Наукові статті

Постійне посилання зібранняhttps://repository.lntu.edu.ua/handle/123456789/289

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2022 - 20255

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Автор: search.filters.author.Selepyna, Yosyp

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  • Ескіз
    Item type:Наукова стаття,
    ЕLECTROMAGNETIC FIELD EQUATIONS IN NONLINEAR ENVIRONMENT
    (2024) Lyshuk, Viktor; Tkachuk, Anatolii; Zablotskyi, Valentyn; Selepyna, Yosyp
    The paper proposes electromagnetic field equations from the point of view of their adaptation to numerical methods. Maxwell'sequations with partial derivatives are used, written concerning field vectors, which most fully reproduce the picture of physical processes in electrical engineeringdevices. The values of these vectors provide comprehensive information about the field at any spatio-temporal point. The concept of creating mathematical models of electrical devices adequate to physical processes has been developed. Mathematical transformations are carried out according to the rulesof differential calculus. Dynamic processes in the elements of electrotechnical devices were analyzed using the apparatus of mathematical modeling.An algorithm for implementing differential equations with partial derivative numerical methods using computer simulation was implemented. The obtained results made it possible to understand the nature of electromagnetic phenomena in nonlinear media. The paper provides calculations of the field parameters in a flat ferromagnetic plate and the groove of the rotor of an electric machine
  • Ескіз
    Item type:Наукова стаття,
    METHOD FOR EVALUATION QUALITY PARAMETERS OF TELECOMMUNICATIONS SERVICES
    (2022-06-30) Zablotskyi, Valentyn; Selepyna, Yosyp; Lyshuk, Viktor; Yakymchuk, Natalia; Tkachuk, Anatolii
    Currently, cellular networks have become widespread, the operators of which simultaneously use the infrastructure of the second generation GSM networks, DCS to build third generation W-CDMA networks that provide broadband multiple access with code division. At the same time,the problem of providing high-speed Internet connections is exacerbated due to the growing volume of data of diverse types transmitted over the Internet. When testing the entire network coverage area, the total number of voice calls increases, so a method of long-term measurement of bit rate of information transmission via wireless communication channels is proposed, which does not increase the service information in the network.Mathematical modelingof Internettraffic consumption using the proposed measurement method is performed and entropy estimates of information channel bandwidthare given.
  • Ескіз
    Item type:Наукова стаття,
    MONITORING OF LINK-LEVEL CONGESTION IN TELECOMMUNICATION SYSTEMS USING INFORMATION CRITERIA
    (2022-12-30) Yakymchuk, Natalia; Selepyna, Yosyp; Yevsiuk, Mykola; Prystupa, Stanislav; Moroz, Serhii
    The successful functioning of telecommunication networks largely depends on the effectiveness of algorithms for detection andprotection against overloads. The article describes the main differences that arise when forecasting, monitoring and managing congestion at the node levelandat the channel level. An algorithm for detecting congestion by estimating the entropy of time distributions of traffic parameters is proposed.The entropy measures of data sets for various types of model distribution, in particular for the Pareto distribution, which optimally describes the behaviorof self-similar random processes, were calculated and analyzed. The advantages of this approach include scalability, sensitivity to changes in distributionsof traffic characteristics and ease of implementation and accessible interpretation.
  • Ескіз
    Item type:Наукова стаття,
    DEVELOPMENT OF A MODIFIED METHOD OF NETWORK TRAFFIC FORMING
    (2023-03-31) Kozlovskiy, Valeriy; Yakymchuk, Natalia; Selepyna, Yosyp; Moroz, Serhii; Tkachuk, Anatolii
    Based on the analysis of the statistical characteristics of heterogeneous network traffic of "Quadruple Play" mobile subscribers, it is shown that it cannot be represented by Poisson or Erlang distributions. It is shown that for such similar traffic, the rate of growth of the required buffer volume increases as the Hurst parameter increases. A method of adaptivetraffic formation using the control of the length of intervals of the intensity of the arrival of data packets has been developed. Congestion management is carried out by changing the frequency of the marker generator (GM) on the basis of the results of forecasting the required bandwidth of the system and the required buffer size. The shaper adapts to changes in the length and instantaneous intensity of packet input in real-time.
  • Ескіз
    Item type:Наукова стаття,
    Modeling dynamic and static operating modes of a low-power asynchronous electric drive
    (2025-06-27) Lyshuk, Viktor; Moroz, Sergiy; Selepyna, Yosyp; Zablotskyi, Valentyn; Yevsiuk, Mykola; Satsyk, Viktor; Tkachuk, Anatolii
    The article presents a mathematical model of the asynchronous motor in oblique coordinates, based on differential equations expressedin the standard Cauchy form. The differential equations of traditional models are implicitly formulated; therefore, during numerical implementationfor prolonged processes, matrix coefficient rotation leads to significant time expenditure and the accumulation of errors during integration. This complex task is proposed to be addressed by ensuring that the differential equations of the electromechanical state are non-stiff and, importantly, writtenin standard Cauchy form. The standard Cauchy form is essential for analyzing asynchronous motors, as changes in the number of unknowns significantlyrestructure the coefficient matrix. This formulation of the equations is convenient for numerical integration, as explicit methods, which are considerably simpler than implicit methods, can be implemented. To create a mathematical model, coordinate transformations were performed based on the classical theory of electric machines. The advantage of the proposed method of using different coordinate axes is the possibility of analyzing new variablesand obtaining constant coefficients in the equations of state of the electric motor.The model accounts for the electromagnetic interactions of the motor’s electrical circuits and their nonlinearity, enabling the simulation of electromagnetic and electromechanical processes. Transitional operating modes of the asynchronous motor have been modeled and analyzed. The proposed model can be utilized for analyzing the operation of motors both as standalone elements and as components of an electromechanical system. It is demonstrated that this model aligns with classical electrical machine theory.Simulation results are provided, along with their analysis.