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Inhaltsverzeichnis - Mathematisches Institut der Universität zu Köln

Inhaltsverzeichnis - Mathematisches Institut der Universität zu Köln

Inhaltsverzeichnis - Mathematisches Institut der Universität zu Köln

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DMV Tagung 2011 - <strong>Köln</strong>, 19. - 22. September<br />

Sergei Pereverzev<br />

Johann Radon <strong>Institut</strong>e for Computational and Applied Mathematics, Austrian Academy of Sciences,<br />

Linz<br />

Multiparameter Regularization in Geodetic Data Processing<br />

We are going to discuss recent developments in multiparameter regularization. The need in this approach<br />

becomes apparent when several model uncertainties affect data processing. Focusing on the context of<br />

satellite geodesy we discuss theoretical and computational aspects of some multiparameter regularization<br />

schemes. Numerical illustrations with synthetic data will be also presented.<br />

Literatur<br />

Lu, S. and Pereverzev, S. (2010). Multiparameter Regularization in Downward Continuation of Satellite<br />

Data. Handbook of Geomathematics, Springer, 813 - 832, Chapter 27.<br />

Robert Plato<br />

<strong>Universität</strong> Siegen<br />

The regularizing properties of some quadrature methods for linear weakly singular Volterra<br />

integral equations of the first kind<br />

The subject of this talk is the stable quadrature of the following class of linear weakly singular Volterra<br />

integral equations of the first kind:<br />

� x<br />

0<br />

(x − y) −(1−α) k(x,y)u(y)dy = f (x) for 0 ≤ x ≤ 1,<br />

with some parameter 0 < α < 1 and a sufficiently smooth kernel function k : [0,1] × [0,1] → R. In addition,<br />

f : [0,1] → R denotes a given function, and u : [0,1] → R is the unknown function. Problems of this kind<br />

arise, e.g., in the inversion of seismic flat-earth travel times.<br />

The quadrature methods un<strong>der</strong> consi<strong>der</strong>ation are the composite trapezoidal scheme and the composite<br />

midpoint rule. In the present talk we consi<strong>der</strong> their regularizing properties, i. e., we discuss appropriate<br />

choices of the step size as a function of the noise level for the right-hand side of the consi<strong>der</strong>ed equation.<br />

Different smoothness assumptions on the involved functions are taken into account. Finally some<br />

numerical results are presented.<br />

Literatur<br />

Eggermont, P.P.B. (1981). A new analysis of the trapezoidal-discretization method for the numerical solution<br />

of Abel-type integral equations. J. Integral Equations, 3, 317–332.<br />

Plato, R. (to appear). The regularizing properties of the composite trapezoidal method for weakly singular<br />

Volterra integral equations of the first kind. Adv. Comput. Math.<br />

157

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