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JOURNALS // Russian Universities Reports. Mathematics // Archive

Russian Universities Reports. Mathematics, 2020 Volume 25, Issue 130, Pages 156–164 (Mi vtamu178)

Scientific articles

On a stable approximate solution of an ill-posed boundary value problem for the metaharmonic equation

E. B. Laneev, P. A. Lesik, A. V. Klimishin, A. M. Kotyukov, A. A. Romanov, A. G. Khegai

RUDN University

Abstract: In this paper, we consider a mixed problem for a metaharmonic equation in a region in a rectangular cylinder. On the side faces cylinder region is set to homogeneous conditions of the first kind. The cylindrical area is bounded on one side by an arbitrary surface on which the Cauchy conditions are set, i. e. the function and its normal derivative are set. The other boundary of the cylindrical region, which is flat, is free. This problem is illposed, and to construct its approximate solution in the case of Cauchy data known with some error, it is necessary to use regularizing algorithms. In this paper, the problem is reduced to the Fredholm integral equation of the first kind. Based on the solution of the integral equation, an explicit representation of the exact solution of the problem is obtained. A stable solution of the integral equation is obtained by the method of Tikhonov regularization. The extremal of the Tikhonov functional is considered as an approximate solution. Based on this solution, an approximate solution of the problem as a whole is constructed. The convergence theorem of the approximate solution of the problem to the exact one is given when the error in the Cauchy data tends to zero and when the regularization parameter is agreed with the error in the data. The results can be used for mathematical processing of thermal imaging data in medical diagnostics.

Keywords: ill-posed problem, metaharmonic equation, integral equation of the first kind, method of Tikhonov regularization.

UDC: 519.6

Received: 10.04.2020

DOI: 10.20310/2686-9667-2020-25-130-156-164



© Steklov Math. Inst. of RAS, 2024