4,458 research outputs found
Ingenieure im Gebirg : Nach dem Original-Gemälde des Hern R. Ritz in Sitten
No full textX. J v A Closs & sc. ; CRDruckgraphik nach dem Gemälde von Raphael Ritz "Ingenieure im Gebirge", 1870, Öl auf Leinwand, Kunstmuseum Bern. 1880 bemühte sich ein Berner Drucker um die Reproduktionsrechte und erhielt von Ritz die Zusage. Ob es sich bei vorliegendem Druck um diese Reproduktion handelt ist unklar. Zum Gemälde siehe: Walter Ruppen: Raphael Ritz (1829-1894). Das künstlerische Werk (Katalog der Werke), Sitten 1972, S. 89, Nr. 64Aus der Sammlung Johann Müller-Wegmann; Depositum der SAC Sektion Uto in der Zentralbibliothek des SA
Le Rorschach d'un halluciné
No full textRitz J.-J. Le Rorschach d'un halluciné. In: Bulletin de la Société française du Rorschach et des méthodes projectives, n°19-20, 1966. pp. 101-109
On the Convergence of Ritz Values, Ritz Vectors, and Refined Ritz Vectors
No full textThis paper concerns the Rayleigh--Ritz method for computing an approximation to an eigenpair (; x) of a non-Hermitian matrix A. Given a subspace W that contains an approximation to x, this method returns an approximation (; ~ x) to (; x). We establish four convergence results that hold as the deviation ffl of x from W approaches zero. First, the Ritz value converges to . Second, if the residual A~x \Gamma ~x approaches zero, then the Ritz vector ~ x converges to x. Third, we give a condition on the eigenvalues of the Rayleigh quotient from which the Ritz pair is computed that insures convergence of the Ritz vector. Finally, we show that certain refined Ritz vectors, introduced by the first author, converge unconditionally. This report is available by anonymous ftp from thales.cs.umd.edu in the directory pub/reports or on the web at http://www.cs.umd.edu/ stewart/. y Department of Applied Mathematics, Dalian University of Technology, Dalian 116024, P.R. China, ([email protected]..
Ritz Bowling Alley P.1
No full text3115 Drawing of the Ritz Bowling Palace, Crystal Palace Market. January 13, 1938. Shipler Comm. Photograph #109
Book Review: Hotel Ritz-Comparing Mexican and U.S. Street Prostitutes: Factors in HIV/AIDS Transmission and Book Review: Women's Experiences with HIV/AIDS: Mending Fractured Selves
No full textTitle: Hotel Ritz-Comparing Mexican and U.S. Street Prostitutes: Factors in HIV/AIDS Transmission
Author: David J. Bellis, Ph.D.
Reviewers: J. Gary Linn & Carol Bompart
Publisher: The Haworth Press, 2003
ISBN 0-7890-1776-8, 128 pp.
Cost: 20.00 US
Pointwise Gradient Estimate of the Ritz Projection
No full textDiening L, Rolfes J, Salgado AJ. Pointwise Gradient Estimate of the Ritz Projection. SIAM Journal on Numerical Analysis. 2024;62(3):1212-1225.Let Ω⊂ℝ be a convex polytope (≤3). The Ritz projection is the best approximation, in the 1,2
0-norm, to a given function in a finite element space. When such finite element spaces are constructed on the basis of quasiuniform triangulations, we show a pointwise estimate on the Ritz projection. Namely, the gradient at any point in Ω is controlled by the Hardy–Littlewood maximal function of the gradient of the original function at the same point. From this estimate, the stability of the Ritz projection on a wide range of spaces that are of interest in the analysis of PDEs immediately follows. Among those are weighted spaces, Orlicz spaces, and Lorentz spaces
The use of positive and negative penalty functions in solving constrained optimization problems and partial differential equations
No full textThe Rayleigh-Ritz Method together with the Penalty Function Method is used to investigate the use of different types of penalty parameters. The use of artificial springs as penalty parameters is a very well established procedure to model constraints in the Rayleigh-Ritz Method, the Finite Element Method and other numerical methods. Historically, large positive values were used to define the stiffness coefficient of artificial springs, until recent publications demonstrated that it is possible to use negative values to define the stiffness coefficients of the springs. Furthermore, recent publications show that constraints can be enforced using positive and negative mass or inertia in vibration problems and in a more generic sense using eigenpenalty parameters which are penalty parameters in the matrix associated with the eigenvalue. Before the commencement of this thesis, solutions using artificial inertia were published only for beams and simple spring-mass systems.
In this thesis the use of all possible types of penalty parameters are investigated in vibration problems of Euler-Bernoulli beams, thin plates and shallow shells and in elastic stability analysis of Euler-Bernoulli beams, including penalty parameters associated with the geometrical stiffness matrix. The study includes the use of penalty parameters for both enforcing support boundary conditions and continuity conditions along structural joints.
This investigation started with the selection of the set of admissible functions that would: (a) allow modelling of beams, plates and shells in completely free boundary conditions; (b) not present any limitation in the number of functions that can be used in the solution. This gives the possibility to converge to the constraint solution and to model any type of boundary conditions.
The procedure proposed in this work combines several advantages: accuracy of the results, relative fast convergence, simplicity of the set of admissible functions and flexibility to define boundary conditions. While there are other procedures that may give better accuracy for specific cases, the proposed method is more widely applicable.
The procedure used in this work also includes a way to check for round-off errors and ill-conditioning in the results; as well as a way to bracket the exact solution with upper and lower-bound results
Drawing of Ritz Bowling Palace, Jan. 1938
No full textMaurice Guss, Drawing of Ritz Bowling Palace, 1/13/38
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