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- Andreas Bartel, Markus Brunk, Sebastian Schöps
- J. Computational Applied Mathematics
- 2014

- Markus Brunk, Heike Ruppertshofen, Sarah Schmidt, Peter Beyerlein, Hauke Schramm
- Bildverarbeitung für die Medizin
- 2011

We present an approach for automatic bone age classification from hand x-ray images using the Discriminative Generalized Hough Transform (DGHT). To this end, a region, characteristic for the bone age (e.g. an epiphyseal plate), is localized and subsequently classified to determine the corresponding age. Both steps are realized using the DGHT, whereat the… (More)

- Andreas Bartel, Markus Brunk, Michael Günther, Sebastian Schöps
- SIAM J. Scientific Computing
- 2013

Coupled systems of differential-algebraic equations (DAEs) may suffer from instabilities during a dynamic iteration. For a general dynamic iteration, we extend the existing analysis on recursion estimates, error transport and stability to a general DAE setting. In this context, we discuss the influence of certain coupling structures and the computational… (More)

- Anton Arnold, N. Ben Abdallah, +11 authors C. NEGULESCU
- 2009

An efficient and accurate numerical method is presented for the solution of highly oscillatory differential equations. While standard methods would require a very fine grid to resolve the oscillations, the presented approach uses first an analytic (second order) WKB-type transformation, which filters out the dominant oscillations. The resulting ODE is much… (More)

- Winfried Auzinger, Herbert Lehner, +16 authors E. Weinmüller
- 2008

A computationally efficient a posteriori error estimator is introduced and analyzed for collocation solutions to linear index-1 DAEs with properly stated leading term. The procedure is based on a modified defect correction principle, extending an established technique from the ODE context to the DAE case. We prove that the resulting error estimate is… (More)

- Thorsten Sickenberger, Ewa Weinmüller, +11 authors Dirk Praetorius
- 2009

The paper consists of two parts. In the first part of the paper, we proposed a procedure to estimate local errors of low order methods applied to solve initial value problems in ordinary differential equations (ODEs) and index-1 differential-algebraic equations (DAEs). Based on the idea of Defect Correction we developed local error estimates for the case… (More)

- Markus Brunk, Ansgar Jüngel
- SIAM J. Scientific Computing
- 2008

A coupled semiconductor–circuit model including thermal effects is proposed. The charged particle flow in the semiconductor devices is described by the energy-transport equations for the electrons and the drift-diffusion equations for the holes. The electric circuit is modeled by the network equations from modified nodal analysis. The coupling is realized… (More)

- M Brunk, H L Barnett
- Mycologia
- 1966

In this work we present the coupling of stationary energy-transport (ET) equations with Modified Nodal Analysis (MNA)equations to model electric circuits containing semiconductor devices. The one-dimensional ET-equations are discretised in space by an exponential fitting mixed hybrid finite element approach to ensure current continuity and positivity of… (More)

- Ansgar Jüngel, Stefan Krause, +15 authors PAOLA PIETRA
- 2007

A hierarchy of diffusive partial differential equations is derived by a moment method and a Chapman-Enskog expansion from the semiconductor Boltzmann equation assuming dominant collisions. The moment equations are closed by employing the entropy maximization principle of Levermore. The new hierarchy contains the well-known drift-diffusion model, the… (More)