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Development of a Finite-Difference Regularized Solution of the One-Dimensional Inverse Problem of the Wave Process

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Development of a Finite-Difference Regularized Solution of the One-Dimensional Inverse Problem of the Wave Process American Journal of Applied Mathematics 2020; 8(2): 64-73 http://www.sciencepublishinggroup.com/j/ajam doi: 10.11648/j.ajam.20200802.13 ISSN: 2330-0043 (Print); ISSN: 2330-006X (Online) Development of a Finite-difference Regularized Solution of the One-Dimensional Inverse Problem of the Wave Process Abdugany Dzhunusovich Satybaev 1, Yuliya Vladimirovna Anishchenko 1, *, Ainagul Zhylkychyevna Kokozova 1, Aliyma Torozhanovna Mamatkasymova 2, 3 Guljamal Abdazovna Kaldybaeva 1Department of Information Technology and Management, Faculty of Cybernetics and Information Technology, Osh Technological University, Osh, Kyrgyzstan 2Department of Informatics, Naturally-technical Faculty, Osh Technological University, Osh, Kyrgyzstan 3Department of Physics, Mathematics and Information Technology, Osh State University, Osh, Kyrgyzstan Email address: *Corresponding author To cite this article: Abdugany Dzhunusovich Satybaev, Yuliya Vladimirovna Anishchenko, Ainagul Zhylkychyevna Kokozova, Aliyma Torozhanovna Mamatkasymova, Guljamal Abdazovna Kaldybaeva. Development of a Finite-difference Regularized Solution of the One-Dimensional Inverse Problem of the Wave Process. American Journal of Applied Mathematics . Vol. 8, No. 2, 2020, pp. 64-73. doi: 10.11648/j.ajam.20200802.13 Received : March 3, 2020; Accepted : March 23, 2020; Published : April 13, 2020 Abstract: We consider a one-dimensional inverse problem for a partial differential equation of hyperbolic type with sources - the Dirac delta-function and the Heaviside theta-function. The generalized inverse problem is reduced to the inverse problem with data on the characteristics using the method of characteristics and the method of isolation of singularities. At the beginning, the inverse problem of the wave process with data on the characteristics with additional information for the inverse problem without small perturbations is solved by the finite-difference method. Then, for the inverse problem of the wave process with data on the characteristics with additional information with small perturbations, that is, with small changes is used by the finite-difference regularized method, which developed by one of the authors of this article. The convergence of the finite-difference regularized solution to the exact solution of the one-dimensional inverse problem of the wave process on the characteristics is shown, and the theorem on the convergence of the approximate solution to the exact solution is proved. An estimate is obtained for the convergence of the numerical regularized solution to the exact solution, which depends on the grid step, on the perturbations parameter, and on the norm of known functions. From the equivalence of the problems, the one-dimensional inverse problem of the wave process with sources - the Dirac delta-function and the Heaviside theta-function and the one-dimensional inverse problem of the wave process with data on the characteristics, it follows that the solution of the last problem will be the solution of the posed initial problem. An algorithm for solving a finite-difference regularized solution of a generalized one-dimensional inverse problem is constructed. Keywords: One-dimensional Inverse Problem, Wave Process, Dirac Delta-Function, Heaviside Theta-Function, Method of Characteristic, Method of Isolation of Singularities, Finite-Difference Regularized Solution Russian Academy of Sciences Valentin K. Ivanov [3]. 1. Introduction The inverse problems of wave processes were considered in Inverse problems are the so-called ill-posed problems, the theoretical terms by the Corresponding members of the foundations of which were laid by Academicians of the Russian Academy of Sciences Vladimir G. Romanov [4], Russian Academy of Sciences Andrei N. Tikhonov [1], Sergey I. Kabanikhin [5], professor Valery G. Yakhno [6], and Mikhail M. Lavrentiev [2], Corresponding Member of the they constructed solutions to the posed inverse problems. 65 Abdugany Dzhunusovich Satybaev et al. : Development of a Finite-difference Regularized Solution of the One-Dimensional Inverse Problem of the Wave Process The regularization method for inverse problems was characteristics of real inhomogeneous layered media, and developed by Andrei N. Tikhonov [7], the method of small according to experimental information, clarified the time parameters was constructed by Mikhail M. Lavrentiev [8] and parameters of the source of disturbances, and also presented the quasi-solution method — by Valentin K. Ivanov [9]. The practical solutions to a number of actual inverse problems in projection-difference method for multidimensional inverse borehole exploration geophysics. problems was developed by Sergey I. Kabanikhin [10], the Dynamic inverse problems, definitions of one or several finite-difference regularization for Volterra integral equation coefficients of hyperbolic equations or systems, methods for of the first kind was investigated by Abdugany Dzh. Satybaev solving one-dimensional inverse problems, scalar inverse [11] and a regularization estimate is obtained. problems of wave propagation in layered media, inverse Aliyma T. Mamatkasymova and Abdugany Dzh. Satybaev problems for the theory of elasticity and acoustic equations are [12] constructed a finite-difference regularized solution and given in the monograph of Alexander S. Blagoveshchenskii [19]. obtained a convergence estimate for the inverse problem Alexander V. Avdeev, Vyacheslav I. Priimenko, E. V. arising in electromagnetic processes. Gorbunov, D. V. Zvyagin [20] considered the inverse problem The purpose of this work is to numerically solve a of electromagneto elasticity with electrodynamics of vibrating one-dimensional inverse problem of the wave process elastic media. proposed by the authors by a finite-difference regularized In the monograph of Sergey I. Kabanikhin [21] outlines method, which allows us to construct a numerical algorithm methods for studying and solving inverse and ill-posed for solving the problem. problems of linear algebra, integral and operator equations, integral geometry, spectral inverse problems and inverse 2. Research Overview scattering problems; linear ill-posed problems and coefficient inverse problems for hyperbolic, parabolic and elliptic Most of the scientific and technical aspects of the inverse equations were considered; given extensive reference material. problems of wave propagation in the medium and the A new globally convergent numerical method is developed mathematical connections between waves and scatterers are for a multidimensional coefficient inverse problem for a determined and presented in work G. Ghavent, G. C. hyperbolic PDE with applications in acoustics and Papanicolaou, P. Sacks, W. Symes [13]. electromagnetics. On each iterative step the Dirichlet The book, edited by G. Chavent and P. C. Sabatier [14], boundary value problem for a second-order elliptic equation is describes the current state of modeling and the numerical solved. The global convergence is rigorously established, and solution of wave propagation and diffraction, their numerical experiments are presented in works Larisa Beilina, applications, and features of inverse scattering problems on Michael V. Klibanov [22]. classical and distributed media. In the book by V. A. Burov and O. D. Rumyantseva [23], The article set forth by F. Natterer [15] three major methods inverse wave problems and their applied aspects related to linear for solving inverse problems: the method of ray tomography, and nonlinear acoustic tomography, as well as acoustic the method of single-particle emission tomography and the thermotomography, are considered. Part I briefly discusses the method of positron-emission tomography and described inverse coherent radiation problems, which are characterized by transfer equations transitions near the infrared region to incorrectness and a strong degree of non-uniqueness. Various elliptic equations in the diffusion approximation. approaches to solving inverse wave problems of radiation and In the article by F. Natterer, A. Wiibbeling [16], a numerical incoherent problems of active-passive acoustic thermotomography calculation of the potential in the Helmholtz equation was laid are described. It is shown that the active-passive mode allows you out and a method was developed which possesses the stability to determine the set of acoustic and thermal characteristics of the of the solution and the convergence of the solution was shown medium within the framework of the general tomographic scheme. in the order O (h 4). Modern mathematical modeling of various wave processes 3. Formulation of the Problem (computed tomography, ultrasonic flaw detection, etc.) in the theory of inverse problems and their examples, main features, perspectives Wave processes of natural phenomena (earthquakes and are presented in the work of Alexander O. Vatulyan [17]. natural explosions, landslides and lavas), electrodynamics and In the Andrey V. Bayev’s dissertation work [18] developed geophysics, etc., are characterized by fields described by stable methods for solving inverse problems, determined the second-order partial differential equations: ϑ+= ϑ ϑ + ϑ + ϑ ∈ 2 ax()tt (,) xt bx ()(,) t xt cx () xx (,) xt dx () x (,) xt ex ()(,),(,) xt xt R + (1) where a(x), (xb ), (xc ), d(x), xe )( are the coefficients of the equation (physical parameters of the equation), ϑ tx ),( is the function describing the process. For (1) we consider the initial and boundary conditions of the form: ϑ(,)xt≡ 0, ϑ (,) xt =+∈ htrttR δθ () (), (2) t<0x x = 0 0 0 + American Journal
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