Showing papers by "Volga State University of Water Transport published in 2020"

When three is a crowd: Chaos from clusters of Kuramoto oscillators with inertia.

Abstract: Modeling cooperative dynamics using networks of phase oscillators is common practice for a wide spectrum of biological and technological networks, ranging from neuronal populations to power grids. In this paper we study the emergence of stable clusters of synchrony with complex intercluster dynamics in a three-population network of identical Kuramoto oscillators with inertia. The populations have different sizes and can split into clusters where the oscillators synchronize within a cluster, but notably, there is a phase shift between the dynamics of the clusters. We extend our previous results on the bistability of synchronized clusters in a two-population network [I. V. Belykh et al., Chaos 26, 094822 (2016)CHAOEH1054-150010.1063/1.4961435] and demonstrate that the addition of a third population can induce chaotic intercluster dynamics. This effect can be captured by the old adage "two is company, three is a crowd," which suggests that the delicate dynamics of a romantic relationship may be destabilized by the addition of a third party, leading to chaos. Through rigorous analysis and numerics, we demonstrate that the intercluster phase shifts can stably coexist and exhibit different forms of chaotic behavior, including oscillatory, rotatory, and mixed-mode oscillations. We also discuss the implications of our stability results for predicting the emergence of chimeras and solitary states.

Chaotic driven maps: Non-stationary hyperbolic attractor and hyperchaos

Abstract: In this paper we study simple examples of non-autonomous maps having different changing in time chaotic attractors. We present the definition of non-stationary hyperbolic attractor of the driven maps. We rigorously prove the existence of non-stationary hyperbolic attractor in 2D driven map and introduce a hyperchaotic attractor for autonomous 3D map of master-slave structure. Our analysis is based on the auxiliary systems approach and the construction of invariant cones.

Bifurcations of Chaotic Attractors in a Piecewise Smooth Lorenz-Type System

Abstract: We study the dynamics of a piecewise-smooth system of differential equations for which the existence of a strange Lorenz-type attractor had been rigorously proved previously and bifurcation mechanisms of its birth had been obtained. In this work we discuss the destruction of this attractor due to the appearance of sliding motions in its structure. Using qualitative and numerical methods, we study a complex sequence of attractor bifurcations that leaves in the system a globally stable limit cycle. We show that this sequence is based on C-bifurcations and bifurcations of multi-loop homoclinic trajectories.

Ghost attractors in blinking Lorenz and Hindmarsh-Rose systems.

Abstract: In this paper, we consider blinking systems, i.e., non-autonomous systems generated by randomly switching between several autonomous continuous time subsystems in each sequential fixed period of time. We study cases where a non-stationary attractor of a blinking system with fast switching unexpectedly differs from the attractors of composing subsystems. Such a non-stationary attractor is associated with an attractor of the averaged system being a ghost attractor of the blinking system [Belykh et al., Phys. D: Nonlinear Phenom. 195, 188 (2004); Hasler et al., SIAM J. Appl. Dyn. Syst. 12, 1031 (2013); Belykh et al., Eur. Phys. J. Spec. Top. 222, 2497 (2013)]. Validating the theory of stochastically blinking systems [Hasler et al., SIAM J. Appl. Dyn. Syst. 12, 1031 (2013); Hasler et al., SIAM J. Appl. Dyn. Syst. 12, 1007 (2013)], we demonstrate that fast switching between two Lorenz systems yields a ghost chaotic attractor, even though the dynamics of both systems are trivial and defined by stable equilibria. We also study a blinking Hindmarsh–Rose system obtained from the original model of neuron activity by using randomly switching sequence as an external stimulus. Despite the fact that the values of the external stimulus are selected from a set corresponding to the tonic spiking mode, the blinking model exhibits bursting activity. For both systems, we analyze changes in the dynamical behavior as the period of stochastic switching increases. Using a numerical approximation of the invariant measures of the blinking and averaged systems, we give estimates of a non-stationary and ghost attractors’ proximity.

Damping of gravity–capillary waves on the surface of turbulent fluid

Abstract: Investigation of damping of gravity–capillary waves (GCW) on the surface of turbulent fluid is a classical problem which geophysical applications are related to the problems of swell damping, interpretation of radar and optical images of ship wakes, development of physical mechanisms of wind wave suppression, etc. Analysis of the relevant literature reveals the necessity of setting reliable experiments to study the effect of damping of GCW due to turbulence. An original laboratory method of investigation of surface wave damping due to turbulence is described. The method is based on the parametric excitation of standing surface waves (so-called Faraday ripples) and simultaneous and independent generation of turbulence. The wave damping coefficient is determined by a threshold acceleration corresponding to the surface wave parametric excitation. The disadvantages of the previously used methods are eliminated or significantly reduced in the presented method, and the results are formulated in terms of eddy viscosity. It is revealed that the eddy viscosity coefficient is proportional to the rms velocity of turbulent pulsations, and achieves a maximum as a function of GCW frequency, when the GCW wavelengths are of order of the scales of turbulent eddies. This effect has never been mentioned in the literature, since the previous studies were focused on the investigation of wave damping due to small-scale (relative to the GCW wavelengths) turbulence. Applications of the obtained results to real-sea conditions are discussed.

Modeling Internet Business Optimization Processes

Abstract: Is considered a number of aspects of evolution of Internet business, in particular, assessment of efficiency of this innovation technology in terms of satisfaction of requests and needs of end users is implemented. The mathematical model is synthesized and modeling of set of processes is carried out. The analysis of results of such modeling allowed authors to formulate an entity of the concept “trust level” to information telecommunication technologies and to offer a way of its assessment, by definition of the so-called “index of trust of Internet users”. This index also to some extent reflects priorities of end users and can quite serve as a peculiar indicator of drivers of growth of the Internet in general and the Internet of things in particular.

Increasing the Efficiency of a Diesel-Generator Power Plant

Abstract: A variant of a diesel generator power plant consisting of a conventional diesel-generator set and a variable-speed diesel-generator set is considered. A transformer-free topology of the power circuit of the variable-speed diesel-generator set is proposed on the basis of an active voltage rectifier, a mains inverter, and a buffer energy storage device. The block diagram for controlling a diesel-generator power plant is developed. The autonomous and parallel operation modes of the diesel-generator sets are considered. A block diagram of the speed controller on the basis of intelligent controls is proposed for the variable-speed diesel generator set. The simulation model of the diesel-generator power plant is implemented in the MATLAB/Simulink suite. Results of simulation modeling of the power plant’s dynamic operational modes under load switching are presented. The variable-speed diesel-generator set is shown to provide energy-efficient operation of the power plant and compliance with the requirements for the quality of generated electricity when the internal combustion engine runs at low energy efficient rotation speeds in the shared load mode.

Information Aspects in the Field of Modern Public Administration and Law

Abstract: The authors analyzed a set of aspects related to the improvement of the sphere of public administration through the implementation of programs for the digitalization of the socioeconomic sphere of modern society. The use of modern information and telecommunication technologies, including to ensure a high level of security of citizens and the quality of life, the ability to effectively protect their interests and rights, minimize various technological and social risks, allows you to quickly solve current problems, contributes to the achievement of relevant local and global goals, both in the current conditions and in the future. The article presents and analyses relevant statistics, as well as conclusions on the stable correlation between the level of security of the population, ensuring basic constitutional rights and freedoms and the intensity of the use of means of obtaining, storing, processing and displaying information, various automated control systems and databases in the field of social management and law.

Tecnología para la formación temprana de resistencia al estrés en el sistema de prevención de la mala adaptación escolar de alumnos de primer grado

Abstract: The relevance of the stated problem of the crisis of 6-7-year old’s is dictated by the recently growing tendency to bring back children to preschool institutions after a short period at school by parents who notice the child’s painful condition associated with school maladaptation. In this regard, many researchers and practicing educators recommend reviewing the start dates for children at school so that the child starts school at the age of seven. Other teachers notice a significant increase in the work load on primary schoolchildren connected to the introduction of the Federal State Educational Standard for Primary General Education and the corresponding forms of control and assessment activities. Thus, there was a need to develop new technologies to preserve the health of younger students and allow them to overcome the crisis of the onset of education. The purpose of this article is to describe the developed technology aimed at helping 6-7-year old to overcome the age crisis and prevent school maladaptation with the help of early formation of stress tolerance. The main method in the study is the design of a technology for early formation of stress tolerance and prediction of the results of its implementation in the experimental groups of 6-7-year-old children. The technology is based on the principles of continuity of the educational process between preschool educational organizations and schools. With the implementation of the developed technology the following results were achieved: increased motivation for success and higher somatic health level manifested in sport and creative activities. The above-mentioned results in their turn contributed to crisis prevention, school deprivation of first graders and comfortable overcoming of the crisis of 6-7 year olds. The materials of the article can be useful to organizers of sport and creative activities in preschool educational institutions, educators of preparatory groups, teachers, methodologists in preschool and primary education, as well as physical education teachers and primary school teachers. The materials of the article can be used in the system of advanced training of teachers of physical education and elementary school, as well as in the preparation for professional activities in preschool educational institutions and elementary schools of students of teacher training colleges and universities.

Variable diesel-generator power plant based on double-fed machine

Abstract: The article considers the problem of improving power efficiency of the diesel generator power plants as one of the priority objectives for development of low power generation in Russia. Improving energy efficiency for autonomous facilities is directly related to the optimization of hydrocarbon fuel consumption by marine diesel engines. It is possible to optimize the fuel consumption of internal combustion engines by creating variable-speed diesel generators (VSDG), which are diesel-generator units with semiconductor converters, i.e. systems with valved generators. Optimization of specific fuel consumption by VSDG is provided by the forced regulation of the rotational speed of the shaft of the internal combustion engine in accordance with its multi-parameter characteristic in the shared load conditions of the power plant. The synchronous electric machine is used as a generator as part of a ship power station. Its use in the classic constant-speed diesel generators is more preferable than an asynchronous electric machine. In the development of VSDG - valved power plant - the use of an electric machine with a phase rotor as a generator is technically justified, because the installed capacity of the frequency converter in the rotor circuit of an asynchronous generator with a phase rotor is determined by the sliding power and, with a limited range of speed control, SDGV significantly reduces the installed capacity of the electrical equipment. Such power topology of a ship’s power plant is called VSDG based on a dual-power machine. There has been proposed to consider a variant of a ship power plant based on VSDG with a dual-power machine. Its functional diagram and mathematical model are developed. A structural diagram is presented and dynamic modes of the amplitude and frequency of the generated voltage are modeled during electrical load switching.

Lawyer's ICC as a Result of Integration of Linguo-Didactics, Linguoculturology, and Jurisprudence: New Perspectives of ESP

Abstract: In terms of the current complicated socio-cultural and economic situations in the global communication system, achieving international cooperation becomes a challenge for Russia. A lawyer carries out legal regulations of interstate disputes with peaceful measures in the process of foreign language professional communications. One of the most important factors of successful international activity in the legal sphere is to master lawyer's intercultural communicative competence (ICC), as knowledge of foreign linguocultural features of verbal and non-verbal lawyers' behavior contributes to mutual understandings in professional interactions. The structure and content of a lawyers' ICC indicates its integrative nature, which enabled the authors to recognize an ESP approach in the intercultural context as a modern and perspective variant of integrated foreign language teaching for future law bachelors. This study offers methodological recommendations to implement an ESP model aimed at the development of lawyer's intercultural communicative competence.