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125 results on '"Volos, Christos K."'

15. Contributors

Author

Ahmadi, Atefeh, primary, Ahmed, Hafiz, additional, Akgul, Akif, additional, Bao, Bocheng, additional, Benrejeb, Mohamed, additional, Boubaker, Olfa, additional, de Jesus Rangel-Magdaleno, Jose, additional, de la Fraga, Luis Gerardo, additional, Dhifaoui, Rachid, additional, Elhadj, Zeraoulia, additional, Fotsin, Hilaire Bertrand, additional, Guillén-Fernández, Omar, additional, Guzan, Milan, additional, Hasanzadeh, Navid, additional, Jafari, Sajad, additional, Kapitaniak, Tomasz, additional, Kengne, Romanic, additional, Khalifa, Narjes, additional, Kingni, Sifeu Takougang, additional, Kol, Guy R., additional, Kyprianidis, Ioannis M., additional, Lassoued, Abir, additional, Lochan, Kshetrimayum, additional, Melendez-Cano, Ashley, additional, Meletlidou, Efthymia, additional, Mliki, Ezzedine, additional, Mousavi, Mohsen, additional, Nana, Bonaventure, additional, Nazarimehr, Fahimeh, additional, Nuñez-Perez, Jose Cruz, additional, P.M., Gokul, additional, Panahi, Shirin, additional, Pham, Viet-Thanh, additional, Prousalis, Dimitrios A., additional, Rajagopal, Karthikeyan, additional, Ríos, Héctor, additional, Rostami, Zahra, additional, Roy, Binoy Krishna, additional, Saad, Afef Ben, additional, Salgado, Ivan, additional, Shekofteh, Yasser, additional, Singh, Jay Prakash, additional, Sobota, Branislav, additional, Stouboulos, Ioannis N., additional, Subudhi, Bidyadhar, additional, Tamba, Victor Kamdoum, additional, Tlelo-Cuautle, Esteban, additional, Vaidyanathan, Sundarapandian, additional, Volos, Christos K., additional, and Woafo, Paul, additional

Published
2019
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20. Analysis, adaptive control and circuit simulation of a novel finance system with dissaving

Author

Tacha Ourania I., Volos Christos K., Stouboulos Ioannis N., and Kyprianidis Ioannis M.

Subjects
chaotic finance system, dissaving, bifurcation diagram, Lyapunov exponent, phase portrait, adaptive control, nonlinear circuit, Information technology, T58.5-58.64, Mathematics, QA1-939
Abstract

In this paper a novel 3-D nonlinear finance chaotic system consisting of two nonlinearities with negative saving term, which is called ‘dissaving’ is presented. The dynamical analysis of the proposed system confirms its complex dynamic behavior, which is studied by using wellknown simulation tools of nonlinear theory, such as the bifurcation diagram, Lyapunov exponents and phase portraits. Also, some interesting phenomena related with nonlinear theory are observed, such as route to chaos through a period doubling sequence and crisis phenomena. In addition, an interesting scheme of adaptive control of finance system’s behavior is presented. Furthermore, the novel nonlinear finance system is emulated by an electronic circuit and its dynamical behavior is studied by using the electronic simulation package Cadence OrCAD in order to confirm the feasibility of the theoretical model.

Published
2016
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37. Circuit Implementation of a Modified Chaotic System with Hyperbolic Sine Nonlinearities Using Bi-Color LED

Author

Volos, Christos K. Moysis, Lazaros Roumelas, George D. and Giakoumis, Aggelos Nistazakis, Hector E. Tombras, George S.

Subjects
Nonlinear Sciences::Chaotic Dynamics, MathematicsofComputing_NUMERICALANALYSIS
Abstract

In this paper, a chaotic three dimansional dynamical system is proposed, that is a modification of the system in Volos et al. (2017). The new system has two hyperbolic sine nonlinear terms, as opposed to the original system that only included one, in order to optimize system's chaotic behavior, which is confirmed by the calculation of the maximal Lyapunov exponents and Kaplan-Yorke dimension. The system is experimentally realized, using Bi-color LEDs to emulate the hyperbolic sine functions. An extended dynamical analysis is then performed, by computing numerically the system's bifurcation and continuation diagrams, Lyapunov exponents and phase portraits, and comparing the numerical simulations with the circuit simulations. A series of interesting phenomena are unmasked, like period doubling route to chaos, coexisting attractors and antimonotonicity, which are all verified from the circuit realization of the system. Hence, the circuit setup accurately emulates the chaotic dynamics of the proposed system.

Published
2021

38. Implementation of a Hyperchaotic System with Hidden Attractors into a Microcontroller

Author

Giakoumis Angelos E., Volos Christos K., Stouboulos Ioannis N., and Kyprianidis Ioannis K.

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

In this work, the implementation of a hyperchaotic oscillator by using a microcontroller is proposed. The dynamical system, which is used, belongs to the recently new proposed category of dynamical systems with hidden attractors. By programming the microcontroller, the three most useful tools of nonlinear theory, the phase portrait, the Poincaré map and the bifurcation diagram can be produced. The comparison of these with the respective simulation results, which are produced by solving the continuous dynamical system with Runge-Kutta, verified the feasibility of the proposed method. The algorithms could be easily modified to add or substitute the hyperchaotic system.

Published
2016
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39. A Chaos Based Pseudo-Random Bit Generator Using Multiple Digits Comparison

Author

MOYSİS, Lazaros, TUTUEVA, Aleksandra, VOLOS, Christos K., and BUTUSOV, Denis

Subjects
Chaos,Pseudo-random bit generator (PRBG),1D chaotic maps,Encryption,Security analysis, Fizik, Uygulamalı, Physics, Applied
Abstract

This work presents a simple method of designing pseudo-random bit generator by generating multiple bits per iteration from the decimal part of a chaotic map. This is done by extracting the decimal part of the state in each iteration and comparing each digit separately to a threshold value. This way, more than one bits can be generated in each iteration, in contrast to most well-known generators based on discrete-time chaotic maps, which generate only one bit. The method is tested on multiple maps and it is seen that for most, around 8 digits can be extracted each time, so that the final bitstream passes all NIST tests. The generated PRBG is then studied through a simple image encryption application, by combining shuffling and the XOR operation.

Published
2020

49. An Inverse Pheromone Approach in a Chaotic Mobile Robot's Path Planning Based on a Modified Logistic Map

Author

Petavratzis, Eleftherios K. Volos, Christos K. Moysis, Lazaros and Stouboulos, Ioannis N. Nistazakis, Hector E. Tombras, George S. Valavanis, Kimon P.

Subjects
Computer Science::Robotics
Abstract

One major topic in the research of path planning of autonomous mobile robots is the fast and efficient coverage of a given terrain. For this purpose, an efficient method for covering a given workspace is proposed, based on chaotic path planning. The method is based on a chaotic pseudo random bit generator that is generated using a modified logistic map, which is used to generate a chaotic motion pattern. This is then combined with an inverse pheromone approach in order to reduce the number of revisits in each cell. The simulated robot under study has the capability to move in four or eight directions. From extensive simulations performed in Matlab, it is derived that motion in eight directions gives superior results. Especially, with the inclusion of pheromone, the coverage percentage can significantly be increased, leading to better performance.

Published
2019

50. Mixed Topology of DF Relayed Terrestrial Optical Wireless Links with Generalized Pointing Errors over Turbulence Channels

Author

Varotsos, George K. Nistazakis, Hector E. Stassinakis, Argyris N. Volos, Christos K. Christofilakis, Vasileios Tombras, George S.

Subjects
Computer Science::Information Theory
Abstract

This study investigated the outage performance of a terrestrial FSO communication system that uses mixed series and parallel decode-and-forward (DF) relay-assisted (i.e., cooperative diversity) configurations, taking into account the influence of both atmospheric turbulence and pointing error effects. Turbulence-induced optical signal fading is modeled by gamma-gamma or the negative exponential distribution for weak to strong and saturated turbulence conditions, respectively. Additionally, weak to strong non-zero boresight misalignment-induced optical signal fading is modeled by the generalized Beckmann distribution. Under these conditions, an outage analysis of the examined FSO system is performed, in terms of both outage probability and mean outage duration metrics. Thus, fairly accurate closed-form mathematical expressions for both performance metrics are derived, while their corresponding analytical results demonstrate concrete performance and availability improvements for the total FSO system, especially when the number of the connected in parallel DF relays increases. Moreover, the obtained results are verified through the corresponding simulation results.

Published
2018

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