Browsing Institut für Mathematik by Title
Now showing items 92-111 of 329
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2011-09-20BuchEstimator competition for Poisson problems
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2005-11-11BuchEvaluation of the epi-convergence The paper presents an equivalent characterization of the epi-convergence of lower semicontinuous functions. The proposed ‘measures’ naturally estimate the distance between optimal values of two optimization programs. A ...
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2009-07-02BuchExistence of turbulent weak solutions to the generalized Navier-Stokes equations in exterior domains and large time behaviour Let $\Omega$ be an exterior domain in $\R^n\,(n=2,3,4)$ , with boundary being not necessarily smooth. For any initial velocity ${\bf u}_0\in L^2(\Omega)^n$ such that $\nabla\cdot {\bf u}_0=0$ (in sense of distribution) and ...
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2005-11-16BuchEXTRA-ordinary differential equations
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2005-11-02BuchFeedback solutions of optimal control problems with DAE constraints An optimal feedback control has been obtained for linear-quadratic optimal control problems with constraints described by differential-algebraic equations. For that purpose, a new implicit Riccati equation (Riccati ...
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2005-11-07BuchFinding Beneficial DAE Structures in Circuit Simulation Circuit simulation is a standard task for the computer-aided design of electronic circuits. The transient analysis is well understood and realized in powerful simulation packages for conventional circuits. But further ...
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2005-11-02BuchFine decouplings of regular differential algebraic equations In this paper, the previously formulated conjecture concerning the existence of fine and complete decouplings of regular DAEs with tractability index $\mu$ is verified.
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2005-11-07BuchFormulating differential algebraic equations properly
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2005-04-08BuchFramework For The A Posteriori Error Analysis Of Nonconforming Finite Elements This paper establishes a unified framework for the a posteriori error analysis of a large class of nonconforming finite element methods. The theory assures reliability and efficiency of explicit residual error estimates ...
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2011-09-27BuchFrom convergence principles to stability and optimality We show in a rather general setting that Hoelder and Lipschitz stability properties of solutions to variational problems can be characterized by convergence of more or less abstract iteration schemes. Depending on the ...
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2005-11-03BuchGeneral linear methods for linear DAEs For linear differential-algebraic equations (DAEs) with properly stated leading terms the property of being numerically qualified guarantees that qualitative properties of DAE solutions are reflected by the numerical ...
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2005-11-03BuchGeneral Linear Methods for nonlinear DAEs in Circuit Simulation The Modified Nodal Analysis leads to differential algebraic equations with properly stated leading terms. In this article a special structure of the DAEs modelling electrical circuits is exploited in order to derive a new ...
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2008-03-07BuchGeometric Brownian Motion with delay A geometric Brownian motion with delay is the solution of a stochastic differential equation where the drift and diffusion coefficient depend linearly on the past of the solution, i.e. a linear stochastic functional ...
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2005-11-11BuchGlobal convergence of multidirectional algorithms for unconstrained optimization in normed spaces Global convergence theorems for a class of descent methods for unconstrained optimization problems in normed spaces, using multidirectional search, are proved. Exact and inexact search are considered and the results allow ...
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2005-11-17BuchGlobal Weak Solutions and Uniqueness for a Moving Boundary Problem for a Coupled System of Quasilinear Diffusion-Reaction Equations arising as a Model of Chemical Corrosion of Concrete Surfaces We show existence and uniqueness for global weak solutions of a moving boundary problem for a coupled system of three quasi-linear diffusion-reaction equations. The model is briefly described. The proofs are based on ...
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2005-11-17BuchGlobal Weak Solutions and Well-Posedness of Weak Solutions for a Moving Boundary Problem for a Coupled System of Diffusion-Reaction Equations arising in the Corrosion Modeling of Concrete The evolution of the corrosion interface separating the uncorroded concrete part and the corroded part of a partially wet concrete wall of a pipe under the influence of hydrogen sulfide can be modelled by a moving boundary ...
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1998-01-10BuchHeights on elliptic curves and the diophantine equation x4 + y4 = cz4 In this paper we give sharp explicit estimates for the difference of the Weil height and the Néron - Tate height on the elliptic curve $v^2 = u^3 - cu$. We then apply this in the proof of the fact that if c > 2 is a fourth ...
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2011-09-20BuchHigher Order Operator-Splitting Methods via Zassenhaus product formula In this paper, we contribute higher order operator-splitting method improved by Zassenhaus product. We apply the contribution to classical and iterative splitting methods. The underlying analysis to obtain higher order ...
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2006-09-10BuchHow fast is fast fictitious play? We present a modification of the fictitious play algorithm for matrix games by aggregating trivial original steps. The resulting new algorithm consists of comparable simple steps but has a much better rate of convergence. ...
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2005-10-26BuchHow Floquet-theory applies to differential-algebraic equations Local stability of periodic solutions is established by means of a corresponding Floquet-theory for index-1 differential-algebraic equations. For this, linear differential-algebraic equations with periodic coefficients are ...