Ein zentrales Problem der quantitativen Texturanalyse ist die numerische Inversion der eindimensionalen Radontransformation auf der Lie--Gruppe SO(3) aller Rotationen im dreidimensionalen euklidischen Raum. In der vorliegenden Dissertation wird die Lösbarkeit und Eindeutigkeit dieses inversen Problems untersucht und Fehlerabschätzungen unter Berücksichtigung unvollständiger und fehlerbehafteter Daten hergeleitet. Weiterhin wird ein Algorithmus zur Lösung des inversen Problems vorgeschlagen, welcher auf einer Diskretisierung mittels radialer Basisfunktionen basiert und schnelle Fouriermethoden auf der Kugel und der Lie-Gruppe SO(3) benutzt. In numerischen Tests wird gezeigt, dass der Algorithmus für die Rekonstruktion scharfer Texturen aus Beugungsdaten gemessen auf einem hochauflösenden, ungleichmäßigen Messraster geeignet ist.

Thèse de doctorat : Physique et instrumentation nucléaire : Strasbourg 1 : 2008. / Titre provenant de l'écran-titre. Bibliogr. p. 126-130.

Neutrino oscillation experiments have shown de nite evidence for non-zero neutrino masses. However, these experiments only tell us about neutrino mass di erences, and nothing about the absolute masses themselves. The observation of neutrinoless double-beta (0 ) decay, a hypothetical nuclear transition, would provide the rst absolute mass scale measurement of the neutrino outside of cosmology. This decay would imply the neutrino to be a Majorana particle, the rst fermion of its kind. 0 decay would also be the rst observation of lepton number violation. The Enriched Xenon Observatory (EXO) is currently searching for 0 decay in 136Xe with a half-life greater than 1025 years. EXO-200 is the rst experiment of the EXO physics program, which has observed twoneutrino double beta decay (2 ) in 136Xe for the rst time, with a half-life of 2:165 0:075 1021 years [1]. This is the longest measured half-life to date. EXO is now designing a 5-tonne scale detector, nEXO, to be sensitive to the inverted-scale hierarchy. Despite the careful selection of radiopure substances for the detector, the existence of trace levels of 222Rn is inevitable. One of the daughters of 222Rn, 214Bi, can emit photons at the Q-value for 0 decay, making it a critical background. This dissertation investigates the method of Rn removal from gaseous Xe through the use of a Cu wool trap.

This thesis contains three articles. The first two concern inversion andlocal injectivity of the weighted Radon transform in the plane. The thirdpaper concerns two of the key results from compressive sensing.In Paper A we prove an identity involving three singular double integrals.This is then used to prove an inversion formula for the weighted Radon transform,allowing all weight functions that have been considered previously.Paper B is devoted to stability estimates of the standard and weightedlocal Radon transform. The estimates will hold for functions that satisfy an apriori bound. When weights are involved they must solve a certain differentialequation and fulfill some regularity assumptions.In Paper C we present some new constant bounds. Firstly we presenta version of the theorem of uniform recovery of random sampling matrices,where explicit constants have not been presented before. Secondly we improvethe condition when the so-called restricted isometry property implies the nullspace property. / <p>QC 20140228</p>

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No description available.

Thesis (Ph. D.)--University of Hong Kong, 2007.

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Typescript. Includes vita and abstract. Includes bibliographical references (leaves 98-99). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Universiẗat, Diss., 2002--Kiel.