPECT Image Reconstruction

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Computer Modeling in Engineering & Sciences 2022年第5期131卷 881-904页

作者： Afef Houimli Issam ben Mhamed Bechir Letaief Dorra ben-Sellem University of Tunis El Manar Higher Institute of Medical Technologies of TunisResearch Laboratory in Biophysics and Medical Technologies LR13ES07Tunis1006Tunisia University of Tunis Higher National School of Engineers of TunisSignal Image and Energy Management Laboratory:LR13 ES03 SIMEENSITMontfleury1008Tunisia Faculty of Medicine of Tunis University of Tunis El ManarTunis1007Tunisia Nuclear Medicine Department Salah AZAIEZ InstituteTunis1006Tunisia

In Single-Photon Emission Computed Tomography(SPECT),the reconstructed image has insufficient contrast,poor resolution and inaccurate volume of the tumor size due to physical degradation ***,nonstationary filtering of the projection or the slice is one of the strategies for correcting the resolution and therefore improving the quality of the reconstructed SPECT *** paper presents a new 3D algorithm that enhances the quality of reconstructed thoracic SPECT images and reduces the noise level with the best degree of *** suggested algorithm is composed of three *** first one consists of denoising the acquired projections using the benefits of the complementary properties of both the Curvelet transformand theWavelet transforms to provide the best noise *** second step is a simultaneous reconstruction of the axial slices using the 3D Ordered Subset Expectation Maximization(OSEM)*** last step is post-processing of the reconstructed axial slices using one of the newest anisotropic diffusion models named Partial Differential Equation(PDE).The method is tested on two digital phantoms and clinical bone SPECT images.A comparative study with four algorithms reviewed on state of the art proves the significance of the proposed *** simulated data,experimental results show that the plot profile of the proposed model keeps close to the original one compared to the other ***,it presents a notable gain in terms of contrast to noise ratio(CNR)and execution *** proposed model shows better results in the computation of contrast metric with a value of 0.68±7.2 and the highest signal to noise ratio(SNR)with a value of 78.56±6.4 in real *** experimental results prove that the proposed algorithm is more accurate and robust in reconstructing SPECT images than the other *** could be considered a valuable candidate to correct the resolution of bone in the SPECT images.

关键词： SPECT image resolution correction thoracic SPECT images wavelet transform curvelet transforms 3D-OSEM PDE