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Adapted Design Process for Continuous Fiber-Reinforced Additive Manufacturing — A Methodological Framework
Get PDFContinuous fiber-reinforced material extrusion is an emerging additive manufacturing process that builds components layer by layer by extruding a continuous fiber-reinforced thermoplastic strand. This novel manufacturing process combines the benefits of additive manufacturing with the mechanical properties and lightweight potential of composite materials, making it a promising approach for creating high-strength end products. The field of design for additive manufacturing has developed to provide suitable methods and tools for such emerging processes. However, continuous fiber-reinforced material extrusion, as a relatively new technology, has not been extensively explored in this context. Designing components for this process requires considering both restrictive and opportunistic aspects, such as extreme anisotropy and opportunities for functional integration. Existing process models and methods do not adequately address these specific needs. To bridge this gap, a tailored methodology for designing continuous fiber-reinforced material extrusion is proposed, building on established process models. This includes developing process-specific methods and integrating them into the process model, such as a process selection analysis to assess the suitability of the method and a decision model for selecting the process for highly stressed components. Additionally, a detailed design process tailored to continuous fiber-reinforced material extrusion is presented. The application of the developed process model is demonstrated through a case study
ELSI researchers for technical innovations in care: Perspectives between critical distance and application-related influence
Get PDFDer Beitrag präsentiert Ergebnisse einer selbstreflexiven Auseinandersetzung mit der Rolle der Forschung zu ethischen, rechtlichen und sozialen Implikationen (ELSI) in Projekten, die sich die Entwicklung und Implementierung von Techniklösungen für die Pflege zum Ziel machen. Anhand von vier Perspektiven der ELSI-Forschung wird ihre Bedeutung für dieses Vorhaben untersucht: (1) ELSI-Forschung als ‚Beitrag zur Akzeptanzförderung‘, (2) ELSI-Forschung als ‚Prüfsiegel für neue Technologien‘, (3) ELSI-Forschung als ‚distanziert-kritische Beobachtung‘, (4) ELSI-Forschung als ‚Bestandteil der integrierten Forschung‘. Es wird deutlich, dass diese Perspektiven sich danach unterscheiden, wie sie sich im Spannungsfeld zwischen den Ansprüchen eines wissenschaftlich begründeten Selbstverständnisses und der Erfüllung praktischer und normativer Anforderungen des Untersuchungsfeldes verorten. Aus der Einsicht in diese Unterschiede ergeben sich Anhaltspunkte für die Gestaltung einer ELSI-Forschung, die ihre vermittelnde Rolle für den Wissenstransfer zwischen Technikentwicklung und Techniknutzung selbstkritisch reflektieren kann.This article presents the results of a self-reflective analysis of the role of research on ethical, legal, and social implications (ELSI) in projects that aim to develop and implement technology solutions for care. Four perspectives of ELSI research are used to examine their significance for this endeavor: (1) ELSI research as a ‘contribution to promoting acceptance,’ (2) ELSI research as a ‘seal of approval for new technologies,’ (3) ELSI research as ‘distanced-critical observation,’ (4) ELSI research as a ‘component of integrated research’. It becomes clear that these perspectives differ according to how they cope with the tension between the demands of a scientifically sound self-image and the fulfillment of practical and normative requirements of the field of investigation. Insights into these differences provide clues for the design of ELSI research that can self-critically reflect on its mediating role in the transfer of knowledge between technology development and technology use
Meta‐Analysis of Diagnostic Accuracy Studies With Multiple Thresholds: Comparison of Approaches in a Simulation Study
Get PDFThe development of methods for the meta‐analysis of diagnostic test accuracy (DTA) studies is still an active area of research. While methods for the standard case where each study reports a single pair of sensitivity and specificity are nearly routinely applied nowadays, methods to meta‐analyze receiver operating characteristic (ROC) curves are not widely used. This situation is more complex, as each primary DTA study may report on several pairs of sensitivity and specificity, each corresponding to a different threshold. In a case study published earlier, we applied a number of methods for meta‐analyzing DTA studies with multiple thresholds to a real‐world data example (Zapf et al., Biometrical Journal. 2021; 63(4): 699–711). To date, no simulation study exists that systematically compares different approaches with respect to their performance in various scenarios when the truth is known. In this article, we aim to fill this gap and present the results of a simulation study that compares three frequentist approaches for the meta‐analysis of ROC curves. We performed a systematic simulation study, motivated by an example from medical research. In the simulations, all three approaches worked partially well. The approach by Hoyer and colleagues was slightly superior in most scenarios and is recommended in practice
Dimensionless quantities in discrete element method: powder model parameterization for additive manufacturing
Get PDFPowder bed-based additive manufacturing processes offer an extended freedom in design and enable the processing of metals, ceramics, and polymers with a high level of relative density. The latter is a prevalent measure of process and component quality, which depends on various input variables. A key point in this context is the condition of powder beds. To enhance comprehension of their particle-level formation and facilitate process optimization, simulations based on the Discrete Element Method are increasingly employed in research. To generate qualitatively as well as quantitatively reliable simulation results, an adaptation of the contact model parameterization is necessary. However, current adaptation methods often require the implementation of models that significantly increase computational effort, therefore limiting their applicability. To counteract this obstacle, a sophisticated formula-based adaptation and evaluation method is presented in this research. Additionally, the developed method enables accelerated parameter determination with limited experimental effort. Thus, it represents an integrative component, which supports further research efforts based on the Discrete Element Method by significantly reducing the parameterization effort. The universal nature of deducting this method also allows its adaptation to similar parameterization problems and its implementation in other fields of research
Onboarding an wissenschaftlichen Bibliotheken
Get PDFDie vorliegende Bachelorarbeit untersucht Onboarding-Prozesse wissenschaftlicher Bibliotheken, insbesondere anhand einer Analyse der Universitätsbibliothek der Friedrich-Alexander-Universität Erlangen-Nürnberg. Im ersten Teil werden organisationstheoretische und interdisziplinäre Grundlagen beleuchtet. Dabei liegt ein Fokus auf den Herausforderungen, Nutzen und Zielen von Onboarding-Maßnahmen in Abhängigkeit ihres Zeitpunktes und der Zielgruppe. Im Praxisteil werden die gewonnenen Erkenntnisse auf die spezifischen Anforderungen von wissenschaftlichen Bibliotheken angewendet. Die Analyse von Onboarding-Prozessen der Universitätsbibliothek der Friedrich-Alexander-Universität Erlangen-Nürnberg beinhaltet eine Mitarbeitendenbefragung von Onboardees und beteiligten Personen. Die Ergebnisse werden nach der SWOT-Methode eingeordnet. Anschließend folgen Konzepte zur Entwicklung von Arbeitsmaterialien, Unterlagen interner Kommunikation und ein Datenbankkonzept.
Schließlich erfolgt eine ableitende Handlungsempfehlung für eine effektive Umsetzung von Onboarding in wissenschaftlichen Bibliotheken. Das Fazit fasst die wichtigsten Erkenntnisse zusammen, während der Anhang alle Informationen zu den durchgeführten Befragungen, deren Auswertung und die erstellten Arbeitsmaterialien bzw. deren Konzept enthält
Integrated Risk and Opportunity Management - Implementing clause 6.1
Get PDFIntegrated Risk and Opportunity Management (IROM) goes far beyond what is found in organizations today. However, it offers the best opportunity not only to keep pace with the VUCA world, but to actually profit from it. Accordingly, the introduction of opportunity-based thinking in addition to risk-based thinking is part of the design specification for ISO 9000 and ISO 9001. The prerequisite for the successful design of an IROM is the individual definition, control and integration of risk and opportunity management processes, considering eight success factors, the "8 C". Top management benefits directly from the result: better, coordinated decision memos enable faster and more appropriate decisions
Forecasting Bitcoin returns: Econometric time series analysis vs. machine learning
Get PDFWe study the statistical properties of the Bitcoin return series and provide a thorough forecasting exercise. Also, we calibrate state-of-the-art machine learning techniques and compare the results with econometric time series models. The empirical assessment provides evidence that the application of machine learning techniques outperforms econometric benchmarks in terms of forecasting precision for both in- and out-of-sample forecasts. We find that both deep learning architectures as well as complex layers, such as LSTM, do not increase the precision of daily forecasts. Specifically, a simple recurrent neural network describes a sensible choice for forecasting daily return series
Postpartum excretion of internal teat sealant after selective dry cow treatment of dairy cows
Get PDFTo comply with antibiotic restriction policies in the European Union, internal teat sealants (TS) are increasingly used at dry off (DO) in selective dry cow treatment protocols to maintain udder health. Postcalving TS residue attachment to milking equipment and associated cleaning difficulties is a reason some farmers stay away from blanket TS use. Our objective was therefore to improve insight into TS excretion visibility and to compare quantity, pattern, and presence versus absence of TS excretion postcalving between the typical 2 cow categories at DO: high (H)- and low (L)-SCC cows, treated with antibiotic (AB) plus TS (H-ABTS) or TS only (L-TS), respectively. In herds in the Netherlands (n = 3), and Germany (n = 4), cows were enrolled at DO, and categorized as H-ABTS (n = 93), or L-TS (n = 99). Postcalving, quarter-level TS visibility, quantities, patterns, and percentage of TS infused and excreted postcalving were recorded from 50 mL of premilk of every quarter at each of the first 15 or 16 milkings. Udder quarter health status was determined by bacteriological culture and SCC of quarter milk samples taken at DO and at d 3 postcalving and by clinical mastitis incidence from DO until 30 DIM. Univariable and multivariable models were created to explore associations of TS excretion presence versus absence at the first 3 milkings. Irrespective of SCC category, both laboratory personnel and farmers saw TS residues at the first milking in an equal 72% of quarters. Compared with laboratory as the gold standard, farmer sensitivity to spotting TS in premilk was 74.5% at the first milking and decreased to a maximum of 8.3% at the last 3 milkings. At the first milking, TS excretion quantities showed a bimodal distribution pattern and the mean percentage of TS infused (3.83 g) that was excreted in premilk at the first milking, was higher in the L-TS cows (45.5%) compared with the H-ABTS cows (32%). At the second and third milking, mean-adjusted TS percentage excreted was higher in the H-ABTS cows (8.5% and 1.8%, respectively) compared with the L-TS cows (4.6% and 0.4%, respectively). The multivariable model of the first 3 milkings showed parity at both the first and second milking, and the study group at both the second and third milking was significantly associated with TS presence. The univariable model showed no association between TS presence at the first milking and udder health. In conclusion, in premilk of the first milking, TS residue excretion was bimodal, higher in L-TS cows, more likely to be present in multiparous cows, and not associated with udder health. At the second and third milking, excretion was higher in H-ABTS cows and TS presence was only more likely in multiparous cows at the second milking
The Influence of Milk Leakage, Udder Pressure and Further Risk Factors on the Development of New Intramammary Infections during the Dry Period of Dairy Cows
Get PDFPrevention of new intramammary infection (NIMI) during the dry period (DP) is essential to prevent the development of mastitis in dairy cows. To investigate risk factors for NIMI, 212 cows, comprising a total of 848 udder quarters, were examined in this study. Quarter milk samples were taken on the day of drying off and 7 ± 3 days after calving. Cow- and quarter-level associated risk factors were assessed at the beginning of the DP and after calving. In total, 7.1% of the udder quarters developed an NIMI between the samplings. Non-aureus staphylococci (40.4%) and Gram-negative pathogens (22.8%) were most frequently the cause of NIMI. The observed milk leakage prevalence was 16.7%, with a peak 24 h after drying off. Simultaneously, the udder pressure peaked 24 h after drying off. A significant correlation between milk yield on the day before drying off and milk leakage could be proven. Cows with quarters leaking milk produced an average milk yield of 28.32 kg on the day before drying off. Generalised linear mixed models and odds ratios were calculated to determine the significant risk factors for NIMI during the DP and early lactation. Quarters leaking milk had 3.4 higher odds for NIMI between the samplings compared to quarters without milk leakage. Quarters from cows with dirty udders had 3.1 higher odds of developing an NIMI between the samplings compared to quarters from cows with clean udders. The results of this study demonstrate the importance of dry cow management before drying off and during the critical period of active involution of the udder tissue
Enhancing Feedback Generation for Autograded SQL Statements to Improve Student Learning
Get PDFSeveral tools to support autograding of student provided SQL statements have already been introduced. The full potential of such tools can only be leveraged, if they extend beyond grading efficiency by also providing tutoring capabilities to the students. With that, tools become really useful by offering self-paced and individually timed learning experiences. In this paper we present an extension for an SQL autograder which improves the hints generated for students in cases where their solution is not entirely correct. Our approach is to compare the student’s solution with the model solution structurally to identify differences between the syntax trees describing the statements. This complements comparing the student’s query with a model solution based on query results. In addition to improving the quality of hints generated for the students, this concept can also be used easily for data manipulation language (DML) or data definition language (DDL) statements, thus extending the applicability of the autograder. Along with details about the concept we present some example hints generated to illustrate the usefulness of the approach. We also report anecdotally on experiences with the system in two different level database courses. Results from different instances of one of them show improvements of student learning as well as student involvement by using the newly generated hints