Linear sufficiency and admissibility in restricted linear models

The linearly sufficient and admissible linear estimators with bounded mean squared error function in linear models with parameter restrictions are identified as special general ridge estimators. This is based on a decomposition result for admissible estimators and on a the characterization of linearly sufficient and admissible estimators in unrestricted models given in MARKIEWICZ (1994) (orig.)Available from TIB Hannover: RO 7722(524) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Verbesserung des benutzerorientierten Zugriffs auf fachspezifische Online-Datenbanken und CD-ROM fuer Mathematische Institute der Bundesrepublik Deutschland Fachlicher Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(40,28) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Some minimal non-orientedable matroids of rank three

SIGLEAvailable from TIB Hannover: RO 7722(226) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Subdifferentiability and Lipschitz continuity in experimental design problems

In this paper we make use of generalized gradients in the sense of Rockafellar (1980) and Clarke (1983). A chain rule is presented for the subdifferential of the composition of an information function with the moment matrix mapping. Lipschitz continuity of the global design function is proved and conditions for strict differentiability are givenAvailable from TIB Hannover: RO 7722(487) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Numerical simulation of Czochralski crystal growth

SIGLEAvailable from TIB Hannover: RO 7722(263) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Entwicklung effizienter Algorithmen zur numerischen Loesung der 3D Neutronentransportgleichungen in Kernreaktoren Abschlussbericht

Examination of the steady-state and transient performance of a nuclear power plant requires simulation of the neutron kinetics and thermohydraulic processes in the reactor, coupled with simulation of the processes for cooling loop and plant control. Siemens AG, KWU makes available for these examinations an integrated program package. Work reported here was to enhance the simulation of the neutron kinetics. An efficient algorithm was developed, analysed and implemented, enabling simultaneous calculation of the neutron flux and neutron streams on the basis of multigroup diffusion equations. The algorithm uses the method of mixed hybridisation and achieves both an efficient multilevel-based iterative solution and a coupled, automatic time increment control and adaptivity for given locality. Extensive simulations were performed for examination of benchmark problems for the IAEA and incidents in real nuclear power plants. (orig./CB)Die Untersuchung des stationaeren und transienten Betriebsverhaltens von Kernkraftwerken erfordert die gekoppelte Simulation der neutronenkinetischen und thermohydraulischen Ablaeufe im Kernreaktor und der Kuehlkreislauf- und Gesamtanlagenregelung. Dazu steht beim industriellen Verbundpartner (Siemens AG, Abt. KWU) ein integriertes Programmpaket zur Verfuegung. Zur Verbesserung der Simulation der Neutronenkinetik wurde im Rahmen dieses Projekts ein effizienter Algorithmus entwickelt, analysiert und implementiert, der die simultane Berechnung der Neutronenfluesse und -stroeme auf der Grundlage der Mehrgruppen-Diffusionsgleichungen ermoeglicht. Der Algorithmus verwendet die Technik der gemischten Hybridisierung und realisiert sowohl einen effizienten Multilevel basierten iterativen Loeser als auch eine gekoppelte automatische Zeitschrittweitensteuerung und Adaptivitaet im Ort. Umfangreiche Simulationen wurden durchgefuehrt fuer Benchmarkprobleme der Internationalen Atomenergiebehoerde und fuer Stoerfaelle in realen Kernkraftanlagen. (orig.)Available from TIB Hannover: DtF QN1(62,38) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

E-optimal designs in weighted polynomial regression

Based on a duality between E-optimality for (sub-) parameters in weighted polynomial regression and a nonlinear approximation problem of Tchebycheff type, in many cases the optimal approximate designs on nonnegative and nonpositive experimental regions [a,b] are found to be supported by the extrema of the only equi-oscillating weighted polynomial over this region with leading coefficient 1. A similar result is stated for regression on symmetric regions [-b,b] for certain sub-parameters, provided the region is 'small enough', e.g. b#<=#1. In particular, by specializing the weight function we obtain results of PUKELSHEIM STUDDEN (1991) and DETTE (1992). (orig.)Available from TIB Hannover: RO 7722(445) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Average complexity of a gift-wrapping algorithm for determining the convex hull of randomly given points

This paper presents an algorithm and its probabilistic analysis for constructing the convex hull of m given points in R"n, the n-dimensional Euclidean space. The algorithm under consideration combines the Gift-Wrapping-concept with the so-called Throw-Away-Principle for nonextremal points. In this paper the Simplex-Method is used to organize a walk over the surface of the convex hull. During this walk all facets are discovered. Under the condition of general position this information is sufficient, because the whole face-lattice can simply be deduced when the set of facets is availableSIGLEAvailable from TIB Hannover: RO 7722(478) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Subdifferentiability and Lipschitz continuity in experimental design problems

In this paper we make use of generalized gradients in the sense of Rockafellar (1980) and Clarke (1983). A chain rule is presented for the subdifferential of the composition of an information function with the moment matrix mapping. Lipschitz continuity of the global design function is proved and conditions for strict differentiability are givenAvailable from TIB Hannover: RO 7722(487) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Stellar structure and evolution Equations and model physics

SIGLEAvailable from TIB Hannover: RO7722(417) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman