Aoun Mohamed

Ecole Nationale d'Ingénieurs de Monastir · Department of Mechanical Engineering

Aim: Repetitive transcranial magnetic stimulation (rTMS) is widely utilized as an effective treatment for major depressive disorder (MDD) with varying response rates. Factors associated with better treatment outcome remains scarce. This naturalistic retrospective chart review hopes to shed light on easily obtainable & measurable predictive factors...

It is well known that, in some practical system identification situations, measuring both input and output signals can commonly be affected by additive noises. In this paper, we consider the problem of identifying continuous-time fractional systems from noisy input and output measurements. The bias correction scheme, which aims at eliminating the b...

A new design method of a robust fractional order PI controller for uncertain First Order Plus Dead Time systems is proposed in this paper. The proposed design method uses a numerical optimization algorithm to determine the unknown controller parameters. The main objective of the proposed design method is improving the robustness in degree of stabil...

Action monitoring deficit is a core underlying characteristic and endophenotype of Obsessive Compulsive Disorder (OCD). Dorsal anterior cingulate cortex (dACC) is heavily involved in error monitoring and cognitive control, and the hyperactivity in this region is associated with OCD symptom severity. This study aimed to test whether low frequency (L...

This study explores different episodic memory domains, namely object, temporal and spatial memory, affected in patients with a clinical diagnosis of single domain amnestic mild cognitive impairment (aMCI). 15 aMCI patients and 25 healthy controls were recruited and tested. Object, spatial, and temporal memory were tested using computerized tasks an...

Predictive control has become very popular with practitioners of automatic control due to its design simplicity and relatively good performances. Recent efforts have concentrated into improving the robustness of predictive controllers. In this paper, a method for the tuning of generalized predictive controllers (GPC) using desired closed-loop trans...

The paper deals with the stabilization problem of the first order system with and without integration. In this work, we present a simple stabilization method to guarantee stability and desired performances. Analytic expressions are developed to determine the stabilizing controller parameters by describing the stability region. Moreover, the time do...

In this paper an interval observer is synthesized for fractional linear systems with additive noise and disturbances. The contribution of system whole past to future output is taken into account as an initialization function. Provided the initialization function is upper and lower bounded, it is shown in this paper that the fractional interval obse...

Major Depressive Disorder (MDD) is typically accompanied by cognitive impairment. Repetitive Transcranial Magnetic Stimulation (rTMS) treatment for MDD involves stimulation of the dorsolateral prefrontal cortex which plays an important role in cognition. This study aimed to identify differences in cognitive profiles between remitters and non-remitt...

Information on land use and land cover is important and much-needed for different aspects of sustainable development and environmental management. Remote sensing datasets have become one of the most important and practical tools for providing this information. The present study aimed at studying the land cover of the Gabes region located in southe...

It is well known that, in some industrial process identification situations, measurements can be collected from closed-loop experiments for several reasons such as stability, safety, and performance constraints. In this paper, we investigate the problem of identifying continuous-time fractional closed-loop linear parameter varying systems. The simp...

The objective of this paper is to propose a reduced-order observer for a class of Lipschitz nonlinear discrete-time systems. The conditions that guarantee the existence of this observer are presented in the form of linear matrix inequalities (LMIs). To handle the Lipschitz nonlinearities, the Lipschitz condition and the Young′s relation are adequat...

A discrete-time robust controller design method is proposed for optimal tracking of future references in preview systems. In the context of preview systems, it is supposed that future values of the reference signal are available a number of time steps ahead. The objective is to design a control algorithm that minimizes a quadratic error between the...

This paper deals with H∞ observer-based controller design for a class of discrete-time systems with Lipschitz nonlinearities. Usually, the observer-based control synthesis for the considered class of systems leads to the feasibility of a Bilinear Matrix Inequality (BMI). Since, solving a BMI constraint has been an NP-hard optimization problem, then...

This brief discusses a new linear matrix inequality (LMI)-based H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> filter for a class of one-sided Lipschitz discrete-time systems. Due to the introduction of a sliding window of delayed measurements, new LMI conditions are proposed. Indeed, the pr...

Model estimation is an important step in quadrotor control design because model uncertainties can cause unstable behavior especially with non-robust control methods. In this paper, a modeling approach of a quadrotor prototype has been proposed. First an initial dynamic model of quadrotor UAV based on Euler-Lagrange formalism was developed. Then the...

This paper deals with a new design method of a fractional order PID controller for time-delay systems based on min-max numerical optimisation. The proposed design method uses a constrained optimisation algorithm to determine the unknown parameters of the controller. The main objective of the proposed method is to improve the transient time response...

This paper deals with a new design method of a fractional order PID controller for time-delay systems based on min-max numerical optimisation. The proposed design method uses a constrained optimisation algorithm to determine the unknown parameters of the controller. The main objective of the proposed method is to improve the transient time response...

This work is devoted to fault estimation of discrete-time Linear Parameter-Varying (LPV) systems subject to actuator additive faults and external disturbances. Under the assumption that the measurement noises and the disturbances are unknown but bounded, an interval observer is designed, based on decoupling the fault effect, to compute a lower and...

In this paper, set-membership parameter estimation of linear fractional-order systems is addressed for the case of unknown-but-bounded equation error. In such bounded-error context with a-priori known noise bounds, the main goal is to characterize the set of all feasible parameters. This characterization is performed using an orthotopic strategy ad...

This paper deals with model-based fractional order controller design. The objective is identification for controller design in order to achieve the desired closed-loop performances. Firstly, the fractional order closed-loop bias-eliminated least squares method is used to identify the process model. Then, based on the numerical optimization of a fre...

This study concerns the decentralized observerbased control for discrete time nonlinear interconnected system. The nonlinear interconnection between subsystem is uncertain and the only information about these uncertainties is that satisfy quadratic constraints. Sufficient conditions ensuring the synthesis of observer based feedback controller are e...

This paper is devoted to investigate interval observers design for linear switched systems. The considered systems are subject to disturbances which are assumed to be unknown but bounded. First, observer gains are computed to ensure the stability of the estimation error. Then, under some changes of coordinates an interval observer is designed. Effi...

This paper presents an actuator fault compensation approach for a class of Linear Parameter-Varying (LPV) systems with noisy measurements. The proposed method is based on interval estimation assuming that the fault vector and the external disturbances are unknown but bounded. The main idea consists in designing a control law, based on a linear stat...

This paper deals with a new structure of Fractional Complex Order Controller (FCOC) with the form PIDx+iy, in which x and y are the real and imaginary parts of the derivative complex order, respectively. A tuning method for the Controller based on numerical optimization is presented to ensure the controlled system robustness toward gain variations...

This paper focuses on the problem of observer-based distributed guaranteed cost control for large scale nonlinear interconnected systems with a chosen quadratic cost function. The aim is to ensures closed-loop stability and guaranteed cost for all planned parameter changes. For that, differential mean value theorem is used to introduce a general co...

The goal of this chapter is to design robust observers for fractional dynamic continuous-time linear systems described by pseudo state space representation. The fractional observer is guaranteed to compute a domain enclosing all the system pseudo states that are consistent with the model, the disturbances and the measurement noise realizations. Unc...

This paper presents a new model-free adaptive fractional order control approach for linear time-varying systems. An online algorithm is proposed to determine some frequency characteristics using a selective filtering and to design a fractional PID controller based on the numerical optimization of the frequency-domain criterion. When the system para...

Abstract: This paper treats the problem of sensor and actuator fault detection and accommodation for a linear stochastic systems subjected to unknown disturbances. A bank of augmented robust three-stage Kalman filters (ARThSKF) is adapted to estimate both the state and the fault as well as to generate the residuals. Besides, this paper presents the...

This paper treats the problem of sensor and actuator fault detection and accommodation for a linear stochastic systems subjected to unknown disturbances. A bank of augmented robust three-stage Kalman filters (ARThSKF) is adapted to estimate both the state and the fault as well as to generate the residuals. Besides, this paper presents the evaluat...

This paper deals with digital fractional order PID controller design. A numerical constrained optimization and a bilinear transform to convert continuous-time system to discretetime system and vice-versa are used in this design method. To obtain the fractional controller parameters a design approach uses bilinear transforminstead of analog design....

This paper addresses model-based prognosis to predict Remaining Useful Life (RUL) of a class of dynamical systems. The methodology is based on singular perturbed techniques to take into account the slow behavior of degradations. The full-order system is firstly decoupled into slow and fast subsystems. An interval observer is designed for both subsy...

In this paper, a Passive Fault Tolerant Control (PFTC) strategy for Linear Time Invariant (LTI) systems subject to actuator faults is proposed. The idea of this PFTC method is to compute a control law to cope with additive actuator faults using interval observers. The considered system is assumed to be subject to bounded noises and disturbances wit...

This paper deals with continuous-time linear parameter varying (LPV) system identification with fractional models. Two variants of instrumental variables based techniques are proposed to estimate continuous-time parameters of a fractional differential equation linear parameter varying model when all fractional orders are assumed known a priori: the...

This paper presents a new orthotopic set-membership method for the identification of linear fractional orders systems. This method consists in recursively constructing an outer orthotope that contains all feasible parameters when the probability distribution of the disturbances is unknown but bounded and when the differentiation orders are known. A...

This paper deals with the continuous-time identification of linear parameter varying (LPV) systems with fractional models in a noisy output context. Two methods developed to identify the continuous-time systems with rational models are extended to identify the coefficients of fractional models. The developed estimators are based on least squares: t...

This paper deals with the design of interval observers for singularly perturbed linear systems. The fullorder system is firstly decoupled into slow and fast subsystems. Then, using the cooperativity theory, an interval observer is designed for the slow and fast subsystems assuming that the measurement noise and the disturbances are bounded and the...

This paper focuses on the design of decentralized state observers based on optimal guaranteed cost control for a class of systems which are composed of linear subsystems coupled by non-linear time-varying interconnections. One of the main contributions lies in the use of the differential mean value theorem (DMVT) to simplify the design of estimatio...

This paper presents a method for the design of decentralized state observer-based control for a class of systems which are modeled as nonlinear subsystems linked by nonlinear time varying interconnections. The non linearity of each subsystem satisfies the Lipschitz condition and the only information about the nonlinear interconnection is that satis...

This note focuses on state observer design for a general class of nonlinear discrete-time systems. The main contribution lies in the use of the differential mean value theorem (DMVT) to transform the nonlinear error dynamics into a linear parameter varying (LPV) system. This has the advantage of introducing a general condition on the non linear fun...

This paper addresses the robust stabilization problem of first-order uncertain systems. To treat the robust stabilization problem, an interval-based stabilization method using stability conditions of the non-commensurate elementary fractional transfer function of the second kind is developed. Some analytic expressions are determined to compute the...

This paper focuses in the observer design for nonlinear discrete time systems. The main objective is the application of the Differential Mean Value Theorem (DMVT) to transform the nonlinear dynamics error to a linear parameter varying (LPV) system. This aims to introduce a less restrictive condition on the nonlinear functions. To ensure asymptotic...

The objective of this paper is the synthesis of decentralized state observers for large class of nonlinear interconnected systems. The procedure uses the Differential Mean Value Theorem (DMVT) to simplify the design of estimation and control matrices gains. A general condition on the nonlinear time-varying interconnections functions is introduced....

The additive fault tolerant control (FTC) for the fractional order model is presented, in this paper. Hence, two steps are compulsory in order to design the additive control. The first one being the estimation of the sensor fault amplitude which is realized by using the fractional Luenberger observer and the second one consists in generating the ad...

This paper addresses unknown input interval estimation and prognosis for a class of uncertain systems. Under the assumption that the measurement noise and the disturbances are bounded, lower and upper bounds for the unmeasured state and unknown inputs are computed. Then, damage state estimation is formulated as a set-inversion problem. The set-memb...

In this paper, the fractional closed-loop system identification using the indirect approach is presented. A bias correction method is developed to deal with the bias problem in the continuous-time fractional closed-loop system identification. This method is based on the least squares estimator combined with the state variable filter approach. The b...

In the recent years, the control of Unmanned Aerial Vehicles (UAV) has become one of the most interesting field of research, especially for Vertical Take-Off and Landing vehicles (VTOL), due to the needs to such system, the simplicity of their construction and due to the important technological advances in control boards, sensors, communication too...

This paper investigates the detection and diagnosis of actuator faults by using an Unknown Input Observer (UIO).The proposed UIO design guarantees robust residual generation through decoupling the disturbances effects from the faults ones. The discrimination between the faults and the effects of uncertain signals and perturbations on the residues m...

In this paper, the fractional closed-loop system identification problem is addressed. Using the indirect approach, which supposes the knowledge of the controller, both coefficients and fractional orders of the process are estimated. The optimal instrumental variable method combined with a nonlinear optimization algorithm is handled to identify the...

The paper deals with the stabilization problem of the Linear Time Invariant system. In this work, we present a new method of stabilization addressed to the first and second order unstable system in order to guarantee the stability and the time domain performances. Analytic expressions are developed in the purpose of setting the stabilizing paramete...

The paper considers the problem of PID controller design for stabilizing fractional systems with time delay. An analytic approach developed for rational systems with time delay is extended for fractional systems with time delay. It consists in determining the stability regions in the PID controller parameters planes and choosing the optimal control...

The errors-in-variables identification problem concerns dynamic systems in which input and output signals are contaminated by an additive noise. Several estimation methods have been proposed for identifying dynamic errors-in-variables rational models. This paper presents new consistent methods for order and coefficient estimation of continuous-time...

This paper develops a fault detection and isolation scheme for fractional order systems. It is an extension to fractional order models of a scheme developed for integer order models to design Generalized Fractional Observers Scheme (GFOS). Such scheme allows to generate residuals perfectly robust to disturbances and to isolate faults. Efficiency of...

This paper deals with continuous-time system identification using fractional models in a noisy input/output context. The thirdorder cumulants based least squares method (tocls) is extended here to fractional models. The derivatives of the third-order cumulants are computed using a new fractional state variable filter. A numerical example is used to...

Although rational orthogonal bases can be used to model any L2[0, α] system, they fail to capture the aperiodic multi-mode behaviour of fractional systems in a limited number of terms. The classical definition of orthogonal Laguerre, Kautz, and GOB functions has been extended for the use of fractional derivatives. An appropriate diagram is thus pro...

The classical Laguerre functions are known to be divergent as soon as their differentiation order is non-integer. They are hence inappropriate for representing fractional differentiation systems. A complete orthogonal basis, having fractional differentiation orders and a single pole, is synthesized. It extends the well-known definition of Laguerre...

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Identification of continuous-time non-linear systems characterised by fractional order dynamics is studied. The Riemann-Liouville definition of fractional differentiation is used. A new identification method is proposed through the extension of Hammerstein-type models by allowing their linear part to belong to the class of fractional models. Fracti...