Search Results - subject:"Inverse problems"

Identification of solitary-wave solutions as an inverse problem: Application to shapes with oscillatory tails

Christov, Christo I.; Marinov, Tchavdar T.; Marinova, … - In: Mathematics and Computers in Simulation (MATCOM) 80 (2009) 1, pp. 56-65

The propagation of stationary solitary waves on an infinite elastic rod on elastic foundation equation is considered. The asymptotic boundary conditions admit the trivial solution along with the solution of type of solitary wave, which is a bifurcation problem.

Persistent link: https://www.econbiz.de/10010870539

Numerical solution of a one-dimensional inverse problem by the discontinuous Galerkin method

Epshteyn, Y.; Khan, T.; Rivière, B. - In: Mathematics and Computers in Simulation (MATCOM) 79 (2009) 7, pp. 1989-2000

In this paper, we combine a Tikhonov regularization with a discontinuous Galerkin method to solve an inverse problem in one-dimension. We show that the regularization is simpler than in the case of the inversion using continuous finite elements. We numerically demonstrate that there exist...

Persistent link: https://www.econbiz.de/10010749503

A generalized conditional gradient method and its connection to an iterative shrinkage method

Bredies, Kristian; Lorenz, Dirk; Maass, Peter - In: Computational Optimization and Applications 42 (2009) 2, pp. 173-193

Persistent link: https://www.econbiz.de/10005169146

Parameter identification, population and economic growth in an extended Lucas and Uzawa-type two sector model

BUCCI, Alberto; KUNZE, Herb E.; TORRE, Davide LA - Dipartimento di Economia, Management e Metodi … - 2008

The aim of this paper is twofold. First of all we re-examine the long-run relationship between population and economic growth. To do this we extend the Lucas-Uzawa model along two different directions: we introduce the growth of the physical capital stock into the human capital supply equation...

Persistent link: https://www.econbiz.de/10005007350

Parameter identification for deterministic and stochastic differential equations using the "collage method" for fixed point equations

CAPASSO, Vincenzo; KUNZE, Herb E.; TORRE, Davide LA; … - Dipartimento di Economia, Management e Metodi … - 2008

A number of inverse problems may be viewed in terms of the approximation of a target element x in a complete metric … as small as possible. We first show how to solve inverse problems for deterministic and random differential equations and … then we switch to the analysis of stochastic differential equations. Here inverse problems can be solved by minimizing the …

Persistent link: https://www.econbiz.de/10005007390

Parameter estimation for differential equations using fractal-based methods and applications to economics

COLAPINTO, Cinzia; FINI, Matteo; KUNZE, Herb E.; … - Dipartimento di Economia, Management e Metodi … - 2008

solutions of the inverse problems are the estimations of the unknown parameters and we use fractal-based methods to get them. We …

Persistent link: https://www.econbiz.de/10005007458

Solving inverse problems for random equations and applications

KUNZE, Herb E.; TORRE, Davide LA; VRSCAY, Edward R. - Dipartimento di Economia, Management e Metodi … - 2007

ABSTRACT: Most natural phenomena are subject to small variations in the environment within which they take place; data gathered from many runs of the same experiment may well show differences that are most suitably accounted for by a model that incorporates some randomness. Differential equations...

Persistent link: https://www.econbiz.de/10005007424

Activity spectrum from waiting-time distribution

Politi, Mauro; Scalas, Enrico - In: Physica A: Statistical Mechanics and its Applications 383 (2007) 1, pp. 43-48

In high frequency financial data not only returns but also waiting times between trades are random variables. In this work, we analyze the spectra of the waiting-time processes for tick-by-tick trades. The numerical problem, strictly related with the real inversion of Laplace transforms, is...

Persistent link: https://www.econbiz.de/10010590856

On the identification of the flatness of a sound-hard acoustic crack

Alves, C.J.S; Serranho, P - In: Mathematics and Computers in Simulation (MATCOM) 66 (2004) 4, pp. 337-353

In this paper, we present results concerning the far field pattern generated by flat and almost flat cracks in 3D and the possibility of identifying these geometrical features from direct inspection of the far field pattern. We address the direct problem using a variational formulation of the...

Persistent link: https://www.econbiz.de/10010748713

Multifrequency inverse obstacle scattering: the point source method and generalized filtered backprojection

Luke, D. Russell - In: Mathematics and Computers in Simulation (MATCOM) 66 (2004) 4, pp. 297-314

We outline two methods for obstacle reconstruction from multifrequency far-field scattering data, the first built upon the point source method proposed by Potthast for solving inverse scattering problems with single frequency data in the resonance region, and the second based on filtered...

Persistent link: https://www.econbiz.de/10010749024