Application Frameworks Technology in Theory and Practice

Application frameworks is a technology concerning with building and implementing reusable software artefacts. Most current application frameworks are object-oriented and often domain specific. Advocates of application frameworks claim that the technology is one of the most promising technologies supporting large-scale reuse, increasing the productivity and quality, and reducing the cost of software development. Many of them project that the next decade would be the major challenge for the development and deployment of the technology. The objective of this study is to investigate the theory and practice of application frameworks and to determine if it has made a difference in systems development. The study indicates that the technology is still immature and not yet to be another silver bullet but potential is imminent

Automatische Kompatibilitätsprüfung Framework-basierter Anwendungen

Software-Frameworks als erweiterbare Software-Architekturbausteine bieten besondere Vorteile. Sie erlauben sowohl die Wiederverwendung der Funktionalität als auch der durch das Framework vorgegebenen Software-Architektur. Beispiele sind Frameworks für Benutzungsoberflächen oder für die Anbindung von Datenbanken. Durch Implementierung anwendungsspezifischer Erweiterungen wird ein Framework für den konkreten Anwendungsfall angepasst. Eine Anwendung, deren Software-Architektur ein Framework einsetzt, benutzt das Framework über dessen Erweiterungspunkte.Im Laufe der Evolution einer solchen Anwendung entsteht häufig die Situation, dass das Framework durch eine neuere Version aktualisiert werden soll. Die Aktualisierung enthält das Risiko, dass Inkompatibilitäten zwischen bestehender Anwendung und neuer Framework-Version auftreten, die wiederum zu aufwendigen Anpassungen führen. Daher müssen mögliche Inkompatibilitäten vor der Aktualisierung erkannt und bewertet werden. Nach aktuellem Stand der Technik ist dies nicht möglich, so dass es in der industriellen Praxis zu unvorhergesehenen Problemen verbunden mit hohen Kosten kommt.Wir stellen ein Verfahren zur automatischen Kompatibilitätsanalyse Framework-basierter Anwendungen vor, mit dem das beschriebene Problem gelöst wird. Durch eine Kombination aus Codeanalyse und neuartiger Framework-Beschreibung lassen sich mögliche Inkompatibilitäten vor Durchführung der Aktualisierung automatisch berechnen. Eine prototypische Implementierung des Verfahrens im Werkzeug »Companian« demonstriert die praktische Einsetzbarkeit unseres Verfahrens.Software frameworks as extensible building blocks have several advantages. They admit to reuse the framework's functionality and its software architecture. Examples are user interface or database connectivity frameworks. A framework is customized by implementing application specific extensions. An application uses a framework through its extension points.During the evolution of such an application the situation arises where the framework has to be updated to a newer version. An update contains the risk of incompatibilities between the existing application and the new framework version. This may result in high efforts for required adjustments. Thus, possible incompatibilities have to be recognized and evaluated before an update is performed. This is not possible in accordance with the current state-of-the-art and results in unforeseen problems accompanied by high consequential costs.We propose a process for an automatic compatibility analysis of framework-based applications that solves the problem. Combining code analysis and a novel framework description our process detects possible incompatibilities before an update is performed. A prototypical implementation in the »Companian« tool demonstrates the practical feasibility of our process.Tag der Verteidigung: 20.12.2012Paderborn, Univ., Diss., 201

Improved 3D MR Image Acquisition and Processing in Congenital Heart Disease

Congenital heart disease (CHD) is the most common type of birth defect, affecting about 1% of the population. MRI is an essential tool in the assessment of CHD, including diagnosis, intervention planning and follow-up. Three-dimensional MRI can provide particularly rich visualization and information. However, it is often complicated by long scan times, cardiorespiratory motion, injection of contrast agents, and complex and time-consuming postprocessing. This thesis comprises four pieces of work that attempt to respond to some of these challenges. The first piece of work aims to enable fast acquisition of 3D time-resolved cardiac imaging during free breathing. Rapid imaging was achieved using an efficient spiral sequence and a sparse parallel imaging reconstruction. The feasibility of this approach was demonstrated on a population of 10 patients with CHD, and areas of improvement were identified. The second piece of work is an integrated software tool designed to simplify and accelerate the development of machine learning (ML) applications in MRI research. It also exploits the strengths of recently developed ML libraries for efficient MR image reconstruction and processing. The third piece of work aims to reduce contrast dose in contrast-enhanced MR angiography (MRA). This would reduce risks and costs associated with contrast agents. A deep learning-based contrast enhancement technique was developed and shown to improve image quality in real low-dose MRA in a population of 40 children and adults with CHD. The fourth and final piece of work aims to simplify the creation of computational models for hemodynamic assessment of the great arteries. A deep learning technique for 3D segmentation of the aorta and the pulmonary arteries was developed and shown to enable accurate calculation of clinically relevant biomarkers in a population of 10 patients with CHD

A component framework for personalized multimedia applications

Eine praktikable Unterstützung für eine dynamische Erstellung von personalisierten Multimedia-Präsentationen bieten bisher weder industrielle Lösungen noch Forschungsansätze. Mit dem Software-technischen Ansatz des MM4U-Frameworks („MultiMedia For You“) wird erstmals eine generische und zugleich praktikable Unterstützung für den dynamischen Erstellungsprozess bereitgestellt. Das Ziel des MM4U-Frameworks ist es den Anwendungsentwicklern eine umfangreiche und anwendungsunabhängige Unterstützung zur Erstellung von personalisierten Multimedia-Inhalten anzubieten und damit den Entwicklungsprozess solcher Anwendungen erheblich zu erleichtern. Um das Ziel eines Software-Frameworks zur generischen Unterstützung der Entwicklung von personalisierten Multimedia-Anwendungen zu erreichen, stellt sich die Frage nach einer geeigneten Software-technischen Unterstützung zur Entwicklung eines solchen Frameworks. Seit der Einführung von objektorientierten Frameworks, ist heute die Entwicklung immer noch aufwendig und schwierig. Um die Entwicklungsrisiken zu reduzieren, sind geeignete Vorgehensmodelle und Entwicklungsmethoden erstellt worden. Mit der Komponenten-Technologie sind auch so genannte Komponenten-Frameworks entstanden. Im Gegensatz zu objekt-orientierten Frameworks fehlt derzeit jedoch ein geeignetes Vorgehensmodell für Komponenten-Frameworks. Um den Entwicklungsprozess von Komponenten-Frameworks zu verbessern ist mit ProMoCF („Process Model for Component Frameworks“) ein neuartiger Ansatz entwickelt worden. Hierbei handelt es sich um ein leichtgewichtiges Vorgehensmodell und eine Entwicklungsmethodik für Komponenten-Frameworks. Das Vorgehensmodell wurde unter gegenseitigem Nutzen mit der Entwicklung des MM4U-Frameworks erstellt. Das MM4U-Framework stellt keine Neuerfindung der Adaption von Multimedia-Inhalten dar, sondern zielt auf die Vereinigung und Einbettung existierender Forschungsansätze und Lösungen im Umfeld der Multimedia-Personalisierung. Mit so einem Framework an der Hand können Anwendungsentwickler erstmals effizient und einfach eine dynamische Erstellung ihrer personalisierten Multimedia-Inhalte realisieren

Super Resolution of HARDI images Using Compressed Sensing Techniques

Effective techniques of inferring the condition of neural tracts in the brain is invaluable for clinicians and researchers towards investigation of neurological disorders in patients. It was not until the advent of diffusion Magnetic Resonance Imaging (dMRI), a noninvasive imaging method used to detect the diffusion of water molecules, that scientists have been able to assess the characteristics of cerebral diffusion in vivo. Among different dMRI methods, High Angular Resolution Diffusion Imaging (HARDI) is well known for striking a balance between ability to distinguish crossing neural fibre tracts while requiring a modest number of diffusion measurements (which is directly related to acquisition time). HARDI data provides insight into the directional properties of water diffusion in cerebral matter as a function of spatial coordinates. Ideally, one would be interested in having this information available at fine spatial resolution while minimizing the probing along different spatial orientations (so as to minimize the acquisition time). Unfortunately, availability of such datasets in reasonable acquisition times are hindered by limitations in current hardware and scanner protocols. On the other hand, post processing techniques prove promising in increasing the effective spatial resolution, allowing more detailed depictions of cerebral matter, while keeping the number of diffusion measurements within a feasible range. In light of the preceding developments, the main purpose of this research is to look into super resolution of HARDI data, using the modern theory of compressed sensing. The method proposed in this thesis allows an accurate approximation of HARDI signals at a higher spatial resolution compared to data obtained with a typical scanner. At the same time, ideas for reducing the number of diffusion measurements in the angular domain to improve the acquisition time are explored. Accordingly, the novel method of applying two distinct compressed sensing approaches in both spatial and angular domain, and combining them into a single framework for performing super resolution forms the main contribution provided by this thesis

Generalized parton distributions of the pion: modeling, evolution and observable implications

Yet the Standard Model of particle physics is so far the most successful theory ever conceived in science, with countless of achievements in the description of Nature; still a number of phenomena remains to be properly understood. A paradigmatic example is confinement. Paving the road towards the understanding of such essential feature thus requires a detailed knowledge of hadrons' inside. The main subject covered in this thesis is precisely the study of hadron structure. Nonetheless this is a really broad field. We thus set sights on an exemplary case: The pions. As mesons, they are potentially simpler to describe that other hadrons like the proton. At the same time, as the pseudo Nambu-Goldstone modes associated to the dynamical breakdown of chiral symmetry, its description is of uttermost relevance for the comprehension of the origin of mass in Nature. We thus address the problem of assessing pions' structure, from first principles up to its observable manifestations. This work is thus divided into two parts: First, the issue of a formal description of hadron's structure is addressed. Relying on the role played by Compton scattering as an essential window into hadrons' inside, we review its formal treatment as understood in the generalized Bjorken limit, leading to the introduction of generalized parton distributions (GPDs). Those parametrize the amplitudes for deeply virtual Compton scattering (DVCS) on hadrons to take place, yielding a unique source of information about the way hadrons are built up from elementary constituents. In the second chapter of this dissertation we review the formal definition and primary properties of generalized parton distributions, together with the main strategies allowing for their evaluation. We identify two essential attributes to be fulfilled: Positivity and polynomiality; a task which, regardless, conventional approaches fail to accomplish. In the third chapter of this thesis we face the problem of obtaining models for pion GPDs which fulfill, by construction, these two features. Following an approach to the description of bound-state systems in quantum field theory based on continuum Schwinger methods, we find the hypothesis of decoupling between longitudinal and transverse degrees of freedom at the level of parton dynamics to be associated with the dynamical breakdown of chiral symmetry. On that assumption, a novel family of generalized parton distributions within the DGLAP region is derived and showed to exhibit two striking characteristics: They satisfy the positivity constraints, and are built from the sole knowledge of parton distribution functions. From that point on we exploit the covariant extension strategy, allowing us to find the corresponding ERBL GPDs, such that polynomiality is also fulfilled by construction. Armed with models for pion GPDs that are complete, in the sense that they satisfy every necessary property, the second part of this work thus exploits them in the derivation of their observable manifestations, allowing for a practical assessment of pions' structure as well their benchmarking. To this end, the fourth chapter pursues the necessary evaluation of scale-evolution for GPDs through an effective approach which encompasses some non-perturbative aspects of the procedure. The results hint the crucial role played by gluons in building pions' up, their associated distributions being commensurate with those for quarks. We thus round-off this dissertation by exploiting the evolved models to deliver predictions on event-rates and beam-spin asymmetries as they could be measured at forthcoming electron-ion colliders. The results reveal that indeed DVCS on pions is expected to be measurable at future facilities; and reveals that gluons dominate the response of pions subjected to DVCS, identifying a sign inversion in the beam-spin asymmetries as clear signal for pinning-down the regime for gluon dominance.Pese a la ingente cantidad de resultados derivados del Modelo Estándar de la física de partículas aún existe una gran cantidad de fenómenos que no llegamos a entender completamente. Un ejemplo es el del confinamiento. Un paso esencial para su comprensión es la descripción de la estructura hadrónica. Esta es precisamente la temática de esta tesis, donde se estudia la estructura de piones mediante el formalismo de las distribuciones generalizadas de partones (GPDs, por sus siglas en inglés). Como mesones, los piones deberían ser más sencillos de describir que otros hadrones como el protón. Más aún, debido a su naturaleza dual como estados ligados pero también como bosones Goldstone asociados a la rotura dinámica de simetría quiral, los piones son una pieza fundamental para comprender el origen de la masa en sistemas físicos. Por todo esto esta tesis aborda la descripción de la estructura piónica a primeros principios y evalúa sus manifestaciones en experimentos. El trabajo está dividido en dos partes. Empezando por abordar el problema de la descripción de la estructura hadrónica desde una perspectiva general, el primer capítulo revisa los procesos de scattering Compton en este sentido. Así, la identificación del límite de dispersión profundamente virtual permite la introducción de las GPDs como objectos fundamentales para la descripción de scattering Compton profundamente virtual (DVCS, en inglés). El segundo capítulo se dedica entonces a un análisis detallado de estas, empezando por su definición, propiedades y una discusión detallada sobre toda la información que codifican sobre la estructura hadrónica. En este proceso se encuentra que las llamadas propiedades de "polinomialidad" y "positividad" juegan un papel central en la construcción de modelos de GPDs realistas, y es por tanto satisfacerlas en todo caso. En este sentido es importante destacar que las estrategias convencionales para el cálculo de GPDs no consiguen este objetivo. Con ello, el tercer capítulo de la tesis aborda el problema de construir modelos de GPDs para piones que satisfagan, por construcción, ambas propiedades. Siguiendo una estrategia basada en el método de las ecuaciones de Dyson-Schwinger para la descripción de estados ligados, se encuentra que la hipótesis de desacoplo entre los grados de libertad longitudinales y transversales de la dinámica partónica está íntimamente relacionada con la restauración de la simetría quiral. Explotando dicha hipótesis derivamos una nueva familia de GPDs en la región DGLAP que satisfacen la condición de positividad y para cuya construcción únicamente es necesario el conocimiento de las llamadas funciones de distribución de partones. Partiendo de ese resultado, la estrategia de extensión covariante permite obtener la correspondiente región ERBL, obteniendo por primera vez modelos de GPDs que satisfacen al mismo tiempo y por construcción las condiciones de positividad y polinomialidad. Con el fin de arrojar luz a nuestro entendimiento sobre la estructura de los piones, así como la contrastación de este estudio, la segunda parte del trabajo parte de los mencionados modelos y evalúa sus manifestaciones en los resultados obtenidos en futuros experimentos. Para ello, el capítulo cuatro se encarga de describir la necesaria evolución de GPDs con la escala de renormalización; implementando una estrategia efectiva capaz de abarcar efectos puramente no perturbativos de la interacción fuerte. Los resultados ponen de manifiesto el importante papel del contenido gluónico en la construcción de la estructura de piones. Finalmente, el quinto capítulo describe el cálculo de número de eventos y asimetrías en futuros aceleradores electrón-ion, mostrando que efectivamente estas instalaciones deberían ser capaces de medir DVCS en piones e identificando la inversión en las correspondientes asimetrías como una clara señal experimental capaz de delimitar el régimen en el que los gluones constituyen la parte dominante en la estructura piónica

Reports of Planetary Geology and Geophysics Program, 1990

Abstracts of reports from NASA's Planetary Geology and Geophysics Program are presented. Research is documented in summary form of the work conducted. Each report reflects significant accomplishments within the area of the author's funded grant or contract