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A call to reconsider certification authority authorization
No full textCertification Authority Authentication (CAA) is a safeguard against illegitimate certificate issuance. We show how shortcomings in CAA concepts and operational aspects undermine its effectiveness in preventing certificate misissuance. Our discussion reveals pitfalls and highlights best practices when designing security protocols based on the Domain Name System.PeerReviewe
AI-based consumption forecast to reduce energy costs for the operation of charging infrastructure in retail
Get PDFThe buildup of the charging infrastructure in retail significantly changes the load profiles of these energy consumers resulting in higher costs due to power peaks. This paper proposes a new approach for energy management at supermarkets where the cooling processes are used as flexibility. The approach makes use of the time gaps between charging processes to selectively intensify the cooling processes. This energy reserve is used when new charging processes begin. Key capability is a forecast module based on deep learning. The proposed CNN-LSTM model with additional input signals for seasonality and public holidays shows good performance for a short-term prediction over two hours.PeerReviewe
Development of a finite element simulation methodology for the analysis of thick-walled hydrogen tanks
Get PDFDas Ziel dieser Thesis ist die Entwicklung einer Methodik für die Simulation von dickwandigen Wasserstofftanks. Die entwickelte Methodik soll die Faserarchitektur sowie das interlaminare Verhalten der Struktur bei inneren und äußeren Lasten abbilden können. Für die Auswahl einer Methodik werden Voruntersuchungen an einem simplifizierten Tankmodell sowie eine finale Untersuchung an einem realen Tankmodell unter verschiedenen Lastfällen durchgeführt. Aus den Untersuchungsergebnissen haben sich die Parameter für eine Simulationsmethodik ergeben. Die Methodik bildet die Faserarchitektur im Detail ab und ist im Rechenaufwand anpassbar. Die Anwendung der Methodik hat gezeigt, dass sinnvolle Ergebnisse erzielt werden.The aim of this thesis is to develop a methodology for the simulation of thick-walled hydrogen tanks. The developed methodology should be able to simulate the fibre architecture as well as the inter-laminar behaviour of the structure under internal and external loads. For the selection of a methodology, preliminary investigations are carried out on a simplified tank model and a final investigation on a real tank model under various load cases. The parameters for a simulation methodology were derived from the test results. The methodology models the fibre architecture in detail and can be adapted in terms of computational effort. The application of the methodology has shown that meaningful results can be achieved
PartiPause : a participatory format for everyday university life
No full textStudentische Partizipation an Hochschulen steht vor Herausforderungen wie Zeitmangel, unzureichenden Informationen über Partizipationsmöglichkeiten sowie dem Gefühl der Einflusslosigkeit. Um diesen Hürden zu begegnen, haben wir an der HAW Hamburg ein niedrigschwelliges Partizipationsformat – die PartiPause – entwickelt. Diese ermöglicht es Studierenden, ihre Perspektiven spontan einzubringen und Einfluss auf das Hochschulgeschehen zu nehmen. Der vorliegende Beitrag stellt das Konzept und die praktische Umsetzung der PartiPause vor, präsentiert ausgewählte Ergebnisse und bespricht die Wirkung des Formats. Ziel des Beitrages ist es nicht nur, gewonnene Erkenntnisse zu teilen, sondern auch andere Hochschulen dazu zu animieren, das Format zu adaptieren und weiterzuentwickeln.Student participation at universities faces challenges such as a lack of time, insufficient information about participation opportunities and a feeling of lack of influence. To overcome these obstacles, we at HAW Hamburg have developed a low-threshold participation format – the PartiPause. This enables students to spontaneously contribute their perspectives and influence university events. This article presents the concept and practical implementation of the PartiPause as well as selected results and discusses the impact of the format. The aim of the article is not only to share the insights gained but also to encourage other universities to adapt and further develop the format.PeerReviewe
Development of the QoLISSY 0–4 questionnaire : a health-related quality of life tool for young children with short stature
No full textShort stature in children aged 0–4 years presents unique physical, social, and emotional challenges that significantly impact health-related quality of life (HRQoL). The QoLISSY 0–4 questionnaire was developed as a Patient Reported Outcome measure (PROMS) to address the absence of an age-specific, condition-focused HRQoL assessment tool for this population. A mixed-method approach was employed to adapt the original QoLISSY questionnaire for children aged 5–18. Qualitative interviews were conducted with 24 parents of children diagnosed with short-stature conditions, including achondroplasia, small for gestational age, growth hormone deficiency, and Silver-Russell Syndrome. Cognitive debriefing sessions and iterative feedback guided the development of new items tailored to the needs of children aged 0–4. Pilot testing involved 20 parents, who evaluated the questionnaire’s clarity, relevance, and comprehensiveness. The development process yielded an 8-domain, 55-item questionnaire addressing physical health, social interactions, emotions, coping mechanisms, medical care, future concerns, and parental impact. Cognitive debriefing results indicated high item clarity (100%), relevance (93%), and importance (94%), with parents confirming that the questionnaire effectively captured their child’s HRQoL experiences. The QoLISSY 0–4 questionnaire provides a tailored, parent-reported tool for assessing HRQoL in children aged 0–4 with short stature. Its development reflects a rigorous, participant-informed process ensuring its relevance and usability. Future validation studies will explore its cross-cultural applicability and psychometric properties to establish its utility in research and clinical settings.PeerReviewe
Design and Implementation of a Centralized Network Switch Management System
Get PDFEfficient network switch management is vital for stability, security, and scalability. This thesis introduces a Centralized Network Switch Management System to prevent configuration drift, human errors, and inconsistent practices. Using Flask for the backend, Ansible for automation, and SQLite for storage, the system offers reliability, monitoring, and secure SSH-based management for Cisco switches. While suitable for ongoing management, it excludes initial switch deployment due to its reliance on pre-configured SSH access. The system lays a robust foundation for future advancements like analytics and broader vendor integration.Eine effiziente Verwaltung von Netzwerk-Switches ist für Stabilität, Sicherheit und Skalierbarkeit unerlässlich. Diese Arbeit stellt ein zentralisiertes Netzwerk-Switch-Verwaltungssystem vor, um Konfigurationsabweichungen, menschliche Fehler und inkonsistente Vorgehensweisen zu verhindern. Das System verwendet Flask für das Backend, Ansible für die Automatisierung und SQLite für die Speicherung und bietet Zuverlässigkeit, Überwachung und sichere SSH-basierte Verwaltung für Cisco-Switches. Es eignet sich zwar für die laufende Verwaltung, schließt jedoch die anfängliche Bereitstellung von Switches aus, da es auf vorkonfigurierten SSH-Zugriff angewiesen ist. Das System legt eine solide Grundlage für zukünftige Weiterentwicklungen wie Analysen und eine breitere Anbieterintegration
Building orientation dependency of recrystallization kinetics in 316L stainless steel produced via laser powder bed fusion
No full text316L stainless steel produced by laser powder bed fusion (LPBF) exhibits distinct microstructural features such as columnar grains, cellular substructures, anisotropy, and secondary phases. This study investigates the influence of building orientation on the recrystallization kinetics of the LPBF 316L stainless steel samples fabricated in vertical and horizontal orientations. Heat treatments were performed at 900 °C, 1000 °C, and 1100 °C for up to 240 min. After annealing at 1100 °C for 240 min, the hardness values of the vertical and horizontal samples decreased by 27 % and 36 % respectively. Avrami values revealed sluggish recrystallization in both orientations compared to conventional 316L stainless steel, mainly due to non-random nucleation and strong Zener pinning from carbide and oxide particles. Despite this, the vertical sample exhibited higher recrystallization rates and coarser grains after annealing, attributed to shorter laser scan lengths and a lower volume fraction of carbide particles, which enhanced grain boundary mobility compared to the horizontal sample. At 1000 °C and 1100 °C, the Avrami exponents for vertical samples (0.7 and 0.79) were higher than those for horizontal samples (0.5 and 0.6). Both orientations also showed low apparent activation energy (∼20 kJ/mol), reflecting high stored energy and restrained grain growth.PeerReviewe
A systematic literature review on the interconnection between climate change impacts and conflicts
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Incorporating local communities into sustainability reporting : a grey systems-based analysis of Brazilian companies
No full textThis paper aims to evaluate the maturity of Brazilian companies regarding the inclusion of local communities in sustainability reporting. The analysis was based on sustainability reports from a sample of 26 companies listed on the Brazilian stock exchange sustainability index. The study employs a mixed-methods approach and includes the following sequential steps: literature review and content analysis of sustainability reporting standards to identify critical success factors; application of the CRITIC method to define weights for decision criteria; analysis of corporate practices related to the inclusion of local communities in sustainability reports performed by Brazilian companies to determine maturity levels using the Grey Fixed Weighted Clustering method and the Kernel technique. The findings reveal that transparency, comprehensive assessment, and accountability are the most critical factors of sustainability reporting maturity regarding local communities. The analysis shows that companies in the energy sector perform better and can serve as a benchmark for companies in other sectors, such as manufacturing, in which most companies present low maturity. Key corporate practices are identified and discussed for improving engagement with local communities aiming to enhance corporate social responsibility and sustainability reporting. This study advances the understanding of corporate sustainability by highlighting the role of businesses in fostering socio-economic development through the inclusion of local communities in sustainability reporting. It extends theoretical discussions on corporate social responsibility by emphasizing transparency, accountability, and comprehensive assessment as critical factors for sustainability reporting. Practically, the findings provide insights for companies seeking to enhance engagement with local communities, offering a benchmark for industries with lower maturity levels. By demonstrating how sustainability reporting can serve as a strategic tool for social impact, the study reinforces the broader role of businesses in sustainable development.PeerReviewe