Offenburg University of Applied Sciences
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A New Method to Accurately Describe Belt-Based Treadmill Perturbations
No full textIntroduction: This study presents a methodology for quantifying belt-based perturbations during treadmill locomotion. In light of the growing interest in understanding perturbations and their implications for fall prevention in older adults and injury risk in dynamic sports, this research aims to provide a framework to report detailed characteristics of belt-based perturbations in a standardized fashion.Methods: We established a series of perturbation parameters, including baseline velocity, perturbation temporal offset, and durations of acceleration phases, among others, to characterize belt-based perturbations comprehensively. We tested the method in fifteen healthy recreational runners who participated in a controlled experiment involving ten sudden foot backward slip-like anteroposterior perturbations on an instrumented treadmill.Results: The results demonstrated different variabilities in the newly established perturbation parameters, highlighting the need to accurately quantify them to allow for comparisons across studies and ensure consistency within a single study. The perturbation temporal offset parameter demonstrated the highest observed variability.Discussion: We recommend routinely describing these perturbation parameters in future studies using belt-based perturbations to improve the knowledge base in the field across labs. The presented parameter set is a standardized way to describe these belt-based perturbations. The code for calculating perturbation parameters is freely available to facilitate this goal
Impact of Multiple Sensory Cues in Immersive Virtual Reality
No full textPrevious works have shown that providing visuo-tactile stimuli synchronously or/and congruent to an artificial and physical body part cause users to perceive the artificial body part as their own. Although this illusion over fake limbs has been extended to immersive virtual reality (VR), the effect of haptic feedback on full body has not been yet examined in depth. This study investigates the effects of visuo-tactile and visuo-motor stimulation on inducing embodiment within VR using a full-body motion capture suit with haptic feedback. Our findings reveal that synchronous and congruent visuo-tactile stimulation significantly enhances the sense of embodiment compared to incongruent visuo-tactile or visuo-motor stimulation alone. Further findings related to heart activity and subjective ratings suggest that incongruent visuo-tactile stimulation or the complete absence of haptic feedback may increase the stress level after the threat event, indicating body disconnection or body disownership. These findings have practical implications for VR system design, particularly in gaming and interactive entertainment. Our results showing the effects of visuo-tactile in addition to the visuo-motor stimuli provide valuable insights for optimizing the sense of embodiment in VR experiences. Ultimately, our research underlines the potential of haptic technologies in creating more engaging and immersive virtual environments
Energiespeicherung
No full textDie Energiespeicherung ist einer der wichtigsten Schlüssel für das Gelingen der Energiewende. In diesem Kapitel lernen Sie die verschiedenen Möglichkeiten kennen, wie überschüssige erneuerbare Energie für Zeiten mit wenig Wind und Sonne gespeichert werden kann. Von klassischen Pumpspeicherkraftwerken über innovative Batterietechnologien bis hin zu zukunftsweisenden Power-to-X Konzepten wird das gesamte Spektrum moderner Speichertechnologien behandelt.
Besonders interessant ist der Bereich der grünen Wasserstofftechnologie, die eine Schlüsselrolle bei der langfristigen Energiespeicherung und Sektorkopplung spielt. Sie erfahren, wie aus erneuerbarem Strom per Elektrolyse grüner Wasserstoff hergestellt wird und wie dieser als vielseitiger Energieträger in verschiedenen Anwendungen zum Einsatz kommen kann - sei es zur Rückverstromung, als Treibstoff für Fahrzeuge oder als Rohstoff für die chemische Industrie.
Das Kapitel vermittelt nicht nur theoretisches Wissen, sondern zeigt auch konkrete Praxisbeispiele wie aktuelle Pilot- und Demonstrationsanlagen. Sie lernen die technischen und wirtschaftlichen Herausforderungen kennen und erhalten einen Ausblick auf zukünftige Entwicklungen im Bereich der Energiespeicherung. Als angehende Ingenieurinnen und Ingenieure werden Sie in Ihrem späteren Berufsleben mit hoher Wahrscheinlichkeit mit diesen Technologien in Berührung kommen. Die hier vermittelten Grundlagen sind daher essentiell für alle, die aktiv an der Gestaltung einer nachhaltigen Energiezukunft mitwirken möchten
Knowledge-Based Dynamic Capabilities in University-Industry Collaboration
No full textThis thesis investigates knowledge generation and transfer mechanisms within university-industry collaboration through a single case study of a robotics-focused partnership involv-ing 14 firms, a foundation association, and a university. Applying the knowledge-based dy-namic capabilities framework of Zheng et al. (2011), the study examines how firms acquire, generate, and combine knowledge in collaborative settings. Through qualitative analysis of six semi-structured interviews and document review, the research identifies specific mani-festations of Knowledge Acquisition Capabilities, Knowledge Generation Capabilities and Knowledge Combination Capabilities in UIC contexts. Findings reveal that knowledge dy-namics in UIC operate as an interconnected process: external impulses are acquired through collaborative research, conversations, and demonstrations - these impulses are then refined internally. Finally, knowledge is embedded in firms through finalization pro-cesses and transferred via observation, co-working, and seminars. The study also maps knowledge flow pathways between UIC participants. This research extends existing KBDC literature by providing concrete mechanisms specific to UIC contexts and demonstrates how theoretical insights translate into practical applications. The findings contribute to both the-oretical understanding of knowledge dynamics in collaborative settings and practical imple-mentation of effective knowledge management strategies in university-industry partner-ships
Hybrid Consensus Mechanisms in Blockchain: A Comprehensive Review
Get PDFBlockchain technology, renowned for its foundational attributes of decentralization, security, and immutability, offers substantial potential for diverse applications. At the heart of blockchain functionality are consensus mechanisms, crucial for preserving the decentralized integrity of the network. However, traditional consensus algorithms like Proof of Work (PoW), Proof of Stake (PoS), and Byzantine Fault Tolerance (BFT) typically require significant computational and communication resources, which may not be feasible for resource-limited environments. The purpose of this paper is to explore hybrid consensus algorithms that integrate conventional consensus mechanisms with advanced nonlinear data structures. We comprehensively analyze a wide range of hybrid consensus mechanisms, emphasizing their architectural design, operational efficiencies, and ability to address both consensus-specific vulnerabilities and network-level threats, such as Sybil attacks, double-spending, and partitioning attacks. To achieve this, we employ a set of comprehensive evaluation criteria for blockchain technologies, namely, validation, IoT, real-time processing, application suitability, security, and implementation. These criteria help assess the adaptability and efficacy of each mechanism in diverse operational contexts. Through this examination, the paper seeks to illuminate the significant contributions and implications of hybrid consensus mechanisms, guiding stakeholders, researchers, and developers toward making informed decisions about optimizing blockchain technology for their specific needs and inspiring the development of innovative solutions
Activation of persulfate by biochar and iron: role of biochar pyrolysis conditions and ash amendments
No full textRedox-active biochars can enhance contaminant transformation in persulfate-based Fenton-like water treatment by facilitating Fe(III) reduction to Fe(II). However, biochar properties vary greatly depending on both feedstock selection and pyrolysis conditions. Best suited biochars for Fe(III) reduction and persulfate activation have yet to be identified. Here, we investigated eight biochars for their ability to activate persulfate with Fe(III) to transform N,N-diethyl-m-toluamide (DEET) in water. Four of the biochars were produced from beech wood under different pyrolysis conditions (450–750 °C, high and low nitrogen flow rate in the reactor) and four biochars were produced from softwood amended with 0 – 43 weight percent (wt%) wood ash prior to pyrolysis at 500 °C. Beech wood biochar produced at 450 °C transformed DEET most efficiently with a half-life time of 39 ± 4 min, likely due to the high concentration of surface oxygen functional groups and persistent free radicals that accelerated Fe(III) reduction and formation of reactive species. Among the ash-amended biochars, biochar with 16 wt% ash amendment showed the most efficient DEET transformation with a half-life time of 27 ± 0.6 min, which is 10-times faster compared to a non-ash-amended biochar produced from the same biomass under similar pyrolysis conditions. Ash amendment led to the formation of crystalline iron minerals in biochars, which likely promoted Fe(III) reduction and persulfate activation. Our results highlight the potential for fine-tuning the redox properties of biochar, e.g., by ash amendment to a woody feedstock, enabling tailored performance for specific water treatment applications
Entwicklung und Fertigung eines biomechanisch optimierten anthropomorphen Prothesenfingers mit sensorischem Feedback zur natürlichen haptischen Wahrnehmung
No full textThis master’s thesis focuses on the development and production of an optimised anthropomorphic prosthetic finger. Building on the previous work of Lea Allmendinger and Laura Stern, a sensory feedback system inspired by the biological mechanoreceptors of a human finger was integrated. A novel approach was pursued, in which liquid-filled chambers are used to transmit the internal pressure to sensors positioned away from the contact surface. Furthermore, the external appearance, biomechanics and mechanical properties of a human finger were designed to closely mimic those of a real human finger.
The thesis begins with a description of the relevant anatomical, biological and technical fundamentals, followed by a review of the current state of the art. Afterwards the conception und the prototyping are discussed. The solution concept, chosen materials and manufacturing processes will be explained. A total of three prototypes were produced to validate or reject different construction ideas. Based on these findings, a functional prosthesis finger is fabricated. This finger consists of a coloured silicone outer shell and an internal structure. This silicone shell acts as an artificial finger skin and encloses the 3D-printed finger bones with integrated sensor technology as well as a silicone element for the liquid chambers. All components were bonded together with silicone glue to form a closed unit.
To evaluate the sensory feedback, the prosthetic finger was connected to a computer via an Arduino microcontroller. A special program was written to read out the measured pressure values in real time. In various measurement scenarios, forces of different intensities were applied to the fingertip. It could be shown that the finger can recognize differences in pressure - however, the plausibility of the measurement results is still limited and requires further investigation
Einsatz von Künstlicher Intelligenz im Controlling
No full textDie Arbeit untersucht die Einsatzmöglichkeiten von Künstlicher Intelligenz im Controlling, insbesondere in den Bereichen Reporting, Forecasting und Risikocontrolling, und analysiert deren Potenziale, Herausforderungen sowie Grenzen
Influence of Hyperparameters in Neural State-Space Models for Data-Driven Black-Box Modelling of Synchronous Motors: A Case Study
No full textThis paper presents an empirical study on the influence of network and training settings in data-driven black-box modelling of synchronous motors using neural state-space models. The objective is to provide a foundational insight into neural state-space modelling and reference points for researchers involved in this field. The study examines correlations between hyperparameters in terms of design and training parameters and the resulting model performance, which are difficult to express analytically. Additionally, an in-depth analysis of training times is conducted to identify configurations that achieve comparable model accuracy with reduced computational time. These findings aim to facilitate efficient model development by offering a systematic approach to parameter selection and optimization in black-box modelling for electrical motor applications
Simulation strömungsinduzierter Segregationsprozesse von Suspensionen hoher Partikeldichte
No full textDer Pulverspritzguss (PIM) ist eine Schlüsseltechnologie zur Herstellung komplexer Bauteile aus Metall- und Keramikpulvern. Trotz seiner Vorteile birgt der Prozess Herausforderungen, die ohne Simulation oft zu kostspieligen Fehlern führen. Ein zentrales Problem ist die Entmischung (Segregation) der homogenen Pulver-Fließmittel-Suspension. Diese kann während des Spritzgießens oder bei Standzeiten auftreten und führt direkt zu Qualitätsmängeln im fertigen Bauteil. Ein präzises Verständnis und die Vorhersage solcher Segregationsprozesse sind entscheidend, um die Bauteilqualität signifikant zu verbessern und den Bedarf an kostenintensiven Tests zu minimieren.
Die eingesetzte Simulationsmethode muss dabei die scherinduzierte Migration beziehungsweise die Segregation durch Massenträgheit akkurat abbilden. Besonderes Augenmerk liegt auf der Eignung der Methoden für hochkonzentrierte Suspensionen mit Millionen bis Milliarden Partikeln im Mikrometerbereich, bei denen Kopplungen aus Strömungs- und Partikelsimulation an ihre Grenzen stoßen.
Die Kopplung zweier Smooth Particle Hydrodynamics (SPH) Solver ist aufgrund des Rechenaufwands für den Pulverspritzgussprozess ungeeignet. Die Multiphase Particle-in-Cell (MP-PIC) Methode kann Segregation durch Massenträgheit plausibel abbilden, ist jedoch bei hohen Partikeldichten anfällig für Instabilitäten und kann scherinduzierte Migration mit dem Modell von Lun für die partikelinterne Spannung nicht zuverlässig reproduzieren.
Das Suspension Balance Model (SBM) hingegen erweist sich als die vielversprechendste Methode: es überzeugt, unabhängig von der Partikelanzahl, durch den geringen Rechenaufwand und bildet scherinduzierte Effekte mit hoher Genauigkeit (unter 6 % Abweichung) ab. Allerdings kann der Einfluss der Massenträgheit nicht berücksichtigt werden, was den Anwendungsbereich auf Suspensionen mit Reynolds-Zahlen kleiner eins beschränkt