With the appearance of modern virtual reality (VR) headsets on the consumer market, there has been the biggest boom in the history of VR technology. Naturally, this was accompanied by an increasing focus on the problems of current VR hardware. Especially the control in VR has always been a complex topic. One possible solution is the Leap Motion, a hand tracking device that was initially developed for desktop use, but with the last major software update it can be attached to standard VR headsets. This device allows very precise tracking of the user’s hands and fingers and their replication in the virtual world. The aim of this work is to design virtual user interfaces that can be operated with the Leap Motion to provide a natural method of interaction between the user and the VR environment. After that, subject tests are performed to evaluate their performance and compare them to traditional VR controllers.

The dissertation examines the self-concept of Indian religious women in German care institutions. For the analysis, the method of grounded theory was selected from empirical social research. The investigation field interviewed 26 Indian religious women and 5 employers. The theoretical foundations of mission history were the standard of the missionary ministry, the expression of the German and Indian concept of care, the concept of culture in its structural conditionality of dimensions and models with reference to the organization "religious community". The direct relation to the research question was served by the hierarchical self-concept model according to Shalveson and another model by Bracken, which was used to interpret the empirical results. In the five core categories and their subcategories, the main motive was "being a missionary". Indian religious women refer to themselves as "European missionaries" and want to bring the love of Christ to the sick, the needy and the elderly through their care and nursing work. In order for the Indian religious women to be able to work even more optimally in their self-concept in Germany, it is advisable to develop a requirement profile, to consider certain framework conditions in advance and to design new models of life.

This bachelor thesis investigates the utilization of the Wii Balance Board in virtual reality applications. For the investigation a snowboard game is implemented, in which the virtual avatar can be controlled with the pressure sensors of the Wii Balance Board. The user should be able to move playfully and intuitively through the virtual environment by balancing his body. The immersiveness and the influence on motion sickness and cybersickness will be investigated. In Addition, the Wii Balance Board will be compared with the Xbox Controller. The aim of the work is to evaluate whether the Wii Balance Board is able to allow free movement in virtual environments and whether it is more advantageous to use it rather than a conventional controller. The results of the survey indicate that the Wii Balance Board has a positive influence on the immersivness of the game, despite better game results by using a conventional controller. The survey also reveals that the use of the Wii Balance Board is responsible for more motion-sickness/cybersickness cases.

In the present dissertation, the structural interaction between potassium waterglass and aluminium metaphosphates (aluminium tetrametaphosphate and aluminium hexametaphosphate) were investigated in terms of the resettlement behaviour of the metaphosphates as hardening agents. The crystalline phase composition was described qualitatively and quantitatively in terms of powder diffraction patterns combined with Rietveld refinement. The amorphous phase content was determined by different spectroscopic methods (e.g. solid-state NMR, ATR-IR, and Raman spectroscopy). The solubility behaviour of the chemical hardening agents was investigated by optical emission spectroscopy and electron absorption spectroscopy. The mechanical properties of the samples were measured by three-point bending tests, resonance damping frequency analysis, and acid test. The structural framework of the chemically hardened waterglasses was explored by scanning electron microscopy method. It could be proven, that the reaction mechanism of the resettlement is strongly dependent on the structure of the aluminium metaphosphate. After the dissolution of the aluminium ions of aluminium tetrametaphosphate through the alkalic environment of the potassium waterglass, a potassium tetrametaphosphate is developed through an ion-exchange reaction with the waterglass` potassium ions. In the hexametaphosphate system, no analogous structure could be proven. Parallel to the ion-exchange reaction an incremental depolymerization of the cyclic metaphosphate structure to the final crystalline product potassium dihydrogen phosphate occurs. The drop in pH value due to the addition of the respective aluminium metaphosphate initiates a polycondensation of the potassium waterglass due to the decreasing stabilization of the waterglass. This process is increased by the depolymerization products of the metaphosphate, that remove further quantities of the alkali ions, which accelerates the polycondensation reaction due to a further decrease in pH value. The dissolved aluminium ions from the aluminium metaphosphate penetrate into the amorphous, hardening silica network and develops an alumosilicate binder matrix. Furthermore, amorphous hydrated aluminium phosphate phases develop in separate domains beside silicate, alumosilicate phases, and the crystalline phase contents e.g. potassium dihydrogenphosphate and the incomplete reacted aluminium metaphosphate. Consequently, the chemically hardened potassium waterglass binder is not necessarily homogenous. Regarding the mechanical and chemical properties, in summary with increasing alkali modulus the mechanical flexural strength, and the young modulus drop, while the chemical resistance towards acid attack, and the porosity of the samples increase. The change in the cyclic structure from aluminium tetrametaphosphate to aluminium hexametaphosphate leads to a drop in the acid resistance, the porosity of the samples, the flexural strength, and the young modulus.

NURBS sind eine Art von Splines, die besondere Eigenschaften besitzen. Das ray tracen von NURBS ist eine der Darstellungsmöglichkeiten von NURBS. Dies ist durch das konkrete berechnen von Schnittpunkten mit Strahlen möglich. Durch die vielseitige Möglichkeiten der Modellierung mittels NURBS sind diese beliebt in Anwendungen die im Maschinenbau verwendet werden und auch anderen CAD-Programmen. Diese Arbeit befasst sich mit der Berechnung von NURBS-Kurven und -Oberflächen, dem direkten rendern von diesen und wägt ab ob sich der Aufwand dafür im Vergleich zu Tesselierung lohnt.

In this master's thesis the principle of hybrid ray tracing, consisting of a rasterization pipeline which includes ray tracing techniques for certain effects, is explained and the implementation of an application which uses a hybrid approach in which ray tracing is used to calculate shadows, ambient occlusion, and reflections and combines those with direct lighting is documented and explained. Hybrid ray tracing is based on the idea of combining the performance and flexibility of rasterization-based approaches with ray tracing to overcome the limitation of not being able to access the complete surrounding geometry at any point in the scene. While describing the implementation of said application, the RTX API which is being used for ray tracing is explained as well Vulkan, the graphics API used. Based on the results and the insights gained while using the RTX API, it is assessed in regards of its usage scenarios and technical sophistication.

The mitral valve is one of four human heart valves. It is located in the left heart and acts as a unidirectional passageway for blood between the left atrium and the left ventricle. A correctly functioning mitral valve prevents a backflow of blood into the pulmonary circulation (lungs) and thus constitutes a vital part of the cardiac cycle. Pathologies of the mitral valve can manifest in a variety of symptoms with severity ranging from chest pain and fatigue to pulmonary edema (fluid accumulation in the tissue and air space of lungs), which may ultimately cause respiratory failure. Malfunctioning mitral valves can be restored through complex surgical interventions, which greatly benefit from intensive planning and pre-operative analysis. Visualization techniques provide a possibility to enhance such preparation processes and can also facilitate post-operative evaluation. The work at hand extends current research in this field, building upon patient-specific mitral valve segmentations developed at the German Cancer Research Center, which result in triangulated 3D models of the valve surface. The core of this work will be the construction of a 2D-view of these models through global parameterization, a method that can be used to establish a bijective mapping between a planar parameter domain and a surface embedded in higher dimensions. A flat representation of the mitral valve provides physicians with a view of the whole surface at once, similar to a map. This allows assessment of the valve's area and shape without the need for different viewing angles. Parts of the valve that are occluded by geometry in 3D become visible in 2D. An additional contribution of this work will be the exploration of different visualizations of the 3D and 2D mitral valve representations. Features of the valve can be highlighted by associating them with specified colors, which can for instance directly convey pathology indicators. Quality and effectiveness of the proposed methods were evaluated through a survey conducted at the Heidelberg University Hospital.

Small headwater streams comprise most of the total channel length and catchment area in fluvial networks. They are tightly connected to their catchments and, thus, are highly vulnerable to changes in catchment hydrologic budgets and land use. Although these small, often fishless streams are of little economic interest, they are vital for the ecological and chemical state of larger water bodies. Although numerous studies investigate the impact of various anthropogenic stressors or altered catchment conditions, we lack an in-depth understanding of the natural conditions and processes in headwater streams. This natural state, however, largely affects how a headwater stream responds to anthropogenic or climatic changes. One of the major threats to aquatic ecosystems is the excessive anthropogenic input of nutrients leading to eutrophication. Nutrients exert a bottom-up effect in the food web, foremost affecting primary producers and their consumers, i.e. periphyton and benthic grazers in headwater streams. The periphyton-grazer link is the main path of autochthonous (in-stream) production into the stream food web and the strength of this link largely determines the effectiveness of this pathway. Therefore, this thesis aims at elucidating important biological processes with the explicit focus on periphyton-grazer interactions. I assessed different aspects of periphyton-grazer interactions using laboratory experiments to solve methodological problems, and using a field study to compare the benthic communities of three morphologically similar, phosphorus-limited, near-natural headwater streams. With the results of the laboratory experiments, I was able to show that periphyton RNA/DNA ratios can be used as proxy for periphyton growth rates in controlled experiments and that the fatty acid composition of grazing mayfly nymphs responds to changes in fatty acids provided by the diet after only two weeks. The use of the RNA/DNA ratio as a proxy for periphyton growth rate allows a comparison of these growth rates even in simple experimental set-ups and thereby permits the inclusion of this important process in ecotoxicological or ecological experiments. The observed fast turnover rates of fatty acids in consumer tissues show that even short-term changes in available primary producers can alter the fatty acid composition of primary consumers with important implications for the supply of higher trophic levels with physiologically important polyunsaturated fatty acids. With the results of the field study, I revealed gaps in the understanding of the linkages between catchment and in-stream phosphorus availability under near-natural conditions and demonstrated that seemingly comparable headwater streams had significantly different benthic communities. These differences most likely affect stream responses to environmental changes.

The goal of this master thesis was to develop a CRM system for the Assist team of CompuGroup Medical that is aiding in integrating open innovation into the development of the Minerva 2.0 software. To achieve this, CRM methodology has been combined with Social Networking Systems, following the research of Lin and Chen (2010, pp. 11 – 30). To achieve the predefined goals literature has been analyzed on how to successfully im- plement a CRM system as well as an online community. Subsequently the results have been applied to the development of the Minerva Community according to the guidelines of Design Science suggested by Hevner et al. (2004, pp. 75 – 104). The finished product is designed based on customer and management requirements and evaluated from a customer and company perspective.

Dieses Dokument umfasst den dritten Zwischenbericht zum Projekt GeKOS – Gemeinsam entdecken Kinder ihren Ort mit Studierenden, der im Oktober 2018 an die Schöpflin-Stiftung übergeben wurde. Das Projekt GeKOS wird vom Ministerium für Wissenschaft, Weiterbildung und Kultur des Landes Rheinland-Pfalz im Rahmen der Programmbudgets Hochschulpakt III sowie von der Schöpflin-Stiftung mit Sitz in Lörrach von 2016 bis 2020 finanziell gefördert. Zudem gewährte das rheinland-pfälzische Ministerium für Integration, Familie, Kinder, Jugend und Frauen im Jahr 2015 eine Anschubfinanzierung.