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Lynda Amel Chaabane,Fouad Bourada,Mohamed Sekkal,Sara Zerouati,Fatima Zohra Zaoui,Abdeldjebbar Tounsi,Abdelhak Derras,Abdelmoumen Anis Bousahla,Abdelouahed Tounsi 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.2
In this investigation, study of the static and dynamic behaviors of functionally graded beams (FGB) is presented using ahyperbolic shear deformation theory (HySDT). The simply supported FG-beam is resting on the elastic foundation (Winkler-Pasternak types). The properties of the FG-beam vary according to exponential (E-FGB) and power-law (P-FGB) distributions. Thegoverning equations are determined via Hamilton’s principle and solved by using Navier’s method. To show the accuracy of thismodel (HySDT), the current results are compared with those available in the literature. Also, various numerical results are discussedto show the influence of the variation of the volume fraction of the materials, the power index, the slenderness ratio and the effect ofWinkler spring constant on the fundamental frequency, center deflection, normal and shear stress of FG-beam.
Design of Robust Fault Detection Observer for Takagi-Sugeno Models Using the Descriptor Approach
Maha Bouattour,Mohammed Chadli,Mohamed Chaabane,Ahmed El Hajjaji 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.5
This paper deals with the design of a robust fault detection observer for a Takagi-Sugeno (T-S) fuzzy model affected by sensor and actuator faults and unknown bounded disturbances simultaneously. An observer based on the technique of descriptor systems is studied. Indeed, by considering faults as auxiliary state variables, both states and faults are estimated simultaneously. In order to guarantee the best robustness to disturbances and sensitivity to faults, the developed observer combine the H__/H_∞ performances. Then, based on Lyapunov method, asymptotic stability conditions are given to design the observer parameters. In order to get convenient and reliable faults estimator in computations, an iterative linear matrix inequality (LMI) algorithm is developed. This algorithm, solved easily using existing numerical tools, allows to minimize influences of disturbances and maximize the ones of faults. Finally, a numerical example is proposed to illustrate the effectiveness of the result.
Mourad Kchaou,Fernando Tadeo,Mohamed Chaabane,Ahmed Toumi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.1
The problem of observer-based robust control design is studied for discrete-time singular systems with norm-bounded uncertainties and a time-varying delay. More precisely, a delay-dependent criterion is established that guarantees the admissibility of the considered systems, without resorting to its decomposition. Based on the proposed criterion and without the assumption that the considered sys-tems are admissible, robust observer-based controllers are designed for discrete-time singular time-delay systems such that the closed-loop systems have the characteristics of regularity, causality and asymptotic stability. Seeking computational convenience, all the developed results are cast in the for-mat of strict linear matrix inequalities (LMIs). Finally, some numerical examples are presented to show the feasibility of the proposed approach.
Afef Be´jaoui,He´dia Chaabane,Maroua Jemli,Abdennacer Boulila,Mohamed Boussaid 한국식품영양과학회 2013 Journal of medicinal food Vol.16 No.12
Variation in the quantity and quality of the essential oil (EO) of wild population of Origanum vulgare at different phenological stages, including vegetative, late vegetative, and flowering set, is reported. The oils of air-dried samples were obtained by hydrodistillation. The yield of oils (w/w%) at different stages were in the order of late vegetative (2.0%), early vegetative (1.7%), and flowering (0.6%) set. The oils were analyzed by gas chromatography (GC) and GC–mass spectrometry (GC-MS). In total, 36, 33, and 16 components were identified and quantified in vegetative, late vegetative, and flowering set, representing 94.47%, 95.91%, and 99.62% of the oil, respectively. Carvacrol was the major compound in all samples. The ranges of major constituents were as follows: carvacrol (61.08–83.37%), p-cymene (3.02– 9.87%), and c-terpinene (4.13–6.34%). Antibacterial activity of the oils was tested against three Gram-positive and two Gram-negative bacteria by the disc diffusion method and determining their diameter of inhibition and the minimum inhibitory concentration (MIC) values. The inhibition zones and MIC values for bacterial strains, which were sensitive to the EO of O. vulgare subsp. glandulosum, were in the range of 9–36mm and 125–600 lg/mL, respectively. The oils of various phenological stages showed high activity against all tested bacteria, of which Bacillus subtilis was the most sensitive and resistant strain, respectively. Thus, they represent an inexpensive source of natural antibacterial substances that exhibited potential for use in pathogenic systems.
Hamdi Gassara,Ahmed El Hajjaji,Mohamed Krid,Mohamed Chaabane 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4
This paper investigates the problems of delay-dependent stability analysis and memory control design of polynomial fuzzy systems with time delay. Using polynomial Lyapunov-Krasovskii functional and slack polynomial matrix variables, delay dependent sufficient stability and stabilizability conditions are derived in terms of sum of squares (SOS) which can be numerically (partially symbolically) solved via the recently developed SOSTOOLS. The main advantage of the proposed design is the reduction of conservatism for three great reasons. The first one is that polynomial matrices are not only dependent on the system state vector but also on the state vector with time delay. The second one is that the design conditions are formulated in delay dependent SOS. It is well known that the delay-dependent conditions are less conservative than those independent of time delay. The third one is that only correlated terms are used in the design of SOS. The simulation and comparison are given to illustrate the lesser conservativeness of the proposed result.
Local Stabilization of Polynomial Fuzzy Model with Time Delay: SOS Approach
Hamdi Gassara,Ahmed El Hajjaji,Fatma Siala,Mohamed Chaabane 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.1
In this paper, a design method of control for Polynomial Fuzzy Models (PFM) with time delay is developed. By using a Polynomial Lyapunov Krasovskii Functional (PLKF) with double integral and by imposingbounds on the derivatives of each state, less conservative sufficient conditions are established to ensure the local stabilityof the closed loop system. Furthermore, a Domain Of Attraction (DOA) in which the initial states are ensuredto converge asymptotically to the origin is estimated. The resulting conditions are formulated in terms of Sum-Of-Squares (SOS) which can be numerically (partially symbolically) solved via the recently developed SOSTOOLS. Some examples are provided to show the effectiveness and the merit of the design procedure.
Polynomial Dynamic Output-feedback Controllers for Positive Polynomial Fuzzy Systems with Time Delay
Imen Iben Ammar,Hamdi Gassara,Mohamed Chaabane,Ahmed El Hajjaji 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.8
This paper investigates the stability and stabilization problems of positive polynomial fuzzy uncertain interval models with time delay. Using the polynomial output feedback fuzzy control strategy, the design problem is firstly studied by considering the unmeasured states and measurable premise variables. Then, the control design problem is extended for both the unmeasurable states and unmeasurable premise variables. To study the considered analysis and design problems, a line-integral polynomial fuzzy Lyapunov function with polynomial terms depending of the estimated states is proposed. For each case, the proposed design conditions of the polynomial dynamic output feedback fuzzy controllers guarantying both the stability and the positivity of the resulting closed loop systems, are solved using the Sum of Squares (SOS) approach with tacking into account the positivity of the error signals. Finally, simulation examples are given to show the effectiveness of the proposed approaches.
Dhouha Kharrat,Hamdi Gassara,Ahmed El Hajjaji,Mohamed Chaabane 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.3
This paper concerns the problem of state, fault estimation (FE) and Fault Tolerant Control (FTC) of Takagi-Sugeno (T-S) descriptor systems affected by sensor, actuator and external disturbances simultaneously. An Adaptive Fuzzy Observer is firstly proposed to achieve a simultaneous estimation of descriptor system states, actuator and sensor faults by using the H∞ optimization technique. A FTC is secondly proposed to stabilize the faulty descriptor system. Based on Lyapunov method, stability analysis and design conditions of the resulting closed-loop system are formulated in a set of Linear Matrices Inequalities (LMIs). The adaptive fuzzy observer and the FTC are independently designed, in order to avoid the coupling problem. Accordingly, the observer and controller gains are computed separately by solving a set of LMIs and then used to estimate the unmeasured states, sensor and actuator faults at the same time. Finally, a truck-trailer system application is given to illustrate the validity of the proposed approach.
3-Hom-Lie superbialgebras and 3-Hom-Lie classical Yang-Baxter equations
Issam Bartouli,Imed Basdouri,Gaith Chaabane,Mohamed Fadous,Jean Lerbet 대한수학회 2024 대한수학회논문집 Vol.39 No.1
3-Lie algebras are in close relationships with many fields. In this paper we are concerned with the study of 3-Hom-Lie super algebras, the concepts of 3-Hom-Lie coalgebras and how they make a 3-Hom-Lie superbialgebras, we study the structures of such categories of algebras and the relationships between each others. We study a super twisted 3-ary version of the Yang-Baxter equation, called the super 3-Lie classical Hom-Yang-Baxter equation (3-Lie CHYBE), which is a general form of 3-Lie classical Yang-Baxter equation and prove that the superbialgebras induced by the solutions of the super 3-Lie CHYBE induce the coboundary local cocycle 3-Hom-Lie superbialgebras.