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The Las Cristina Au-Cu deposit in the Venezuelan Guayana Shield: Geological, petrological and geochemical aspects
(1998)This report summarises results of 'Diplom' thesis research projects by R. D. Eichenberger and M. J. Riedi over the period 1996 - 1998 at ETH, Zürich, Switzerland, on the geology of the Las Cristinas deposit in Venezuela. In these projects, core was logged from two sections each through Mesones-Sofia and Conductora-Cuatro Muertos, with emphasis on primary lithology, and the distribution and paragenesis of minerals. Ore and alteration ...Report -
Restarted GMRES preconditioned by deflation
(1994)SAM Research ReportThis paper presents a new preconditioning technique for solving linear systems. It is based on an invariant subspace approximation for the restarted GMRES algorithm. It uses the flexible GMRES scheme by designing a new preconditioning after each restart. Numerical examples show that this approach may converge almost as fast as full-GMRES at a, possibly, much lower cost.Report -
Kunde oder Bürger
(1999)Arbeitsberichte Verkehrs- und RaumplanungVerkehrsteilnehmer wissen oft sehr genau, dass ihr Verhalten nicht dem allgemeinen Interesse entspricht, fühlen sich aber trotzdem gerechtfertigt, da sie ihr Handeln als Teil ihrer Konsumentenfreiheit verstehen. Dieses Dilemma findet seinen Widerhall in den aktuellen Schwierigkeiten der westlichen Staaten einen angemessenen Ordnungsrahmen für ihre grossen Infrastrukturen zu definieren: alles vom staatlichem Monopol bis zu unregulierten ...Report -
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Invariant manifolds and global error estimates of numerical integration schemes applied to stiff systems of singular perturbation type - Part II: Linear multistep methods
(1995)SAM Research ReportIt is shown that appropriate linear multi-step methods (LMMs) applied to singularly perturbed systems of ODEs preserve the geometric properties of the underlying ODE. If the ODE admits an attractive invariant manifold so does the LMM. The continuous as well as the discrete dynamical system restricted to their invariant manifolds are no longer stiff and the dynamics of the full systems is essentially described by the dynamics of the systems ...Report -
Radial Functions on Compact Support
(1995)SAM Research ReportIn this paper, radial basis functions that are compactly supported and give rise to positive definite interpolation matrices for scattered data are discussed. They are related to the well-known thin plate spline radial functions which are highly useful in applications for gridfree approximation methods. Also, encouraging approximation results for the compactly supported radial functions are shown.Report -
Circuits in Power Electronics
(1994)SAM Research ReportThe dynamics of circuits in power electronics may often be modelled by means of systems of linear differential equations with piecewise constant coefficients and sinusoidal inhomogeneities. The Static Var (Volt-Ampere reactive) Compensator (SVC, a device for power network control) is a representative example. Initial value problems of this type may be handled by means of the matrix exponential, whereas the construction of periodic solutions ...Report -
Long-Term Evolution of Coorbital Motion
(1998)SAM Research ReportIn these lectures the planar problem of three bodies with masses $m_0$, $m_1$, $m_2$ will be used as a model of coorbital motion, thus leaving the analysis of three-dimensional effects to later work. For theoretical as well as for numerical studies the choice of appropriate variables is essential. Here Jacobian coordinates and a rotating frame of reference will be used. The application of the Hamiltonian formalism in connection with complex ...Report -
An hp a-priori error analysis of the DG time-stepping method for initial value problems
(1999)SAM Research ReportThe Discontinuous Galerkin (DG) time-stepping method for the numerical solution of initial value ODEs is analyzed in the context of the hp-version of the Galerkin method. New a-priori error bounds explicit in the time steps and in the approximation orders are derived and it is proved that the DG method gives spectral and exponential accuracy for problems with smooth and analytic time dependence, respectively. It is further shown that ...Report -
Coupling of an Interior Navier-Stokes Problem with an Exterior Oseen Problem
(1998)SAM Research ReportThe paper is concerned with the modelling of viscous incompressible flow in an unbounded exterior domain with the aid of the coupling of the nonlinear Navier--Stokes equations considered in a bounded domain with the linear Oseen system in an exterior domain. These systems are coupled on an artificial interface via suitable transmission conditions. The present paper is a continuation of the work [8], where the coupling of the Navier--Stokes ...Report