Publikationsserver der Ostbayerischen Technischen Hochschule Regensburg
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Prediction of the wear behavior of a conveyor belt with flexible rollers
No full textThis paper introduces a method to predict wear behavior in conveyor belt systems using a lumped mass modeling approach. While previous research has focused primarily on lateral belt walking, this study shifts attention to belt deformation and its associated wear. Both significantly affect system efficiency and component lifespan. The authors propose using local frictional power as a wear indicator, leveraging its direct relation to frictional work in established wear models. To solely demonstrate the method, the study simulates a conveyor belt with three flexible rollers and a deformable belt modeled through rigid spheres connected by spring-damper elements. The authors visualize frictional power density across the belt width, distinguishing between running and transverse directions. The results demonstrate that the frictional power distribution depends heavily on discretization quality, particularly due to the polygon effect inherent in the lumped mass approach. A convergence analysis reveals the minimum necessary discretization of the belt, ensuring reliable qualitative results. To support the credibility of the work, this study compares theoretical expectations and initial wear observations from a real belt with the results from the shown approach. The plausibility check already shows promising results. The proposed methodology provides an adaptable framework to evaluate wear in belt-like structures. It can be readily adapted to a variety of multibody dynamics applications and integrated into larger MBS models that include the overall drivetrain and engine control. Future work will focus on refining discretization strategies and contact models, as well as validation of the wear model to enable quantitative predictions
BPConvNet: a deep learning based ρ-Filtered layergram reconstruction method for computed tomography
No full textIn this article, we address the reconstruction problem in computed tomography (CT) when dealing with sparse view
data. Traditional approaches like filtered backprojection (FBP) often fail under these conditions, leading to streaking artifacts.
We propose BPConvNet, a deep learning based version of the ρ-filtered layergram or backprojection filtration (BPF) technique
(cf. [1]). Unlike FBP, the BPF method applies filtering (F) after backprojection (BP), hence the name. The proposed BPConvNet
adapts the BPF workflow by substituting the filtering step with a residual convolutional neural network. Our numerical experiments
demonstrate that BPConvNet is competitive to similar deep learning methods. Moreover, we explain that BPConvNet can be easily
adapted to to different CT acquisition geometries, such as fan beam and 3D configuration
Unraveling jingle-jangle fallacies in digital assistant technologies : a comprehensive systematic review and research agenda
No full textDigital assistant technologies (DATs) such as chatbots, virtual assistants,
and intelligent agents have gained widespread attention, yet inconsistent terminology remains a critical challenge. The fragmented nature of previous research has led to significant confusion due to overlapping and interchangeable use of terms across industries. This systematic literature review, following the PRISMA protocol, consolidates the current state of knowledge on DATs and addresses the prevalent jingle-jangle fallacies in their terminology. Analysis of 137 articles identified keycharacteristics, applications, and conceptual overlaps of various DATs, uncovering 39 distinct technologies categorized under three overarching concepts: assistants, chatbots, and agents. Despite shared functionalities, terminological inconsistencies persist across different sectors, presenting challenges for both academic research and practical implementation. This review emphasizes the need for standardized terminology and clearer classification frameworks to facilitate broader DAT adoption across organizational contexts
Physiotherapy as an Allied Health Profession – joint advocacy for the therapy sciences : development of an interdisciplinary position statement to highlight the research needs of the profession in Germany
No full textDevelop an interdisciplinary position statement to establish common ground amongst the research community of AHPs in Germany to aid the academic discourse on research needs
Single-Task vs. Dual-Task: Altersunterschiede in Gleichgewicht und Kognition
No full textEinleitung: In vielen Alltagssituationen werden motorische und kognitive Aufgaben als Dual-Task (DT) bewältigt. Studien zeigen im DT Leistungseinbußen gegenüber dem Single-Task (ST). Vor diesem Hintergrund stellt sich die Frage, welche Rolle das Lebensalter spielt. Diese Studie untersuchte Unterschiede von Gleichgewicht und kognitiver Leistung zwischen ST und DT sowie Veränderungen im Alter.
Material und Methodik: An der experimentellen Querschnittsstudie nahmen
32 gesunde Erwachsene (je 16 im Alter von 18–30 und 55–67 Jahren) teil. Konditionen und Pathologien, die das Gleichgewicht maßgeblich beeinträchtigen, galten als Ausschlusskriterien. Es wurden drei Testungen mit einer Dauer von jeweils 30 Sekunden mit je zwei Minuten Pause durchgeführt. Die ST-Aufgaben bestanden aus standardisiertem Einbeinstand (offene Augen) sowie Serial-Seven-Rechnungen. Die dritte Testung kombinierte beide Aufträge zu einer DT-Aufgabe. Als Outcome des kognitiven Tasks diente die Anzahl korrekt gelöster Rechenaufgaben. Das Moticon-OpenGo-Sensorsohlen-System erfasste während der motorischen Aufgabe das Gleichgewicht mittels Centre-of-Pressure-Pfadlänge (PL) und -Schwankgeschwindigkeit (SV). Die Prüfung der
Normalverteilungsannahme der Daten erfolgte mittels Shapiro-Wilk-Test. In Abhängigkeit der Verteilung wurden Effektstärken und deren Signifikanz mit Hilfe des t-Tests – bei Nichterfüllung der Normalverteilung – des Mann-Whitney-U- oder Wilcoxon-Tests berechnet. Ergebnisse: Eine Analyse der Gesamtstichprobe ergab keinen signifikanten Unterschied bei kleiner Effektstärke zwischen ST und DT in PL (3,44 ± 1,06m zu 3,55 ± 0,94m; p = 0,161; d = 0,25) und SV (119,37 ± 33,96m/s zu 122,54 ± 36,12m/s; p = 0,117; r = 0,277). Die Veränderungen (DT minus ST) von jüngeren und älteren Erwachsenen zeigten in PL (0,07 ± 0,35m zu 0,16 ± 0,53m; p = 0,836; r = 0,037) und SV (2,34 ± 11,49m/s zu 4,01 ± 30,54m/s; p = 0,865; r = 0,030) keine signifikanten Abweichungen. Es ergaben sich weder in der Gesamtstichprobe noch altersgruppenspezifisch signifikante Unterschiede in der kognitiven Rechenleistung. Zusammenfassung: Klinisch betrachtet stellte die Kombination aus Einbeinstand und der kognitiven Aufgabenschwierigkeit in der vorliegenden Studie – analog zu den Ergebnissen vergleichbarer Studien – eine mäßige Anforderung dar, die bei gesunden Erwachsenen unterschiedlichen Alters keine signifikante kognitiv-motorische Interferenz hervorrief.
Interessenskonflikt: Es besteht kein Interessenkonflikt
Quantification of Cannula Influence on Negative Pressure in Syringe Assisted Liposuction
No full textTo make the results of the autologous fat transfer more satisfactory, all parameters of suction, preparation, and reapplication must be well understood. Since syringe-assisted liposuction is frequently used for small-volume procedures, we quantified the influence of the cannula on negative pressure.
For these experiments, we used a digital manometer to which a syringe and one of seven different cannulas were connected. Data was collected and analyzed using LabVIEW and Matlab. The volume of our measurement setup was calculated using Boyle-Mariotte's law to ease interpretation, which revealed a volume of 2.82 ± 0.03 mL.
We demonstrate that the volume of the measurement setup significantly affects the measurement results. Consequently, we accounted for this factor and calculated the theoretical values accordingly. Statistical analysis shows a significant influence on negative pressure across different cannulas, except for two pairs, which had minimal volume differences. Exemplary, for cannulas with volumes under 1.75 mL, a 2 mL syringe plunger pull was sufficient to create a - 0.5 bar (- 14.8 inHg) negative pressure.
The present data indicate that the size of the suction cannula must be considered in syringe-assisted suction to ensure a specific negative pressure is not exceeded. Other research groups have demonstrated that adipocyte vitality and the amount of stromal vascular fraction are reduced by excessively strong negative pressure
Ein Beitrag zur axialen Bettung von Kunststoffmantelrohren der Fernwärme in Zeitweise fließfähigen, selbstverdichtenden Verfüllbaustoffen (ZFSV)
No full textQML-Essentials: A Framework for Working with Quantum Fourier Models
No full textIn this work, we propose a framework in the form of a Python package, specifically designed for the analysis of Quantum Machine Learning models. This framework is based on the PennyLane simulator and facilitates the evaluation and training of Variational Quantum Circuits. It provides additional functionality ranging from the ability to add different types of noise to the classical simulation, over different parameter initialisation strategies, to the calculation of expressibility and entanglement for a given model. As an intrinsic property of Quantum Fourier Models, it provides two methods for calculating the corresponding Fourier spectrum: one via the Fast Fourier Transform and another analytical method based on the expansion of the expectation value using trigonometric polynomials. It also provides a set of predefined approaches that allow a fast and straightforward implementation of Quantum Machine Learning models. With this framework, we extend the PennyLane simulator with a set of tools that allow researchers a more convenient start with Quantum Fourier Models and aim to unify the analysis of Variational Quantum Circuits