Wyniki 1-10 spośród 15 dla zapytania: authorDesc:"Petro STAKHIV"

Stability of parallel computations of transient processes in the electric circuits

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A diakoptic method of the analysis of transient processes in the electric circuits shows a certain lack of asynchrony of the process of computation. External variables are computed with a delay in relation to internal variables. It means that implicit methods of integration are used in computation. The main disadvantage of implicit methods is potential instability that may be controlled in the p[...]

New approach to stability of parallel computations of transient processes.

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A diakoptic method of the analysis of transient processes in the electric circuits shows a certain lack of asynchrony of the process of computation. External variables are computed with a delay in relation to internal variables. It means that implicit methods of integration are used in computation. The main disadvantage of implicit methods is potential instability that may be controlled in the p[...]

Simplification of Optimization Process during Mathematical Models Creation

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The paper is devoted to the problem of development of mathematical macromodels creation using optimization approach. The methods of acceleration of dynamic systems macromodels creation due to separation of linear submodel and step-by-step optimization on groups of variables are considered. Streszczenie. Artykuł poświęcono problemom rozwoju matematycznych makromodeli wykorzystywanych do optymali[...]

Implementation of parallel algorithm of computations of dynamic processes in cluster systems

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A parallel process of computation of dynamic processes in the electric circuits is based on a diakoptic theory of the portioning of the circuit into the sub-circuits, that are computed independent of each other, in the fixed time intervals. Every process is defined by the complexity of computation. This complexity is changed in the time of process of computations. These properties are utilized to implement computation in parallel systems. Currently the growth of parallel systems has been observed for several years. In this article, idea of cluster system and parallel algorithms are presented. The results of computation on tested parallel system are shown and interpreted. Streszczenie. Równoległa realizacja obliczeń analizy stanów dynamicznych obwodów elektrycznych bazuje na diakoptycz[...]

Modeling of Electric Power Systems Based on Diakoptic Approach and Parallel Algorithms in Modern Computer Tools

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Electric power systems modeling using modern computer tools based on macromodeling and diakoptics principles and prospects of their research on uni- and multiprocessor computers are discussed. Electric systems splitting on several parts with the purpose of their further analysis by means of parallel processing algorithms, possibility and expediency of computer tools usage for their practical implementation are considered. Streszczenie: W artykule zaprezentowano metody makromodelowania i diakoptyki do badania systemów elektroenergetycznych. Podejście to jest zorientowane na zastosowanie obliczeń równoległych. Rozpatrywana jest możliwość praktycznej implementacji proponowanych algorytmów. (Modelowanie systemów elektroenergetycznych z wykorzystaniem nowoczesnego, równoległego oprogramowa[...]

Mathematical models and macromodels of electric power transformers

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In the paper different approaches used for creation of electric power transformers are discussed and main types of their mathematical models and macromodels are described. Mathematical model of transformer is created in the hybrid coordinate basis, and macromodel of the power transformer is developed using the “black box" approach in the form of state space equations, the features of such type models usage are analyzed. Streszczenie. W artykule opisano alternatywne podejścia do konstrukcji transformatorów i podstawowe rodzaje ich matematycznych model i makromodeli. Omówiono tworzenie matematycznego model transformatora w hybrydowym układzie współrzędnych i budowę makromodelu w postaci równań stanu z wykorzystaniem podejścia typu ,,czarna skrzynka". Przedyskutowano własności opracowanych modeli. (Matematyczne modele i makromodele transformatorów mocy) Keywords: mathematical model, macromodel, power transformer, optimization Słowa kluczowe: modele matematyczne, makromodele, transformatory mocy, optymalizacja Introduction Mathematical models of electric power system elements, including power transformers, intended for research of electromagnetic transient processes were considerably improved during last ten years and adapted for simulation using various computer programs. During simulation of electric power transformers it is necessary to consider such physical phenomena as deep saturation, hysteresis, losses due to eddy currents and thermal effects and etc. Development of transformer models with high level of adequacy based on their equivalent circuits causes their high complexity, and, consequently, considerable difficulties during their adaptation to modern computer programs and environments usually used for computer analysis of transient processes [1, 2]. If the researcher is interested just in reaction of the object to test signal just on its terminals then it is expedient to use principles of macromodelling, namely to cre[...]

The Impact of Calculation Precision on the Process of Mathematical Model Construction with the Use of Optimization

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The usage of calculation power of GPU cards for macromodel construction based on optimization approach can lead to significant decrease of model construction time. Unfortunately, most GPU cards do not work well with double-precision calculations. In the paper the comparison of optimization process conducted using single-precision and double-precision has been done. It is shown that the reduction of computation precision to single-precision values does not worsen the precision of obtained model and the number of required iterations of optimization algorithm. Streszczenie. Wykorzystanie mocy obliczeniowej procesorów kart graficznych do budowy makromodeli matematycznych może prowadzić do skrócenia czasu obliczeń. Niestety większość procesorów wykorzystywanych jako GPU nie pracuje w podwójnej precyzji. W artykule wykazano, że redukcja dokładności obliczeń do pojedynczej precyzji nie pogarsza jakości otrzymanego modelu, ani nie zwiększa liczby iteracji algorytmu optymalizacyjnego. (Wpływ dokładności obliczeń na proces tworzenia zoptymalizowanych modeli matematycznych) Keywords: mathematical model, macromodel, optimization, calculation precision, parallelization Słowa kluczowe: model matematyczny, optymalizacja, dokładność obliczeń, zrównoleglenie obliczeń Introduction The complexity of dynamical systems being developed and analyzed is constantly increasing. Currently such systems include elements of different nature which are described by models of different types. Another problem is the complexity of mathematical models of some components included in the system being designed. All these issues result in the complexity of simulation task in terms of required computation resources. The use of macromodels in such conditions allows to replace some components or entire subsystems with the relatively simple mathematical models, and thus to significantly decrease required computation resources needed for the analysis. So for efficient usage of[...]

The estimation of radio-electronic devices reliability on the basis

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Estimation the radio-electronic device's reliability by the efficiency probability has been research in this paper. The approach based on interval data analysis proposed. Its low calculable complexity in comparing to the known methods has been shown. Streszczenie. Artykuł przedstawia sposób oszacowania bezawaryjnego czasu pracy urządzeń radioelektronicznych. Zaproponowana metoda bazuje na analizie interwałowej charakterystyk wyjściowych urządzeń. W artykule wykazano również niski koszt obliczeniowy prezentowanego podejścia w stosunku do innych metod. (Określanie stopnia niezawodności urządzeń elektronicznych na podstawie analizy interwałowej) Keywords: Radio-Electronic Circuit, Reliability, Operational Suitability, Tolerance Domain of Parameters, Interval Data Analysis. Słowa kluczowe: urządzenia radioelektroniczne, bezawaryjny czas pracy, interwałowa analiza danych Introduction Reliability of radio-electronic devices (RED) is their ability to perform their specified functions while maintaining, for a required period of time, operational performance within acceptable limits, and to resume their operation that was lost due to some reasons [1]. The concept of reliability is directly related to the estimation of the probability of operational suitability of RED in the course of its development and operation. In general, reliability of RED is directly determined by reliability and operational suitability of its components which are radio-electronic circuits (REC). While designing a REC one should find the vector of nominal parameters of the elements, which provides nominal values of output characteristics. In the process of production and operation of the equipment the real values of the output characteristics differ from the nominal ones. Moreover, the significant deviations of the real values from the nominal ones leading to the loss of operational suitability of REC, i.e. the output characteristics fall outside specified inte[...]

Discrete mathematical macromodel of electric transmission line

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In the paper the problem of development of mathematical models and macromodels of transmission lines is discussed. Mathematical discrete macromodel of single-phase transmission line in the form of state variables using a "black box" approach was developed. Description of procedure of its creation and verification of obtained results are presented. Streszczenie. W artykule przedstawiono makromodel energetycznej linii przesyłowej. Prezentowany model został zapisany w formie zmiennych stanu i dotyczy linii jednofazowej. Dodatkowo w artykule opisano proces tworzenia modelu, sposób jego walidacji wraz z kryterium poprawności, a na końcu zamieszczono wyniki.(Makromodel linii elektroenergetycznej) Keywords: mathematical model, macromodel, transmiision line, optimization Słowa kluczowe: model matematyczny, linia przesyłowa, optymalizacja Introduction Over the last decade a considerable progress in creation of mathematical models of electric systems intended for the analysis of transient and periodic processes and further prognosis of electric power equipment operation was achieved. Improvement of the modeling process in order to obtain adequate simulation results of electric systems containing single- and three phase transmission lines is an actual problem till now. Development of electric power transmission line models with a high level of adequacy using their equivalent schemes leads to their excessive complication, and as a result, there are significant difficulties during their adaptation to modern program tools intended for the transients’ analysis. If a researcher is interested only in a reaction of the modeled object, it is possible to use the principles of macromodeling. Therefore it is expedient to create macromodels of specific objects instead of their precise mathematical models. Mathematical macromodels in the form of state variables (the “black box" approach) is the best type of macromodels which can solve the [...]

Application of algorithms of classification for uncertainty reduction

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The methods of construction of classification rules for elimination of equivocations are described in the paper. The algorithms for the solution of primary goals are presented. Streszczenie. W niniejszym opracowaniu opisano metody budowy zasad klasyfikacji do eliminacji ekwiwokacji. W artykule przedstawiono algorytmy do rozwiązania podstawowych zagadnień (Zastosowania algorytmów klasyfikacji do minimalizacji niepewności). Keywords: classification rule, database, data warehouse, data space, tuple, uncertainty data. Słowa kluczowe: zasada klasyfikacji, baza danych, hurtowni danych, data space, krotność, niepewność. Introduction In quantities of data domains it is necessary to process the indistinct information; at what the outcome of a data analysis completely depends on a degree of their entirety in a system. The representative data domains of appearance of illegibility are a sociological orb (exchange of activity, public funds, marketing researches of the market etc.), historical researches, planning of economic activities etc. In the article the algorithms of classification and classiftion of objects are tendered, the information on which one is saved in repository. The main problems, which one arise in problems to the analysis and structuring of the data, are the problems of creation of classes of objects and reference to them, the information on which one just has entered the database. The problem of creation of the class contains two subtasks: 1) Construction of classification functions, according to which one the object is categorized as the quotes of the definite class; 2) Breakdown on classes and identification of the obtained classes. Information products describe the specific subject area, and consolidated data constitute the data space. One of the problems that persist in the process of consolidation is the uncertainty of data, the result of duplication, inaccuracies, data absence, contradictions of the data (Fig. 1[...]

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