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Institute
Today, augmented reality is becoming more and more important in several areas like industrial sectors, medicine, or tourism. This gain of importance can easily be explained by its powerful extension of real world content. Therefore, augmented realty became a way to explain and enhance the real world information. Yet, to create a system which can enhance a scene with additional information, the relation between the system and the real world must be known. In order to establish this relationship a commonly used method is optical tracking. The system calculates its relation to the real world from camera images. To do so, a reference which is known is needed in the scene to serve as an orientation. Today, this is mostly a 2D-marker or a 2D-texture. These are placed in the real world scenery to serve as a reference. But, this is an intrusion in the scene. That is why it is desirable that the system works without such an additional aid. An strategy without manipulating the scene is object-tracking. In this approach, any object from the scene can be used as a reference for the system. As an object is far more complex than a marker, it is harder for the system to establish its relationship with the real world. That is why most methods for 3D-object-tracking reduce the object by not using the whole object as reference. The focus of this thesis is to research how a whole object can be used as a reference in a way that either the system or the camera can be moved in any 360 degree angle around the object without loosing the relation to the real world. As a basis the augmented reality framework, the so called VisionLib, is used. Extensions to this system for 360 degree tracking are implemented in different ways and analyzed in the scope of this work. Also, the different extensions are compared. The best results were achieved by improving the reinitialization process. With this extension, current camera images of the scene are given to the system. With the hek of these images, the system can calculate the relation to the real world faster in case the relation went missing.
Web application testing is an active research area. Garousi et al. did a systematic mapping study and classified 79 papers published between 2000-2011. However, there seems to be a lack of information exchange between the scientific community and tool developers.
This thesis systematically analyzes the field of functional, system level web application testing tools. 194 candidate tools were collected in the tool search and screened, with 23 tools being selected as foundation of this thesis. These 23 tools were systematically used to generate a feature model of the domain. The methodology to support this is an additional contribution of this thesis. It processes end user documentation of tools belonging to an examined domain and creates a feature model. The feature model gives an overview over the existing features, their alternatives and their distribution. It can be used to identify trends and problems, extraordinary features, help decision making of tool purchase or guide scientists how to focus research.
Software systems are often developed as a set of variants to meet diverse requirements. Two common approaches to this are "clone-and-owning" and software product lines. Both approaches have advantages and disadvantages. In previous work we and collaborators proposed an idea which combines both approaches to manage variants, similarities, and cloning by using a virtual platform and cloning-related operators.
In this thesis, we present an approach for aggregating essential metadata to enable a propagate operator, which implements a form of change propagation. For this we have developed a system to annotate code similarities which were extracted throughout the history of a software repository. The annotations express similarity maintenance tasks, which can then either be executed automatically by propagate or have to be performed manually by the user. In this work we outline the automated metadata extraction process and the system for annotating similarities; we explain how the implemented system can be integrated into the workflow of an existing version control system (Git); and, finally, we present a case study using the 101haskell corpus of variants.
Heat exchangers are used for thickening of various products or desalination of saltwater. Nevertheless, they are used as cooling unit in industries. Thereby, the stainless steel heat transferring elements get in contact with microorganism containing media, such as river water or saltwater, and corrode. After at least two years of utilization the material is covered with bacterial slime called biofilm. This process is called biofouling and causes loss in efficiency and creates huge costs depending on cleaning technique and efficiency. Cleaning a heat exchanger is very expensive and time consuming. It only can be done while the device is out of business.
Changing the surface properties of materials is the best and easiest way to lengthen the initial phase of biofilm formation. This leads to less biofouling (Mogha et al. 2014).
Thin polymer films as novel materials have less costs in production than stainless steel and are easy to handle. Furthermore, they can be functionalzed easily and can be bougth in different sizes all over the world. Because of this, they can reduce the costs of cleaning techniques and lead to a longer high efficiency state of the heat exchanger. If the efficiency of the heat exchanger decreases, the thin polymer films can be replaced.
For a successful investigation of the microbial and the process engineering challenges a cooperation of Technical University of Kaiserslautern (chair of seperation science and technology) and University of Koblenz-Landau (working goup microbiology) was established.
The aim of this work was design engineering and production of a reactor for investigation of biofouling taking place on thin polymeric films and stainless steel. Furthermore, an experimental design has to be established. Several requirements have to be applied for these tasks. Therefore, a real heat exchanger is downscaled, so the process parameters are at least comparable. There are many commercial flow cell kits available. Reducing the costs by selfassembling increased the number of samples, so there is a basis for statistic analysis. In addition, fast and minimal invasive online-in-situ microscopy and Raman spectroscopy can be performed. By creating laminary flow and using a weir we implemented homogenous inflow to the reactors. Reproduceable data on biomass and cell number were created.
The assessment of biomass and cell number is well established for drinking water analysis. Epifluorescense microscopy and gravimetric determination are the basic techniques for this work, too. Differences in cell number and biomass between surface modifications and materials are quantified and statistically analysed.
The wildtype strain Escherichia coli K12 and an inoculum of 500 ml fresh water were used to describe the biofouling of the films. Thereby, we generated data with natural bacterial community in unknown media properties and data with well known media properties, so the technical relevance of the data is given.
Free surface energy and surface roughness are the first attachment hurdles for bacteria. These parameters were measured according to DIN 55660 and DIN EN ISO 4287. The materials science data were correlated with the number of cells and the biomass. This correlation acts as basal link of biofouling as biological induced parameter to the material properties. Material properties for reducing the biofouling can be prospected.
By using Raman spectroscopy as a cutting edge method future investigations could be shortened. If biomass or cell number can be linked with the spectra, new functional materials can be investigated in a short time.
Code package managers like Cabal track dependencies between packages. But packages rarely use the functionality that their dependencies provide. This leads to unnecessary compilation of unused parts and to speculative conflicts between package versions where there are no conflicts. In two case studies we show how relevant these two problems are. We then describe how we could avoid them by tracking dependencies not between packages but between individual code fragments.
This thesis conducts a text and network analysis of criminological files. The specific focus during the research is the field money laundering. The analysis showed the most important concepts present in the text which were classified in eleven different classes. The relationships of those concepts were analysed using ego networks, key entity identification and clustering. Some of the statements given about money laundering could be validated by the findings of this analysis and their interpretation. Specific concepts like banks and organizations as well as foreign subsidiaries were identified. Aggregating these concepts with the statements in chapter 1.4.3 on the circular process of money laundering it can be stated that different organizations and individuals, present in the criminological files, were placing money through different banks, organizations and investments in the legal financial market. At last this thesis tries to validate the benefits of the used tools for the kind of conducted research process. An estimation on ORA's and Automap's applicability for this kind of research is given in the end.
Einfluss eines Ausrichtungswerkzeugs auf die Bedienbarkeit in unbeaufsichtigten Eyetrackingsystemen
(2015)
Eye gaze trackers are devices that can estimate the direction of gaze of a person. Among usability testing eye tracking also allows persons with decreased limb mobility to control or to interact with the computer. The quality and availability of eye tracking equipment has been increasing while costs have been decreasing. This development leads to entering new markets by using eye tracking as an additional input dimension for a variety of applications. Up to now eye tracking has been supervised by qualified experts, who assured that the important conditions like position in front of the eye tracking device, calibration and light conditions has been kept, while using.
This thesis examines an adjustment tool, which is helping the user to adjust in front of the eye tracker and helping to keep this position during the experiment. Furthermore the accuracy while moving the head has been analysed. In this experiment an remote eye gaze tracker has been used to control a game character in the video game called 'Schau Genau!'. The goal was to determine whether the game is playable without the barrier of adjusting and calibration. The results show that adjusting in front of an eye tracker is not a problem, keeping this position is. Small changes of the head position after the calibration process leads to a lack of accuracy. Giving up the calibration and using someone else calibration shows way bigger deviation. Additional head movement increases error rate and makes controlling more difficult.
In current research of the autonomous mobile robots, path planning is still a very important issue.
This master's thesis deals with various path planning algorithms for the navigation of such mobile systems. This is not only to determine a collision-free trajectory from one point to another. The path should still be optimal and comply with all vehicle-given constraints. Especially the autonomous driving in an unknown and dynamic environment poses a major challenge, because a closed-loop control is necessary and thus a certain dynamic of the planner is demanded.
In this paper, two types of algorithms are presented. First, the path planner, based on A*, which is a common graph search algorithm: A*, Anytime Repairing A*, Lifelong Planning A*, D* Lite, Field D*, hybrid A*. Second, the algorithms which are based on the probabilistic planning algorithm Rapidly-exploring Random Tree (Rapidly-exploring Random Tree, RRT*, Lifelong Planning RRT*), as well as some extensions and heuristics. In addition, methods for collision avoidance and path smoothing are presented. Finally, these different algorithms are evaluated and compared with each other.
Im Rahmen dieser Arbeit wird untersucht, wie sich Modellfehler auf die Positionsgenauigkeit und Handhabbarkeit beim Rangieren mit einem Fahrerassistenzsystem auswirken. Besonderer Wert wird dabei auf die Bestimmung von Fehlergrenzen gelegt. Es wird der Frage nachgegangen, wie groß der Eingangsfehler sein darf, damit die Assistenz noch hinreichende Qualitätseigenschaften hinsichtlich ihrer Präzision und Robustheit aufweist. Dazu erfolgt zunächst eine quantitative Betrachtung der Fehler anhand des kinematischen Modells. Danach wird eine qualitative Betrachtung anhand von systematischen Experimenten durchgeführt. Es wird zunächst ein Controller entwickelt, mit dem sich ein Manöver mithilfe der visuellen Informationen der Assistenz simulieren lässt.
Dann wird eine Methode vorgestellt, mit deren Hilfe man das Manöver anhand definierter Fehlergrenzen bewerten kann. Um einen großen Raum möglicher Fehlerkombinationen effizient zu durchsuchen, wird das probabilistische Verfahren des Annealed Particle Filters benutzt. Mithilfe einer Testumgebung werden schließlich systematische Experimente durchgeführt. Zur weiteren Evaluation des Assistenzsystems in einer kontrollierten Umgebung erfolgte in Zusammenarbeit mit dem Fraunhofer ITWM in Kaiserslautern die Portierung des Assistenzsystems auf die dortige Simulationsumgebung RODOS.
In der vorliegenden Arbeit sollen weltweit herrschende inhaltliche Ausprägungen und Schwerpunkte des Themengebiets "BMI" bzw. "GMI" mit Hilfe des Literatur-Reviews akademischer Artikel herausgearbeitet werden. Die festgestellten Beziehungen und Zusammenhänge sollen visualisiert und lokalisiert werden, um eine globale Sicht über das Thema herzustellen. Unter anderem sollen die in das finale Set aufgenommenen Artikel auf eine Korrelation zwischen BMI und Controlling bzw. Management hin überprüft werden. Als letzter Schritt soll eine Ableitung möglicher Forschungslücken unternommen werden.