Hochschule Bonn-Rhein-Sieg
Publikationsserver der Hochschule Bonn-Rhein-Sieg - pub H-BRSNot a member yet
7939 research outputs found
Sort by
Making Waves: Empowering Users to Sustainable Water Use
No full textSustainable water use is an emerging issue for both industry and consumers, as water scarcity is becoming one of the great challenges of our time, In this regard, Consumption Feedback (CF) is a commonly used approach to provide consumers with information on individual consumption data; however, CF has primarily been applied in the context of energy consumption. Regarding water usage, CF holds significant potential to raise awareness and to help identify saving opportunities. To understand users’ existing practices and challenges in water consumption monitoring and saving behaviors, we conducted 11 semi-structured interviews with private households in a living lab. With this contribution we present preliminary results of the study on participants’ water consumption practices and present initial prototypical design drafts for a dashboard based on these results, which should address the identified practices and challenges. Finally, based on the results we conclude with design considerations for the visualization of water consumption data
Positionierung und Qualitätsbewertung von Mikrooptiken für laserbasierte optische Sensorsysteme
No full textLaserbasierte optische Sensoren nutzen aktiv erzeugte Laserstrahlung, um Informationen über Objekte oder ihre Umgebung zu erfassen. Für präzise und effiziente Messungen ist es entscheidend, dass ein möglichst hoher Anteil dieser Laserstrahlung in den Erfassungsbereich des Sensorsystems gelenkt wird. Während eine solche Strahlformung grundsätzlich durch den Einsatz von Mikrooptiken realisiert werden kann, ist deren gezielte Entwicklung Gegenstand aktueller Forschung.
Diese Arbeit befasst sich mit der experimentellen Untersuchung solcher strahlformenden Mikrooptiken. Ein besonderer Fokus liegt dabei auf der Evaluierung der Positionsabhängigkeit und der Messung der erzeugten Strahlprofile. Betrachtet werden dabei zunächst randomized Microlens Arrays (rMLA) und collimating randomized Microlens Arrays (crMLA). Jedoch kann das beschriebene Verfahren ohne weiteren Aufwand für jede Art von strahlformenden Mikrooptiken angewandt werden.
Zur Analyse wurde ein modularer Messaufbau entwickelt, der die transmissionsbasierte Charakterisierung von Strahlprofilen ermöglicht. Zur Reduktion der durch die Transmission hervorgerufenen systematischen Fehler wurde außerdem ein Kalibrierungsprozess implementiert. Daraufhin wurde durch kontrollierte Verschiebung der Mikrooptiken relativ zur Laserquelle die Auswirkungen der Positionierungsgenauigkeit auf die Strahlformung untersucht. Die Messungen zeigen, dass rMLA-Mikrooptiken durch ihre zufällige Linsenverteilung eine von der Position weitgehend unbeeinflusste Strahlformung aufweisen, während crMLA-Mikrooptiken eine signifikante Sensitivität gegenüber lateralen Positionsabweichungen zeigen.
Die durchgeführten Messungen liefern eine qualitative Einschätzung der durch Positionierung verursachten Effekte auf das Strahlprofil und unterstreichen die Relevanz einer präzisen Justierung. Die Arbeit liefert somit einen wertvollen Beitrag zur weiteren Entwicklung von angepassten strahlformenden Mikrooptiken für laserbasierte Sensorsysteme
Qualitative and Quantitative Analysis of Lignins from Different Sources and Isolation Methods for an Application as a Bio-Based Chemical Resource and Polymeric Material
No full text
From Composable Models to Correct-by-Construction Software for Contact-Rich Robotic Mobile-Manipulation Tasks
No full textSoftware frameworks like the Stack of Tasks (SoT), the Stanford Whole-Body Control (WBC) library, or the instantaneous Task Specification using Constraints (iTaSC) have enabled robots to perform advanced, contact-oriented manipulation tasks. jgeom_constr and eTaSL are among the few formal, computer-interpretable languages that allow users to specify such tasks independent of these frameworks. We analyse these languages for their limitations with respect to composability, the design for extensibility without having to change existing models, and compositionality, meaning that the semantics of compositions unambiguously follows from the semantics of the components and of the composition relations. To overcome these limitations we design a graph-structured and well-defined interchange format for such tasks. The associated tooling enables us to generate correct-by-construction code that adheres to predefined rules and constraints. We showcase our models and toolchain by incrementally constructing a workspace-alignment application for a highly-redundant mobile platform that is equipped with two 7-DoF, torque-controlled manipulators
COIL Multidisciplinary Global Engineering Capstone Class Impact: Faculty and Student Insights Across Four Countries
No full textEvaluating the visual design of science publications—a quantitative approach comparing legitimate and predatory journal papers
No full textThe rise of predatory publishing poses a significant challenge to the integrity of scientific research, potentially undermining the credibility of scholarly communications. As parts of the academic community grapple with distinguishing legitimate from dubious publications, understanding the subtle differences between them becomes paramount. Therefore, this study focuses on some of these subtleties by examining the aesthetic differences in journal research papers published by potential predatory publishers versus legitimate ones. A comprehensive analysis was undertaken on 443 legitimate and 555 predatory Open Access publications, utilizing a rigorous quantitative approach. This investigation encompassed an evaluation of metadata, layout elements (such as typography, white space, page sizes, and figures), and other measurable visual attributes. Not only do the findings reveal statistically significant disparities in the visual presentation and embedded metadata of the published PDFs (potentially shedding light on the tools used for document creation), but the investigation also serves as a proof of concept for the employed analytical method: Using Python as scripting language, we offer a scalable solution for scrutinizing large datasets of PDF files based on design criteria, all while upholding a stringent quantitative approach
Beam Shaping of VCSEL Arrays Using Randomized Microlens Arrays with Integrated Collimation
No full textIn active 3D imaging systems, the circular, Gaussian-shaped output of VCSEL arrays must be converted into rectangular patterns aligned with the camera’s field of view. To maximize energy efficiency, the beam edges must be sharply confined to avoid illumination outside the target area. For this purpose, this work presents the design, fabrication, and experimental evaluation of randomized microlens arrays (RMLAs) and the novel collimating RMLAs (cRMLAs), which are tailored specifically to the emission characteristics of VCSEL arrays. The freeform optical elements were fabricated using grayscale two-photon polymerization and verified using confocal microscopy. Far-field beam profiles were recorded with a cost-efficient, camera-based setup and analyzed with respect to efficiency, field-of-view coverage, and intensity distribution. The results show that the cRMLAs offer a significant increase in beam shaping efficiency and spatial resolution. This represents the first monolithic randomized microlens array with integrated collimation. The approach enables compact and energy-efficient beam shaping in future active sensing systems
Coarse-Grained Molecular Dynamics Study of the Melting Dynamics in Long Alkanes
No full textThe melting behavior of alkanes plays a critical role in a wide field of applications. While experimental studies have established the occurrence of premelting phenomena in both short- and long-chain alkanes, molecular-level insights remain limited. In this work, we employ coarse-grained molecular dynamics simulations to investigate the melting behavior of high-molecular-weight alkanes, with a particular focus on continuous premelting dynamics in the transition regime toward polymer-like systems. By simulating alkane chains of varying lengths and analyzing temperature-dependent structural changes, we identify a crossover from discrete phase transitions to a gradual premelting process beyond chain lengths of N≈40 coarse-grained beads. The extrapolation of melting temperatures to zero heating rate yields values that agree well with the experimental data for the longest simulated chains. Compared to previous simulation studies, the slower heating rates used here offer enhanced quantitative agreement. Overall, the results provide new molecular-level insights into the melting of long-chain alkanes and highlight the utility of coarse-grained models in capturing complex phase behavior