Mohamed Mabrok

• PhD
• Professor (Associate) at Qatar University

Strokes are the leading cause of mortality worldwide. According to the WHO, fifteen million people encounter strokes each year. Out of these, five million die, and another five million become permanently crippled, increasing the burden on families and communities. Three-dimensional stroke lesion segmentation is a challenging task in magnetic resona...

Stroke remains a significant global health concern, necessitating precise and efficient diagnostic tools for timely intervention and improved patient outcomes. The emergence of deep learning methodologies has transformed the landscape of medical image analysis. Recently, Transformers, initially designed for natural language processing, have exhibit...

This study focuses on stabilizing a bidirectional inductive wireless power transfer (WPT) system using an event‐triggered approach. It is only assumed the inductor currents on both the primary and pickup sides are measurable, and they are sent synchronously to the controller via a digital channel. To estimate the unmeasured states and maintain plan...

Accurate segmentation of the stroke lesions using magnetic resonance imaging (MRI) is associated with difficulties due to the complicated anatomy of the brain and the different properties of the lesions. This study introduces the Neuro-TransUNet framework, which synergizes the U-Net's spatial feature extraction with SwinUNETR's global contextual pr...

The development of artificial intelligence (AI) has revolutionised the medical system, empowering healthcare professionals to analyse complex nonlinear big data and identify hidden patterns, facilitating well-informed decisions. Over the last decade, there has been a notable trend of research in AI, machine learning (ML), and their associated algor...

Ensuring robust and precise tracking control in the presence of uncertain multi-input–multi-output (MIMO) system dynamics and environmental variations is a significant challenge in the field of robust and adaptive control theory. While fuzzy control strategies have demonstrated good tracking performance in normal conditions, designing and tuning fu...

Federated learning (FL) has gained attention for enabling efficient distributed learning while maintaining data privacy. However, the data privacy constraint reduces the transparency in the agents’ model update making the learning process vulnerable to Byzantine attacks. In this paper, a mathematical proof is provided to show that when the traditio...

The accurate segmentation of stroke lesions is crucial for the diagnosis and treatment of stroke patients, as it provides spatial information about affected brain regions and the extent of damage. While conventional manual techniques are time-consuming and prone to errors, advanced deep learning models have shown promising results in medical image...

In the evolving era of social robots, managing a swarm of autonomous agents to perform particular tasks has become essential for numerous industries. The task becomes more challenging for large-scale swarms and complex environments, which have not been fully explored yet. Therefore, this research introduces a methodology incorporating multiple coor...

This paper considers the problem of robust stabilization of linear time‐invariant systems with respect to unmodelled dynamics and structure uncertainties. To that end, a methodology to find the nearest negative imaginary system for a given non‐negative imaginary system is presented first. Then, this result is employed to construct a near optimal li...

Nonlinear Negative Imaginary (NI) systems arise in various engineering applications, such as controlling flexible structures and air vehicles. However, unlike linear NI systems, their theory is not well-developed. In this paper, we propose a data-driven method for learning a lifted linear NI dynamics that approximates a nonlinear dynamical system u...

Nonlinear Negative Imaginary (NI) systems arise in various engineering applications, such as controlling flexible structures and air vehicles. However, unlike linear NI systems, their theory is not well-developed. In this paper, we propose a data-driven method for learning a lifted linear NI dynamics that approximates a nonlinear dynamical system u...

Autonomous robots require control tuning to optimize their performance, such as optimal trajectory tracking. Controllers, such as the Proportional–Integral–Derivative (PID) controller, which are commonly used in robots, are usually tuned by a cumbersome manual process or offline data-driven methods. Both approaches must be repeated if the system co...

Being one of the highest water-risk ranked countries in the world, Kuwait is in an urgent need of new advanced techniques and methodologies to conserve and optimize its water infrastructure. Water consumption, water quality, and network design optimization are among the challenges that face Kuwait water distribution system. This study is a step for...

Quadrotors are one of the popular unmanned aerial vehicles (UAVs) due to their versatility and simple design. However, the tuning of gains for quadrotor flight controllers can be laborious, and accurately stable control of trajectories can be difficult to maintain under exogenous disturbances and uncertain system parameters. This article introduces...

In this paper, the design and the implementation of a stabilising feedback law for an engine throttle valve system are investigated while taking into account the digital communication over the vehicle network. In particular, the digital communication between sensors, controller, and actuators is studied using the event-triggered theory. Considering...

The negative imaginary (NI) systems theory has attracted interests due to the robustness properties of feedback interconnected NI systems. However, a full output optimal controller-synthesis methodology, for such class of systems, is yet to exist. In order to develop a solution towards this problem, we first develop a methodology to find the neares...

Quadrotors are one of the popular unmanned aerial vehicles (UAVs) due to their versatility and simple design. However, the tuning of gains for quadrotor flight controllers can be laborious, and accurately stable control of trajectories can be difficult to maintain under exogenous disturbances and uncertain system parameters. This paper introduces a...

Quadrotor system is subject to multiple disturbances, including both internal and external effects (e.g. wind gusts, coupling effects, and unmodeled dynamics). For example, severe wind disturbances may significantly degrade trajectory tracking during the flight of autonomous aerial vehicles, or even cause loss of control or failure of a tracking mi...

This study evaluates the use of Negative Imaginary (NI) theory to model and control forces in external prestressing cables used in retrofitting bridge superstructures. The study analytically and experimentally applied the concept to assess the system robustness and its overall performance. A small-scale prototype was built to represent an aged brid...

We present the Robotics Intelligent Systems & Control (RISC) Lab multiagent testbed for reliable search and rescue and aerial transport in outdoor environments. The system consists of a team of three multirotor unmanned aerial vehicles (UAVs), which are capable of autonomously searching, picking up, and transporting randomly distributed objects in...

This paper extends the concept of dissipativity to a new class of dynamical systems known as negative imaginary systems. The paper also introduce a new definition for nonlinear negative imaginary systems to extend the existent definition. Two different quadratic dynamic supply rates are introduced to allow for extending the dissipativity concept to...

In this paper, we focus on studying the passivity properties of different versions of replicator dynamics (RD). RD represents a deterministic monotone non-linear dynamic, which allow incorporation of the distribution of population types through a fitness function. We use tools for control theory, in particular, the passivity theory, to study the st...

We present the RISC Lab multi-agent testbed for reliable search and rescue and aerial transport in outdoor environments. The system consists of a team of three multi-rotor Unmanned Aerial Vehicles (UAVs), which are capable of autonomously searching, picking, and transporting randomly distributed objects in an outdoor field. The method involves visi...

Understanding the collaboration between physical systems and human is an essential task in man-machine systems. This area of research has been significantly explored in the recent years with the focus on the machine side. Much less attention has been directed to the other side in the man-machine systems, which is the human. The aim of this review i...

In this paper, a new model of 3-qubits quantum annealing processor is designed. The spin-chain model is used to simulate the quantum annealing processor. The Hamiltonian which describes the system is introduced and analytically solved using the unitary operator method taking into account, processor in, ground state. The generated entanglement betwe...

Extracting repeated unknown maneuvers or patterns preformed by a human operator in a cyber-physical systems can lead to better understanding of the behavior of the human operator who is controlling or sharing tasks with dynamical systems. These repeated maneuvers can be extracted by analyzing the inputs and outputs of the human operator using contr...

Negative imaginary (NI) systems theory has attracted considerable attention in the area of robust control of highly resonant flexible structures systems and nono-positioning systems, where the NI property is naturally satisfied. In this paper, we present a control synthesis methodology for NI systems based on nonlinear optimization techniques. In t...

The ground robotics challenge in the Mohammed Bin Zayed International Robotics Challenge required a ground vehicle equipped with a robotic arm to autonomously locate a panel, select a proper size wrench among several options mounted on the panel, and use the wrench to rotate a valve. Autonomy was the critical factor in this challenge, which require...

In this paper, we focus on studying the passivity properties of different versions of replicator dynamics (RD). RD is an important class of evolutionary dynamics in evolutionary game theory. Evolutionary dynamics describe how the population composition changes in response to the fitness levels, resulting in a closed-loop feedback system. RD is a de...

Precise knowledge of an optical device’s frequency response is crucial for it to be useful in most applications. Traditional methods for determining the frequency response of an optical system (e.g. optical cavity or waveguide modulator) usually rely on calibrated broadband photo-detectors or complicated RF mixdown operations. As the bandwidths of...

Feedback control systems using sensors and actuators such as piezoelectric sensors and actuators, micro-electro-mechanical systems (MEMS) sensors and opto-mechanical sensors, are allowing new advances in designing such high precision technologies. The negative imaginary control systems framework allows for robust control design for such high precis...

Feedback control systems using sensors and actuators such as piezoelectric sensors and actuators, micro-electro-mechanical systems (MEMS) sensors and opto-mechanical sensors, are allowing new advances in designing such high precision technologies. The negative imaginary control systems framework allows for robust control design for such high precis...

Precise knowledge of an optical device's frequency response is crucial for it to be useful in most applications. Traditional methods for determining the frequency response of an optical system (e.g. optical cavity or waveguide modulator) usually rely on calibrated broadband photo-detectors or complicated RF mixdown operations. As the bandwidths of...

In population games, a large population of players, modeled as a continuum, is divided into subpopulations, and the fitness or payoff of each subpopulation depends on the overall population composition. Evolutionary dynamics describe how the population composition changes in response to the fitness levels, resulting in a closed-loop feedback system...

In this paper, we introduce a mathematical framework that allows the designer to consider more of the proposed ideas and options in conceptual design phase into the design process. The proposed model allows for dynamical relationship between the system’s high-level requirements and the detailed design parameters, where an optimization engine can op...

Robust control design for quantum systems has been recognized as a key task in the development of practical quantum technology. In this paper, we present a systematic numerical methodology of sampling-based learning control (SLC) for control design of quantum systems with uncertainties. The SLC method includes two steps of training and testing. In...

Axiomatic design (AD) theory is a general framework for system design process based on mapping between several domains. In the AD theory, only the functional requirements (system functions) are considered in the design process, since the mapping between requirements and design parameters in AD does not include nonfunctional requirements (system att...

The negative imaginary (NI) property occurs in many important applications. For instance, flexible structure systems with collocated force actuators and position sensors can be modelled as negative imaginary systems. In this study, a data-driven controller synthesis methodology for NI systems is presented. In this approach, measured frequency respo...

The negative imaginary (NI) property occurs in many important applications. For instance, flexible structure systems with collocated force actuators and position sensors can be modeled as negative imaginary systems. In this paper, we present a controller synthesis methodology for negative imaginary systems based on data driven controller. In this a...

Axiomatic Design Theory is a general framework for system design process based on mapping between several domains. In the Axiomatic Design theory, only the functional requirements (systems' functions) are considered in the design process, since the mapping between requirements and design parameters in Axiomatic Design does not include non-functiona...

In this paper, a sampling-based learning control (SLC) algorithm is used to find a robust control law that can steer a quantum system with uncertainties into a maximally entangled state. The quantum system under consideration consists of two two-level atoms interacting with a quantized electromagnetic field. In the sampling-based learning control m...

In this paper, we present a modified subspace system identification algorithm that ensures the negative imaginary property in the identified model. This is achieved by imposing constraints that guarantee negative imaginariness and stability of the identified model. The importance of having negative imaginary model comes from the fact that the negat...

In this paper, we introduce Category Theory as a formal foundation for model-based systems engineering. A generalised view of the system based on category theory is presented, where any system can be considered as a category. The objects of the category represent all the elements and components of the system and the arrows represent the relations b...

The negative imaginary (NI) property occurs in many important applications. For instance, flexible structure systems with collocated force actuators and position sensors can be modeled as negative imaginary systems. Obtaining a mathematical model for this class of systems using system identification methods may result into inaccurate models that po...

In this paper, we develop a control algorithm to generate entanglement in a quantum system with uncertainties. The system under consideration is an uncertain system of two two-level atoms interacting with each other through a dipole-dipole interaction. The sampling-based learning control (SLC) strategy is employed to find a control law. An SLC stra...

The negative imaginary (NI) property is exhibited by many systems such as flexible structures with force actuators and position sensors and can be used to prove the robust stability of flexible structure control systems. In this paper, we derive methods to check for the NI and strict negative imaginary (SNI) properties in both the single-input sing...

In this paper, the effect of homogeneous and non-homogeneous magnetic fields as an external noisy on the entanglement dynamics over partial entangled state quantum network is studied. The Dzyaloshiniskii-Moriya (DM) interaction is used to generate entangled network from partially entangled states in the presence of the spin-orbit coupling. The enta...

In this paper, we present an example of control system design based on negative imaginary (NI) system theory. The system under consideration is an optical cavity system. A dynamical model of the cavity system is obtained through system identification of applied to experimental input output frequency response data obtained using a digital signal ana...

In this paper, we present an example of control system design based on negative imaginary (NI) system theory. The system under consideration is an optical cavity system. A dynamical model of the cavity system is obtained through system identification of applied to experimental input output frequency response data obtained using a digital signal ana...

This paper presents the application of an integral resonant controller (IRC) to the problem of frequency locking an optical cavity. Such frequency locking is necessary to ensure maximum constructive interference inside the cavity. This is achieved by altering the resonant frequency of the optical cavity to match the frequency of the input laser. Th...

Flexible structures with collocated force actuators and position sensors lead to negative imaginary dynamics. However, in some cases, the mathematical models obtained for these systems, for example, using system identification methods may not yield a negative imaginary system. This paper provides two methods for enforcing negative imaginary dynamic...

Flexible structure systems arise in many important applications such as ground and aerospace vehicles, atomic force microscopes, rotating flexible spacecraft, ro- tary cranes, robotics and flexible link manipulators, hard disk drives and other nano-positioning systems. In control systems design for these flexible systems, it is important to conside...

Negative imaginary (NI) systems play an important role in the robust control of highly resonant flexible structures. In this paper, a generalized NI system framework is presented. A new NI system definition is given, which allows for flexible structure systems with colocated force actuators and position sensors, and with free body motion. This defi...

In this paper, we develop a control algorithm to generate entanglement in a quantum system with uncertainties. The system under consideration is an uncertain system of two two-level atoms interacting with each other through a dipole-dipole interaction. The sampling-based learning control (SLC) strategy is employed to find a control law. An SLC stra...

In this paper, a stabilization procedure that forces an uncertain system to be stable and satisfy the negative imaginary property is presented. The controller synthesis procedure is based on the negative imaginary lemma. As a result, the closed-loop system can be guaranteed to be robustly stable against any strict negative imaginary uncertainty, su...

In this paper, we present an example of control system design based on negative imaginary (NI) system theory. The system under consideration is an optical cavity system. A dynamical model of the cavity system is obtained through system identification of applied to experimental input output frequency response data obtained using a digital signal ana...

Flexible structure dynamics with collocated force actuators and position sensors lead to negative imaginary (NI) systems. In this paper, we study the extension of NI theory to descriptor systems. We derive an NI lemma for descriptor systems. An illustrative example is presented to support the result.

This paper is concerned with stability conditions for the positive feedback interconnection of negative imaginary systems. A generalization of the negative imaginary lemma is derived, which remains true even if the transfer function has poles on the imaginary axis including the origin. A sufficient condition for the internal stability of a feedback...

Flexible structure dynamics with collocated force actuators and position sensors lead to negative imaginary (NI) systems. However, in some cases, the models obtained for these systems may not satisfy the NI property. This paper provides a new method for enforcing such models to be NI. The results are based on a study of the spectral properties of r...

This paper derives some necessary and sufficient conditions for linear time invariant systems to have the negative imaginary property in both the single-input-single-output as well as the multi-input-multi-output cases. The conditions for a system to be negative imaginary are described in terms of spectral conditions obtained for a given transfer f...

In this paper, we study a class of negative imaginary linear time invariant multiple-input multiple-output systems. We generalize an existing negative imaginary lemma to include systems containing a simple pole at the origin. Also, a stability analysis result is presented for generalized negative imaginary systems including an integrator and an ill...

A consortium of researchers at University of New South Wales (UNSW@ADFA), and Loyola University New Orleans (LU NO), together with Australian government security agencies (e.g., Australian Federal Police), are working to develop highly sensitive laser-based forensic sensing strategies applicable to characteristic substances that pose chemical, biol...

In this paper, we study the interaction between two two-level atoms and two nondegenerate cavity modes when the atoms and the field are initially in the atomic superposition states and the pair-coherent state (PCS), respectively. We investigate the atomic inversions, tangles and joint probability distribution. We show that the system can generate l...

This paper derives some necessary and sufficient conditions for linear time invariant systems to have the negative imaginary property in both the single-input-single-output as well as the multi-input-multi-output cases. The conditions for a system to be negative imaginary are described in terms of spectral conditions obtained for a given transfer f...