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Is the transonic flow around a cylinder always periodic?
(1992)SAM Research ReportThe inviscid transonic flow about a circular cylinder is investigated at large times. For this scope the Euler equations are integrated numerically, according to a time dependent technique. The integration is based on an high resolution finite volume upwind method. Transitions to qualitatively different families of solutions have been observed by increasing the value of the free stream Mach number from 0.5 up to 1. In particular the ...Report -
Invariant manifolds of numerical integration schemes applied to stiff systems of singular perturbation type - Part I: RK-methods
(1992)SAM Research ReportFor implicit RK-methods applied to singularly perturbed systems of ODEs it is shown that the resulting discrete systems preserve the geometric properties of the underlying ODE. As an application of this invariant manifold result sharp bounds on the global error are derived.Report -
Extensible attribute grammars
(1992)TIK ReportThis report introduces a new idea to make attribute grammars (AG) extensible. Both the context-free grammar and the attribution system of an AG may be extended. This concept is a valuable structuring technique when defining language-based programming environments or compilers. For instance, it allows passes of a multipass compiler to be decomposed into different grammar levels, which renders the definition much clearer. Another application ...Report -
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Elemente eines computergestützten Werkzeugs zur Entwicklung von Eisenbahnsicherungsanlagen mit Petri-Netzen
(1992)IVT SchriftenreiheEisenbahnsicherungsanlagen sind hochkomplexe Systeme, die sehr hohen Sicher-heitsanforderungen genügen müssen. Ihre detaillierte, vollständige und korrekte Beschreibung bereitet Probleme. In dieser Arbeit werden Grundlagen für die Spezifikation von Eisenbahnsicherungsanlagen mit einer formalen Methode gelegt. Für die statischen Aspekte werden formale Gleistopologien basierend auf Doppelpunktgra-phen verwendet, die dynamischen Eigenschaften ...Report -
Optimum extrapolations of Wendland-Bruhn iteration for a class of nonnormal linear systems
(1992)IPS research reportReport -
Using nP-based analysis in information retrieval
(1992)ETH, Eidgenössische Technische Hochschule Zürich, Departement Informatik, Institut für InformationssystemeReport -
Smooth attractive invariant manifolds of singularly perturbed ODE's
(1992)SAM Research ReportUnder hypotheses suitable for applications an invariant manifold result for singularly perturbed ODE's is proved with sharp smoothness properties of the manifold.Report -
A Shock Tracking Technique Based on Conservation in One Space Dimension
(1992)SAM Research ReportIn this paper, which is a continuation of [20], [21], [22] and [24], we present a shock tracking technique in one space dimension. The main feature of the technique is that it uses the conservativity of the hyperbolic conservation laws rather than the Hugoniot condition to track discontinuities. Roughly speaking, the technique is as follows: The computation of a numerical solution on each side of a discontinuity uses information only from ...Report -
Stagnation point analysis
(1992)SAM Research ReportThe numerical solution of a symmetric hypersonic blunt body flow in two space dimensions is considered, and the problem of the arising chemical boundary layer is discussed. Analytical and numerical investigations are used to analyze the solution on the stagnation point streamline. We point out the necessary assumptions to obtain an equivalent system of ordinary differential equations along this line and to get a unique solution. We also ...Report