Browsing by Author "Kuznetsova, Yevheniia"

Now showing 1 - 5 of 5
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    Improvement of Technical Service of Track Circuits
    (Institute of Electrical and Electronics Engineers, IEEE, 2019) Serdiuk, Tetiana M.; Kuznetsov, Vitaliy V.; Serdiuk, Kseniia; Nikolenko, Anatoliy V.; Kuznetsova, Yevheniia; Kuznetsova, Alisa
    ENG: The automated method of measuring the time and amplitude parameters of code current and parameters of track circuits (input impedance of the track circuit, a characteristic impedance, a propagation constant) were elaborated. The mathematic model of track circuits’ channel of transferring code current was improved and considered in this paper. The algorithms of definition of parameters of track circuit are offered.
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    Improving the Reliability of Simulating the Operation of an Induction Motor in Solving the Technical and Economic Problem
    (Springer, Cham, 2020) Tryputen, Mykola; Kuznetsov, Vitaliy; Kuznetsova, Alisa; Tryputen, Maksym; Kuznetsova, Yevheniia; Serdiuk, Tetiana M.
    ENG: The article is devoted to the control of the statistical laws of linear voltages reproduced on a computer during computational studies on an energy-economic model when solving the problem of choosing protection tools for induction motors operating in workshop electric networks of industrial enterprises with low-quality electricity. Simultaneous and continuous estimation of average values, variances, autocorrelation and cross-correlation functions of harmonics of linear voltages is based on the adaptive approach. The article presents mathematical expressions for correcting the values of statistical quantities with the accumulation of information and proposes structural schemes for a comprehensive analysis of the results of reproduction of random variables and functions on a computer. The results of checking the values of the average values and dispersions of six harmonics of simulated linear voltages supplying an induction motor with a power of 7.5 kW are shown for the conditions of the rolling shop No. 1 of Dneprospetsstal LLC.
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    Integrated Use of Photovoltaic and Wind Power Plants in Power Supply Systems
    (Springer, Singapore, 2022) Ostapchuk, Oleksandr; Kuznetsov, Valeriy; Bydko, Maryna; Kuznetsov, Vitaliy V.; Kuznetsova, Yevheniia
    ENG: The use of energy from only one type of renewable energy source (e.g., solar and wind generation) leads to a significant increase in the cost of electricity supply due to the need to install a backup power source (energy storage system or power system). This phenomenon is caused by the significant dependence of these sources on weather conditions. The wind speed is less than 4 m/s for a long time in summer, and solar energy is not available at all in dark day periods, which in December can last up to 16 h. Accordingly, the effective use of such systems is possible only if constructing a complex application of several sources of different nature (solar and wind generation). This measure allows increasing their energy efficiency by 30–50%. The combined use of these types of distributed generation is accompanied by the equalization of the daily energy intake due to the spread of the annual maximums of energy intake, but the daily fluctuations remain pretty significant. As a result of the conducted researches, it is established that when using the share of solar energy at the level 0.4… 0.55 of the total amount, the shortest period of energy deficit (at the level of 8 days per year) is observed. At other ratios between the shares of solar and wind energy, the period of energy deficit will increase. In case of increased requirements for providing responsible consumers with electricity, it is advisable to use systems with buffer electricity storage. The developed mathematical models allow calculating the equipment parameters used in the construction of efficient power supply systems.
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    Lyapunov Function in the Hyper-Complex Phase Space
    (Springer, Singapore, 2022) Voliansky, Roman; Volianska, Nina; Kuznetsov, Valeriy; Sadovoi, Aleksandr; Kuznetsov, Vitaliy V.; Kuznetsova, Yevheniia; Ostapchuk, Oleksandr
    ENG: The paper deals with the development of background for defining Lyapunov functions for a wide range of linear dynamical objects. This background is based on assuming that the Lyapunov function is redundant energy in the considered object, and this energy is dissipated only during controlled motion. We assume the full derivative of the Lyapunov function for an autonomous motion of the control objects equals zero, and we use its summands to define linear algebraic equations. The solution of these equations allows us to find unknown terms of the Lyapunov function. The use of these terms, while the Lyapunov equation is being written down, shows that the left-hand expression in the Lyapunov equation is equal to the zero matrix. Thus, we avoid subjective assuming of quadratic form terms in the right-hand of the Lyapunov equation. We extend the proposed approach to the class dynamical system with uncertainty. This extension is performed by using interval methods, which allow defining object motions for minimal and maximal values of parameters. We show that for the control object, which parameters are not exactly known, one should consider two equations of object motions, which correspond to its trajectories on the boundaries of the intervals. Lyapunov functions are defined for these boundary trajectories. Since such an approach increases the number of the considered equations, we offer to decrease them by using hyper-complex numbers while object equations are written down.
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    Mathematical Model of Dynamics of Homomorphic Objects
    (Petro Mohyla Black Sea National University, Mykolaiv, 2019) Kuzenkov, Olexandr; Serdiuk, Tetiana M.; Kuznetsova, Alisa; Tryputen, Mykola; Kuznetsov, Vitaliy; Kuznetsova, Yevheniia; Tryputen, Maksym
    ENG: Abstract. The paper concerns topical problem of mathematical modeling of dynamics of heterogeneous groups with a logistic function as a basic one. Joint use of mathematical models of biological systems and computer-based simulation makes it possible to minimize time and save material resources while determining general tendencies of subpopulation progress; and to forecast state of the system as well as possible consequences of artificial intervention in the environment. Among other things, it concerns forecasting of genetic abnormalities. The paper proposes a model of dynamics of progress of a population consisting of n subpopulations. The model is represented in the form of differential equations with transition coefficients within their right sides. The transition coefficients mirror the share of species getting from ith subpopulation to jth one. The proposed system is not Voltairian one since its phase trajectories may cross coordinate axes. It has been proved that the system of differential equations is degenerated in the neighbourhood of equilibrium points. Analysis of the system of differential equations for n=2 has demonstrated a potential for three bifurcations. It has been proved that nine bifurcation types are possible for n=3. Numerical computer-based experiments have shown that the proposed model is stable as for the disturbance of its coefficients, and the obtained characteristics of the degenerated system are close to real ones.