Ahmad Taher Azar

Ahmad Taher Azar
Prince Sultan University · Computer Science

Research Professor, IEEE Senior Member, ISA Member, IFAC member

About

529
Publications
199,542
Reads
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12,503
Citations
Citations since 2017
331 Research Items
10002 Citations
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201720182019202020212022202305001,0001,5002,000
201720182019202020212022202305001,0001,5002,000
Introduction
Prof. Ahmad Azar has received the M.Sc. degree in 2006 and Ph.D degree in 2009 from Faculty of Engineering, Cairo University, Egypt and he got his post- doctoral from USA. He is a research Professor at Prince Sultan University, Riyadh, Kingdom Saudi Arabia. He is also an associate professor at the Faculty of Computers and Artificial intelligence, Benha University, Egypt. Prof. Azar is the Editor in Chief of International Journal of System Dynamics Applications (IJSDA) and International Journal
Additional affiliations
September 2019 - present
Prince Sultan University
Position
  • Professor
March 2018 - present
Benha University, Faculty of Computers and Artificial Intelligence
Position
  • Professor (Associate)
April 2013 - March 2018
Benha University
Position
  • Professor (Assistant)

Publications

Publications (529)
Article
Full-text available
Citation: Hussain, M.M.; Azar, A.T. ; Ahmed, R.; Umar Amin, S.; Qureshi, B.; Dinesh Reddy, V.; Alam, I.; Khan, Z.I. SONG: A Multi-Objective Evolutionary Algorithm for Delay and Energy Aware Facility Location in Vehicular Fog Networks. Sensors 2023, 23, 667. https://doi. Abstract: With the emergence of delay-and energy-critical vehicular application...
Article
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In actual industrial control, many objects have the characteristics of large lag and time-varying parameters, which makes it difficult for traditional PID control to obtain satisfactory control effects. Therefore, engineers need a control algorithm with a better control effect and a simple structure, and thus the internal model control is introduce...
Article
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Recent advances in machine and deep learning algorithms and enhanced computational capabilities have revolutionized healthcare and medicine. Nowadays, research on assistive technology has benefited from such advances in creating visual substitution for visual impairment. Several obstacles exist for people with visual impairment in reading printed t...
Article
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In this paper, we consider the problem involved when designing the interval observer for the system described by a linear discrete-time model under external disturbances and measurement noises. To solve this problem, we used the reduced order model of the initial system, which is insensitive or has minimal sensitivity to the disturbances. The relat...
Article
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In this work, the differential mobile robot is controlled utilizing fuzzy PID speed control, which combines fuzzy control with conventional PID control in real time. The path may be convoluted, and the surrounding environment may contain a range of arbitrary shape and size obstacles. A monocular camera is used to detect obstacles during the navigat...
Article
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In the photovoltaic system, the performance, efficiency, and generated power of the PV system are affected by changes in the environment, disturbances, and parameter variations, and this leads to a deviation from the operating maximum power point (MPP) of the PV system. Therefore, the main aim of this paper is to ensure the PV system operates at th...
Conference Paper
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The COVID-19 outbreak has impacted network operators and data centers in terms of congestion and high traffic that lead to outages and significant pressure on the network. The overhead traffic is generated from web, voice calls, and Internet activity. In this paper, we are investigating data center congestion control for SDN network data centers. A...
Article
Smart traffic engineering and intelligent transportation services are in increasing demand from governmental authorities to optimize traffic performance and thus reduce energy costs, increase the drivers' safety and comfort, ensure traffic laws enforcement, and detect traffic violations. In this paper, we address this challenge, and we leverage the...
Article
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Dynamic observers are commonly used in feedback loops to estimate the system’s states from available control inputs and measured outputs. The presence of measurement noise degrades the performance of the observer and consequently degrades the performance of the controlled system. This paper presents a novel nonlinear higher-order extended state obs...
Article
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In this study, synergetic-based adaptive control design is developed for trajectory tracking control of joint position in knee-rehabilitation system. This system is often utilized for rehabilitation of patients with lower-limb disabilities. However, this knee-assistive system is subject to uncertainties when applied to different persons undertaking...
Article
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Due to the existence of system noise and unknown state variables, it is difficult to realize unbiased estimation with minimum variance for the parameter estimation of canonical state space model. This paper presents a new least squares estimator based on bias compensation principle to solve this problem, transforms canonical state space into the fo...
Article
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In order to extract efficient power generation, a wind turbine (WT) system requires an accurate maximum power point tracking (MPPT) technique. Therefore, a novel robust variable-step perturb-and-observe (RVS-P&O) algorithm was developed for the machine-side converter (MSC). The control strategy was applied on a WT based permanent-magnet synchronous...
Article
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This work proposes a new kind of trajectory tracking controller for the differential drive mobile robot (DDMR), namely, the nonlinear neural network fractional-order proportional integral derivative (NNFOPID) controller. The suggested controller’s coefficients comprise integral, proportional, and derivative gains as well as derivative and integral...
Article
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Systems are naturally or purposely formed with functional components and connection structures [...]
Article
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AIDS, which is caused by the most widespread HIV-1 virus, attacks the immune system of the human body, and despite the incredible endeavors for finding proficient medication strategies, the continuing spread of AIDS and claiming subsequent infections has not yet been decreased. Consequently, the discovery of innovative medicinal methodologies is hi...
Chapter
This paper presents an asynchronous distributed switched controller for robotic systems with a dynamic model derivation based on fractional-order Euler–Lagrange formulation. This study begins with the dynamic model derivation of a two links robotic manipulator by a fractional-order Euler–Lagrange formulation. This objective is achieved by selecting...
Chapter
This chapter displays a control strategy for a photovoltaic system (PV) linked to the network with two phases of a PWM converter, where the first phase is a DC-DC converter linked among the photovoltaic source and the DC-AC converter. The second phase is a DC-AC converter linked to the grid. The maximum power point (MPP) is tracked by DC-DC convert...
Chapter
Power converters assume a significant part in fuel cell power generation systems and solar power conversion systems which are an alternative to fossil fuel production systems. There is therefore a demand for high quality power conditioning used in PEMFC systems and photovoltaic panels. This chapter proposes a hybrid electric power (FC/PV) productio...
Chapter
In this chapter, a new technique has been proposed for reducing the harmonic content of a three-phase PWM rectifier connected to the networks with a unit power factor and also providing decoupled control of the active and reactive instantaneous power. This technique called direct power control (DPC) is based on artificial neural network (ANN) contr...
Article
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Big data analysis applications in the field of medical image processing have recently increased rapidly. Feature reduction plays a significant role in eliminating irrelevant features and creating a successful research model for Big Data applications. Fuzzy clustering is used for the segment of the nucleus. Various features, including shape, texture...
Article
In recent years, the switched reluctance machine (SRM) represents a contemporary competitive technology in the fields of automotive and aeronautics, because their growing needs for electric drives with a frequent and important high-speed variation. This paper presents an application of the fractional order control of the speed of switched reluctanc...
Article
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The selection of an algorithm to tackle a certain problem is a vital undertaking that necessitates both time and knowledge. Non-functional needs, such as the size, quality, and nature of the data, must frequently be taken into account. To develop a generalized machine learning model for any domain, the most relevant features must be chosen because...
Article
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Recent advances in deep learning techniques and acoustic sensor networks offer a new way for continuously monitoring birds. Deep learning methods have led to considerable progresses in audio source separation (ASS). However, it is still a challenge to deploy models based on deep learning on embedded devices. Therefore, find an efficient solution to...
Article
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In this paper, a new approach for hybridizing Rough Set Quick Reduct and Relative Reduct approaches with Black Hole optimization algorithm is proposed. This algorithm is inspired of black holes. A black hole is a region of spacetime where the gravitational field is so strong that nothing— not even light— that enters this region can ever escape from...
Article
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This paper provides a new approach for human identification based on Neighborhood Rough Set (NRS) algorithm with biometric application of ear recognition. The traditional rough set model can just be used to evaluate categorical features. The neighborhood model is used to evaluate both numerical and categorical features by assigning different thresh...
Article
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In this study, the design of adaptive backstepping sliding mode control (ABSMC) has been developed for vibration suppression of earth-quaked building supported by magneto-rheological (MR) damper. The control and adaptive laws developed based on ABSMC methodology has been established according to stability analysis based on Lyupunov theorem. A Singl...
Article
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In this work, an n-th order Generalized Tracking Differentiator (GTD) is proposed based on sigmoid function with a continuous structure, including both linear and nonlinear parts, thus increasing the estimation accuracy of the input signal and its derivatives, and overcoming the inherent issues related to the classical Tracking Differentiators (TDs...
Article
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Analog electronic circuits play an essential role in many industrial applications and control systems. The traditional way of diagnosing failures in such circuits can be an inaccurate and time-consuming process; therefore, it can affect the industrial outcome negatively. In this paper, an intelligent fault diagnosis and identification approach for...
Chapter
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This chapter seeks to give a better understanding of the complexity of reconstructing the hidden endogenous innovation cycle in the currently complicated instable domain of Tunisia’s energy transition. We aim to evaluate whether energy innovation cycle dynamics analysis in Tunisia helps boost energy efficiency and transition performance to sustaina...
Article
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In this paper, the robust stabilization and synchronization of a novel chaotic system are presented. First, a novel chaotic system is presented in which this system is realized by implementing a sigmoidal function to generate the chaotic behavior of this analyzed system. A bifurcation analysis is provided in which by varying three parameters of thi...
Article
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This study presents a control design of roll motion for a vertical take-off and landing unmanned air vehicle (VTOL-UAV) design based on the Model Reference Adaptive Control (MRAC) scheme in the hovering flight phase. The adaptive laws are developed for the UAV system under nonparametric uncertainty (gust and wind disturbance). Lyapunov-based stabil...
Chapter
In this paper, a novel nature motivated optimization technique known as moth flame optimization (MFO) technique is proposed for a multi-area interrelated power system with a deregulated state with multi-sources of generation. A three-area interrelated system with multi-sources in which the first area consists of the thermal and solar thermal unit;...
Chapter
In this paper, a novel passivity-based controller for flexible links robotic mechanisms is proposed. Something that is a substantial contribution to the field is that the dynamic model of two degrees of robotic freedom mechanism is proposed considering, that in this case, a suitable shaping function is implemented in FEM derivations. Along with the...
Chapter
In this paper, the dynamic modeling of a non-holonomic unmanned aerial vehicle UAV with the Euler Lagrange formulation and the design of an energy shaping controller for UAVs is proposed. A 2D unmanned aerial vehicle kinematic model with non-holonomic constraints that satisfy the involutivity properties considers Pfaffian constraints. Then, the unm...
Article
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Unmanned Aerial Vehicles (UAVs) are increasingly being used in many challenging and diversified applications. These applications belong to the civilian and the military fields. To name a few; infrastructure inspection, traffic patrolling, remote sensing, mapping, surveillance, rescuing humans and animals, environment monitoring, and Intelligence, S...
Article
Most applications for small unmanned aerial vehicles (sUAVs) have a critical need for appropriate position and attitude control in environments with extreme external dynamic disturbances such as wind gusts. Moreover, to maximize flight time, UAVs have to operate within strict constraints on payload and under computational efficiency. This article p...
Article
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Purpose The hybrid control system of the nonlinear PID (NLPID) controller and improved active disturbance rejection control (IADRC) are proposed for stabilization purposes for a 6-degree freedom (DoF) quadrotor system with the existence of exogenous disturbances and system uncertainties. Design/methodology/approach IADRC units are designed for the...
Chapter
This paper proposes a robust decentralized asynchronous controller for unmanned aerial vehicle (UAV) swarms with fast convergence topology. The unmanned aerial vehicle’s analyzed mathematicalmodel is a 2D kinematic model that considers the position and attitude in two dimensions. For this purpose, two robust gains are tuned considering the switchin...
Chapter
In this paper, a dynamic PID sliding mode controller for the path following of unmanned aerial vehicles UAV is shown. This strategy consists of dividing the quadrotor UAV dynamics into the position and attitude loop, and by implementing a coordinate transformation, the desired attitude is obtained. First, a dynamic control law is implemented for th...
Chapter
This paperFekik, Arezki processesAzar, Ahmad Taher theKamal, Nashwa Ahmad outputDenoun, Hakim voltage control system for energy source based on a fuel cell linked to a DC voltage generator. The suggested technique is based on the design of a fractionalAlmustafa, Khaled Mohamad controller to regulate the output voltage of this DC–DC converter for di...
Chapter
This paper is addressed to investigate the synchronization between two-dimensional fractional discrete-time systems with chaotic hidden attractors. A nonlinear control strategy is proposed for the complete synchronization based on the stability theory of linear fractional discrete-time systems. Some numerical examples have been carried out to test...
Chapter
Biometric identification methods are proved to be very useful, natural, and easy for users than conventional methods of human identification. Ear biometric is used for personal identification and verification. Ear recognition is the most prominent ongoing biometric research. Ear image has rich edges due to intricate curves. Therefore, in this work,...
Chapter
Some of the best methods for enhancing the efficiency of the transmission of electric energy from source to receiver is the use of pulse width modulators (PWM). This paper proposes an approach for regulating the PWM three-phase rectifier and for removing the total harmonic distortion (THD) in order to generate a unit power factor non-contaminated d...
Chapter
Pulse Width Modulation (PWM) rectifiers belong to the best solutions to improve the quality of electrical energy transfer from a source to a receiver. In fact, this chapter proposes a method for regulating the three-phase PWM rectifier and ensuring the elimination of total harmonic distortion to obtain a non-contaminated system operating within a u...
Chapter
Modeling and applications of jerk chaotic systems have received much attention in the chaos literature. A classical jerk system is the thermal dissipative chaotic system developed by Moore and Spiegel in 1966, which consists of just a cubic nonlinearity in its dynamics. By adding a quadratic nonlinearity and taking different parameter values, this...
Chapter
Chaos control in nonlinear dynamical systems has been an attractive research trend in the literature. This chapter aims to control chaotic behavior of a new chaotic system without linear term, which has been received attention recently. By exploiting dynamics and properties of the system, we show that the system displays complex behavior. Backstepp...
Chapter
Mechanical systems such as jerk dynamical systems and their control constitute attractive research trend in the literature. This chapter aims to control chaotic behavior of a new jerk mechanical chaotic system with an egg-shaped strange attractor. By exploiting dynamics and properties of the jerk system, we show that the system displays egg-shaped...
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This chapter presents the multi-switching synchronization of nonlinear hyperchaotic systems via active backstepping control. The multi-switching complete synchronization scheme has been examined such that the state variables of slave system synchronize with different state variables of master system. The controllers are computed via active backstep...
Chapter
A single-link flexible joint manipulator (SLFJM) is a highly complex and nonlinear system and therefore, design of a controller for such a system has always been a challenging task. Evidently, the backstepping control technique has provided one of the simplest and most advantageous way of controlling a completely known nonlinear system as it is a s...
Chapter
Mechanical systems such as hyperjerk dynamical systems and their control constitute an attractive research trend in the literature. This chapter proposes a new 4-D chaotic hyperjerk system with a hyperbolic sinusoidal nonlinearity. In this chapter, we aim to control the chaotic behavior of the new hyperjerk mechanical chaotic system with multi-stab...
Chapter
In this book chapter, novel backstepping controller and synchronization techniques for time delayed systems are proposed. One of the first contributions of this chapter is that backstepping control technique has not been extensively considered for the control of many kinds of time delayed complex systems, so the results of this study will be extend...
Chapter
Jerk chaotic systems have many applications in science and engineering. In the past few decades, significant attention has been paid on the modeling of new jerk differential equations arising in engineering. An important model of a plasma torch jerk differential equation exhibiting chaos was reported by Ghorui et al. (2000). The Ghorui jerk system...
Chapter
In the last few decades, several control techniques are deployed for the stabilization, regulation, and control of linear and nonlinear dynamical systems. For linear autonomous systems, it is easy to find a control Lyapunov function for stability and optimization problems. However, finding a suitable control Lyapunov function is a challenging probl...
Chapter
In this research work, we build a new 5D hyperchaos four-wing system with three quadratic nonlinear terms. Since the new 5D system has no rest point, it has hidden attractor. It is shown that the new 5D hyperchaos four-wing system has multistability with coexisting hyperchaos attractors. Using the backstepping control method, we achieve global hype...
Chapter
In this chapter, a backstepping controller is presented for a nonlinear active suspension system (ASS) of a quarter car model. The quarter car is a highly uncertain system as the number of occupants may vary. The ride comfort of the passengers can be improved by minimizing the root mean square of the vertical acceleration (RMSVA) of the sprung mass...
Chapter
Jerk systems are important classes of 3-D mechanical systems. The analysis and their control of jerk dynamical systems have good applications in engineering. This chapter proposes a new 3-D chaotic jerk system with two quadratic nonlinear terms. We show that the jerk system has a unique rest point at the origin, which is an unstable saddle-focus re...
Chapter
A famous 3D system for temperature variations in the eastern and western parts of the equatorial ocean was modeled by Vallis (1986). The Vallis model is known to have significance for describing the global weather climate patterns. In this research work, we build a 4D hyperchaos temperature variation system by means of introducing a state feedback...
Chapter
In this chapter, we introduce a novel chaotic system with a closed curve consisting of four quarter circles of equilibrium points. The equilibrium curve is symmetric about the straight lines x=±y. Thus, the new chaotic system exhibits hidden chaotic attractor. The complex behavior of the new chaotic system has been verified by using phase portraits...
Chapter
This work details a new 5-D hyperchaotic dynamo system with three quadratic nonlinearities. It is shown that the new hyperchaos dynamo system shows multistability and has coexisting attractors. The equilibrium analysis for the new hyperchaos dynamo system describes that there are no rest points for the hyperchaos dynamo system. Hence, the new 5-D d...
Chapter
Unmodeled dynamics is one of the problems found in mathematical modeling of many kinds of physical systems, such as electrical and mechanical systems. For this reason, robust control is a solution for this kind of problem, considering the unmodeled dynamics as a matched uncertainty. Unmodeled dynamics affect the robust stability and robust performa...
Chapter
Full-text available
An improved active disturbance rejection control (IADRC) is proposed to stabilize and reject exogenous disturbances and system uncertainties for a six-degree of freedom (DOF) quadrotor system. We used the nonlinear model of the 6-DOF quadrotor system to design four IADRC units for altitude and attitude stabilization. Stability analysis is demonstra...
Chapter
Due to the increasing application of unmanned aerial vehicles (UAVs), it is necessary to design new strategies related to the complexity of the maneuvering task of UAVs because it is sometimes necessary to avoid obstacles or to maneuver in reduced spaces. Sliding mode controllers (SMCs) have now become a superior alternative for tracking robotics a...
Chapter
This chapter focuses on path planning techniques for autonomous navigation of small unmanned aerial vehicles (UAVs) in complex urban environments. It is difficult for UAVs to navigate at low altitudes in dynamic or complex urban environments because they encounter large structures, unpredictable or unrecognized environments, or other UAVs or obstac...
Chapter
A nonlinear proportional integral derivative (NLPID) controller is proposed to stabilize the translational and rotational motion of a six-degree of freedom (DOF) unmanned aerial vehicle (UAV) quadrotor system and enforce it to track a given trajectory with minimum energy and error. The complete nonlinear model of the 6-DOF quadrotor system is obtai...
Chapter
Full-text available
Trajectory tracking of unmanned aerial vehicles (UAVs) has been studied nowadays because it is necessary to design new controllers under different conditions. Severe atmospheric conditions are one of the major problems to overcome according to the path of the UAV. Conditions such as wind speed that can vary according to the weather conditions can a...