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A sample set of calculations is presented in this supplemental document to analytically estimate joint distortion for gas metal arc lap joining of aluminum and steel thin sheets following the published article "Analytical Estimation of Thermomechanical Distortion and Interface Layer Thickness for Gas Metal Arc Lap Joining of Dissimilar Sheets"
Due to the increasing number of complaints alleging privacy violations against companies to data protection authorities, the translation of business goals to system design goals and the subsequent consequences for customers’ privacy poses a challenge for many companies. For this reason, there is a need to bridge the economics of privacy and threats to privacy. To this end, our work relies on the concept of privacy as contextual integrity. This framework defines privacy as appropriate information flows subjected to social norms within particular social contexts or spheres. In this paper, we introduce a preliminary version of a semantic model which aims to relate and provide understanding on how well-established business goals may affect their customers’ privacy by designing IoT devices with permission access, data acquired by sensors, among other factors. Finally, we provide a use case application showing how to use the semantic model. The model aims to be an educational tool for professionals in business informatics during the modeling and designing process of a product which may gather sensitive data or may infer sensitive information, giving an understanding of the interaction of the product and its footprint with diverse actors (humans or machines). In the future, a further complete model of the presented may also target other groups, such as law enforcement bodies, as part of their educational training in such systems.
4.1.: Grundlagen
(2022)
4.2.: Sicherheit
(2023)
Der vorliegende Beitrag befasst sich mit den Herausforderungen, die im Rahmen von Remote Work
in Kooperationen bezüglich der Informations- und
IT-Sicherheit bestehen, insbesondere im Hinblick auf
den sicheren Datenaustausch. Des Weiteren wird die
Wichtigkeit einer ganzheitlichen Sicht von IT-Governance-, Risiko- und Compliance-Management in Verbünden kleiner und mittlerer Unternehmen (KMU)
behandelt. Weiterhin wird aufgezeigt, was bei der
informationstechnischen Absicherung von Kooperationen und IT-Konsortien beachtet werden sollte.
In dieser Forschung wird es gezeigt, wie sicher und benutzerfreundlich eine Authentifizierung mit Passkey/FIDO2 auf Ebene des Web-Browsers ist, im Vergleich zu einer Authentifizierung mit einem starken Passwort oder eine Authentifizierung aus einer Kombination von einem Passwort und einer Zwei-Faktor-Authentifizierung.
In der heutigen digitalisierten Welt spielt die Sicherheit von IT-Infrastrukturen eine
entscheidende Rolle. Diese Bachelorarbeit untersucht das Potenzial von Network
Access Control (NAC) als eine IT-Lösung zur Verbesserung der Netzwerksicherheit in
modernen IT-Umgebungen. Dabei steht die Zugriffskontrolle von Personen und
Geräten im Vordergrund. Damit soll erreicht werden, dass unautorisierter Zugriff zum
Netzwerk verhindert wird. Es werden die Begrifflichkeiten, Funktionsweise und
potenzielle Angriffsvektoren von NAC untersucht. Des Weiteren werden die jeweiligen
Funktionen der NAC-Produkte macmon und der Open-Source Lösung PacketFence
gegenübergestellt. Im praktischen Teil der Arbeit werden dann die vorgestellten
Angriffsvektoren an einem Test-Netzwerk durchgeführt und analysiert.
Die Arbeit zeigt, dass NAC eine wichtige Komponente in der Zugriffskontrolle für eine
moderne IT-Infrastruktur ist. Während einige Angriffe auf das Test-Netzwerk
abgewehrt werden konnten, war es dennoch möglich, sich als Angreifer am Netzwerk
anzumelden. NAC ist ein unerlässliches Tool für größere IT-Infrastrukturen, jedoch
erfordert eine korrekte Konfiguration und effektive Nutzung von NAC ein
umfangreiches Wissen über die verschiedenen Aspekte und Themenbereiche der
Netzwerksicherheit.
Untersuchung der Rotorfestigkeit von permanenterregten Synchronmaschinen mit vergrabenen Magneten
(2023)
Diese Projektarbeit behandelt die mechanische Simulation der Rotoren von permanenterregten Synchronmaschinen für den Festigkeitsnachweis. Hierzu wird die Finite-Elemente-Methode mit dem Programm CalculiX verwendet. Als Beispiel wird der Elektromotor des Toyota Prius II im Detail betrachtet. Hierbei werden die unterschiedlichen Lasten modelliert, dazu zählen neben der Zentrifugalkraft auch der Innendruck durch eine Presspassung sowie die elektromagnetischen Kräfte. Für die Modellierung von Kräften auf der Rotoroberfläche wird eine Methodik zur Umsetzung in CalculiX entwickelt und anhand eines Beispielmodells demonstriert. Der angestrebte Festigkeitsnachweis kann im Rahmen dieser Arbeit erbracht werden. Weiterhin wird gezeigt, dass der Einfluss der elektromagnetischen Kräfte im Arbeitspunkt mit der höchsten Drehzahl sehr gering ausfällt. Insgesamt bietet diese Arbeit die Grundlagen für mechanische Modellierungen von Rotoren unter Berücksichtigung aller Kräfte. Dies kann direkt auf andere Elektromotoren angewendet werden.
Einsicht in die Abläufe und Leistung heutiger Software und verteilter Systeme zu erlangen, wird durch stetig steigende Komplexität zunehmend erschwert. Die Firma Peterson Technologies GmbH implementierte zur Linderung dieser Problematik ein internes Telemetriesystem. Ziel dieser Arbeit ist es, das System auf Wunsch der Firma durch ein neues zu ersetzen, um so die Überwachung zu verbessern und aktuellere Software zu verwenden. Nach einer Untersuchung des vorherigen Systems werden Prioritäten festgelegt, welche die spätere Nutzung, Instandhaltung und Erweiterung des neuen Systems erleichtern sollen. Darauf folgen die Planung seiner Architektur, die Auswahl und Implementierung der Software und schließlich das Erzeugen einer einfachen Dokumentation. Der resultierende Telemetriestack ist funktionstüchtig und erfüllt die Vorstellungen der Firma. Dennoch weist er einige Probleme, wie beispielsweise eine hohe CPU Belastung auf, welche zusammen mit Möglichkeiten der Verbesserung und Erweiterung abschließend betrachtet werden.
Single dielectric microspheres can manipulate light focusing and collection to enhance optical interaction with surfaces. To demonstrate this principle, we experimentally investigate the enhancement of the Raman signal collected by a single dielectric microsphere, with a radius much larger than the exciting laser spot size, residing on the sample surface. The absolute microsphere-assisted Raman signal from a single graphene layer measured in air is more than a factor of two higher than that obtained with a high numerical aperture objective. Results from Mie’s theory are used to benchmark numerical simulations and an analytical model to describe the isolated microsphere focusing properties. The analytical model and the numerical simulations justify the Raman signal enhancement measured in the microsphere-assisted Raman spectroscopy experiments.
Biomass gasification is recognized as a viable avenue to accelerate the sustainable production of hydrogen. In this work, a numerical simulation model of air gasification of rice husks is developed using the Aspen Plus to investigate the feasibility of producing hydrogen-rich syngas. The model is experimentally validated with rice husk gasification results and other published studies. The influence of temperature and equivalence ratio on the syngas composition, H2 yield, LHVSyngas, H2/CO ratio, CGE, and PCG was studied. Furthermore, the synchronized effects of temperature and ER are studied using RSM to determine the operational point of maximizing H2 yield and PCG. The RSM analysis results show optimum performance at temperatures between 820 °C and 1090 °C and ER in the range of 0.06–0.10. The findings show that optimal operating conditions of the gasification system can be achieved at a more refined precision through simulations coupled with advanced optimization techniques.
Glass-ceramic composites consisting of potassium-iron-silicate glass and barium titanate mixed in various proportions were successfully synthesized by low-temperature sintering. The crystal structure of the obtained composite samples, the porosity and the microhardness were studied by the X-ray diffraction, the electron microscopy, the weight method, and the Vickers method. Electrical characteristics (dielectric permittivity, tunability and losses) of as-prepared and annealed in oxygen medium samples were investigated at microwaves. According to structural analysis, the synthesized samples are a mixture of KFeSi glass, ferroelectric BaTiO3, and dielectric barium polytitanates; the ratio of the latter determines the electrical properties of the composites. Depending on the content of barium titanate, the studied composite samples show a permittivity from 50 to 270 with a dielectric loss level of 0,1–0,02 in frequency range from 3 to 10 GHz. Annealing of composite samples in an oxygen-containing environment leads to an increase in their dielectric permittivity and tunability by 10–25% and a twofold decrease in dielectric loss.
Companies are increasingly facing the challenges of a persistent cyber threat landscape. By means of AI, cyber attacks can be efficiently conducted more successful through offensive AI. As for cyber defense, AI can be also utilized against cyber threats (defensive AI). Due to limited resources, especially in small and medium-sized companies (SMEs), there is a need to deploy more effective defensive cyber security solutions. Precisely, the adaptation of AI-based resilient defenses must be driven forward. Therefore, the aim of this paper is to identify and evaluate AI-related use cases with a high impact potential on the cyber security level, while being applicable to SMEs at the same time. In order to reach the research goal, an extensive literature review of several online catalogs, surveys and online platforms was conducted. In conclusion, seven crucial AI-based security features were outlined that are providing a high impact potential to the security level for SMEs. Afterwards, the results are discussed and set into a broader context. Even though AI-based security solutions are providing a large range of advantages, certain challenges and barriers using AI-related security applications are addressed in the paper as well. A high need for usable state of the art AI based cyber security solution for SMEs was identified.
How do we interact with the digital world in the future by only using our thoughts to interact? To interact with the digital world, we use gestures (most common: swipe gestures), voice, facial expressions and mental commands. The latter has become more important by recent press releases about scientific achievements, for example, from Neuralink [1] using invasive technology to control a computer game by thoughts only [2]. Another study says an application can display text on a screen by just thinking about a word [3]. Currently, BCIs are mainly developed for neurotechnology and healthcare. However, it is a question of time when these services will be available for commercial products for everyday life. (Until then, manufacturers have to minimize health risks and face privacy and safety regulations.) The thesis is that in the future, you will be able to interact with your digital devices just by using your thoughts and you’ll do much faster. This makes sense in many situations where you f. e. do not have a free hand (manufacturing, sports) or cannot speak (underwater). But for such services, you cannot rely on conventional visual design guidelines or interaction patterns, frameworks or libraries. Navigation interacting with a digital service by mental command has a lot of advantages, the human brain comes naturally with some specific features that force us to find a radically new way to interact with digital interfaces. The following study introduces you first into working conditions with mental commands, comparing invasive and non-invasive technologies, and later on comparing several possibilities of interaction patterns for a BCI of everyday usage. [1] Neuralink is a US neurotechnology company founded in July 2016 by Elon Musk and eight other persons. Neuralink’s goal is to develop a device for communication between human brain and computers, a so-called brain-computer-interface(BCI). [2] The Guardian, Fr. 9th April 2021 “Elon Musk startup shows monkey with brain chip implants playing video game”. https://www.theguardian.com/technology/2021/apr/09/elon-musk- neuralink-monkey-video-game . [3] Scientific American, 15th July 2021, Neuroscience, author Emily Willingham: “New Brain Implant Transmits Full Words from Neural Signals”.
Making and interpretation of drawings and schematics is an important skill to be developed in engineering education. The question type STACK in the Moodle learning management system combined with the interactive graphics library JSXGraph has a great potential for implementation of e-learning resources addressing these skills in formative and summative settings. The authoring process of such materials is complex due to multiple markup and programming languages like HTML, LaTeX, Maxima and JavaScript (JS) being involved. The Meclib concept mitigates this complexity and allows for efficient bulk production of material with consistent appearance and user experience. The core of Meclib is a set of pre-defined JSXGraph-based objects with an interface to Maxima, such that no problem specific JS code is required at all. The present paper outlines the basic ideas of the implementation and demonstrates the approach for some typical examples of different complexity. The focus is on applications in engineering mechanics, starting from static illustrations up to an editor for free body diagrams, with rich adaptive formative feedback.
In this study we have examined the potential of excess wind use in Germany. Excess wind constitutes roughly 40% of unused capacities of installed wind power in Germany. Using LP modelling and representative annual load profiles on an hourly resolution, we investigate the impact of the price level for wind peak power supply of residential quarters with heat, cold and electricity in Germany in combination with different power ratios of wind supply and demand. As we show, an application of wind peak tariff is technically and economically feasible and allows using green leftover energy without going in competition with e.g., green fuels or green H2 production.
This study analyzes approaches to decarbonize the energy supply of the secondary steel processing industry. Therefore, real data from a secondary steel production company is used in combination with state-of-the art low carbon energy supply technologies. Also, the use of waste heat from a pusher furnace for process integration is considered. The developed temporal process model allows holistic optimizing and expanding the steel making process system regarding techno-economic criteria. As we show, implementing the annual heat demand of a municipality shows that a nearly 100 % self-sufficient heat supply is possible.