Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет
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- Некоторые метрики заблокированы вашиминастройками согласия
Тип записи:Публикация, Method for solving the periodic problem for an impulsive system of hyperbolic integro-differential equationsThe periodic problem for a system of integro-differential equations of hyperbolic type with impulse effects is considered. This problem is reduced to an equivalent problem, consisting of a family of periodic boundary value problems for system of ordinary differential equations with parameter and impulse effects and integral relations by method of introducing additional functions. Sufficient conditions for existence of unique solution to the family of periodic boundary value problem with the impulse effects for system of the ordinary differential equations are received by parametrization method. Conditions for the unique solvability of periodic problem for system of integro - differential equations of hyperbolic type with impulse effects are established in the term of initial data.Цитирования (OpenAlex) 2Цитирования (OpenCitations) 2 - Некоторые метрики заблокированы вашиминастройками согласия
Тип записи:Публикация, On one algorithm for finding a solution to a two-point boundary value problem for loaded differential equations with impulse effectOn one algorithm for finding a solution to a two-point boundary value problem for loaded differential equations with impulse effect A linear two-point boundary value problem for a system of loaded differential equations with impulse effect is investigated.The parameterization method is used to solve the problem.The essence of parameterization method is that segment, where the loaded differential equation is considered, is divided into parts by loading points, and the initial problem is reduced to the boundary value problem with a parameter.The solution to boundary value problem with parameter is defined as a limit of systems sequence, consisting of the pairs of parameter and function.Parameters are defined by a system of linear algebraic equations.System of linear algebraic equations is determined by the matrices of boundary conditions, the system of loaded differential equations, and the conditions of impulse effect.An algorithm for finding the solution to linear two-point boundary value problem for the systems of loaded differential equations with impulse effect is offered.The convergence conditions of the algorithm providing the existence and uniqueness of solution to the considered problem are established.Sufficient conditions for unique solvability of the problem in the terms of initial data are received.Цитирования (OpenAlex) 13Цитирования (OpenCitations) 7 - Некоторые метрики заблокированы вашиминастройками согласия
Тип записи:Публикация, Recovery problem for a singularly perturbed differential equation with an initial jumpThe article investigates the asymptotic behavior of the solution to reconstructing the boundary conditions and the right-hand side for second-order differential equations with a small parameter at the highest derivative, which have an initial jump. Asymptotic estimates of the solution of the reconstruction problem are obtained for singularly perturbed second-order equations with an initial jump. The rules for the restoration of boundary conditions and the right parts of the original and degenerate problems are established. The asymptotic estimates of the solution of the perturbed problem are determined as well as the difference between the solution of the degenerate problem and the solution of the perturbed problem. A theorem on the existence, uniqueness, and representation of a solution to the reconstruction problem from the position of singularly perturbed equations is proved. The results obtained open up possibilities for the further development of the theory of singularly perturbed boundary value problems for ordinary differential equations.Цитирования (OpenAlex) 4Цитирования (OpenCitations) 1 - Некоторые метрики заблокированы вашиминастройками согласия
Тип записи:Публикация, Two-Point Boundary Value Problem for Volterra–Fredholm Integro-Differential Equations and Its Numerical AnalysisAbstract A two-point boundary value problem for Volterra–Fredholm integro-differential equations is considered. To solve this problem, Dzhumabaev parametrization method is used. Conditions for the existence and uniqueness of two-point boundary value problem for Volterra–Fredholm integro-differential equations are established. An algorithm for finding solution of this problem is proposed. Then, numerical approach for analysis of two-point boundary value problem for Volterra–Fredholm integro-differential equations is offered. Results are illustrated by numerical example.Цитирования (OpenAlex) 7Цитирования (OpenCitations) 7 - Некоторые метрики заблокированы вашиминастройками согласия
Тип записи:Публикация, РЕШЕНИЕ НЕЛИНЕЙНОЙ СТАЦИОНАРНОЙ ЗАДАЧИ БАРОКЛИННОГО ОКЕАНА МЕТОДОМ ФИКТИВНЫХ ОБЛАСТЕЙ(2024-01-24) ;O.S. Akhmetova; A.N. KaziyevaModeling is a key tool for understanding physical processes, analyzing the global spatial and temporal structure of the ocean, its interaction with the atmosphere, and regional variability in marine and ocean systems. Models also play an important role in processing and assimilating data from field observations. The development of mathematical modeling of ocean dynamics, which has more than a century of experience, has led to a significant increase in understanding of the physical processes occurring in the marine environment, as well as improved methods and models for their analysis. In addition, in recent years there has been increasing interest in studying the patterns of baroclinic fields, disturbances, and anomalies inthe ocean, including the analysis of observational data, theoretical studies of the propagation of disturbances in a simplified oceanic environment, and numerical modeling. The basic principles of the theory of the baroclinic layer in the ocean can be derived from a complete set of primitive equations, including horizontal projections of the momentum balance equations, the hydrostatic equation, the mass conservation equation, the heat and salt diffusion equations, and the equation of state.This article discusses the fictitious domain method for the nonlinear stationary problem of the Baroclinic Ocean. A generalized solution to the problem is given and its uniqueness is proved. The theorem of existence and convergence of solutions to approximate models obtained using the fictitious domain method are studied. Моделирование является ключевым инструментом для осмысления физических процессов, анализа всемирной пространственно-временной структуры океана, его взаимодействия с атмосферой и региональной изменчивости морских и океанических систем. Модели также играют важную роль в обработке и ассимиляции данных из натурных наблюдений. Развитие математического моделирования динамикиокеана, имеющего более чем столетний опыт, привело к значительному углублению понимания физических процессов, происходящих в морской среде, а также к улучшению методов и моделей их анализа. Помимо этого, в последние годы усиливается интерес к исследованиюзакономерностей бароклинных полей, возмущений и аномалий в океане, включая анализ данных наблюдений, теоретическое исследование распространения возмущений в упрощенной океанической среде и численное моделирование. Основные принципы теории бароклинного слоя в океане могут быть выведены из полного набора примитивных уравнений, включающих горизонтальные проекции уравнений баланса количества движения, уравнение гидростатики, уравнение сохранения массы, уравнения диффузии тепла и соли, а также уравнение состояния.В данной статье рассматривается метод фиктивных областей для нелинейной стационарной задачи бароклинного океана. Дается обобщенное решение задачи и доказывается его единственность. Исследованы теорема существования и сходимости решения приближенных моделей, полученных с помощью метода фиктивных областей. Модельдеу физикалық процестерді түсінудің, мұхиттың ғаламдық кеңістіктік және уақыттық құрылымын, оның атмосферамен әрекеттесуін және теңіз және мұхит жүйелеріндегі аймақтық өзгермелілігінталдаудыңнегізгі құралы болып табылады. Модельдер далалық бақылаулардан алынған деректерді өңдеу мен ассимиляциялауда да маңызды рөл атқарады. Ғасырдан астам тәжірибесі бар мұхит динамикасын математикалық модельдеудің дамуы теңіз ортасында болып жатқан физикалық процестерді түсінудің айтарлықтай артуына, сондай-ақ оларды талдаудың әдістері мен үлгілерінің жетілдірілуіне әкелді. Сонымен қатар, соңғы жылдары мұхиттағы бароклинді өрістердің заңдылықтарын, бұзылулар мен аномалияларды зерттеуге, соның ішінде бақылау деректерін талдауға, жеңілдетілген мұхиттық ортада бұзылулардың таралуын теориялық зерттеуге және сандық модельдеуге қызығушылық артуда. Мұхиттағы бароклинді қабат теориясының негізгі принциптері импульс тепе-теңдік теңдеулерінің горизонталь проекцияларын, гидростатикалық теңдеулерді, массаның сақталу теңдеулерін, жылу мен тұздардың диффузия теңдеулерін қоса алғанда, қарабайыр теңдеулердің толық жиынтығынан алынуы мүмкін. күй теңдеуі.Бұл мақалада бароклинді мұхиттың сызықты емес стационарлық мәселесі үшін жалғандомен әдісі талқыланады. Мәселенің жалпыланған шешімі келтіріліп, оның бірегейлігі дәлелденеді. Жалған домен әдісі арқылы алынған жуықталған модельдерге шешімдердің бар болуы және жинақтылығы теоремасы зерттеледі.Цитирования (OpenAlex) 1Цитирования (OpenCitations) 1 - Некоторые метрики заблокированы вашиминастройками согласия
Тип записи:Публикация, STATIONARY DIFFUSION MODEL IN HETEROGENEOUS MEDIA WITH SMALL PARAMETERS(2025-06-01) ;O.S. AkhmetovaThis study presents a theoretical and applied investigation of a stationary diffusion problem in heterogeneous media incorporating small parameters and modified boundary conditions. The relevance of this work stems from the necessity to accurately represent boundary layer effects in complex physical systems with variable internal structures, such as multilayered materials, biological tissues, and natural geophysical environments. Traditional models often oversimplify such effects, resulting in distortions in the solution near domain boundaries.The primary objective of the research is to construct a rigorous mathematical framework that accounts for both the presence of small parameters and altered boundary conditions. The analysis includes deriving a priori stability estimates and constructing asymptotic expansions for the solution. The methodology relies on functional formulation in Sobolev spaces, the Galerkin method, asymptotic techniques, and weak convergence theory. Special attention is given to the existence and uniqueness of both strong and generalized solutions, as well as to their convergence properties as the small parameters tend to zero.The results confirm the solvability of the problem, provide robust energy estimates, and establish solution stability under various types of boundary modifications. It is demonstrated that changes in boundary conditions primarily affect solution behavior near the domain edges, while preserving the global structure of the field. The model is applied in various fields, including climate modeling, thermal diffusion, and hydrophysical systems. This work lays a foundation for the development of adaptive numerical schemes and for extending the analysis to non-stationary problems.
