4,669 research outputs found
Error estimates for variational regularization of inverse problems with general noise models for data and operator
No full textSigrid Blömeke/Thorsten Bohl/Ludwig Haag/ Gregor Lang-Wojtasik/Werner Sacher (Hrsg.): Handbuch Schule. Theorie – Organisation – Entwicklung. Bad Heilbrunn: Klinkhardt 2009, 608 S. [Rezension]
No full textRezension zu: Sigrid Blömeke/Thorsten Bohl/Ludwig Haag/ Gregor Lang-Wojtasik/Werner Sacher (Hrsg.): Handbuch Schule. Theorie – Organisation – Entwicklung. Bad Heilbrunn: Klinkhardt 2009, 608 S
Iteratively regularized Newton-type methods for general data misfit functionals and applications to Poisson data
No full textWe study Newton type methods for inverse problems described by nonlinear operator equations F(u)=g in Banach spaces where the Newton equations F′(un;un+1−un)=g−F(un) are regularized variationally using a general data misfit functional and a convex regularization term. This generalizes the well-known iteratively regularized Gauss–Newton method (IRGNM). We prove convergence and convergence rates as the noise level tends to 0 both for an a priori stopping rule and for a Lepskiĭ-type a posteriori stopping rule. Our analysis includes previous order optimal convergence rate results for the IRGNM as special cases. The main focus of this paper is on inverse problems with Poisson data where the natural data misfit functional is given by the Kullback–Leibler divergence. Two examples of such problems are discussed in detail: an inverse obstacle scattering problem with amplitude data of the far-field pattern and a phase retrieval problem. The performance of the proposed method for these problems is illustrated in numerical examples
Convergence rates in expectation for Tikhonov-type regularization of Inverse Problems with Poisson data
No full textWerner Helsper / Rolf-Thorsten Kramer / Merle Hummrich / Susann Busse: Jugend zwischen Familie und Schule. Eine Studie zu pädagogischen Generationsbeziehungen. Wiesbaden: VS Verlag für Sozialwissenschaften 2009 (440 S.) [Rezension]
No full textRezension von: Werner Helsper / Rolf-Thorsten Kramer / Merle Hummrich / Susann Busse: Jugend zwischen Familie und Schule. Eine Studie zu pädagogischen Generationsbeziehungen. Wiesbaden: VS Verlag für Sozialwissenschaften 2009 (440 S.; ISBN 978-3-531-16574-5; 39,90 EUR)
Sidonie Werner Collection. 1957
No full textThis collection contains 2 letters from Grete Stern describing the work of Sidonie Werner (1957), as well as a brief biographical sheet of Sidonie Werner by another
author (circa 1957). There is also a letter of thanks from Leo Baeck Institute regarding Greta Sterns' efforts to provide information on Werner (1957).Social worker, founder of Jüdischen Frauenbundes (JFB) and Israelitischen Humanitären Frauenvereins (home for senior women) in Hamburg.The original German language inventory is available in the folderProcessed for digitizationLinked to online manifestationdigitize
Inverse problems with Poisson data: Statistical regularization theory, applications and algorithms.
No full textInverse problems with Poisson data arise in many photonic imaging modalities in medicine, engineering and astronomy. The design of regularization methods and estimators for such problems has been studied intensively over the last two decades. In this review we give an overview of statistical regularization theory for such problems, the most important applications, and the most widely used algorithms. The focus is on variational regularization methods in the form of penalized maximum likelihood estimators, which can be analyzed in a general setup. Complementing a number of recent convergence rate results we will establish consistency results. Moreover, we discuss estimators based on a wavelet-vaguelette decomposition of the (necessarily linear) forward operator. As most prominent applications we briefly introduce Positron emission tomography, inverse problems in fluorescence microscopy, and phase retrieval problems. The computation of a penalized maximum likelihood estimator involves the solution of a (typically convex) minimization problem. We also review several efficient algorithms which have been proposed for such problems over the last five years
Werner Warmbrunn Collection. 1885-2006
No full textThe Werner Warmbrunn Collection documents life and professional activities of Werner Warmbrunn and to a smaller extent, members of his immediate family. The collection consists of correspondence, diaries and memoirs, educational documents, printed materials, and unpublished poetry by David Warmbrunn and Werner Warmbrunn. Included in the collection are Werner Warmbrunn’s personal correspondence (mostly from the late 1930s); professional correspondence pertaining to his work at Stanford University and Pitzer College; as well as correspondence of his parents, David and Lilly. However, the core of the collection consists of Werner Warmbrunn’s diaries dating back to the late 1930s. Additionally, there is unpublished poetry by Werner Warmbrunn and David Warmbrunn, printed materials, and photo albums arranged topically by Werner Warmbrunn.Werner Warmbrunn was born on July 3rd, 1920, in Frankfurt am Main, Germany. His father, Dr. David Warmbrunn was a chemist, who owned a commercial laboratory. In 1936 the Warmbrunn family moved to Amsterdam, Holland. In 1939, his parents left Holland and settled in the United States. Werner Warmbrunn remained in Holland and attended a Quaker agricultural boarding school. In 1941 he came to the United States where he stayed with his sister on a farm near Cornell, Ithaca. He earned his BA in 1943 at Cornell University and his Ph.D. in History at Stanford University. Between 1949 and 1952 Werner Warmbrunn served as a Co-Director at the Peninsula School in Menlo Park, California. From 1952 to 1964 he was a foreign student adviser and director at Bechtel International Student Center, Stanford University. In 1963, he was invited to Pitzer College by its president, John Atherton. Werner Warmbrunn helped design the academic programs for the new college (Pitzer College, an undergraduate liberal college was founded in 1963) and developed its community. Werner Warmbrunn is the author of two books: The Dutch Under German Occupation, 1940-1945 and The German Occupation of Belgium 1940-1945. Werner Warmbrunn retired in 1991. He died in 2009.Processeddigitize
Werner Bergengrün Collection. 1941-1966
No full textThis collection contains photocopies of correspondence and obituarial material regarding Werner Bergengrün. There is
also material pertaining to Johannes Urzidil that may or may not be connected with Werner Bergengrün. The earliest correspondence is
to the Urzidils in New York from an acquaintance in England, indicating that the war will get worse but he should visit when it is
over (1941). Following the 1941 Urzidil letter are obituaries for Werner Bergengrün from 1964. There is a 1966 letter from Lotte
Bergengrün to Johannes Urzidil, indicating that Werner was sick for some time and his last poem is dated 1962. The last item in the
collection is a letter from "Fritta B." in Munich to Johannes Urzidil, exchanging greetings.Werner Bergengrün (1892-1964) was a Baltic German author. He married Lotte Hensel, a descendent of Moses
Mendelssohn.Processed for digitizatio
Financial crises in Japan during the 20th century
No full textI have two aims with this paper. Firstly, I would like to extract lessons for theory and policy from Japan’s experience with banking crises. As such, this paper falls into the body of research on banking crises, recent works within which include Caprio and Klingebiel (1996), Caprio et al. (2005), Demirgüç-Kunt and Detragiache (2005), Werner (2005), Beck et al. (2006), and Reinhart and Rogoff (2008). Secondly, I aim to gain insights into the link between the banking sector and the economy (which are again of importance for both theory and policy). This is an important topic that has slowly but steadily grown to a substantial body of literature. Many authors recognise that banks are ‘special’ in some way (Fama, 1985, Bossone, 1999, James and Smith, 2000, Ashcraft, 2005), and that the link between the banking sector and the economy is of great importance (King and Levine, 1996, Levine, 1997). However, the precise details of just what makes banks special, as well as the precise nature of their link to the economy have remained unclear or at least disputed. Analysing crises may help elucidate these issues
- …
