Viet-Thanh Pham

Hanoi University of Science and Technology

In modern audio processing systems like speech recognition, medical devices, and IoT sensors, effective noise filtering is crucial. High noise levels degrade signal quality and reduce system accuracy. Traditional methods often fail under high noise, requiring new approaches. This paper presents an innovative method combining horizontal visibility g...

Memristor maps verified the universial usage of memristors in nonlinear maps. Although almost published works investigate chaotic maps constructing with only one memristor, maps including multiple memristors attract interest because of their flexible structures. By combining three memristors, we introduce a triple-memristor model, which is general...

https://dergipark.org.tr/en/pub/chaos/issue/88057

In this manuscript, we carried out a thorough analysis of the generalSIR model for epidemics. We broadened the model to includevaccination, treatment, and incidence rate. The vaccination rate isa testament to the alternatives made by individuals when it comesto receiving vaccinations and merging with the community of therecovered. The treatment rat...

We present a hyperchaotic oscillator with two linear terms and seven nonlinear terms that displays special algebraic properties. Notably, the introduced oscillator features distinct equilibrium types: single-point, line, and spherical equilibria. The introduced oscillator exhibits attractive dynamics like hyperchaos with two wing attractors. To gai...

This paper introduces a modified Morris–Lecar neuron model that incorporates a memristor with a ReLU-based activation function. The impact of the memristor on the dynamics of the ML neuron model is analyzed using bifurcation diagrams and Lyapunov exponents. The findings reveal chaotic behavior within specific parameter ranges, while increased magne...

The intricate tapestry of the modern world presents a multitude of complex problems that span various domains, including healthcare, environmental science, economics, and engineering. Addressing these challenges requires a profound understanding of underlying systems and the ability to predict and optimize their behaviors. Mathematical modeling and...

https://dergipark.org.tr/en/pub/chaos/issue/86422

The memristor, a revolutionary electronic component, mimics both neural synapses and electromagnetic induction phenomena. Recent study challenges are the development of effective neural models and discovering their dynamics. In this study, we propose a novel Hopfield neural network model leveraging multistable memristors, showcasing its efficacy in...

We explore an oscillator with nonlinear functions and equilibrium lines that displays chaos. The equilibrium stability and complexity of the oscillator have been analysed and investigated. The presence of multiple equilibrium lines sets it apart from previously reported oscillators. The synchronization of the oscillator is considered as an applicat...

A significant attention has concentrated on systems with "hidden attractors" in recent years. The aim of this work is to study an oscillator displaying "hidden attractors". The oscillator has all nonlinear terms but no equilibrium. The oscillator exhibits attractive dynamics such as chaos, bubble bifurcation, symmetrical attractors, and boosting at...

In this study, the higher order interactions, which are complex interactions involving more than two neurons, are studied in two real-world networks. These interactions play a crucial role in the brain's functioning, as they can influence the network's synchronization and dynamics. This paper analyzes the application of directed simplicial complexe...

Call for Papers Special Issue on Application of Fractional Calculus: Mathematical Modeling and Control https://www.worldscientific.com/page/fractals/callforpapers16 I am looking forward to hearing from you soon Guest editors

Dear my colleagues You are most welcome for my special issue in journal of computational modeling (IF. 5, Top ten journal in web of sciences) https://www.sciencedirect.com/journal/applied-mathematical-modelling/about/call-for-papers#applications-of-fractional-calculus-for-complex-engineering I am looking forward to hearing from you regarding you...

https://dergipark.org.tr/en/pub/chaos/issue/83761

The classification of time series using machine learning (ML) analysis and entropy-based features is an urgent task for the study of nonlinear signals in the fields of finance, biology and medicine, including EEG analysis and Brain–Computer Interfacing. As several entropy measures exist, the problem is assessing the effectiveness of entropies used...

Memristors offer a crucial element for constructing discrete maps that have garnered significant attention in complex dynamics and various potential applications. In this study, we have integrated memristive and sigmoidal function to propose innovative mapping techniques. Our research confirms that the amalgamation of memristor and sigmoidal functi...

In nonlinear dynamics, there is a continuous exploration of introducing systems with evidence of chaotic behavior. The presence of nonlinearity within system equations is crucial, as it allows for the emergence of chaotic dynamics. Given that quadratic terms represent the simplest form of nonlinearity, our study focuses on introducing a novel chaot...

The emergence of memristors has piqued significant interest in memristive maps due to their unique characteristics. In this paper, we introduce a novel and effective method for constructing memristor maps, leveraging the power of exponential units. Interestingly, the incorporation of these exponential units disrupts symmetry and alters the count of...

In this paper, we propose a method for assessing the effectiveness of entropy features using several chaotic mappings. We anlyze fuzzy entropy (FuzzyEn) and neural network entropy (NNetEn) on four discrete mappings: the logistic map, the sine map, the Planck map, and the two-memristor-based map, with a base length time series of 300 elements. Fuzzy...

In this article the keywords were missing. The following keywords are for the published original article https:// doi.org/10.1140/epjs/s11734-023-01002-4: Bacterial infection · Mathematical model · Fractional-calculus, Endemic indicator · Caputo-Fabrizio operator · Dynamical behavior · Ordinary differential equations · Mathematical operators The or...

https://dergipark.org.tr/en/pub/chaos/issue/80150

Fractional calculus analysis

Fractional calculus is particularly useful for describing the behavior of complex physical systems. Many natural phenomena exhibit nonlocal characteristics, meaning that their current state depends not only on their immediate past but also on events from a more distant past. These nonlocal dependencies can be expressed more accurately through fract...

Visit the following link https://www.sciencedirect.com/journal/partial-differential-equations-in-applied-mathematics/about/call-for-papers

Dynamical systems research has long been a fundamental branch of science that studies the behaviour of complex systems evolving over time. From weather patterns and ecological ecosystems to economic models and physiological processes, understanding the dynamics of these intricate systems is crucial for predicting outcomes, optimizing processes, and...

The use of the advancements in memristor technology to construct chaotic maps has garnered significant research attention in recent years. The combination of memristors and nonlinear terms provides an effective approach to proposing novel maps. In this study, we have leveraged memristors and sine terms to develop three-dimensional maps, capable of...

https://dergipark.org.tr/en/pub/chaos/issue/77246

The Lozi map is well-known and has been studied in various researches. By combining three research trends (discrete map, memristor and fractional calculus) we investigate a fractional memristive Lozi map in this work. Firstly the Grunwald–Letnikov fractional difference operator is used to introduce the new fractional map with no equilibrium point....

https://dergipark.org.tr/en/pub/chaos/issue/75756

A memristor is a two-terminal passive electronic device that exhibits memory of resistance. It is essentially a resistor with memory, hence the name “memristor”. The unique property of memristors makes them useful in a wide range of applications, such as memory storage, neuromorphic computing, reconfigurable logic circuits, and especially chaotic s...

In the nineteenth-century, fractional calculus had its origin in extending differentiation and integration operators from the integer-order case to the fractional-order case. Discrete fractional calculus has recently become an important research topic, useful in various science and engineering applications. The first definition of the fractional-or...

Human immunodeficiency virus (HIV) infection is said to be a dangerous, extremely severe, and potentially fatal disease. After weakening a person's immune system, it impedes the body's ability to fend off future illnesses. In this study, we use the Caputo operator's fractional framework to describe how antiretroviral therapy (ART) affects the HIV/A...

In this chapter, the construction of an efficient method for a fast and complete scanning of a given area is presented. An additional aspect is the insertion of FitzHugh–Nagumo chaotic system in order to create random-like motions. Then, a modulo operator was used in the production of the necessary motion commands. For further improvement of the pr...

https://dergipark.org.tr/en/pub/chaos/issue/73767

https://www.epj.org/open-calls-for-papers/85-epj-st/2496-epjst-special-issue-application-of-fractional-calculus-in-physical-systems

https://dergipark.org.tr/en/pub/chaos/issue/73033

Recent works have focused the analysis of chaotic phenomena in fractional discrete memristor. However, most of the papers have been related to simulated results on the system dynamics rather than on their hardware implementations. This work reports the implementation of a new chaotic fractional memristor map with “hidden attractors”. The fractional...

https://www.mdpi.com/journal/fractalfract/special_issues/fractional_physical Special Issue Information Dear Colleagues: It is well known that fractional calculus has numerous applications in engineering, science, and technology. The dynamics of challenging physical systems are closely connected to fractional calculus. Due to their non-local natur...

Synchronization in coupled oscillators is of high importance in secure communication and information processing. Due to this reason, a significant number of studies have been performed to investigate the synchronization state in coupled circuits. Diffusive coupling is the simplest connection between the oscillators, which can be implemented through...

Chaotic maps have simple structures but can display complex behavior. In this paper, we apply discrete memristance and a nonlinear term in order to design new memristive maps. A general model for constructing memristive maps has been presented, in which a memristor is connected in serial with a nonlinear term. By using this general model, different...

Fractional calculus in discrete time systems represent a very recent topic. The field of fractional order discrete time systems showing hidden attractors has been only recently investigated. Based on this consideration this chapter presents a simple two-dimensional fractional discrete systems. It starts by introducing some basic notions and primary...

This issue is dedicated to the memory of Prof. Tenreiro Machado. https://dergipark.org.tr/en/pub/chaos/issue/64884

The simplest megastable chaotic system is built by employing a piecewise-linear damping function which is periodic over the spatial domain. The unforced oscillator generates an infinite number of nested limit cycles with constant distances whose strength of attraction decreases gradually as moving to outer ones. The attractors and the basins of att...

The deadly outbreak of the second wave of Covid-19, especially in worst hit lower-middle-income countries like India, and the drastic rise of another growing epidemic of Mucormycosis, call for an efficient mathematical tool to model pandemics, analyse their course of outbreak and help in adopting quicker control strategies to converge to an infecti...

A novel memristive oscillator with infinite equilibria is proposed in this paper. The oscillator has six lines of equilibria, which make it different from known ones. Interestingly, the oscillator displays chaos and attractive features. Implementation of the oscillator via analog components is presented to verify its feasibility.

Chaos Theory and Applications (March 2022 - Volume 4 - Issue 1) https://dergipark.org.tr/en/pub/chaos/issue/63571 ----------- 1) Jun MA. "Chaos Theory and Applications：The Physical Evidence, Mechanism are Important in Chaotic Systems. " 2) Burak ARICIOĞLU, Sezgin KAÇAR. "Circuit Implementation and PRNG Applications of Time Delayed Lorenz System....

Recently, to balance the increased electricity demands and total generated power, the multiarea power system (MAPS) has been introduced with multipower sources such as gas, nuclear, hydro, and thermal, which will impact the load frequency control (LFC). Therefore, the LFC of the two-area gas-hydro-thermal power system (TAGHTPS) is introduced by app...

As applications of chaotic systems span numerous fields in engineering, physics, encryption, communications, and robotics, there is a continuing need to introduce novel chaotic systems and study their applicability in the aforementioned fields. In this chapter, a four-dimensional hyperchaotic system is introduced and analyzed through calculation of...

Chaotic maps, memristive maps, and maps with special fixed points have attracted significant researches recently. We introduce a simple methodology to construct a memristor-based map without fixed points in this work. In our methodology, a tiny perturbation is included into a memristor-based map to change its fixed points. Therefore, the presence a...

Chaotic dynamics and synchronization in fractional systems described by non-integer order difference operators have attracted increasing attention in recent years. However, very few papers have been published regarding the chaotic behaviors of fractional discrete-time neural networks and their synchronization properties. A novel chaotic h-fractiona...

In the last decades, chaotic systems and their applications have received significant attention [1–13]. When discovering chaotic systems, equilibrium points are studied seriously because of their important role [12, 14–16]. Conventional chaotic systems, especially 3-D chaotic systems, like Lorenz system [17], Rössler system [18], Arneodo system [19...

The study of chaotic dynamics in fractional-order maps has received great attention in the past years. Dynamics and control of fractional discrete-time systems in chaos theory have been only recently investigated. So far, few control techniques have been designed for stabilizing at zero the chaotic dynamic of fractional maps. Based on this consider...

Oscillations and oscillators appear in various fields and find applications in numerous areas. We present an oscillator with infinite equilibria in this work. The oscillator includes only nonlinear elements (quadratic, absolute, and cubic ones). It is different from common oscillators, in which there are linear elements. Special features of the osc...

Researchers have recently paid significant attention to special chaotic systems. In this work, we introduce an oscillator with different special features. In addition, the oscillator is symmetrical. The features and oscillator dynamics are discovered through different tools of nonlinear dynamics. An electronic circuit is designed to mimic the oscil...

Chaos Theory and Applications (November 2021 - Volume 3 - Issue 2) https://dergipark.org.tr/en/pub/chaos/issue/58077

In this paper, the nonlinear dynamics of the biological system modeled by the fractional incommensurate order Van der Pol equations are investigated. The stability of the proposed fractional non-autonomous system is analyzed by varying both the fractional order derivative and system parameters. Moreover, very interesting phenomena such as symmetry,...

Recently, numerous chaotic systems in the form of fractional difference equations have received considerable attention. Based on the stability theory of linear fractional difference systems, this chapter presents combined synchronization between fractional-order chaotic maps described by the left Caputo difference operator. Some nonlinear controlle...

The study of the chaotic dynamics in fractional-order maps has received great attention in the past years. This chapter proposes 2D and 3D fractional maps based on the Caputo difference operator. The dynamics of these fractional systems are experimentally investigated via bifurcation diagrams, phase portraits, the maximum Lyapunov exponent, and the...

Understanding extreme events attracts scientists due to substantial impacts. In this work, we study the emergence of extreme events in a fractional system derived from a Liénard-type oscillator. The effect of fractional-order derivative on the extreme events has been investigated for both commensurate and incommensurate fractional orders. Especiall...

In recent years, some efforts have been devoted to nonlinear dynamics of fractional discrete-time systems. A number of papers have so far discussed results related to the presence of chaos in fractional maps. However, less results have been published to date regarding the presence of hyperchaos in fractional discrete-time systems. This paper aims t...

Introduction: Robust, stable financial systems significantly improve the growth of an economic system. The stabilization of financial systems poses the following challenges. The state variables’ trajectories (i) lie outside the basin of attraction, (ii) have high oscillations, and (iii) converge to the equilibrium state slowly. Objectives: This p...

The study of the chaotic dynamics in fractional-order discrete-time systems has received great attention in the past years. In this paper, we propose a new 2D fractional map with the simplest algebraic structure reported to date and with an infinite line of equilibrium. The conceived map possesses an interesting property not explored in literature...

This work considers full and reduced-order observer design for rectangular descriptor systems with application to secure communications. The output of the system is assumed to have a nonlinear term coupled with the linear part, a case that is often overlooked in the literature. The observer design is feasible under some algebraic conditions and the...

Most of the papers published so far on fractional discrete systems are related to theoretical results on their chaotic behaviors or to applications based on the mathematical modeling of the chaotic phenomena. No paper has been published to date regarding the hardware implementation of hyperchaotic fractional maps. This manuscript makes a contributi...

To provide a more practical method of controlling the frequency and tie-line power flow of a multi-area interconnected power system (MAIPS), a state observer based on sliding mode control (SOboSMC) acting under a second-order time derivative is proposed. The proposed design is used to study load frequency control against load disturbance, matched a...

Nowadays, the power systems are getting more and more complicated because of the delays introduced by the communication networks. The existence of the delays usually leads to the degradation and/or instability of power system performance. On account of this point, the traditional load frequency control (LFC) approach for power system sketches a des...