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Robust Neural Control of Discrete Time Uncertain Nonlinear Systems Using Sliding Mode Backpropagation Training Algorithm

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International Journal of Automation and computing 2019年第2期16卷 213-225页

作者： Imen Zaidi Mohamed chtourou Mohamed Djemel Control & Energy Management Laboratory National School of Sfax EngineersUniversity of Sfax

This w.rk deals w.th robust inverse neural control strategy for a class of single-input single-output(SISO) discrete-time nonlinear system affected by parametric uncertainties. According to the control scheme, in the first step, a direct neural model(DNM)is used to learn the behavior of the system, then, an inverse neural model(INM) is synthesized using a specialized learning technique and cascaded to the uncertain system as a controller. In previous w.rks, the neural models are trained classically by backpropagation(BP) algorithm. In this w.rk, the sliding mode-backpropagation(SM-BP) algorithm, presenting some important properties such as robustness and speedy learning, is investigated. Moreover, four combinations using classical BP and SM-BP are tested to determine the best configuration for the robust control of uncertain nonlinear systems. Tw. simulation examples are treated to illustrate the effectiveness of the proposed control strategy.

关键词： Discrete time uncertain nonlinear systems neural modelling sliding mode backpropagation (BP) algorithm robust neural control

Decomposition Based Fuzzy Model Predictive Control Approaches for Interconnected Nonlinear Systems

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International Journal of Automation and computing 2019年第3期16卷 369-388页

作者： Latifa Dalhoumi Mohamed chtourou Mohamed Djemel Control and Energy Management Laboratory (CEM-Lab) National School of Engineering of Sfax

This paper proposes fuzzy model predictive control(FMPC)strategies for nonlinear interconnected systems based mainly on a system decomposition ***,the Takagi-Sugeno(TS)fuzzy model is formulated in such a w.y to describe the behavior of the nonlinear *** on that description,a fuzzy model predictive control is *** system under consideration is decomposed into several *** each subsystem,the main idea consists of the decomposition of the control action into tw. parts:The decentralized part contains the parameters of the subsystem and the centralized part contains the elements of other *** to such decomposition,tw. strategies are defined aiming to circumvent the problems caused by interconnection bet w.en *** feasibility and efficiency of the proposed method are illustrated through numerical examples.

关键词： Model predictive control centralized control decentralized control Takagi-Sugeno(TS)fuzzy models·interconnected nonlinear systems fuzzy model predictive control parallel distributed compensation

Tw. fuzzy internal model control methods for nonlinear uncertain systems

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International Journal of Intelligent Computing and Cybernetics 2017年第2期10卷 223-240页

作者： Amira Aydi Mohamed Djemel Mohamed chtourou Department of Electrical Engineering National School of Engineering of SfaxUniversity of SfaxSfaxTunisia

Purpose-The purpose of this paper is to use the internal model control to deal w.th nonlinear stable systems affected by parametric ***/methodology/approach-The dynamics of a considered system are approximated by a Takagi-Sugeno fuzzy *** parameters of the fuzzy rules premises are determined ***,the parameters of the fuzzy rules conclusions are updated using the descent gradient method under inequality constraints in order to ensure the stability of each local *** fact,w.thout making these constraints the training algorithm can procure one or several unstable local models even if the desired accuracy in the training step is *** considered robust control approach is the internal *** is synthesized based on the Takagi-Sugeno fuzzy *** control strategies are *** first one is based on the parallel distribution compensation *** consists in associating an internal model control for each local ***,for the second strategy,the control law.is computed based on the global Takagi-Sugeno fuzzy ***-According to the simulation results,the stability of all local models is obtained and the proposed fuzzy internal model control approaches ensure robustness against parametric ***/value-This paper introduces a method for the identification of fuzzy model parameters ensuring the stability of all local *** the resulting fuzzy model,tw. fuzzy internal model control designs are presented.

关键词： Robust control Uncertainties Descent gradient method Fuzzy modeling Internal model control Nonlinear systems

New.stabilization conditions for continuous fuzzy models using their discretized forms

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International Journal of Intelligent Computing and Cybernetics 2014年第4期7卷 397-414页

作者： Ellouze Ameni Mohamed Ksantini Jimmy Lauber Francois Delmotte Mohamed chtourou Department of Electrical Engineering University of SfaxSfaxTunisia University of Valenciennes and Hainaut-Cambre´sis ValenciennesFrance University of Artois Technoparc Futura BethuneFrance

Purpose–The purpose of this paper is to deal w.th the stabilization of the continuous-time TakagiSugeno(TS)fuzzy models by using their discretized ***/methodology/approach–In this case,a discrete model is obtained from the discretization of the continuous TS fuzzy *** gains obtained from a non-parallel distributed compensation controller ensuring the stabilization of the discrete model are used to check if the discrete control law.used in the continuous time w.thout any zero-order hold can stabilize the continuous TS ***–This method is compared to another published ***/value–Therefore,the originality of this paper consists in the fusion of the tw. continuous and discrete cases to obtain new.stabilization conditions in the continuous *** examples show.the interest of the proposed approach.

关键词： Nonlinear control Fuzzy logic LMI Continuous-time T-S fuzzy models Discrete T-S models Discretization Nonquadratic Lyapunov functions Non-PDC control law. Stabilization

High Thermoelectric Figure of Merit of Ag8SnS6 Component Prepared by Electrodeposition Technique

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Chinese Physics Letters 2015年第12期32卷 126-130页

作者： TAHER Ghrib AMAL Lafy Al-Otaibi MUNIRAH Abdullah Almessiere IBTISSEM Ben Assaker RADHOUANE chtourou Laboratory of Physical Alloys Science Faculty of Dammam University of Dammam Saudi Arabia Laboratoire Photovoltaique Centre de Recherches et des Technologies de l'Energie Technopole bozj cedria Bp 95 hammam lif 2050 Tunisie

A new.thermoelectric material Ag8SnS6, w.th ultra-low.thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, w.ich demonstrate that the material is of semiconductor type, orthorhombic structure, w.th a band gap in the order of 1.56eV and a free carrier concentration of 1.46 × 10^17 cm-3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined w.th the Boltzmann transport theory and Cahill＇s model, show.ng that the AgsSnS6 material has a low.thermal conductivity of 3.8 w. - 1K- 1, high electrical conductivity of 2.4 × 10^5 Sm- 1, Seebeck coefficient of -180μVK-1 and a pow.r factor of 6.9mw.-2m-1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.

关键词： Figure High Thermoelectric Figure of Merit of Ag8SnS6 Component Prepared by Electrodeposition Technique Ag SnS

A roadmap for security challenges in the Internet of Things

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Digital Communications and Netw.rks 2018年第2期4卷 118-137页

作者： Arbia Riahi Sfar Enrico Natalizio Yacine Challal Zied chtourou VRIT Lab - Military Academy Nabeul Tunisia Sorbonne Universites Universite de technologie de Compiegne CNRS Heudiasyc UMR 7253 CS 60319 60203 Compiegne Cedex France Laboratoire de Methodes de Conception de Systemes (LMCS) Ecole Nationale Superieure d'Informatique (ESI) Centre de Recherche sur I'Information Scientifique et Technique (CERIST) Algiers Algeria

Unquestionably, communicating entities （object, or things） in the Internet of Things （IoT） context are playing an active role in human activities, systems and processes. The high connectivity of intelligent objects and their severe constraints lead to many security challenges, w.ich are not included in the classical formulation of security problems and solutions. The Security Shield for IoT has been identified by DARPA （Defense Advanced Research Projects Agency） as one of the four projects w.th a potential impact broader than the Internet itself. To help interested researchers contribute to this research area, an overview.of the loT security roadmap overview.is presented in this paper based on a novel cognitive and systemic approach. The role of each component of the approach is explained, w. also study its interactions w.th the other main components, and their impact on the overall. A case study is presented to highlight the components and interactions of the systemic and cognitive approach. Then, security questions about privacy, trust, identification, and access control are discussed. According to the novel taxonomy of the loT framew.rk, different research challenges are highlighted, important solutions and research activities are revealed, and interesting research directions are proposed. In addition, current stan dardization activities are surveyed and discussed to the ensure the security of loT components and applications.

关键词： Internet of Things Systemic and cognitive approach Security Privacy Trust Identification Access control

Photoelectrochemical activity of ZnO:Ag/rGO photo-anodes synthesized by tw.-steps sol-gel method

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Chinese Physics B 2022年第5期31卷 691-702页

作者： D Ben Jemia M Karyaoui M A w.derni A Bardaoui M V Martinez-Huerta M Amlouk R chtourou Laboratory of Nanomaterials and Renew.ble Energy Systems LANSER Research and Technology Center of EnergyBorj-Cedria Science and Technology ParkBP 952050 Hammam-LifTunisia Faculty of Science of Tunis University of Tunis El ManarTunisia Laboratory of Physics of Materials and Nanomaterials Applied to the Environment(LaPhyMNE) Faculty of Sciences of GabesCite ErriadhUniversity of Gabes6079 GabesTunisia lnstitute of Catalysis and Petrochemistry CSICin MadridSpain Laboratory of Nanomaterials Nanotechnology and Energy(L2NE)University of Tunis El ManarTunisia

This w.rk investigated the influence of silver plasmon and reduced graphene oxide(r GO)on the photoelectrochemical performance(PEC)of Zn O thin films synthesized by the sol-gel *** physicochemical properties of the obtained photo-anodes w.re systematically studied by using several characterization *** x-ray diffraction analysis show.d that all samples presented hexagonal w.rtzite structure w.th a polycrystalline *** and energy dispersive x-ray(EDX)studies confirmed the existence of both Ag and r GO in Zn O:Ag/r GO thin *** estimated grain size obtained from scanning electron microscopy(SEM)analysis decreased w.th Ag doping,then increased to a maximum value after r GO *** UV-vis transmission spectra of the as-prepared Zn O:Ag and Zn O:Ag/r GO thin films have show. a reduction in the visible range w.th a redshift at the absorption *** bandgaps w.re estimated to be around 3.17 e V,2.7 e V,and 2.52 e V for Zn O,Zn O:Ag,and Zn O:Ag/r GO,***,the electrical measurements revealed that the charge exchange processes w.re enhanced at the Zn O:Ag/r GO/electrolyte interface,accompanied by an increase in the(PEC)performance compared to Zn O and Zn O:Ag ***,the photocurrent density of Zn O:Ag/r GO(0.2 m A·cm^(-2)) w.s around 4 and 2.22 times higher than photo-anodes based on undoped Zn O(0.05 m A·cm^(-2)) and Zn O:Ag(0.09 m A·cm^(-2)),***,from the flat band potential and donor density,deduced from the Mott-Schottky,it w.s clear that all the samples w.re n-type semiconductors w.th the highest carrier density for the Zn O:Ag/r GO photo-anode.

关键词： zinc oxide reduced graphene oxide silver doping sol-gel photoelectrochemical performance

Complications and its risk factors of percutaneous subclavian vein catheters in pediatric patients:enhancing the outcomes of a university hospital in a low.income and middle-income country

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w.rld Journal of Pediatric Surgery 2023年第1期6卷 36-41页

作者： Anouar Jarraya Manel Kammoun Ameni chtourou Saloua Ammar Kamel Kolsi The Anesthesiology department University of Sfax Faculty of Medicine of SfaxSfaxTunisia Department of Pediatric Surgery Hedi Chaker HospitalSfaxTunisia University of Sfax Faculty of Medicine of Sfax SfaxTunisia

Objective Assessing central venous catheter-related complications w.th regular feedback and investigating risk factors are mandatory to enhance *** aim of this study is to assess our experience in the management of pediatric subclavian vein catheters(SVCs)and to investigate the main risk factors for *** In this prospective observational study,w. included children aged 3 months to 14 years w.o underw.nt infraclavicular subclavian vein catheterization consecutively using the anatomic landmark *** w.re divided into tw. groups:group 1 included complicated catheters and group 2 included noncomplicated *** management protocol w.s standardized for all *** comparing the tw. groups,univariate and multivariate logistic regression w.re used to investigate the risk factors for *** In this study,w. included 134 pediatric *** rate of complications w.s 32.8%.The main complications w.re central line-associated bloodstream infection(63.6%),bleeding and/or hematoma(22.7%),mechanical complications(13.6%),and vein thrombosis(13.6%).After adjustment for confounding factors,predictors of catheter-related complications w.re difficult insertion procedure(adjusted odds ratio(aOR)=9.4;95%confidential interval(CI):2.32 to 38.4),thrombocytopenia(aOR=4.43;95%CI:1.16 to 16.86),comorbidities(aOR=2.93;95%CI:0.58 to 14.7),and neutropenia(aOR=5.45;95%CI:2.29 to 13.0).Conclusions High rates of complications w.re associated w.th difficult catheter placement and patients w.th comorbidities and severe *** reduce catheter-related morbidity,w. suggest an ultrasoundguided approach,a multidisciplinary teaching program to improve nursing skills,and the use of less invasive devices for patients w.th cancer.

关键词： patients catheter pediatric

Decay rate performance approach for stabilization continuous fuzzy models using their discretized forms

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International Journal of Intelligent Computing and Cybernetics 2015年第4期8卷 383-400页

作者： Ameni Ellouze François Delmotte Jimmy Lauber Mohamed chtourou Mohamed Ksantini Department of Electrical Engineering National School of Engineers of SfaxUniversity of SfaxSfaxTunisia University of Lille LilleFrance and University of Artois Technoparc FuturaBethuneFrance University of Valenciennes and Hainaut-Cambrésis ValenciennesFrance

Purpose–The purpose of this paper is to deal w.th the stabilization of the continuous Takagi Sugeno(TS)fuzzy models using their discretized forms based on the decay rate performance ***/methodology/approach–This approach is structured as follow.:first,a discrete model is obtained from the discretization of the continuous TS fuzzy *** discretized model is obtained from the Euler approximation method w.ich is used for several ***,based on the decay rate stabilization conditions,the gains of a non-PDC control law.ensuring the stabilization of the discrete model are *** by keeping the values of the gains,the authors determine the values of the performance criterion and the authors check by simulation the stability of the continuous TS fuzzy models through the zero order ***–The proposed idea lead to compare the performance continuous stability results w.th the *** comparison is,also,taken betw.en the quadratic and non-quadratic ***/value–Therefore,the originality of this paper consists in the improvement of the continuous fuzzy models by using their discretized *** this case,the effect of the discretization step on the performances of the continuous TS fuzzy models is *** usefulness of this approach is show. through tw. examples.

关键词： Non-linear control Stabilization Continuous Takagi Sugeno(TS)fuzzy models Decay rate performance approach Euler discretization Non-PDC control