scholarly journals One-dimensional Wiener process with the properties of partial reflection and delay

2021 ◽  
Vol 13 (2) ◽  
pp. 534-544
Author(s):  
B.I. Kopytko ◽  
R.V. Shevchuk

In this paper, we construct the two-parameter semigroup of operators associated with a certain one-dimensional inhomogeneous diffusion process and study its properties. We are interested in the process on the real line which can be described as follows. At the interior points of the half-lines separated by a point, the position of which depends on the time variable, this process coincides with the Wiener process given there and its behavior on the common boundary of these half-lines is determined by a kind of the conjugation condition of Feller-Wentzell's type. The conjugation condition we consider is local and contains only the first-order derivatives of the unknown function with respect to each of its variables. The study of the problem is done using analytical methods. With such an approach, the problem of existence of the desired semigroup leads to the corresponding conjugation problem for a second order linear parabolic equation to which the above problem is reduced. Its classical solvability is obtained by the boundary integral equations method under the assumption that the initial function is bounded and continuous on the whole real line, the parameters characterizing the Feller-Wentzell conjugation condition are continuous functions of the time variable, and the curve defining the common boundary of the domains is determined by the function which is continuously differentiable and its derivative satisfies the Hölder condition with exponent less than $1/2$.

2018 ◽  
Vol 10 (2) ◽  
pp. 333-345
Author(s):  
B.I. Kopytko ◽  
R.V. Shevchuk

The paper deals with the problem of construction of Feller semigroup for one-dimensional inhomogeneous diffusion processes with membrane placed at a point whose position on the real line is determined by a given function that depends on the time variable. It is assumed that in the inner points of the half-lines separated by a membrane the desired process must coincide with the ordinary diffusion processes given there, and its behavior on the common boundary of these regions is determined by the nonlocal conjugation condition of Feller-Wentzell's type. This problem is often called a problem of pasting together two diffusion processes on a line. In order to study the described problem we use analytical methods. Such an approach allows us to determine the desired operator family using the solution of the corresponding problem of conjugation for a linear parabolic equation of the second order (the Kolmogorov backward equation) with discontinuous coefficients. This solution is constructed by the boundary integral equations method under the assumption that the coefficients of the equation satisfy the Holder condition with a nonzero exponent, the initial function is bounded and continuous on the whole real line, and the parameters characterizing the Feller-Wentzell conjugation condition and the curve defining the common boundary of the domains, where the equation is given, satisfies the Holder condition with exponent greater than $\frac{1}{2}.$


2019 ◽  
Vol 11 (2) ◽  
pp. 463-474
Author(s):  
R.V. Shevchuk ◽  
I.Ya. Savka ◽  
Z.M. Nytrebych

This paper is devoted to a partial differential equation approach to the problem of construction of Feller semigroups associated with one-dimensional diffusion processes with boundary conditions in theory of stochastic processes. In this paper we investigate the boundary-value problem for a one-dimensional linear parabolic equation of the second order (backward Kolmogorov equation) in curvilinear bounded domain with one of the variants of nonlocal Feller-Wentzell boundary condition. We restrict our attention to the case when the boundary condition has only one term and it is of the integral type. The classical solution of the last problem is obtained by the boundary integral equation method with the use of the fundamental solution of backward Kolmogorov equation and the associated parabolic potentials. This solution is used to construct the Feller semigroup corresponding to such a diffusion phenomenon that a Markovian particle leaves the boundary of the domain by jumps.


2012 ◽  
Vol 591-593 ◽  
pp. 1942-1948
Author(s):  
Hai Hu ◽  
Xin Yue Wu ◽  
Long Ma

The common requests of the meshless interpolating functions are researched, and its construction method and procedures using the moving least squares method are introduced. The point collocation method is adopted to discretize the Kirchhoff-Helmholtz boundary integral equations into equation groups that constrained by boundary conditions. Constrained equation groups are solved by matrix-division method finally. Therefore, the discrete numeric expression of acoustic radiating and transferring model is obtained. In the example, acoustic field is calculated by the acoustic radiating and transferring model that obtained through both BMLM and BEM, and the results are contrasted between the computational values and the true values. It shows that the interpolating functions of BMLM could be built more flexible. So the accuracy of interpolation and calculation by BMLM is higher.


2018 ◽  
Vol 64 (1) ◽  
pp. 20-36
Author(s):  
E A Baderko ◽  
M F Cherepova

We consider the mixed problem for a one-dimensional (with respect to the spatial variable) second-order parabolic system with Dini-continuous coefficients in a domain with nonsmooth lateral boundaries. Using the method of boundary integral equations, we find a classical solution of this problem. We investigate the smoothness of solution as well.


2004 ◽  
Vol 15 (4) ◽  
pp. 409-450 ◽  
Author(s):  
C. ATKINSON ◽  
F. MONMONT ◽  
A. F. ZAZOVSKY

This paper presents a powerful approximate method for modelling the steady single-phase flow into a horizontal well completed with an Inflow Control Device (ICD) in an anisotropic reservoir. Two types of problems are investigated: the forward problem, which allows the user to find the flux distribution along the wellbore for a specified pressure drawdown, and the inverse problem to determine the ICD properties when the flux or reservoir pressure drawdown along the wellbore is given. The method is based on structuring the flow patterns around and, inside the wellbore and across the ICD and on the reduction of the dimensionality of the problem by using boundary integral equations. The resulting one dimensional singular nonlinear integro-differential equation is solved numerically, using the appropriate quadrature formula for singular integrals with Cauchy kernels.


2003 ◽  
Vol 10 (3) ◽  
pp. 467-480
Author(s):  
Igor Chudinovich ◽  
Christian Constanda

Abstract The existence of distributional solutions is investigated for the time-dependent bending of a plate with transverse shear deformation under mixed boundary conditions. The problem is then reduced to nonstationary boundary integral equations and the existence and uniqueness of solutions to the latter are studied in appropriate Sobolev spaces.


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