OPUS Online Publikationen der Universität Stuttgart
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A framework for on-demand creation of vector tiles for OpenStreetMap data
No full textWithin the OpenStreetMap (OSM) project, the traditional approach for delivering map tiles relies on raster tiles. To ensure fast response times, a subset of the raster tiles, typically corresponding to low zoom levels is prerendered and stored on disk. However, this preparation step is time-consuming and demands significant storage resources. For instance, storing all tiles up to a zoom level of 14 requires approximately 200 GB of disk space [1]. Furthermore, as OSM data is frequently updated, this process must be repeated occasionally to ensure an up-to-date map. In contrast, vector tiles offer a modern alternative to raster tiles, as they are rendered on the client side and can be generated much more quickly. Instead of relying on existing vector tile services with fixed map generalization strategies, the goal of this work is the development of a framework for on-demand creation of vector tiles for OpenStreetMap Data, by leveraging query data structures like in [2].
To achieve this, we begin with a review of the relevant background and related work, covering key concepts in web mapping, including the Web Mercator projection and the Mapbox Vector Tile (MVT) format. We also introduce the shortest path problem and Contraction Hierarchies (CH), and briefly survey existing approaches.
Based on this foundation, Chapter 3 presents the conceptual design of the framework, detailing its key components. In Chapter 4, we present a prototype implementation of the proposed framework. This prototype integrates the query data structure introduced in [2], which is described in more detail. Furthermore, we address key challenges and solutions related to the required spatial indexing structure, the tile creation process, and the selection of suitable LoD candidates. Chapter 5 provides an evaluation of the methods implemented in the prototype, followed by the conclusion and outlook
Nutzerzentrierte Entwicklung der VitaBeat-App zur Verknüpfung von Smartwatch-Sensordaten mit Spotify-Songs
No full textThe adoption of wearable technologies, particularly smartwatches, is rapidly increasing, offering new opportunities for collecting and analyzing health data. Music streaming has also become integral to daily life, creating potential for linking music with physiological signals like heart rate. The VitaBeat app was developed as part of a student research project to provide a tool for analyzing the relationship between music and heart rate. Connects music to heart rate measurements, collecting data from smartwatch and smartphone sensors and Spotify playback via the Spotify SDK, which is transmitted to a central back-end for analysis. A requirements analysis was conducted using an online survey to gather insights from potential users. The survey aimed to identify user needs and preferences for the app’s features and usability. Based on the survey findings, several new features were implemented, including heart rate diagrams for individual songs, heart rate overviews, and gamified micro-breaks to enhance engagement. The user interface was also redesigned for better usability and clearer data presentation.
This thesis outlines the methodology and results of the survey, the new features developed from those insights, and recommendations for future improvements.Die Verbreitung von Wearable-Technologien, insbesondere Smartwatches, nimmt rasant zu und eröffnet neue Möglichkeiten zur Erfassung und Analyse von Gesundheitsdaten. Auch Musikstreaming ist ein fester Bestandteil des Alltags geworden, wodurch sich Potenziale für die Verknüpfung von Musik mit physiologischen Signalen wie der Herzfrequenz ergeben. Die VitaBeat-App wurde im Rahmen eines studentischen Forschungsprojekts entwickelt, um ein Tool zur Analyse der Beziehung zwischen Musik und Herzfrequenz bereitzustellen. Sie verbindet Musik mit Herzfrequenzmessungen, indem sie Daten von Sensoren der Smartwatch und des Smartphones sowie von der Spotify-Wiedergabe über das Spotify SDK sammelt und diese zur Analyse an ein zentrales Backend überträgt. Im Rahmen einer Bedarfsanalyse wurde eine Online-Umfrage durchgeführt, um Einblicke von potenziellen Nutzer*innen zu gewinnen. Ziel der Umfrage war es, Bedürfnisse und Präferenzen hinsichtlich der Funktionen und Benutzerfreundlichkeit der App zu identifizieren. Auf Basis der Umfrageergebnisse wurden mehrere neue Funktionen implementiert, darunter Herzfrequenzdiagramme zu einzelnen Songs, Herzfrequenzübersichten sowie gamifizierte Mikro-Pausen zur Steigerung der Nutzerinteraktion. Zudem wurde die Benutzeroberfläche neu gestaltet, um die Bedienbarkeit zu verbessern und die Daten klarer darzustellen.
Diese Arbeit beschreibt die Methodik und Ergebnisse der Umfrage, die daraus abgeleiteten neuen Funktionen sowie Empfehlungen für zukünftige Verbesserungen
SUDA : A SUrface Dust Analyser for compositional mapping of the Galilean moon Europa
No full textThe Surface Dust Analyser (SUDA) is a mass spectrometer onboard the Europa Clipper mission for investigating the surface composition of the Galilean moon Europa. Atmosphereless planetary moons such as the Galilean satellites are wrapped into a ballistic dust exosphere populated by tiny samples from the moon’s surface produced by impacts of fast micrometeoroids. SUDA will measure the composition of such surface ejecta during close flybys of Europa to obtain key chemical signatures for revealing the satellite’s composition such as organic molecules and salts, history, and geological evolution. Because of their ballistic orbits, detected ejecta can be traced back to the surface with a spatial resolution roughly equal to the instantaneous altitude of the spacecraft. SUDA is a Time-Of-Flight (TOF), reflectron-type impact mass spectrometer, optimized for a high mass resolution which only weakly depends on the impact location. The instrument will measure the mass, speed, charge, elemental, molecular, and isotopic composition of impacting grains. The instrument’s small size of 268mm×250mm×171mm, radiation-hard design, and rather large sensitive area of 220 cm 2 matches well the challenging demands of the Clipper mission.Jet Propulsion LaboratoryDeutsches Zentrum für Luft- und RaumfahrtNAS
Generating 3D topiaries from base geometric shapes
No full textVirtual Reality (VR) is increasingly used to simulate real-world environments in immersive digital spaces. One notable application is VR tours, which enable users to explore historically and culturally significant sites-whether they still exist or have been lost-on demand. This thesis presents a method for generating topiaries based on arbitrarily complex 3D geometries. The system requires two primary inputs: a 3D model that defines the desired topiary shape, and an image of the leaf to be applied as surface detail. Leveraging Unreal Engine's Nanite technology, highly detailed leaf textures can be rendered with exceptional efficiency. This allows for the creation of topiaries that maintain visual fidelity even in performance-critical VR environments. The quality and performance of the generated results are evaluated through comparisons with real photographs and benchmark testing
Real-time visualized and GPU-accelerated lattice Boltzmann simulations
No full textIn a preceding project, four lattice Boltzmann algorithms were implemented on the CPU using HPX. Building up on this project, the goal of this work is to implement the two most suitable algorithms on the GPU together with a framework permitting real-time visualization. In the propaedeuticum, fundamental concepts of GPU programming are elaborated, and based on the insights gained, the aptitude of the four algorithms from the project for a portation to the GPU is investigated. The two-lattice and the swap algorithm were identified as the most promising candidates. The visualization framework was designed using the Dear ImGui and ImPlot APIs. In the bachelor thesis, the swap algorithm and multiple variants of the two-lattice algorithm were realized using AdaptiveCpp, which is one of two major implementations of the SYCL standard. Kármán vortex streets were chosen as a scenario demonstrating the capabilities of the proposed simulations. Since all algorithms update the lattice faster than the frontend can accept new frames, all of them are suitable for fulfilling the objective under the limitations imposed by the visualization framework. Similarly to the project, a simple and mostly runtime-coordinated two-lattice variant was recognized as the most convenient and, at the same time, very competitive implementation. Out of the data layouts proposed by Mattila et al., the bundle layout is well suited for devices with small caches, while the stream layout uses the memory bandwidth more efficiently. The optimal work group size and subdomain shape also depend on the targeted hardware.In einem vorangegangenen Projekt wurden vier Lattice-Boltzmann-Algorithmen auf der CPU mit HPX implementiert. Darauf aufbauend ist es das Ziel dieser Arbeit, die zwei am besten geeigneten Algorithmen zusammen mit einem Framework für Visualisierung in Echtzeit auf der GPU zu implementieren. Im Propaedeuticum werden fundamentale Konzepte der Programmierung auf einer GPU herausgearbeitet. Basierend auf den dort gewonnenen Erkenntnissen wird die grundsätzliche Eignung der vier Algorithmen aus der Projektarbeit für eine Portierung auf die GPU untersucht. Der Two-Lattice- und der Swap-Algorithmus wurden als die aussichtsreichsten Kanditaten identifiziert. Das Framework zur Visualisierung wurde mit den APIs Dear ImGui und ImPlot entworfen. In der Bachelorarbeit wurden anschließend der Swap-Algorithmus und mehrere Varianten des Two-Lattice-Algorithmus mit AdaptiveCpp realisiert. Hierbei handelt es sich um eine von zwei weitverbreiteten Implementierungen des SYCL-Standards. Kármánsche Wirbelstraßen wurden als ein passendes Szenario gewählt, um die Fähigkeiten der vorgestellten Simulationen zu demonstrieren. Da alle Algorithmen das Gitter schneller aktualisieren als das Frontend neue Bilder annehmen kann, sind sie alle im Rahmen gewisser Limitierungen durch das Visualisierungs-Framework zur Erfüllung der Zielsetzung geeignet. Ähnlich wie in der Projektarbeit stellte sich eine einfache und hauptsächlich durch das Runtime-System verwaltete Two-Lattice-Variante als die praktischste und gleichzeitig sehr leistungsfähige Option heraus. Von den von Mattila et al. vorgeschlagenen Datenlayouts eignet sich das Bundle-Layout am besten für GPUs mit kleinen Caches, wohingegen das Stream-Layout die verfügbare Speicherbandbreite besonders gut nutzt. Die optimale Größe einer Work Group und die ideale Form der Subdomänen hängen von der verwendeten Hardware ab
AI-based clustering of numerical flow fields for accelerating the optimization of an axial turbine
No full textThe growing number of Renewable Energy Sources has increased the demand for innovative and high-performing turbine designs. Due to the increase in computing resources over recent years, numerical optimization using Evolutionary Algorithms (EAs) has become established. Nevertheless, EAs require many expensive Computational Fluid Dynamics (CFD) simulations, and more computational resources are needed with an increasing number of design parameters. In this work, an adapted optimization algorithm is introduced. By employing an Artificial Intelligence (AI)-based design assistant, turbines with a similar flow field are clustered into groups and provide a dataset to train AI models. These AI models can predict the flow field’s clustering before a CFD simulation is performed. The turbine’s efficiency and cavitation volume are predicted by analyzing the turbine’s properties inside the predicted clustering group. Turbines with properties below a certain threshold are not CFD-simulated but estimated by the design assistant. By this procedure, currently, more than 30% of the CFD simulations are avoided, significantly reducing computational costs and accelerating the overall optimization workflow.German Research Foundation (DFG
Direct consideration of process history during intensified design of experiments planning eases interpretation of mammalian cell culture dynamics
No full textIntra-experimental factor setting shifts in intensified design of experiments (iDoE) enhance understanding of bioproduction processes by capturing their dynamics and are thus essential to fulfill quality by design (QbD) ambitions. Determining the influence of process history on the cellular responses, often referred to as memory effect, is fundamental for accurate predictions. However, the current iDoE designs do not explicitly consider nor quantify the influence of process history. Therefore, we propose the one-factor-multiple-columns (OFMC)-format for iDoE planning. This format explicitly describes stage-dependent factor effects and potential memory effects as across-stage interactions (ASIs) during a bioprocess. To illustrate its utility, an OFMC-iDoE that considers the characteristic growth phases during a fed-batch process was planned. Data were analyzed using ordinary least squares (OLS) regression as previously described via stage-wise analysis of the time series and compared to direct modeling of end-of-process outcomes enabled by the OFMC-format. This article aims to provide the reader with a framework on how to plan and model iDoE data and highlights how the OFMC-format simplifies planning, and data acquisition, eases modeling and gives a straightforward quantification of potential memory effects. With the proposed OFMC-format, optimization of bioprocesses can leverage which factor settings are most beneficial in which state of the mammalian culture and thus elevate performance and quality to the next level.Boehringer Ingelheim Development CMC Biological
Checklist of tardigrades in Germany as a contribution to biodiversity research
No full textOver 250 years ago Johann August Ephraim Goeze, a Protestant pastor from Quedlinburg, Germany, discovered the first tardigrade. The German physiologist and anatomist Carl August Sigismund Schultze (1795-1877) later named the first species Macrobiotus hufelandi C.A.S. Schultze, 1834, a designation that remains valid today. By the first third of the twentieth century numerous new species had been discovered in Germany and were comprehensively compiled for the first time by the German zoologist Ernst Marcus in 1936. Since then additional faunistic studies have been conducted. This new checklist of tardigrades in Germany provides an overview of all known species found in the country to date. It includes 91 limno-terrestrial or limnic species and eight marine species, with 21 belonging to Heterotardigrada and 78 to Eutardigrada. Germany is the type locality (terra typica) for 24 tardigrade species. The number of identified tardigrade species varies significantly depending on the extent of studies conducted in different federal states. Baden-Württemberg has the highest number of species identified, with 80 species recorded across eleven studies. In this state the Black Forest, with its remarkable diversity of 72 identified tardigrade species is one of the most intensively studied regions worldwide. In Hesse 30 species have been recorded from five studies, while Berlin has documented 23 species from two studies. Fewer species have been reported from other federal states. The 99 tardigrade species identified in Germany represent about 7% of the total 1,488 described tardigrade species worldwide.Projekt DEALUniversität Stuttgar
A fully-implicit solving approach to an adaptive multi-scale model : coupling a vertical-equilibrium and full-dimensional model for compressible, multi-phase flow in porous media
No full textVertical equilibrium models have proven to be well suited for simulating fluid flow in subsurface porous media such as saline aquifers with caprocks. However, in most cases the dimensionally reduced model lacks the accuracy to capture the dynamics of a system. While conventional full-dimensional models have the ability to represent dynamics, they come at the cost of high computational effort. We aim to combine the efficiency of the vertical equilibrium model and the accuracy of the full-dimensional model by coupling the two models adaptively in a unified framework and solving the emerging system of equations in a monolithic, fully-implicit approach. The model domains are coupled via mass-conserving fluxes while the model adaptivity is ruled by adaptive criteria. Overall, the adaptive model shows an excellent behaviour both in terms of accuracy as well as efficiency, especially for elongated geometries of storage systems with large aspect ratios.Projekt DEALDeutsche Forschungsgemeinschaf
Wandel versus Stabilität im Informations- und Wissensmanagement : optimierte Handhabung eines Spannungsfelds
No full textDas spannungsgeladene Zusammenspiel von Wandel und Stabilität lässt sich mit einem Hybridansatz besser verstehen und gestalten als mit den vorliegenden Ansätzen der Path Constitution, des geschichteten Wandels oder des durchbrochenen Gleichgewichts. Der Beitrag vermittelt einen Überblick über die generischen Architekturen von Hybridansätzen, vor allem die Prinzipien, qualitativen Muster und quantitativen Proportionen der Kopplung von Wandel und Stabilität und gibt damit neue Antworten auf die Fragen nach dem Wie, Wann, Wo und Wie viel einer Konfiguration von kontinuierlicher und diskontinuierlicher Veränderung