Volumetric MRI Reconstruction from 2D Slices in the Presence of Motion

Despite recent advances in acquisition techniques and reconstruction algorithms, magnetic resonance imaging (MRI) remains challenging in the presence of motion. To mitigate this, ultra-fast two-dimensional (2D) MRI sequences are often used in clinical practice to acquire thick, low-resolution (LR) 2D slices to reduce in-plane motion. The resulting stacks of thick 2D slices typically provide high-quality visualizations when viewed in the in-plane direction. However, the low spatial resolution in the through-plane direction in combination with motion commonly occurring between individual slice acquisitions gives rise to stacks with overall limited geometric integrity. In further consequence, an accurate and reliable diagnosis may be compromised when using such motion-corrupted, thick-slice MRI data. This thesis presents methods to volumetrically reconstruct geometrically consistent, high-resolution (HR) three-dimensional (3D) images from motion-corrupted, possibly sparse, low-resolution 2D MR slices. It focuses on volumetric reconstructions techniques using inverse problem formulations applicable to a broad field of clinical applications in which associated motion patterns are inherently different, but the use of thick-slice MR data is current clinical practice. In particular, volumetric reconstruction frameworks are developed based on slice-to-volume registration with inter-slice transformation regularization and robust, complete-outlier rejection for the reconstruction step that can either avoid or efficiently deal with potential slice-misregistrations. Additionally, this thesis describes efficient Forward-Backward Splitting schemes for image registration for any combination of differentiable (not necessarily convex) similarity measure and convex (not necessarily smooth) regularization with a tractable proximal operator. Experiments are performed on fetal and upper abdominal MRI, and on historical, printed brain MR films associated with a uniquely long-term study dating back to the 1980s. The results demonstrate the broad applicability of the presented frameworks to achieve robust reconstructions with the potential to improve disease diagnosis and patient management in clinical practice

Einstein-Podolsky-Rosen correlations from colliding Bose-Einstein condensates

We propose an experiment which can demonstrate quantum correlations in a physical scenario as discussed in the seminal work of Einstein, Podolsky and Rosen. Momentum-entangled massive particles are produced via the four-wave mixing process of two colliding Bose-Einstein condensates. The particles' quantum correlations can be shown in a double double-slit experiment or via ghost interference.Comment: 5 pages, 5 figures, published versio

Regenerated Cellulose Fiber Solar Cell

Wearable electronics and smart textiles are growing fields in the cause to integrate modern communication and computing tools into clothing instead of carrying around smart phones and tablets. Naturally, this also requires power sources to be integrated in textiles. In this paper, a proof-of-concept is presented in form of a photovoltaic cell based on a commercially available viscose fiber. This has been realized using a silver nanowire network around the viscose fiber to establish electrical contact and a photoactive coating using the standard workhorse among organic thin film solar cells, a blend of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM). Structure and performance of single fiber devices demonstrate their feasibility and functionality. The applied materials and methods are compatible to solution processing therewith qualifying for potential roll-to-roll large-scale production

Die Verwendung von GPS-Empfängern, Geodatenbanken und Webapplikationen als wichtige Werkzeuge in Naturschutzprojekten am Beispiel des Botanischen Gartens der Universität Wien

Der Botanische Garten der Universität Wien beherbergt fast 1500 Bäume und Sträucher. Diesen großen Bestand genau zu dokumentieren und zu verwalten ist eine wichtige Aufgabe. Eine eigene Datenbank sowie ein Gruppen- und Gehölzlageplan stehen zur Verfügung. Ziel dieser Diplomarbeit war es, Teile dieser Daten allen interessierten Besuchern online zur Verfügung zu stellen. In der Vorbereitungsphase wurde eine Geodatenbank zum Speichern und Verwalten aller relevanten Geo- und Sachdaten installiert und eingerichtet. Der Schwerpunkt lag in der Installation und Administration von Geodatenbanken mit besonderem Bezug auf Mehrbenutzersysteme. Alle bereits vorhandenen Daten wurden in diese Geodatenbank importiert. Aus Teilen dieser Daten wurde anschließend ein Projekt für eine mobile GIS Software erstellt, welches für die gesamte Freilandarbeit eingesetzt wurde. Durch den Einsatz eines Handheld GPS Computers wurden Bäume und Sträucher aus dem Botanischen Garten räumlich verortet. Die neu gewonnenen Daten wurden anschließend wieder in die Geodatenbank importiert und mit Hilfe einer Desktop GIS Anwendung aufbereitet. Im letzten Teil dieser Diplomarbeit wurde durch den kombinierten Einsatz einer modernen GIS Serversoftware und einer integrierten Entwicklungsumgebung eine Webapplikation entwickelt. Über diese Webapplikation, welche sowohl in einer deutschen als auch in einer englischen Version verfügbar ist, können nun alle interessierten Besucher aktuelle Informationen über den Bestand, das natürliche Vorkommen und durch die verlinkten Webseiten zahlreiche weitere Informationen über die Bäume und Sträucher aus dem Botanischen Garten online abfragen. Die Applikation ist über die Internetadresse http://biodiv3.biodiv.univie.ac.at/hbv erreichbar.The Botanical Garden of the University of Vienna is home to nearly 1,500 trees and shrubs. Documenting and managing this large stock is an important task. A database as well as a group- and a site plan of all wood are available. The aim of this thesis was to provide parts of these data online for all interested visitors. In the preparatory phase, a spatial database for storing and managing all relevant data was set up. The main focus was on the installation and administration of spatial databases with particular reference to multi-user systems. All existing data were imported into this so called Geodatabase. Parts of these data were used to create a project for mobile GIS-software, which was then used for field work. By using a handheld GPS computer, trees and shrubs in the Botanical Gardens were located. The newly obtained data were then imported into the Geodatabase and preprocessed by a desktop GIS application. In the last part of this thesis a web application was developed by combining the use of modern GIS server software and an integrated development environment. By means of this web application, which is available in a German and an English version, all interested visitors can get up-to-date information on the existence, the natural occurrence and, by links to numerous other websites, more information about the trees and shrubs of the Botanical Garden online. The application is available via the URL http://biodiv3.biodiv.univie.ac.at/hbv_e

Flächendeckende Entsorgung bis 2005. Liegt Brandenburg in der Zeit?

Der Begriff „Abwasserentsorgung“ entbindet uns nicht von der Verpflichtung des Kreislaufwirtschafts- und Abfallgesetzes, erst zu entsorgen, wenn wir keine umweltpolitische und wirtschaftliche Möglichkeit zur Verwertung mehr sehen. Schließen wir nicht mit vielen Formulierungen in Gesetzen und Verordnungen über die „Abwasserentsorgung“ diese Pflicht, nach Verwertungsmöglichkeiten zu suchen, von vornherein aus

Potential of EPUB3 for Digital Textbooks in Higher Education

The e-book market is currently in a strong upswing. This research study deals with the question which practical uses the e-book format EPUB3 offers for (higher) education. By means of a didactic content analysis, a range of interactive exercise types were developed as a result of conversations with teachers. For this purpose, a didactic and technical concept has been developed. Different kinds of exercises were prototypically implemented in an e-book. Finally, a brief overview reflects the present state of the current e-book readers. A subsequent discussion illuminates the strengths and weaknesses of the format. In summary, it can be remarked that EPUB3 is suitable for a variety of different exercises and that it is able to serve as a basic format for forthcoming digital textbooks. Furthermore the openness of EPUB3 will assist Open Learning and Teaching in a meaningful way.Comment: Conference, 13 page

Emulation in Practice

Since 1999, determining the viability of emulation as a means to preserve digital assets has been up for debate. Throughout the last twenty years, emulation has been refuted, proven effective, and compared to other digital preservation strategies, like migration, almost simultaneously. This paper analyzes the various considerations involved when using emulation as a digital preservation strategy between 1999 and 2019. Three research methodologies are employed: 1) historical research as described in published literature, 2) case studies described in various sources, and 3) personal open-ended interviews conducted with experts active in the field over the past couple of decades and currently

Goodness-of-fit tests for complete spatial randomness based on Minkowski functionals of binary images

We propose a class of goodness-of-fit tests for complete spatial randomness (CSR). In contrast to standard tests, our procedure utilizes a transformation of the data to a binary image, which is then characterized by geometric functionals. Under a suitable limiting regime, we derive the asymptotic distribution of the test statistics under the null hypothesis and almost sure limits under certain alternatives. The new tests are computationally efficient, and simulations show that they are strong competitors to other tests of CSR. The tests are applied to a real data set in gamma-ray astronomy, and immediate extensions are presented to encourage further work