
Akif AkgulHitit University · Department of Computer Engineering
Akif Akgul
PhD
ADBA Information Technology and Publishing
(https://www.adbascientific.com)
About
166
Publications
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Introduction
Dr. AKGUL received his B.S. degree in Electronics-Computer Education from Kocaeli University in 2009 and in Electrical-Electronics Engineering from Sakarya University in 2013, M.S. and Ph.D. degrees from Sakarya University in 2011 and 2015, respectively, in Electronics-Computer Education and Electrical-Electronics Engineering. He has been to The Institute of Electronics, Communications and Information Technology (ECIT) of Queen's University Belfast, UK in 2015 as a Visiting Researcher.
Skills and Expertise
Additional affiliations
November 2009 - April 2016
February 2015 - May 2015
Education
September 2013 - July 2014
February 2010 - June 2015
September 2009 - January 2010
Publications
Publications (166)
A novel chaotic system is explored in which all terms are quadratic except for a linear function.
The slope of the linear function rescales the amplitude and frequency of the variables linearly
while its zero intercept allows offset boosting for one of the variables. Therefore, a free-controlled
chaotic oscillation can be obtained with any desired...
Recent evidence suggests that a system with only stable equilibria can generate chaotic behavior. In this work, we study a chaotic system with two stable equilibrium points. The dynamics of the system is investigated via phase portrait, bifurcation diagram and Lyapunov exponents. The feasibility of the system is introducing its electronic realizati...
In the recent years, interdisciplinary studies on and applications of nonlinear systems have been increased significantly. Some of these studies are chaos-based applications. Chaos-based encryption, one of the most popular type of applications, has some security drawbacks. In this article, to overcome those drawbacks a secure steganography applicat...
There has recently been an increase in the number of new chaotic system designs and chaos-based engineering applications. In this study, since homoclinic and heteroclinic orbits did not exist and analyses like Shilnikov method could not be used, a 3D chaotic system without equilibrium points was included and thus different engineering applications...
In this study, the Arneodo chaotic system was designed as an incommensurate fractional-order system, and the equilibrium points, time series, and phase portraits of the system were obtained, while the Lyapunov exponents were calculated. The incommensurate fractional-order system was modeled and simulated on the Nvidia Jetson AGX Orin, and its pract...
https://dergipark.org.tr/en/pub/chaos/issue/88057
Discrete-time chaotic systems exhibit nonlinear and unpredictable dynamic behavior, making them very difficult to classify. They have dynamic properties such as the stability of equilibrium points, symmetric behaviors, and a transition to chaos. This study aims to classify the time series images of discrete-time chaotic systems by integrating deep...
This study uses deep learning methods to classify projection of the attractors images of five different chaotic systems. The chaotic systems addressed in the research are Sprott C, Sprott F, Sprott G, Sprott H, and Sprott M. A dataset was created for classification using the projection of attractors of these five different chaotic systems. This dat...
https://dergipark.org.tr/en/pub/chaos/issue/86422
Chemical compound classification, toxicity prediction, and environmental risk assessments are critically important in various applications within the field of chemistry. Deep learning models provide highly effective tools for extracting features from complex large datasets and performing classification tasks. Four different deep learning models, na...
Robust chaotic systems offer unpredictability, complex dynamics, noise-like properties, efficient bifurcation behavior, and the ability to model real-world phenomena, making them valuable in diverse scientific and engineering applications. This paper details on the dynamical appraisal, amplitude controls, microcontroller execution, Random number ge...
Fractional-order (FO) chaotic systems exhibit random sequences of significantly greater complexity when compared to integer-order systems. This feature makes FO chaotic systems more secure against various attacks in image cryptosystems. In this study, the dynamical characteristics of the FO Sprott K chaotic system are thoroughly investigated by pha...
The complexity of lung cancer treatment presents a formidable challenge in oncology, which necessitates innovative and personalized approaches that transcend conventional therapeutic modalities. Accordingly, this study introduces a groundbreaking integrative approach by synergizing a fractionalorder mathematical model with surgical and immunotherap...
The current study delves into the intricate association between meteorological conditions and the incidence of Upper Respiratory Tract Infections (URTIs), leveraging the advanced capabilities of the CatBoost machine learning algorithm in conjunction with a Fractional Order Chaotic System and cutting-edge Explainable Artificial Intelligence (XAI) te...
A chaotic map with two-dimensional offset boosting is exhaustively studied, which is derived from the Lozi map and shows the controllability of amplitude control. The mechanism of two-dimensional offset boosting is revealed based on the cancelation of offset-involved feedback terms. Furthermore, the coexistence of homogeneous multistability and het...
Fractional-order (FO) chaotic systems exhibit richer and more complex dynamic behaviors compared to integer-order ones. This inherent richness and complexity enhances the security of FO chaotic systems against various attacks in image cryptosystems. In the present study, a comprehensive examination of the dynamical characteristics of the fractional...
Metaheuristic techniques are capable of representing optimization frames with their specific theories as well as objective functions owing to their being adjustable and effective in various applications. Through the optimization of deep learning models, metaheuristic algorithms inspired by nature, imitating the behavior of living and non-living bei...
https://dergipark.org.tr/en/pub/chaos/issue/83761
Countable systems with infinite attractors are called megastable systems and found significance for its wide application. In this research work we are dealing with a Quadratic megastable oscillator (QMO) and exposing various dynamical behaviors which will enhance the complexity of the system. Usually the megastable oscillators were designed with ex...
This study introduces an innovative filter topology capable of providing simultaneous positive and negative gain outputs for one-fractional order LP, with high-pass, all-pass, and fractional-order shelving filter responses. The circuit, utilizing multi-output second-generation current-controlled conveyors, stands out as the first to deliver ten out...
Offset boosting provides a direct channel for chaotic signal conditioning in chaos-based engineering. The broadband random-like property of chaos poses a great challenge to the design of a chaotic system with independent non-bifurcation parameters. In this work, a chaotic jerk oscillator with two independent offset parameters is constructed, one of...
The investigation in this paper is founded on the theoretical study of a neuronal circuit driven by a Josephson junction (JJ) under the effects of light and temperature, and its microcontroller design. The neuronal circuit is made of a resistor in series to a phototube (PT) to which an excitation which is a direct current (DC) source, a thermistor,...
In this research paper, a new chaotic jerk system is proposed, which is constructed using cubic and hyperbolic sine nonlinearities. A detailed dynamical analysis of the chaotic jerk system is presented with the bifurcation diagrams and Lyapunov exponent spectrums. The novelties of the proposed system are that it can exhibit multistability for diffe...
Chaotic systems are often used in cryptology applications thanks to their complex dynamic structures. By increasing the dynamic diversity of chaotic systems through fractional-order analysis, more complex systems for data security can be obtained. In this study, fractional calculus analyses of the Arneodo chaotic jerk system with cubic nonlinearity...
https://dergipark.org.tr/en/pub/chaos/issue/80150
https://dergipark.org.tr/en/pub/chaos/issue/77246
This paper investigates the dynamical characteristics of current-modulated edge-emitting semiconductor lasers (CMEESLs) and their image encryption application. The associated dynamical characteristic of the CMEESL is divulged in the two-dimensional coordinate space of the system parameters by altering the modulation’s frequency and amplitude. The C...
Chaotic systems have different characteristics that can be utilized for the purpose of cyber security. These features result from the erratic structure of images, making it difficult for systems to comprehend those images. Therefore, chaotic systems can serve as an effective means of securely storing and concealing images by implementing them in th...
The network connectivities play an important role in displaying the vastly different collective dynamics in many complex systems. To demonstrate the presence of different dynamical states and their transition, we consider Hindmarsh-Rose neurons, which are linked up by electromagnetic interactions. The dynamical behaviors of the proposed system are...
Based on boundary rationality and relative profit maximization, quantum game theory is applied to develop a dynamic model of the quantum Cournot duopoly game. We investigate the effect of quantum properties on game stability and nonlinear dynamics. The results show that quantum entanglement can improve the model’s stability and control the generati...
In this study, we consider a network of nonlocally coupled Brockett oscillators (BOs) with attractive and repulsive (AR) couplings. In the absence of coupling, the individual BO oscillator shows stable periodic oscillations (PO) or stable steady state (SS) depending on the critical values of the parameters. We first begin by examining the collectiv...
https://dergipark.org.tr/en/pub/chaos/issue/75756
The major interest of this article is to investigate a single and an array of mechanical arms driven by Josephson junction (JJ) circuits and their applications in mimicking the locomotion of myriapods. Stability analysis of a single mechanical arm driven by a JJ circuit resulted in two equilibrium points and a switch of their stability for specific...
The coexistence of different attractors with fixed parameters affords versatility in the performance of the dynamical system. As a result, recent research has focused on defining nonlinear oscillators with infinite coexisting attractors, the vast majority of which are non-autonomous systems. In this study, we present an infinite number of equilibri...
https://dergipark.org.tr/en/pub/chaos/issue/73767
Chaotic neuronal oscillation is fired up when a locally active memristor is introduced into the Rössler system. Such a memristive Rössler system has two independent parameters providing local amplitude control, one of which even adjusts the amplitude and frequency of variables in a specific intermittent mode. Different neuronal firing modes are mod...
Crypto assets succeeded in making their name known to large masses with Bitcoin, which emerged as a result of the creation of the first genesis block in 2008. Until 2010, the aforementioned recognition showed itself mostly in areas such as games, but over time it managed to enter the portfolios of individual investors. Especially as of end of 2017,...
https://dergipark.org.tr/en/pub/chaos/issue/73033
Memristive circuits and systems have been widely studied in the last years due to their potential applications in several technological areas. They are capable of producing nonlinear periodic and chaotic oscillations, due to their locally-active characteristics. In this paper, we consider a cubic four-parameter differential system which models a me...
With an immense increase in Internet multimedia applications over the past few years, digital content such as digital images are stored and shared over global networks, the probability for information leakage and illegal modifications to the digital content is at high risk. ese digital images are transferred using the network bandwidth; therefore,...
Cell studies play an important role in the basis of studies on cancer diagnosis and treatment. Reliable viability assays on cancer cell studies are essential for the development of effective drugs. Lens-less digital in-line holographic microscopy (DIHM) has become a powerful tool in the characterization and viability analysis of microparticles such...
In order to further discover the hidden chaotic attractor and its generating mechanism in the chaotic system by Vijayakumar et.al. in 2021, we give a generalized system showing hidden chaotic attractors which are not from homoclinic orbit or heteroclinic orbit, consider Hopf bifurcations (codimension one and two) by first Lyapunov coefficient and s...
Studies on fractional-order chaotic systems have increased significantly in the last decade. This paper presents Rucklidge chaotic system’s dynamical analyses and its fractional-order circuit implementations. Component values required for realizing the circuit of the fractional-order system are calculated for different fractional-orders. The feasib...
Watermarking is one of the most common techniques used to protect data's authenticity, integrity, and security. The obfuscation in the frequency domain used in the watermarking method makes the watermarking stronger than the obfuscation in the spatial domain. It occupies an important place in watermarking works in imperceptibility, capacity, and ro...
A linear resistive capacitive inductive shunted model of a Josephson junction with a topologically nontrivial behavior is considered in this paper. We have considered a fractional order flux controlled memristor to effectively model the feedback flux effects across the Josephson junction (JJ). The mathematical model of the proposed JJ oscillator is...
This issue is dedicated to the memory of Prof. Tenreiro Machado.
https://dergipark.org.tr/en/pub/chaos/issue/64884
Objective: Hand vein images have become important biometric signs used for identification systems. Also, dorsal hand vein images have noteworthy advantages in terms of reliability and contactless procedure. Surgically changing the vascular pattern under the skin is extremely difficult. Therefore, the use of such patterns in identity recognition app...
One of the most important topics in science and engineering technology is the use of chaos. Fast growths in research on engineering applications and chaotic systems with integer and fractional orders have been reported in recent years. A diversity of innovative chaotic systems for usefulness in engineering applications have been proposed.
We welcom...
Complex biorhythms are characteristic of ubiquitous phenomena appearing in many disciplines of human knowledge. This Special Issue collects articles devoted to different complex biorhythms phenomena such as cardiac dynamics, Covid-19 dynamics, dynamics of neural networks, cell dynamics, and a few articles devoted to general methods. It furnishes a...
Fractional-order systems can come across in chemical processes, biological systems, viscoelastic systems, propagation of electromagnetic waves and electrochemical systems. In the literature, fractional systems are encountered in the modelling and controlling of such systems, synchronization applications, communication, modelling and controlling of...
Chaos Theory and Applications (March 2022 - Volume 4 - Issue 1)
https://dergipark.org.tr/en/pub/chaos/issue/63571
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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....
In this paper, a three-dimensional chaotic system with a line equilibrium is studied, in which a single nonbifurcation parameter is used to control the amplitude and frequency. A variety of chaotic signals can be modified using the amplitude-frequency control switch. e realization of circuit simulation based on multisim further verifies the theoret...
Chaos Theory and Applications (November 2021 - Volume 3 - Issue 2)
https://dergipark.org.tr/en/pub/chaos/issue/58077
Coordination of a power system with the phasor measurement devices (PMUs) in real time on the load and generation sides is carried out within the context of smart grid studies. Power systems equipped with information systems in a smart grid pace with external security threats. Developing a smart grid which can resist against cyber threats is consid...
In this study, 8 arrhythmic ECG signals from vital signals (Sinus Tachycardia, Supraventricular Tachycardia, Premature Ventricular Complex (PVC), Atrial Fibrillation, AV block: 3rd degree, Ventricular Fibrillation, Sinus Bradycardia, First Degree AV Block) were designed mathematically, and then modelled on FPGA by VHDL and Xilinx-Vivado software. T...
Mem-elements play an important part in the design of high-density memory systems and low power memory. In this paper, we created a novel fractional-order chaotic circuit with a memristor and a memcapacitor with a linear inductor. The various dynamical properties of the fractional-order system are investigated by using some dynamic analysis methods...
This special issue selects some interesting contributions of recent scientific achievements in circuit application of chaotic systems, focusing on showing the new methods and technologies of the modeling, dynamical analysis and control of chaotic systems. This presented letter summarizes the work of the special issue and discusses some thoughts on...
Stroke is one of the leading causes of disability in Turkey with more than 210,000 incidence annually. Intensity of stroke rehabilitation sessions has a great importance to regain ability to perform some of the activities of daily living. There are successful results achieved with conventional therapy, electrical stimulation and robotics rehabilita...
Chaos Theory and Applications (June 2021 - Volume 3 - Issue 1)
https://dergipark.org.tr/tr/pub/chaos/issue/56378
In this study, an equation is derived by changing the parameter values of a chaotic system in the literature and analyzing its chaotic behavior. In the analysis of chaotic behaviors, chaotic system analyses such as phase portraits, sensitivity to initial conditions, Lyapunov exponential spectrum and dimension analysis, bifurcation diagram with Matl...
There are many control methods for systems that have been developed and continued to be developed, linear or non-linear, time-varying or invariant. In this study, in the control of the nonlinear Lorenz Chaotic system, model predictive control method with integrator action, which has not been applied to this system before, is applied. In addition to...
Chaotic systems with cyclic symmetry are very rare and have been less discussed in the literature. Similarly, megastable oscillators, which can have a finite or infinite number of coexisting attractors, have also attracted researchers. We propose a class of cyclic symmetry oscillators with the megastable property with infinite coexisting attractors...
In this study, a new chaotic mixer based on delta robot was designed and produced which had been controlled with Arduino Uno card and MATLAB. First of all, chaotic mixing systems with different dynamic properties were chosen for the chaotic mixing process. Then, by solving the chaotic systems selected in the MATLAB with Runge Kutta 45 (RK45) numeri...
The purpose of this paper is to develop new four dimensional hyperchaotic system by adding another state variable and linear controller to three dimensional (3D) T chaotic dynamical systems. Its dynamical analyses, circuit experiment, control and synchro-
nization applications are presented. A new four dimensional (4D) hyperchaotic attractor is ach...
Chua’s circuit has been used as a classical chaotic model and a generator for chaos communication. In this paper, an improved circuit realization of Chua’s system with x |x| and its engineering applications are proposed. In addition, the fractional order form of this modified 3D Chua’s system is examined by bifurcation analysis, route to chaos, mul...
Josephson junction resonators are the devices which exhibits complex behaviours as a consequence of its inductive properties. Even though the insulating medium between Josephson junctions (JJs) are normally considered homogeneous, the fact that lithography is used to form the layer, it has fractal substrates. Such JJs are identified as fractal Jose...
This paper presents the design, simulation, and experimental verification of the fractional-order multiscroll Lü chaotic system. We base them on op-amp-based approximations of fractional-order integrators and saturated series of nonlinear functions. The integrators are first-order active realizations tuned to reduce the inaccuracy of the frequency...
Josephson junction devices play a significant role in various physical nonlinear systems because of their complex characteristics. Chaotic phenomenon in various types of Josephson junction devices has been widely reported, but many of those literature studies exempted the analysis into multistability and megastability features of the device. In thi...
In this work, linear quadratic regulator (LQR) method is proposed for controlling and synchronizing memcapacitor based chaotic system (MMCO). The MMCO is constructed with a charge controller memcapacitor, a resistor, a conductance and two capacitors. The proposed oscillators dimensionless model is derived and considered for analysis. The investigat...