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An Accuracy Barrier for Stable Three-Time-Level DifferenceSchemes for Hyperbolic Equations
(1997)SAM Research ReportWe consider three-time-level difference schemes for the linear constant coefficient advection equation $u_t$ = $cu_x$. In 1985 it was conjectured that the varrier to the local order $p$ of schemes which are stable is giben by $p \le $2 min {$R$,$S$}. Here $R$ and $S$ denote the number of downwind and upwind points, respectively, in the difference stencil with respect to the characteristic of the differential equation through the update ...Report -
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Analysis of membrane locking in hp FEM for a cylindrical shell
(1997)SAM Research ReportIn this paper we analyze the performance of the hp-Finite Element Method for a cylindrical shell problem. Our theoretical investigations show that the hp approximation converges exponentially, provided that appropriate boundary layer elements are used. The numerical results illustrate the robustness and exponential convergence properties of the hp-Finite Element Method.Report -
NFS performance investigations based on classical IP over ATM
(1997)TIK ReportThe NFS performance over Classical IP over ATM is investigated. ATM technology deployed in LANs delivers desktop speeds of 155 Mbps and more to modern computer systems. However, legacy applications such as NFS, created in the early 1980 were implemented over typical LAN speeds of less than 20 Mbps. In contrast to NFS version 2 which is implemented using UDP as the default transport protocol, and which adapts very well on ATM networks, NFS ...Report -
Architektur moderner RISC-Mikroprozessoren
(1997)Technical report / Eidgenössische Technische Hochschule Zürich, Departement InformatikSeit der Entwicklung des ersten Mikroprozessors vor rund 25 Jahren konnte die Prozessorleistung kontinuierlich um jährlich 50 % verbessert werden. Diese Leistungsverbesserung ist im wesentlichen den Fortschritten der Halbleiterindustrie zu verdanken, welche den Entwicklern von integrierten Schaltungen einerseits immer schnellere Transistoren und andererseits eine immer grössere Anzahl Transistoren auf einem Chip zur Verfügung stellt. Damit ...Report -
Virtual reality and geoinformation systems
(1997)Technical report / Federal Institute of Technology, Computer Science DepartmentReport -
Error estimates for reconstruction using thin plate spline interpolants
(1997)SAM Research ReportUsing thin plate spline interpolants we derive error bounds for the reconstruction of point values where the interpolation data is given by cell values. Sonar investigates in [IMA J. of Num. Analysis 16, 1996, 549-581] numerical solutions of hyperbolic conservation laws where the local reconstruction step is performed using thin plate spline interpolants. We show that local reconstruction yields second order as in the global case but ...Report -
Operator adapted spectral element methodsOperator Adapted Spectral Element Methods. I. Harmonic and Generalized Harmonic Polynomials
(1997)SAM Research ReportThe paper presents results on the approximation of functions which solve an elliptic differential equation by operator adapted systems of functions. Compared with standard polynomials, these operator adapted systems have superior local approximation properties. First, the case of Laplace's equation and harmonic polynomials as operator adapted functions is analyzed and sharp estimates for the approximation properties of harmonic polynomials ...Report -
Two notes on the implementation of wavelet Galerkin boundary element methods
(1997)SAM Research ReportWe report, in two notes, recent progress in the implementation of wavelet-based Galerkin BEM on polyhedra and study the performance.Report -
Mixed hp - FEM on anisotropic meshes
(1997)Mixed hp-FEM for incompressible fluid flow on anisotropic meshes are analyzed. A discrete inf-sup condition is proved with a constant independent of the meshwidth and the aspect ratio. For each polynomial degree $k\geq 2$, velocity-pressure subspace pairs are presented which are stable on quadrilateral mesh-patches, independently of the element aspect ratio implying in particular divergence stability on the so-called Shishkin-meshes. ...Working Paper