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Correlation between surface-to-volume ratio of the particle shape and elastic properties of the particulate composites
Get PDFThis work is motivated by real-world particle shapes, observed using a scanning electron microscopy. The focus of the presented studies was to understand the influence of the particle shapes on the effective elastic properties of the two-phase composites. For this, particles with polyhedral, undulated and other shapes were numerically modeled using analytical functions. Creation of some shapes, like polyhedral, are known from the literature but Laplace’s spherical harmonics, as well as the Goursat’s surface and some others, were used for the first time to create novel particle shapes. Elastic properties of the composites with different particle shapes were calculated using the finite element analysis. The obtained results show good agreement with mean-field homogenization methods such like Mori-Tanaka and Lielens as well as other numerical results available in the literature. Further, the dependence of the effective Young’s moduli of the composite on the shape and the corresponding surface-to-volume ratio of the particles was studied. It was observed that the effective Young’s moduli increase with the surface-to-volume ratio of the particles in the case where particles are stiffer in comparison to the matrix. It was also remarked that, in the case of particles of similar shapes, the particle surface-to-volume ratio and the effective Young’s moduli differ significantly with the surface curvature and the edge sharpness of the particles
Separation and Analysis of Connected, Micrometer-Sized, High-Frequency Damage on Glass Plates due to Laser-Accelerated Material Fragments in Vacuum
Get PDFIn this paper, we present a new processing method, called MOSES—Impacts, for the detection of micrometer-sized damage on glass plate surfaces. It extends existing methods by a separation of damaged areas, called impacts, to support state-of-the-art recycling systems in optimizing their parameters. These recycling systems are used to repair process-related damages on glass plate surfaces, caused by accelerated material fragments, which arise during a laser–matter interaction in a vacuum. Due to a high number of impacts, the presented MOSES—Impacts algorithm focuses on the separation of connected impacts in two-dimensional images. This separation is crucial for the extraction of relevant features such as centers of gravity and radii of impacts, which are used as recycling parameters. The results show that the MOSES—Impacts algorithm effectively separates impacts, achieves a mean agreement with human users of (82.0 ± 2.0)%, and improves the recycling of glass plate surfaces by identifying around 7% of glass plate surface area as being not in need of repair compared to existing methods
Rapid Determination of Kinetic Constants for Slow-Binding Inhibitors and Inactivators of Human Histone Deacetylase 8
Get PDFThe kinetics and mechanism of drug binding to its target are critical to pharmacological efficacy. A high throughput (HTS) screen often results in hundreds of hits, of which usually only simple IC50 values are determined during reconfirmation. However, kinetic parameters such as residence time for reversible inhibitors and the kinact/KI ratio, which is the critical measure for evaluating covalent inactivators, are early predictive measures to assess the chances of success of the hits in the clinic. Using the promising cancer target human histone deacetylase 8 as an example, we present a robust method that calculates concentration-dependent apparent rate constants for the inhibition or inactivation of HDAC8 from dose–response curves recorded after different pre-incubation times. With these data, hit compounds can be classified according to their mechanism of action, and the relevant kinetic parameters can be calculated in a highly parallel fashion. HDAC8 inhibitors with known modes of action were correctly assigned to their mechanism, and the binding mechanisms of some hits from an internal HDAC8 screening campaign were newly determined. The oxonitriles SVE04 and SVE27 were classified as fast reversible HDAC8 inhibitors with moderate time-constant IC50 values of 4.2 and 2.6 µM, respectively. The hit compound TJ-19-24 and SAH03 behave like slow two-step inactivators or reversible inhibitors, with a very low reverse isomerization rate
Real-Time Ideation Analyzer and Information Recommender
Get PDFThe benefits of ideation for both industry and academia alike have been outlined by countless studies, leading to research into various approaches attempting to add new ideation methods or examine how the quality of the ideas and solutions created can be measured. Although AI-based approaches are being researched, there is no attempt to provide the ideation participants with information that inspire new ideas and solutions in real time. Our proposal presents a novel and intuitive approach that supports users in real time by providing them with relevant information as they conduct ideation. By analyzing their ideas within the respective ideation sessions, our approach recommends items of interest with high contextual similarity to the proposed ideas, allowing users to skim through, for example, publications and inspire new ideas quickly. The recommendations also evolve in real time. As more ideas are written during the ideation session, the recommendations become more precise. This real-time approach is instantiated with various ideation methods as a proof of concept, and various models are evaluated and compared to identify the best model for working with ideas
Staatliche Anerkennung von Sozialarbeiter_innen und Sozialpädagog_innen
Get PDFDie staatliche Anerkennung von Sozialarbeiter_innen und Sozialpädagog_innen blickt auf eine lange Tradition zurück und ist seit vielen Jahren Gegenstand zahlreicher und kontroverser Auseinandersetzungen. Der Beitrag widmet sich neben einer grundlegenden Einführung zur Thematik, der gegenwärtigen Relevanz sowie der aktuellen Vergabepraxis der staatlichen Anerkennung, identifiziert zentrale
Diskussionsbedarfe und führt in den Schwerpunkt ein
Blockchain-Technologie in der Energiewirtschaft – Blockchain als Treiber der Energiewende
Get PDFRezension, keine Zusammenfassung verfügba
Distributed Cooperative Communication (DisCoCom) to Improve the Scaling Behaviour of Mobile Ad-Hoc Networks (MANETs)
Get PDFConventional communication systems like the cellular mobile system rely on a preinstalled
and incessantly available infrastructure. This dependency makes them vulnerable to natural catastrophes as well as terrorist and cyber attacks. If the infrastructure is damaged, communication can come to a stillstand. In contrast, mobile ad-hoc networks (MANETs) do not require any infrastructure and allow every node to exchange messages directly with all remaining nodes. Due to that, MANETs are widely considered to be disaster-resistant and highly flexible.
If traditional multiple-access schemes are employed, MANETs scale poorly with respect to the total number of nodes. However, cooperative communication on the physical layer can enable a linear scaling behaviour. To this end, transmitting nodes support each other by simultaneously sending in the same interference domain. Until now, cooperative communication approaches have mostly been considered theoretically. Particularly, implementation strategies for practical systems have not been discussed. With regard to the latter, many challenges arise. Thereby, the greatest difficulty is that multiple imperfections occur simultaneously.
In this thesis communication systems are presented that enable distributed cooperative
communication (DisCoCom) for practical MANETs. Besides a single-carrier and multi-carrier system tailored for standalone single-antenna nodes, a singlecarrier communication system for standalone multi-antenna nodes is proposed. All systems are extremely robust against typical imperfections like multiple carrier frequency and timing offsets. Furthermore, a clustering strategy is exemplified that allows to significantly reduce the network energy consumption to realize DisCoCom. Overall, these systems enable distinctly more robust, effective and efficient broadcasts in MANETs, which can pave the way towards a linear scaling behaviour. The applicability of the introduced systems is not only shown by appropriate simulations, but additionally with an SDR-based MANET demonstration system that has specifically been implemented for this purpose.Herkömmliche Kommunikationssysteme, wie das Mobilfunksystem, stützen sich auf eine aufwändige Infrastruktur, die jederzeit verfügbar sein muss. Diese Abhängigkeit macht sie anfällig für Naturkatastrophen, aber auch Terror- oder Cyberangriffe.
Wird die Infrastruktur beschädigt, kann die Kommunikation zum Erliegen kommen.
Im Gegensatz zu diesen benötigen mobile ad-hoc Netzwerke (MANETs) grundsätzlich keinerlei Infrastruktur und ermöglichen es jedem Netzwerkteilnehmer (Knoten) unmittelbar Nachrichten mit jedem anderen Knoten auszutauschen. Daher gelten sie als besonders katastrophen- sicher und anpassungsfähig.
Werden klassische Multiplexverfahren eingesetzt, skalieren MANETs im Hinblick auf die unterstützen Netzwerkteilnehmer schlecht. Allerdings kann der Einsatz von kooperativer Kommunikation auf dem Physical Layer ein lineares Skalierungsverhalten ermöglichen. Dabei unterstützen sich die einzelnen Knoten bei der Verbreitung einer gemeinsamen Nachricht gegenseitig, indem sie gleichzeitig in der identischen Interferenz-domäne aktiv sind. Bisher wurden kooperative Kommunikationsformen meist theoretisch betrachtet. Insbesondere mögliche Implementierungen für praktische Systeme wurden nicht erörtert. Hinsichtlich letzterer gibt es eine Reihe von Herausforderungen, die überwunden werden müssen. Dabei liegt die größte Schwierigkeit darin, dass Imperfektionen vielfach zur gleichen Zeit auftreten und entsprechend kompensiert werden müssen.
In dieser Arbeit werden Kommunikationssysteme vorgestellt, die kooperative Kommunikation für solche praktischen Systeme ermöglichen. Insgesamt werden ein Ein- und Mehrträger-System für verteilte Ein-Antennen-Knoten sowie ein Einträger-System für verteilte Mehr-Antennen-Knoten eingeführt. Jedes dieser Systeme ist äußerst robust gegenüber typischen Imperfektionen wie Frequenz- und Timing-Offsets, die vielfach auftreten. Ferner wird ein Clustering-Ansatz diskutiert, der es erlaubt, den Energieverbrauch des Netzwerkes zur Realisierung von kooperativer Kommunikation signifikant zu reduzieren. Insgesamt werden so deutlich robustere, effektivere und effizientere Broadcasts in MANETs ermöglicht, die den Weg für ein lineares Skalierungsverhalten ebnen können. Dabei wird die Anwendbarkeit der eingeführten Konzepte neben geeigneten Simulationen mit Hilfe eines eigens zu diesem Zweck entwickelten SDR-basierten MANET Demo-Systems gezeigt
Dispositionale Achtsamkeit und ihre Rolle im Kontext der Suffizienzorientierung
Get PDFDispositionale Achtsamkeit ist Gegenstand vieler Studien zur Nachhaltigkeit. In Bezug darauf soll die vorliegende Studie neue Erkenntnisse über einen spezifischeren, bisher kaum erforschten Zusammenhang liefern: Wie hängt das Konstrukt der dispositionalen Achtsamkeit mit einer Suffizienzorientierung zusammen? Dazu wurde eine Querschnittstudie, mittels einer Online-Befragung durchgeführt, aus der zunächst N = 424 Versuchsteilnehmende resultierten und von denen letztendlich n = 309 in die Analyse einbezogen wurden. Erhebungsinstrumente stellten hierbei zum einen die deutsche Version des „Five Facet Mindfulness Questionnaires“ (FFMQ-D) (Michalak et al., 2016), und zum anderen die „Sufficiency Attitude Scale“ (Henn, 2013) dar. Die anschließende Analyse wurde primär mit Hilfe des Programmes IBM SPSS Statistics durchgeführt.
Zur Überprüfung der aufgestellten Hypothesen wurde eine lineare multiple Regressionsanalyse berechnet. Es resultiert ein signifikantes Modell, in dem allerdings kein signifikanter Effekt der dispositionalen Achtsamkeit oder einzelnen Facetten dieser auf eine Suffizienzorientierung festgestellt werden kann. Signifikante Effekte werden lediglich für zwei Kontrollvariablen,
Naturverbundenheit und Meditationserfahrung, beobachtet. Die Ergebnisse deuten darauf hin, dass dispositionale Achtsamkeit womöglich kein Prädiktor für die Suffizienzorientierung einer Person darstellt und dass es noch weitere Prädiktoren geben muss. Anzumerken ist jedoch, dass diese Studie Limitationen aufweist, die die Ergebnisse beeinflusst haben könnten. Diese Analyse stellt daher einen ersten spezifischen Versuch zur Untersuchung des Zusammenhangs dar und soll als Grundlage für zukünftige Forschungen dienen
Secure Face Recognition Against Digital And Physical Manipulations
Get PDFBiometric systems, particularly face recognition (FR) systems, have become ubiquitous and are used in many real-world authentication scenarios, ranging from unlocking smartphone devices to automated border control systems at airports. FR systems offer a seamless and convenient authentication method, as faces can be captured at a distance. Furthermore, advancements in deep learning-based methods and accessibility to large training datasets have meant that state-ofthe-art FR systems achieve near-perfect biometric performance on several challenging benchmarks. However, the high generalisability of FR systems has also meant that these systems are vulnerable to different digital and physical face manipulations, which can impair their security. For instance, alterations to a face might be performed by a malicious actor in the physical domain (e.g., using makeup or silicone masks) or in the digital domain (e.g., using morphing or face swapping techniques) with the intention to impersonate another target identity and, as such, gain fraudulent access to a system. To mitigate this security risk, methods for detecting various digital and physical face manipulations have been proposed. However, most of these approaches consider only a few well-studied types of digital face manipulations or physical face manipulations and struggle to generalise beyond the data they were trained on. Motivated by the need to enhance the security of FR systems towards digital and physical face manipulations, this thesis investigates in more detail the impact of different digital and physical face manipulations on FR systems. Moreover, this thesis proposes novel algorithms for detecting digital and physical face manipulations by both developing methods focusing on detecting specific types of digital face manipulations or physical face manipulations and by developing highly generalisable methods for the unified detection of attacks on FR systems across both the digital and physical domains. Furthermore, methods for adapting existing pre-trained FR systems to be more resilient towards digital and physical face manipulations are proposed, and it is investigated how algorithms might be used in collaboration with human examiners to detect digital face manipulations. Comprehensive and realistic experimental evaluations demonstrate the capabilities of the proposed algorithms for detecting different digital and physical face manipulations and for making FR systems more resistant towards such manipulations
Context-Aware Fault Diagnosis in Smart Manufacturing
Get PDFThe manufacturing industry is undergoing a transformation marked by the emergence of Industry 4.0 and Industry 5.0 paradigms, which are characterized by the integration and automation of machinery. Thereby, the machinery evolves into Cyber-Physical Systems (CPSs). These CPSs consist of software and hardware modules implementing complex manufacturing processes. The ongoing integration of machinery, and external technologies, e.g., the Industrial Internet of Things (IIoT), led to an evolving Smart Manufacturing (SM) environment. At the same time, legacy machinery, the brownfield machinery, exists side-by-side with modern CPSs. The brownfield machinery might be integrated by retrofitting in the modern manufacturing process. Therefore, the evolution of the SM domain thriven by the Industry 4.0 and Industry 5.0 paradigms leads to a more complex SM environment. Moreover, the integration and ongoing adaption of technologies and processes introduce novel relationships and dependencies between employed machinery and systems. Fault Diagnosis (FD) in such a complex SM environment becomes more time-consuming and laborious. A side effect of the ongoing evolution is the advancing capabilities of the machinery and the ability to produce data. Therewith, not only complex data has to be analyzed during any FD but also vast quantities. The search for the origin of the fault is challenging. Additionally, technical challenges in the SM environment hinder a thorough FD. For instance, the available bandwidth for data transmission is unequal to the capabilities of the machinery to produce vast data quantities. Therefore, the application challenge exists to focus on specific areas of the SM environment while choosing a reasonable granularity in data surveillance to cover the fault traces without losing too much information. Thereby, any FD depends heavily on the domain knowledge of the professionals entrusted with the FD task. On top, there is also economic pressure, which raises the tension on the employed professionals as an unexpected downtime, and the loss in production quantity equals the economic loss.
The thesis introduces context-aware FD to mitigate the risen complexity of the SM environment and support the professionals in their work. By supporting the professionals, the time for FD can be reduced, which results in faster fault amendment and reduced cost-intensive production downtimes. The Context-Aware Diagnosis in Smart Manufacturing (TAOISM) Visual Analytics (VA) model backs the context-aware FD. The TAOISM VA model is the theoretical foundation for the context-aware FD and defines the data layer, the models layer, the visualization layer, and the knowledge layer for SM. Hereby, the VA model enables the definition of context, context models, and context hierarchies for their integration in the respective layers. The main idea behind the context-aware FD is to use the narrowing character of the context definition to slice vast amounts of data into manageable context-separated data groups. Thereby, the context model works as a virtual boundary across machinery and systems, which encloses the physical domain (hardware) and the immaterial domain (software) equally. Further, the thesis focuses on contextual faults, which arise from context model violations, and proposes approaches for collecting contextual data. Also, the automated building of context models and the extraction and transformation of contextual data is part of the thesis. Employing the context models impacts each layer of the proposed TAOISM VA model. For each layer, various approaches show the impact of the context models and their employment in three different application scenarios for FD in SM. The performed research is tested and verified in the scenarios of Robotics Application Development (RAD), Maintenance of Industrial Inspection Machines (MIIM) and Abnormal Event Management in Production Lines (AEMPL). Along with employing context models, data augmentation with context models is proposed. Along with other benefits, the presented data augmentation technique has the ability to balance undersampled datasets, which would enable a reduction of data recordings for any context-aware FD in the future. Thereby, the data augmentation technique is to answer the existing inaccuracies in an SM environment, which also impacts the quality of any employed Artificial Intelligence (AI). Another approach targets the unsupervised selection of production-relevant variables to focus FD-related data recordings and surveillance on areas of the SM environment active during production automatically without any domain knowledge involved. The hypothesis, which was proven right, was that faults, especially contextual faults, occur more often on active software and hardware modules. Another challenge from the vast amount of data is that labeling data for AI becomes uneconomical, even for small fault cases in AI. As a result, evaluating any AI model in SM becomes challenging, as standard measures, e.g., accuracy, precision, recall, and F1-score, cannot be applied. In this case, the thesis proposes novel AI performance metrics that decouple comparability and correctness to enable the evaluation of AI models in an SM environment. All the contributions have led to the development of two distinct Proof of Concepts (PoCs). The PoCs are the reference implementation of the context-aware FD and reflect a knowledge-based FD Expert System (ES) and an unsupervised data-driven FD system. The latter was part of the thorough evaluation of the context-aware FD by two groups of domain experts and junior professionals. The successful qualitative evaluation not only hints towards a working context-aware FD but also unveils future research directions and a future vision for SM. Additional domain expert interviews expose the views on the relevancy of a context-aware FD in SM for the future. In general, the evaluation hints towards a context-aware FD, which has versatile applicability, usability, and suitability in SM-related FD