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EN
A simple and efficient method for creating a motion trajectory is presented with an aim to achieve sufficient coverage of a given terrain. A chaotic map has been used in order that the motion trajectory should be unpredictable. The chaotic path generator which has been created, is used for implementing a robot’s movement in four and eight directions. The path generator is tested in various scenarios and the results are discussed. After thorough examination, the proposed method shows that the motion in eight directions gives better and very satisfactory results.
EN
A novel symmetric cryptosystem of the substitution permutation network type is presented for image encryption in 14 rounds. An algorithm is developed to generate 15 keys to encrypt images where each key is the image size. These keys are calculated using an elliptic curve with a constant zero value. The proposed curve is non-singular, non-supersingular, nor trace one. Chaos is employed to find a generating element in a cyclic subgroup and it is produced using the logistic map equation. In addition, a 16 × 16 substitution box is constructed using both chaos and an algorithm that defines a bijective function. The following tools are used in order to measure the degree of randomness of the encrypted figures: entropy, correlation, the discrete Fourier transform and a goodness-of-fit test with the chi-square distribution. Furthermore, an image size variable permutation is applied in the first round, and its inverse in the fourteenth.
EN
Researchers have paid significant attention on hyperjerk systems, especial hyperjerk ones with chaos. A new hyperjerk system with seven terms and two parameters is analyzed. Chaotic attractors as well as coexisting attractors are displayed by the hyperjerk system. Thus it is a new multi-stable chaotic hyperjerk system. Further properties of the proposed hyperjerk system such as circuit design and backstepping-based control and synchronization are reported.
EN
A new 4-D dynamical system with hyperchaos is reported in this work. It is shown that the proposed nonlinear dynamical system with hyperchaos has no equilibrium point. Hence, the new dynamical system exhibits hidden hyperchaotic attractor. An in-depth dynamic analysis of the new hyperchaotic system is carried out with bifurcation transition diagrams, multistability analysis, period-doubling bubbles and offset boosting analysis. Using Integral Sliding Mode Control (ISMC), global hyperchaos synchronization results of the new hyperchaotic system are described in detail. Furthermore, an electronic circuit realization of the new hyperchaotic system has been simulated in MultiSim software version 13.0 and the results of which are in good agreement with the numerical simulations using MATLAB.
EN
The encryption of image data is artful as compare to others due to some special characteristics such as entropy, contrast, the correlation between the pixels, intensity, and homogeneity. During encryption process, it is conventionally not easy to manage these characteristics with non-chaotic cryptosystems. Therefore for the sake of strong encryption algorithms, in last decades many cryptographers have presented invulnerable schemes for image encryption based on the chaotic maps. This manuscript aims to propose a strong encryption scheme based on a symmetric group of permutation advanced encryption standard (AES) substitution boxes and modified Chebyshev map. Principally, the secret key depends upon the parameters of Chebyshev map to create confusion in the main image and is encrypted by the scheme made from the S8 AES S-boxes and chaotic map. By this procedure, one can obtain an encrypted image that is entirely twisted. The results of analyses showed that the presented image encryption is strong and invulnerable.
EN
This paper proposes an improved chaos-based M-ary modulation system. It reproduces deterministic chaotic dynamics to create M-ary non-coherent modulation. The proposed modulation system transmits data using autonomous chaotic sequences. It separates the chaotic dynamics through the use of interleavers and realigns them through the use deinterleavers. The simulation results show that the improved scheme overperforms its traditional counterpart. The degree of improvement grows as the M-ary order is increased, with a penalty of increased system complexity.
EN
Intelligent and personalized dynamic maintenance and spare parts configuration of high-speed railway have been the main trend to guarantee the safety capability of trains. In this paper, a new Automatic Train Protection (ATP) system failure rate calculation method is proposed, and the delay time and embedded dimension are determined by C-C algorithm. Then the phase space is reconstructed from one-dimensional time series to high-dimensional space. Based on chaotic characteristics of failure rate, a short-term intelligent forecasting model of failure rate of ATP system is established. The actual failure statistics from 2010 to 2018 are used as samples to train and test the validity of the model. From prediction results, it shows that the proposed chaos prediction model has an accuracy of 99.71%, which is better than the support vector machine model. Through the intelligent prediction of failure rate, this paper solves the maintenance inflexibility and imbalance of supply and demand of spare parts configuration.
PL
Inteligentna i spersonalizowana dynamiczna konserwacja i konfiguracja części zamiennych pociągów kolei dużych prędkości stanowią ostatnio główny trend w zakresie zapewniania bezpieczeństwa pociągów. W niniejszym artykule zaproponowano nową metodę obliczania intensywności uszkodzeń systemu Automatycznej Ochrony Pociągu (ATP), a czas opóźnienia i wymiar zanurzenia określano za pomocą algorytmu CC. Następnie, przestrzeń fazową przekształcono z jednowymiarowego szeregu czasowego do przestrzeni wielowymiarowej. Opierając się na chaotycznych charakterystykach intensywności uszkodzeń, utworzono model krótkoterminowego inteligentnego prognozowania awaryjności systemu ATP. Do uczenia modelu i weryfikacji jego trafności wykorzystano rzeczywiste dane statystyczne dotyczące awarii pociągów z lat 2010–2018. Z wyników prognoz wynika, że proponowany model predykcji, oparty na teorii chaosu, cechuje się dokładnością na poziomie 99,71%, czyli wyższą niż model maszyny wektorów nośnych. Dając możliwość inteligentnej predykcji intensywności uszkodzeń, niniejsza praca rozwiązuje problem braku elastyczności w utrzymaniu ruchu pociągów oraz braku równowagi między podażą a popytem na części zamienne.
EN
Based on Chebyshov polynomials, one can create an asymmetric cryptosystem that allows for secure communication. Such a cryptosystem is based on the fact that these polynomials form a semi-group due to the composition operation. This article presents two new cryptosystems based on modifications of Chebyshev's polynomials. The presented analysis shows that their security is the same as in the case of algorithms associated with the problem of discrete logarithms. The article also shows methods that allow for the faster calculation of Chebyshev polynomials.
EN
A method of suppressing chaotic oscillations in a tubular reactor with mass recycle is discussed. The method involves intervention in the temperature of the input flow by the recirculation flow and the temperature set from the exterior. The most advantageous solution was proved to be heat coupling elimination and maintenance of the reactor input temperature on the set level. Moreover, the reactor modelwas identified on the basis of a chaotic solution, as it provides the biggest entropy of information.
EN
J. L. Hindmarsh, R. M. Rose introduced the concept of neuronal burst. In this paper, synchronization is investigated for the construction of a model of neuronal burst using backstepping control with recursive feedback. Synchronization for a model of neuronal bursting system is established using Lyapunov stability theory. The backstepping scheme is a recursive procedure that links the choice of a Lyapunov function with the design of a controller. The backstepping control method is effective and convenient to synchronize identical systems. Numerical simulations are furnished to illustrate and validate the synchronization result derived in this paper.
EN
We study an elegant snap system with only one nonlinear term, which is a quadratic nonlinearity. The snap system displays chaotic attractors, which are controlled easily by changing a system parameter. By using analysis, simulations and a real circuit, the dynamics of such a snap system has been investigated. We also investigate backstepping based adaptive control schemes for the new snap system with unknown parameters.
EN
A new 4-D dynamical system exhibiting chaos is introduced in this work. The proposed nonlinear plant with chaos has an unstable rest point and a line of rest points. Thus, the new nonlinear plant exhibits hidden attractors. A detailed dynamic analysis of the new nonlinear plant using bifurcation diagrams is described. Synchronization result of the new nonlinear plant with itself is achieved using Integral Sliding Mode Control (ISMC). Finally, a circuit modelusing MultiSim of the new 4-D nonlinear plant with chaos is carried out for practical use.
PL
W artykule przedstawiono przykład zachowania chaotycznego w wybranym fragmencie sieci elektroenergetycznej zamodelowanej nieliniowym układem równań różniczkowych. Artykuł omawia najistotniejsze aspekty identyfikacji zachowań chaotycznych w systemie na podstawie zarejestrowanego przebiegu czasowego tylko jednej zmiennej stanu bez znajomości wymiaru rzeczywistej przestrzeni fazowej.
EN
The article presents an example of chaotic behavior in a selected piece of the power network modeled by nonlinear system of differential equations. This article also discusses the most important aspects of identifying chaotic behavior in a system, based on only the recorded time course of one state variable without knowing the real dimension of the phase space.
PL
Artykuł przedstawia wyniki badań symulacyjnych z użyciem procedur Eckmanna i Rosensteina wyznaczających wykładniki Lapunowa na podstawie szeregu czasowego. Dla weryfikacji i oceny przydatności tych procedur, jako wzorcowy szereg czasowy wyko­rzysta­no punkty generowane przez odwzorowanie logistyczne, dla którego znana jest trajektoria współczynników Lapunowa.
EN
This paper presents the results of simulation tests using the Eckmann and Rosenstein procedures for calculating Lyapunov exponents based on a time series. For verifying and evaluating the suitability of these procedures as a reference time series, points generated by logistic mapping for which the trajectory of Lyapunov's coefficients is known was applied.
EN
Dynamic properties of the three degrees of freedom autoparametric system with spherical pendulum including the magnetorheological (MR) damper are investigated. It was assumed that the spherical pendulum is suspended to the oscillator excited harmonically in the vertical direction. The influence of damping force described by Bingham’s model on the energy transfer can be modified by magnetic field. The equation of motion have been solved numerically. In this type system one mode of vibration may excite or damp another one, and for except different kinds of periodic vibrations there may also appear chaotic vibration. Results show that MR damper can be used to change the dynamic behavior of the autoparametric system with spherical pendulum giving semiactive control possibilities.
16
Content available remote The conflict in Ukraine : a new-generation warfare
EN
The aim of this paper is to illustrate the underlying concepts and characteristics of hybrid warfare – a new type of modern warfare utilising unconventional methods and “proxy wars” which involve national minorities, terrorist groups and local communities. The paper also describes the current capabilities of states to engage in new warfare without declaring war while using all resources available, and identifies the advanced disinformation and propaganda mechanisms employed to achieve political objectives. The paper further provides a background to the outbreak of war in Ukraine by highlighting the causes and consequences of Russia’s preparing for and launching the invasion of a European country in contravention of all international laws and agreements. The subject is dealt with comprehensively, from the annexation of Crimea to the destabilisation of south-eastern Ukraine by separatist military groups.
PL
Celem artykułu jest przedstawienie idei oraz charakterystyki nowego rodzaju konfliktu zbrojnego, jakim jest wojna hybrydowa ‒ wojna niekonwencjonalna, nowoczesna, toczona przy wykorzystaniu mniejszości narodowych, ugrupowań terrorystycznych czy lokalnej społeczności, tzw. „wojna zastępcza”. Przybliżono zdolności prowadzenia nowoczesnych działań wojennych bez ich oficjalnego wypowiedzenia przy wykorzystaniu wszelkich dostępnych środków oraz zwrócono uwagę na wykorzystywanie zaawansowanych mechanizmów dezinformacji i propagandy do osiągania zakładanych celów politycznych. Następnie przedstawiono genezę zarzewia konfliktu i wybuchu wojny na Ukrainie poprzez uwypuklenie przyczyn i następstw przygotowania i przeprowadzenia łamiącej wszelkie prawa i umowy międzynarodowe inwazji na europejski kraj, poczynając od zaanektowania Półwyspu Krymskiego poprzez destabilizację południowo-wschodniej części Ukrainy przy wykorzystaniu separatystycznych ugrupowań bojowych.
EN
To study chaos and bifurcation of a gear system, a five-degree-of-freedom nonlinear dynamic model of a gear-rotor-bearing system is established. It consists of a gear pair, supporting shafts, bearings and other auxiliary components. The effects of frequency, backlash, bearing clearance, comprehensive transmission error and stiffness on nonlinear dynamics of the system are investigated according to bifurcation diagrams, phase portraits and Poincar´e maps by a numerical method. Some nonlinear phenomena such as grazing bifurcation, Hopf bifurcation, inverse-Hopf bifurcation, chaos and coexistence of attractors are investigated. Different grazing bifurcations and their causes are discussed. The critical parameters are identified, too.
EN
The present paper is dedicated to computer simulations performed using a numerical model of a one-stage gear. The motion equations were derived utilizing the bond graph method. The formulated model takes into consideration the variable stiffness of toothings as well as an inter-tooth clearance which has been represented via discontinuous elements with so called dead zones. As a result of these assumptions, the nonlinear model was obtained which enables representation of the dynamic phenomena of the considered gear. In the paper, an influence of errors of gear wheels’ co-operation on the character of excited dynamic phenomena was studied. The methodology of the analyses consists in utilization of the following tools: color maps of distribution of the maximal Lapunov coefficient and bifurcation diagrams. Based upon them, the parameters were determined, for which the Poincare portrait represents a structure of the chaotic attractor. For the identified attractors, the initial attractors were calculated numerically - which along with the changes of the control parameters are subjected to multiplication, stretching or rotation.
EN
DC/DC converters are wealthy of nonlinear phenomena that appear when the converter parameters are subject to perturbation or variation. The converter may exhibit bifurcation from behavior to another, quasi periodic and chaotic responses. In such cases, it is difficult and even impossible to analyze, to predict and to control the converter behavior. This paper gives a description of a DC/DC converter and shows their desirable and undesirable behaviors; then a solution, based on type-2 fuzzy logic controller, is proposed to eliminate the undesirable behaviors and to enhance the converter dynamics.
EN
The one-dimensional Φ4 Model generalizes a harmonic chain with nearest-neighbor Hooke’s-Law interactions by adding quartic potentials tethering each particle to its lattice site. In their studies of this model Kenichiro Aoki and Dimitri Kusnezov emphasized its most interesting feature: because the quartic tethers act to scatter long-wavelength phonons, Φ4 chains exhibit Fourier heat conduction. In his recent Snook-Prize work Aoki also showed that the model can exhibit chaos on the three-dimensional energy surface describing a two-body two-spring chain. That surface can include at least two distinct chaotic seas. Aoki pointed out that the model typically exhibits different kinetic temperatures for the two bodies. Evidently few-body Φ4 problems merit more investigation. Accordingly, the 2018 Prizes honoring Ian Snook (1945-2013) will be awarded to the author(s) of the most interesting work analyzing and discussing few-body Φ4 models from the standpoints of dynamical systems theory and macroscopic thermodynamics, taking into account the model’s ability to maintain a steady-state kinetic temperature gradient as well as at least two coexisting chaotic seas in the presence of deterministic chaos.
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