004 Datenverarbeitung; Informatik
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Social media platforms such as Twitter or Reddit allow users almost unrestricted access to publish their opinions on recent events or discuss trending topics. While the majority of users approach these platforms innocently, some groups have set their mind on spreading misinformation and influencing or manipulating public opinion. These groups disguise as native users from various countries to spread frequently manufactured articles, strong polarizing opinions in the political spectrum and possibly become providers of hate-speech or extremely political positions. This thesis aims to implement an AutoML pipeline for identifying second language speakers from English social media texts. We investigate style differences of text in different topics and across the platforms Reddit and Twitter, and analyse linguistic features. We employ feature-based models with datasets from Reddit, which include mostly English conversation from European users, and Twitter, which was newly created by collecting English tweets from selected trending topics in different countries. The pipeline classifies language family, native language and origin (Native or non-Native English speakers) of a given textual input. We evaluate the resulting classifications by comparing prediction accuracy, precision and F1 scores of our classification pipeline to traditional machine learning processes. Lastly, we compare the results from each dataset and find differences in language use for topics and platforms. We obtained high prediction accuracy for all categories on the Twitter dataset and observed high variance in features such as average text length especially for Balto-Slavic countries.
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.
The goal of this thesis is to create a recommender system (RS) for business processes, based on the existing ProM plugin RegPFA. To accomplish this task, firstly an interface must be created that sets up and expands a database receiving probabilistic finite automata (PFA) created by RegPFA in tsml format as input. Secondly, a Java program must be designed that uses said database to recommend the process elements that are most likely to follow a given sequence of process elements.
Abstract
This bachelor thesis delivers a comprehensive overview of the topic Internet of Things (IoT). With the help of a first literature review, important characteristics, architectures, and properties have been identified. The main aim of this bachelor thesis is to determine whether the use of IoT in the transport of food, considering the compliance with the cold chain, can provide advantages for companies to reduce food waste. For this purpose, a second literature review has been carried out with food transport systems without the use, as well as with the use of IoT. Based on the literature review, it is possible at the end to determine a theoretical ‘ideal’ system for food transport in refrigerated trucks. The respective used technologies are also mentioned. The findings of several authors have shown that often significant improvements can be achieved in surveillance, transport in general, or traceability of food, and ultimately food waste can be reduced. However, benefits can also be gained using new non-IoT-based technologies. Thus, the main knowledge of this bachelor thesis is that a theoretical ‘ideal’ transport system contains a sensible combination of technologies with and without IoT. This system includes the use of a Wireless Sensor Network (WSN) for real-time food monitoring, as well as an alarm function when the temperature exceeds a maximum. Real-time monitoring with GPS coupled with a monitoring center to prevent traffic jams is another task. Smart and energy-efficient packaging, and finally the use of the new supercooling-technology, make the system significantly more efficient in reducing food waste. These highlights, that when choosing a transport system, which is as efficient and profitable as possible for food with refrigerated transport, companies need not just rely on the use of IoT. On this basis, it is advisable to combine the systems and technologies used so far with IoT in order to avoid as much food waste as possible.
This thesis presents an approach to optimizing the computation of soft shadows from area lights. The light source is sampled uniformly by traversing shadow rays as packets through an N-tree. This data structure stores an additional line space for every node. A line space stores precomputed information about geometry inside of shafts from one to another side of the node. This visibility information is used to terminate a ray. Additionally the graphics processing unit (short GPU) is used to speed up the computations through parallelism. The scene is rendered with OpenGL and the shadow value is computed on the GPU for each pixel. Evaluating the implementation shows a performance gain of 86% by comparison to the CPU, if using the GPU implementation. Using the line space instead of triangle intersections also increases the performance. The implementation provides good scaling with an increasing amount of triangles and has no visual disadvantages for many rays.
This thesis shows an interaction of primitives in a three-dimensional space which is done by gestures. Functions which are difficult to do by gestures without any absolute feeling of the position are implemented with a touchscreen. Besides the touchscreen a second input device, a Leap-Motion, is used to obtain data of the motion of the hand. To get its data the Leap-Motion uses two CCD-cameras and three infrared LEDs. The interactions that can be done without any feedback of the absolute position are the translation, rotation and scale. These three and the movement through space are implemented as gestures in this thesis. This is done in Blender with the BlenderrnGame Engine and Python. The only function which has been implemented for the touchscreen is to select an object. Later on, a comparative control of the mouse was invented to contrast it with the control of the gestures. There are two big differences between these two controls. On the one hand, the gesture controls can be done in a three-dimensional space but most people aren't used to it yet. On the other hand, there is just a two-dimensional input possibility with the mouse control. Otherwise it is familiar to most persons. The evaluation should reveal if people prefer interaction by mouse control or by gestures. The result shows that the prefered control is done by the mouse. However in some categories of the tests the gestures are quite close to the result of the mouse.
Real-time graphics applications are tending to get more realistic and approximate real world illumination gets more reasonable due to improvement of graphics hardware. Using a wide variation of algorithms and ideas, graphics processing units (GPU) can simulate complex lighting situations rendering computer generated imagery with complicated effects such as shadows, refraction and reflection of light. Particularly, reflections are an improvement of realism, because they make shiny materials, e.g. brushed metals, wet surfaces like puddles or polished floors, appear more realistic and reveal information of their properties such as roughness and reflectance. Moreover, reflections can get more complex, depending on the view: a wet surface like a street during rain for example will reflect lights depending on the distance of the viewer, resulting in more streaky reflection, which will look more stretched, if the viewer is locatedrnfarther away from the light source. This bachelor thesis aims to give an overview of the state-of-the-art in terms of rendering reflections. Understanding light is a basic need to understand reflections and therefore a physical model of light and its reflection will be covered in section 2, followed by the motivational section 2.2, that will give visual appealing examples for reflections from the real world and the media. Coming to rendering techniques, first, the main principle will be explained in section 3 followed by a short general view of a wide variety of approaches that try to generate correct reflections in section 4. This thesis will describe the implementation of three major algorithms, that produce plausible local reflections. Therefore, the developed framework is described in section 5, then three major algorithms will be covered, that are common methods in most current game and graphics engines: Screen space reflections (SSR), parallax-corrected cube mapping (PCCM) and billboard reflections (BBR). After describing their functional principle, they will be analysed of their visual quality and the possibilities of their real-time application. Finally they will be compared to each other to investigate the advantages and disadvantages over each other. In conclusion, the gained experiences will be described by summarizing advantages and disadvantages of each technique and giving suggestions for improvements. A short perspective will be given, trying to create a view of upcoming real-time rendering techniques for the creation of reflections as specular effects.
In this thesis, an interactive application is developed for Android OS. The application is about a virtual-reality game. The game is settled in the genre of first-person shooters and takes place in a space scenario. By using a stereo renderer, it is possible to play the game combined with virtual-reality glasses.
The subject of this thesis was to analyse the involvement of classical creativity techniques and IT tools in different phases of the innovation process. In addition, the present work deals with the integration of Design Thinking and TRIZ into the innovation process. The aim was to define a specific innovation process based on diverse existing Innovation process models from the literature. This specific innovation process should serve as a basis for the analysis of integration of creativity techniques, IT tools, Design Thinking and TRIZ. Summarizing it can be said that the application of creativity techniques and IT Tools is admissible and useful in every phase of the innovation process. In this work it was shown that the design thinking method can be integrated in the early stages of the innovation process. Also, the process model of TRIZ, which differs from traditional innovation processes, can be combined with classical innovation processes.
Simulation von Schnee
(2015)
Physic simulations allow the creation of dynamic scenes on the computer. Computer generated images become lively and find use in movies, games and engineering applications. GPGPU techniques make use of the graphics card to simulate physics. The simulation of dynamic snow is still little researched. The Material Point Method is the first technique which is capable of showing the dynamics andrncharacteristics of snow.
The hybrid use of Lagrangian particles and a regular cartesian grid enables solving of partial differential equations. Therefore articles are transformed to the grid. The grid velocities can then be updated with the calculation of gradients in an FEM-manner (finite element method). Finally grid node velocities are weight back to the particles to move them across the scene. This method is coupled with a constitutive model to cover the dynamic nature of snow. This include collisions and breaking.
This bachelor thesis connects the recent developments in GPGPU techniques of OpenGL with the Material Point Method to efficiently simulate visually compelling, dynamic snow scenes.