name
Kovalenko Anna Vladimirovna
Scholastic degree
•
Academic rank
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Honorary rank
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Organization, job position
• Kuban State University
кафедра прикладной математики
доцент
Research interests
Современные информационные технологии, нейронные сети, нечёткие продукционные системы, гибридные системы, многомерный статистический анализ, финансово-экономическое состояние предприятия, отрасли, региона, кредитоспособность, инвестиционная привлекательность
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TOP5 co-authors
Articles count: 51
Сформировать список работ, опубликованных в Научном журнале КубГАУ
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CALCULATION AND ANALYSIS OF TIME BEHAVIOR OF ELECTROCONVECTION IN MEMBRANE SYSTEMS
01.00.00 Physical-mathematical sciences
DescriptionThe aim of this work is to carry out numerical analysis of time behavior of electroconvection in membrane systems, such as a desalting channel of electrodialysis apparatus. The current-voltage curve and the solution flaw were analyzed theoretically using mathematical models of ions transfer taking into account electroconvection in smooth desalting channel consisting of ideally selective anion- and cation-exchange membranes. The Hurst numbers for different parts of the current-voltage curve were calculated in order to determine whether the parts were persistent. The Fourier-analysis of the oscillating term of the current-voltage curve was carried out for the first time so as to determine predominant frequencies in the signal. Frequencies of passing of complexes of vortexes through the cross-section of the desalting channel were calculated. Frequencies of oscillations of concentration profiles were determined. It was found that the frequencies of oscillations of the concentration profiles coincide with the frequencies of passing of complexes of vortexes through the cross-section of the desalting channel. The oscillations of the current-voltage curve were physically interpreted. Namely, it was shown that the main frequency of oscillations of the current-voltage curve corresponds to the frequency of oscillations of the concentration profiles. The oscillations of the concentration profiles, produced by the passing of complexes of vortexes, cause oscillations of conductivity and, consequently, cause oscillations of resistance and of the current density. It was shown that the main frequency of the signal corresponds to the frequency of passing of complexes of vortexes through the cross-section of the desalting channel
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THE DEVELOPMENT OF COUNTRIES' CREDIT RATING ASSESSMENT SYSTEM
01.00.00 Physical-mathematical sciences
DescriptionThis work presents a new approach to the countries’ credit rating definition, based on the advanced mathematical models, such as neural network model, multiple regression, cluster analysis and discriminant analysis. A range of the analyses such as discriminant, cluster, multiple regression models and a neural network were performed on the following economic figures: GDP per capita, GDP value, annual growth rate of GDP, FDI - foreign investment, rate of unemployment, consumer price inflation index, the size of government debt in percentage of GDP. The results, obtained for each model were combined in the countries’ credit rating estimation system called "7M"
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05.13.18 Mathematical modeling, numerical methods and software complexes
DescriptionThe article presents ways to estimate the socio-economic condition of the subjects of the Russian Federation using fuzzy production systems, discriminant analysis and neural networks. This study is based on the thirteen indicators of the socio-economic condition of the regions of the Russian Federation identified by RIA Rating rating agency. The goal of the work is to develop a software package combining the estimation methods above and allowing to get three alternative estimation options for a subject of the Russian Federation, using these thirteen indicators. The developed program assigns each region an estimation from the following set: AAA– the highest socio-economic condition, AA - very high, A– high, BBB– above average, BB– average, B– below average, CCC– low, CC– very low, C– the lowest indicators of the socio-economic conditions in the region of the Russian Federation. The software package is developed in Matlab and has an intuitive interface. The results can be used as an alternative to current methods of estimation of the socio-economic indicators
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SOFTWARE TOOLS TO ANALYZE THE REGION'S CREDITWORTHINESS
DescriptionThis article is a continuation of [1, 2] and is devoted to the description of a program complex "Region-Credit" for the assessment of financial stability, economic development, credit, socio-economic status and investment attractiveness of Russian regions. The article is an example of a comprehensive credit analysis, socio-economic status and investment attractiveness of Krasnodar Region for the period from 2008 to 2014 with the help of a program complex "Region-Credit", whose results are compared with peer review rating agency AK&M
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REASONS OF ELECTRO CONVECTION IN ELECTRO MEMBRANE SYSTEMS
01.00.00 Physical-mathematical sciences
DescriptionIn the article, the reasons of occurrence and development of electro convection in electro membrane systems are analyzed. The basic rules of occurrence and development of process of electro convection in the channel desalination of electro dialysis apparatus are revealed
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FINANCIAL RISK WARNING AT OIL PRODUCTION COMPANIES
08.00.13 Mathematical and instrumental methods of Economics
DescriptionThis article is devoted to a problem of effective management of a financial and economic condition of companies on the example of the enterprises of oil products supply. We consider questions of support of adoption of management decisions which concern stabilization of a financial condition of the company and as a result of decrease in financial risks. The article also provides a description of the program complex called FESP_ON developed by the authors allowing to carry out the profound complex assessment of a financial and economic condition of Societies of oil products supply
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01.00.00 Physical-mathematical sciences
DescriptionThis article describes a mathematical model of transport of salt ions in a cell with a rotating disk cation exchange membrane at transcendent current regimes, taking into account electroconvection. Based on this model, we had a theoretically study of the process of transfer of salt ions and the dependence of the thickness of the diffusion layer from the fall of potential. This article is a continuation of [8] and [9], it conducted a numerical analysis of boundary value problem for a system of equations Nernst-Planck-Poisson and Navier-Stokes equations, modeling the transport of salt ions in a cylindrical cell with a rotating disc cation exchange membrane based on electroconvection. It is shown there is an electroconvection vortex in the center of the membrane disc. The solution flows around this vortex and forms a stagnation zone in front of it. With the increase in the size of the fall of potential, the electroconvective vortex decreases and at some value, the electroconvective vortex disappears. The study was conducted in the 1000 s when the angular velocity of 30 turns in a minute and change of the potential difference of 0.2V to 1.4V with a step 0.1. As a result, in this study it is shown that the thickness of the diffusion layer is practically linearly dependent on the fall of potential. The linear dependence of the thickness of diffusion layer from the fall of potential, in the first approximation, is disturbed by a slight deflection curve, the causes of which are needed to be found by means of extra experiments
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01.00.00 Physical-mathematical sciences
DescriptionThis article is a continuation of the works [1,2], which were devoted to the study of hydrodynamics and transport of salt ions in the experimental electrochemical cell with a rotating disk with a cation exchange membrane of exact current modes, when the condition of local electroneutrality. This article presents a mathematical model of transport of salt ions in a cell with a rotating disk with a cation exchange membrane exorbitant current regimes, taking into account electroconvection. Under these conditions, fluid dynamics depends on the ion transport process salt and described by the system of Navier-Stokes equations in cylindrical coordinate system with the electric forces
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01.00.00 Physical-mathematical sciences
DescriptionAn analysis of the experimental data obtained by the authors, as well as reference books, allowed to hypothesize about the essential role of gravitational convection in electromembrane systems with ampholytes even in underlimiting current regimes. The article is devoted to the development of the mathematical model of ion transport in a flow elecrtomembrane system during electrodialysis of ampholyte-containing solutions with taking into account a possible appearance of gravitational convection, in particular, due to nonisothermal protonation–deprotonation reactions of ampholytes. The article presents the boundary value problem that is the new mathematical model for diffusion, convection and electromigration of four components of the solution (ions of sodium, dihydrogen phosphate and hydrogen, as well as molecules of orthophosphoric acid) in a half of an electrodialysis desalination channel, adjacent to an anion-exchange membrane. The membrane is considered as ideally selective and homogeneous. The system of partial differential equations, that is the base of the model, also includes equations of Navier-Stokes, material balance, convective heat conduction and the electroneutrality condition. The system of equations is supplemented by a number of natural and original boundary conditions. A distinctive feature of this study is the absence of assumptions about the equilibrium of chemical reactions in a diffusion layer. The results of the study can be used for the development of environmentally rational and resource saving membrane technologies for a processing of products of agro-industrial complex
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MODELS OF NEURONET INFLATION IN RUSSIA
01.00.00 Physical-mathematical sciences
DescriptionThe article’s conclusion is that for adequate and effective inflation modeling in Russia by means of modern neuronet technologies it is necessary to consider tendencies of economic development. For training and forecast, it is necessary to use only those periods of time within the limits of which identical economic tendencies work. The article uses modern tool means, such as neuronet, which is offered to technology, for approximation and forecasting of rates of inflation