OPUS Online Publikationen der Universität Stuttgart
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On-body visualization with extended reality : exploration and application
No full textExtended Reality (XR), which encompasses Virtual Reality (VR), Augmented Reality (AR) and Mixed Reality (MR), has significant potential across numerous fields by offering immersive and interactive experiences. This thesis addresses the increasing demand for effective on-body visualization technologies, particularly in the areas of biomechanical visualization, motion guidance, and feedback systems. The motivation behind this research is to leverage XR to enhance the presentation and understanding of biomechanical data and to improve performance in personal training scenarios, such as physiotherapy and exercise workouts.
The thesis begins by exploring design choices for visualizing biomechanical data directly on the human body using AR, even in situations constrained by limited resources or time. It focuses on enhancing the interactivity and user comprehension of biomechanical visualizations in various everyday contexts. Through an investigation of different design options, the research identifies effective methods for presenting complex biomechanical information in an intuitive and interactive manner, making it accessible to a wide range of users, from patients undergoing physiotherapy to athletes in training.
Expanding on broader applications such as physiotherapy and workouts, the research then investigates general design principles for presenting upper limb motion guidance using XR. This includes examining the impact of different perspectives, visual encoding techniques, and motion features on user performance and comprehension. The insights gathered lay a foundation for developing systems that provide clear, actionable feedback to support users in performing exercises with accuracy and efficiency.
Building on these studies, the thesis applies its findings to practical deadlift training, investigating user performance and preferences for guidance visualization in this context. This study bridges the gap in previous general design implications for XR-based motion guidance systems, revealing considerations for XR systems in physically intensive exercises.
Finally, the thesis presents a comprehensive review and empirical analysis of the design space for visual feedforward and corrective feedback mechanisms in XR environments. By addressing practical limitations and proposing solutions for improved system implementation, this part of the research offers a detailed framework to guide future developments in XR-based motion guidance systems.
Overall, this thesis provides a thorough examination of XR-based on-body visualization for biomechanical data presentation and 3D motion guidance. It makes substantial contributions to the field, setting the stage for future advancements in XR technology for on-body visualization. The findings have broad implications for building applications in biomechanical visualization, designing effective motion guidance systems, and improving future XR-related applications and system designs
Inferring kinetics and entropy production from observable transitions in partially accessible, periodically driven Markov networks
No full textFor a network of discrete states with a periodically driven Markovian dynamics, we develop an inference scheme for an external observer who has access to some transitions. Based on waiting-time distributions between these transitions, the periodic probabilities of states connected by these observed transitions and their time-dependent transition rates can be inferred. Moreover, the smallest number of hidden transitions between accessible ones and some of their transition rates can be extracted. We prove and conjecture lower bounds on the total entropy production for such periodic stationary states. Even though our techniques are based on generalizations of known methods for steady states, we obtain original results for those as well.Projekt DEALUniversität Stuttgar
On the distances within cliques in a soft random geometric graph
No full textWe study the distances of vertices within cliques in a soft random geometric graph on a torus, where the vertices are points of a homogeneous Poisson point process, and far-away points are less likely to be connected than nearby points. We obtain the scaling of the maximal distance between any two points within a clique of size k . Moreover, we show that asymptotically in all cliques with large distances, there is only one remote point and all other points are nearby. Furthermore, we prove that a re-scaled version of the maximal k-clique distance converges in distribution to a Fréchet distribution. Thereby, we describe the order of magnitude according to which the largest distance between two points in a clique decreases with the clique size.NW
LUBAC enables tumor-promoting LTβ receptor signaling by activating canonical NF-κB
No full textLymphotoxin β receptor (LTβR), a member of the TNF receptor superfamily (TNFR-SF), is essential for development and maturation of lymphoid organs. In addition, LTβR activation promotes carcinogenesis by inducing a proinflammatory secretome. Yet, we currently lack a detailed understanding of LTβR signaling. In this study we discovered the linear ubiquitin chain assembly complex (LUBAC) as a previously unrecognized and functionally crucial component of the native LTβR signaling complex (LTβR-SC). Mechanistically, LUBAC-generated linear ubiquitin chains enable recruitment of NEMO, OPTN and A20 to the LTβR-SC, where they act coordinately to regulate the balance between canonical and non-canonical NF-κB pathways. Thus, different from death receptor signaling, where LUBAC prevents inflammation through inhibition of cell death, in LTβR signaling LUBAC is required for inflammatory signaling by enabling canonical and interfering with non-canonical NF-κB activation. This results in a LUBAC-dependent LTβR-driven inflammatory, protumorigenic secretome. Intriguingly, in liver cancer patients with high LTβR expression, high expression of LUBAC correlates with poor prognosis, providing clinical relevance for LUBAC-mediated inflammatory LTβR signaling.Tri-service General Hospital, National Defense Medical CentreDeutsche ForschungsgemeinschaftJurgen Manchot Stiftun
Digitalisierungsbezogene Kompetenzen für das Lehramt technikbezogener Fächer : ein Modell zur Orientierung für Bildungseinrichtungen und Lehrkräfte der ersten, zweiten und dritten Phase
No full textDas DiKoLAT Kompetenzmodell präsentiert einen systematischen Überblick über die Kompetenzen, die im Zusammenhang mit der Lehrtätigkeit mit und über digitale Technologien im Bereich der technikbezogenen Fächer stehen. DiKoLAT stellt ein Modell zur Orientierung für Bildungseinrichtungen und Lehrkräfte der ersten, zweiten und dritten Phase dar, mit dem Ziel möglichst umfänglich jene Kompetenzen zu beschreiben, welche für die immer stärker digital geprägte Zukunft der Lernenden (und der Lehrenden) relevant erscheinen, um an dieser Welt reflektiert zu partizipieren. DiKoLAT versucht somit nicht zu definieren, was eine einzelne Lehrkraft braucht, um guten technikbezogenen Unterricht zu gestalten. Das Kompetenzmodell dient der Orientierung darüber, die eigenen Kompetenzen zu reflektieren und auf individueller Ebene sowie auf Ebene der Bildungseinrichtung systematisch weiterzuentwickeln. Ziel ist dabei den Lernenden eine möglichst umfängliche Grundlage für das eigene lebenslange Lernen mit, durch und über digitale Technologien zu ermöglichen
Uncertainties and robustness with regard to the safety of a repository for high-level radioactive waste : introduction of a research initiative
No full textThe Federal Company for Radioactive Waste Disposal (BGE mbH) is tasked with the selection of a site for a high-level radioactive waste repository in Germany in accordance with the Repository Site Selection Act. In September 2020, 90 areas with favorable geological conditions were identified as part of step 1 in phase 1 of the Site Selection Act. Representative preliminary safety analyses are to be carried out next to support decisions on the question, which siting regions should undergo surface-based exploration. These safety analyses are supported by numerical simulations building on geoscientific and technical data. The models that are taken into account are associated with various sources of uncertainties. Addressing these uncertainties and the robustness of the decisions pertaining to sites and design choices is a central component of the site selection process. In that context, important research objectives are associated with the question of how uncertainty should be treated through the various data collection, modeling and decision-making processes of the site selection procedure, and how the robustness of the repository system should be improved. BGE, therefore, established an interdisciplinary research cluster to identify open questions and to address the gaps in knowledge in six complementary research projects. In this paper, we introduce the overall purpose and the five thematic groups that constitute this research cluster. We discuss the specific questions addressed as well as the proposed methodologies in the context of the challenges of the site selection process in Germany. Finally, some conclusions are drawn on the potential benefits of a large method-centered research cluster in terms of simulation data management.Projekt DEALTechnische Universität Bergakademie Freiber
The B-spline mapping function (BMF) : representing anisotropic troposphere delays by a single self-consistent functional model
No full textTroposphere’s asymmetry can introduce errors ranging from centimeters to decimeters at low elevation angles, which cannot be ignored in high-precision positioning technology and meteorological research. The traditional two-axis gradient model, which strongly relies on an open-sky environment of the receiver, exhibits misfits at low elevation angles due to their simplistic nature. In response, we propose a directional mapping function based on cyclic B-splines named B-spline mapping function (BMF). This model replaces the conventional approach, which is based on estimating Zenith Wet Delay and gradient parameters, by estimating only four parameters which enable a continuous characterization of the troposphere delay across any directions. A simulation test, based on a numerical weather model, was conducted to validate the superiority of cyclic B-spline functions in representing tropospheric asymmetry. Based on an extensive analysis, the performance of BMF was assessed within precise point positioning using data from 45 International GNSS Service stations across Europe and Africa. It is revealed that BMF improves the coordinate repeatability by approximately 10%horizontally and about 5% vertically. Such improvements are particularly pronounced under heavy rainfall conditions, where the improvement of 3-dimensional root mean square error reaches up to 13%.Projekt DEA
Geometry modifications of circular saw blades to reduce aeroacoustic noise emissions
No full textIn the manufacturing industries, noise is one of the most common health hazards at workplaces. In wood machining, for instance, circular sawing processes in particular produce high noise emissions that often exceed the permitted limits. The main source of noise is the rotating circular saw blade, whose aeroacoustic behavior is influenced by air turbulence on the tool contour. So far, no numerical approach to study and optimize the aeroacoustic noise emissions from circular saw blades has been investigated. This paper addresses this deficit and presents a methodology for modeling the flow-induced sound generation on rotating circular saw blades based on computational fluid dynamics (CFD) simulations. With the implementation of the acoustic analogy according to Ffowcs-Williams/Hawkings, the sound pressure levels could be calculated with sufficient accuracy. With deviations between 7 and 10%, the influence of the rotational speeds could be plausibly modeled. Based on the validated numerical model, geometry variants with various modifications were investigated regarding their potential for reducing sound pressure levels. Based on a conventional reference geometry, different chip space volumes and various modifications to the tooth rim and tooth shape were investigated and evaluated as part of simulative parameter studies. Sound pressure level reductions in the range of 2.2-10.8 dB were achieved. The results obtained and the systematic approach investigated provide a suitable set of instruments for industrial practice. Digital prototypes can be designed at an early stage in the product development phase of circular saw blades regarding their aeroacoustic properties.Projekt DEALGerman Research Founfation (DFG
Subcellular fractionation enables assessment of nucleotide sugar donors Inside the Golgi apparatus as a prerequisite for unraveling culture impacts on glycoforms of antibodies
No full textGlycosylation is a critical quality attribute in biopharmaceuticals that influences crucial properties, such as biological activity and blood clearance. Current methods for modeling glycosylation typically rely on imprecise or limited data on nucleotide sugar donor (NSD) dynamics. These methods use in vitro transporter kinetics or flux balance analysis, which overlook the key aspects of metabolic regulation. We devised an integrative workflow for absolute subcellular NSD quantification in both cytoplasm and secretory organelles. Using subcellular fractionation, exhaustive sample extraction, and liquid chromatography triple‐quadrupole tandem mass spectrometry, we accurately measured NSD concentrations ranging from 1.6 amol/cell to 3 fmol/cell. As expected, NSD concentration profiles aligned closely with the glycan distributions on antibodies, particularly after nutrient pulsing to stimulate NSD production, showcasing method validity. This method enables empirical observation of compartment‐specific NSD dynamics. Thus, this study provides novel insights indicating that N‐glycosylation, which governs NSD supply, is primarily regulated within the Golgi apparatus (GA). This method offers a novel tool to obtain sophisticated data for a more efficient optimization of glycosylation processes in production cell lines.Projekt DEA
Health and liver diagnostic markers influencing glycemia in subjects with prediabetes : Preview study
No full textIntroduction: Glucose homeostasis may be dependent on liver conditions and influence health-related markers and quality of life (QoL) objective measurements. This study aimed to analyze the interactions of glycemia with liver and health status in a prediabetic population. Subjects and methods: This study included 2220 overweight/obese prediabetics from the multinational PREVIEW project. Anthropometrics; clinical, metabolic and other health-related markers; and QoL variables were analyzed. Univariate and multilinear-adjusted regression models were run to explain the interrelationships and effect modification between glycemia, health-related QoL (applying SF-12) and metabolic/liver health (using the HSI, a putative marker of fatty liver). Results: Relevant age/sex interactions were found concerning the levels of insulin, HOMA-IR, C peptide and transaminases in this prediabetic population. Multivariate models identified age, sex, glucose, WC and QoL as important predictors of HSI variability (adj. R value = 0.1393, p < 0.001), whereas the QoL status was statistically related to age, sex, HOMA-IR and HSI (adj. R value = 0.1130, p < 0.001) in this glycemia-impaired group. Furthermore, the QoL values declined with increased HSI scores, where a significant interaction was found ( p = 0.011) when the data were analyzed when comparing lower glycemia vs. higher glycemia in prediabetics. Indeed, an effect modification was featured depending on the glycemia levels concerning the QoL and HSI worsening. Conclusion: Glycemia associations with the QoL status and liver metabolism markers were evidenced, with clinical implications for diabetes and liver disease precision management given the modification of the QoL outcomes depending on the liver status and glycemia concentrations. Notably, independent associations of circulating glucose with age, sex, adiposity, inflammation and C peptide levels were found.This research was supported by the EU Seventh Framework Programme (FP7; 2007–2013) (grant no. 312057), National Health and Medical Research Council (EU Collaborative Grant AUS 8, ID 1067711), Glycemic Index Foundation Australia through royalties to the University of Sydney, Health Research Council of New Zealand (grant no. 14/191), University of Auckland Faculty Research Development Fund, Cambridge Weight Plan, Danish Agriculture and Food Council, Danish Meat Research Institute, National Institute for Health Research Biomedical Research Centre (NIHR BRC) (UK), Biotechnology and Biological Sciences Research Council (BBSRC) (UK), Engineering and Physical Sciences Research Council (EPSRC) (UK), Nutritics (Dublin), Juho Vainio Foundation (Finland), Academy of Finland (grants no. 272376, 314383, 266286 and 314135), Finnish Medical Foundation, Gyllenberg Foundation (Finland), Novo Nordisk Foundation, Finnish Diabetes Research Foundation, University of Helsinki, Government Research Funds for Helsinki University Hospital, Jenny and Antti Wihuri Foundation (Finland), Emil Aaltonen Foundation (Finland) and China Scholarship Council.EU Seventh Framework ProgrammeNational Health and Medical Research CouncilGlycemic Index Foundation AustraliaUniversity of Auckland Faculty Research Development FundCambridge Weight PlanDanish Agriculture and Food CouncilNational Institute for Health Research Biomedical Research Centre (NIHR BRC) (UK)Helsinki University HospitalEmil Aaltonen Foundation (Finland)China Scholarship Counci