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Bei diesem Service handelt es sich um das Institutionelle Repositorium der Technischen Universität Dortmund. Hier werden Ressourcen aus und für Lehre, Studium und Forschung gespeichert, erschlossen und der Öffentlichkeit zugänglich gemacht.

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Aktuellste Veröffentlichungen

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    In defense of ‘surveillance capitalism’
    (Springer Science and Business Media LLC, 2024-10-16) Königs, Peter
    Critics of Big Tech often describe ‘surveillance capitalism’ in grim terms, blaming it for all kinds of political and social ills. This article counters this pessimistic narrative, offering a more favorable take on companies like Google, YouTube, and Twitter/X. It argues that the downsides of surveillance capitalism are overstated, while the benefits are largely overlooked. Specifically, the article examines six critical areas: i) targeted advertising, ii) the influence of surveillance capitalism on politics, iii) its impact on mental health, iv) its connection with government surveillance, v) its effects on the rule of law and social trust, and vi) privacy concerns. For each area, it will be argued that concerns about surveillance capitalism are unfounded or exaggerated. The article also explores some benefits of the services provided by these technology companies and concludes with a discussion of the practical implications. Throughout, the article draws on empirical evidence relating to the societal and political impact of digital technologies.
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    How representative is the Swedish PISA sample? A comparison of PISA and register data
    (Springer Science and Business Media LLC, 2024-07-06) Borger, Linda; Johansson, Stefan; Strietholt, Rolf
    PISA aims to serve as a “global yardstick” for educational success, as measured by student performance. For comparisons to be meaningful across countries or over time, PISA samples must be representative of the population of 15-year-old students in each country. Exclusions and non-response can undermine this representativeness and potentially bias estimates of student performance. Unfortunately, testing the representativeness of PISA samples is typically infeasible due to unknown population parameters. To address this issue, we integrate PISA 2018 data with comprehensive Swedish registry data, which includes all students in Sweden. Utilizing various achievement measures, we find that the Swedish PISA sample significantly overestimates the achievement levels in Sweden. The observed difference equates to standardized effect sizes ranging from d = .19 to .28, corresponding to approximately 25 points on the PISA scale or an additional year of schooling. The paper concludes with a plea for more rigorous quality standards and their strict enforcement.
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    KI-Systeme instrumentell verstehen
    (2026) Mann, Sara; Schmidt, Eva; Kästner, Lena
    Viele moderne KI-Systeme sind epistemisch opak. Das Forschungsfeld der erklärbaren KI (XAI) versucht, diese Opazität durch die Entwicklung von Erklärbarkeitsmethoden zu reduzieren und relevante Aspekte von KI-Systemen für verschiedene Stakeholder verständlich zu machen. Häufig wird angenommen, dass das resultierende Verstehen als Mediator zwischen Erklärbarkeit und der Erfüllung gesellschaftlicher Desiderata (z.B. Fairness von KI, Wahrung menschlicher Verantwortlichkeit bei KI-gestützten Entscheidungen) fungieren kann. Doch bleibt in der XAI-Literatur weitestgehend offen, worin dieses Verstehen besteht und wie es seiner Mediatorrolle gerecht werden kann. Diese Dissertation entwickelt mithilfe von Conceptual Engineering und auf Grundlage aktueller erkenntnis- und wissenschaftstheoretischer Debatten einen kontextsensitiven Verstehensbegriff, der speziell auf erklärbare KI zugeschnitten ist und die behauptete Mediatorrolle von Verstehen in XAI-Kontexten erklärt. Das entscheidende Merkmal dieses Verstehens ist sein zweckgerichteter Charakter: Es dient der Erfüllung legitimer gesellschaftlicher Desiderata und heißt daher „instrumentelles Verstehen“. Instrumentelles Verstehen wird durch zwei notwendige und zusammen hinreichende Bedingungen definiert. Diese verlangen ein gerechtfertigtes, moderat faktives Überzeugungssystem über systembezogene Aspekte sowie das Verfügen über verstehensbezogene Fähigkeiten und berücksichtigen den Einfluss mehrerer Kontextfaktoren. Weiterhin argumentiert diese Arbeit, dass so genannte „Exemplare“ besonders vorteilhafte Mittel sind, um instrumentelles Verstehen zu erwerben. Exemplare zeichnen sich dadurch aus, dass sie kontextuell relevante Aspekte exemplifizieren und besonders leicht zu interpretieren sind. Der Begriff instrumentellen Verstehens konkretisiert ein wichtiges epistemisches Ziel in XAI-Kontexten. Exemplare bieten wiederum einen Ausgangspunkt, um XAI-Erklärungen und andere Verstehensermöglicher in Hinblick auf ihre Eignung für den instrumentellen Verstehenserwerb zu evaluieren.
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    Glycerol-mediated improvement of heterologous aurachin D production in E. coli
    (Springer Science and Business Media LLC, 2026-05-30) Korb, Jonas; Demir, Büsra; Graw, Kai; Nett, Markus
    Neglected tropical diseases and the increasing prevalence of antibiotic resistance in nosocomial infections represent a major challenge in medicine. Intensive research into bioactive compounds has identified the myxobacterial natural product aurachin D as promising drug candidate due to its potent antibiotic and antiprotozoal properties. The biosynthesis of aurachin D from 2-methyl-1H-quinolin-4-one (MQO) is catalyzed by the membrane-bound farnesyltransferase AuaA. Recently, this enzymatic conversion was reconstructed in the heterologous host Escherichia coli, yielding an aurachin D titer of 17 mg L−1. In this study, we investigated the influence of the medium on aurachin D biosynthesis in E. coli in order to improve the product titer. Our analyses revealed that the glycerol concentration has a major impact on both the growth of the production host and the biocatalytic formation of aurachin D. After switching to a glycerol-based minimal medium and adjustment of the MQO precursor concentration, an aurachin D titer of 124 mg L−1 was achieved in a microbioreactor system, highlighting the superior performance of minimal over complex medium as well as the beneficial effect of glycerol compared to glucose. Further studies were conducted to elucidate the mechanism underlying glycerol’s effects. While improved growth and substrate solubilization were found to be insignificant for increasing the product titer, it was demonstrated that glycerol supplementation positively influenced the expression of the enzyme AuaA. Using a folding reporter, we were able to show that the availability of correctly folded AuaA increased until growth defects of the host, presumably resulting from osmotic stress, began to appear. Key points • Product toxicity is negligible in the production of aurachin D using E. coli • The media supplement glycerol improves the availability of the enzyme AuaA • Aurachin D titers increase after switching to a minimal medium
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    In situ observation of the pore formation during laser-based reactive air brazing of alumina
    (Springer Science and Business Media LLC, 2024-03-16) Wojarski, Lukas; Ulitzka, Henrik; Geldmacher, Anna; Ulitzka, Tim; Tillmann, Wolfgang
    Reactive air brazing (RAB) is a low-cost process for joining ceramic composites in air. However, due to the comparably low strength values that can be achieved by RAB, the process is only used in special applications like solid oxide fuel cells as a sealant. The limited strength values are the result of a severe pore formation during the brazing operation that remain in the brazing fillet after the solidification of the brazing filler. In this work, the formation of the pores during RAB brazing of alumina using a paste containing Ag4CuO powder and various binders was investigated. The formation and evolution of the pores were observed and quantified in in situ X-ray measurements. It could be observed that during debinding, pores have developed in the filler metal. The pore structure depends on the binder and the heating rate in the debinding stage. With the melting of the filler metal, many pores are closed by the melt flow. But it seems that the wetting of the alumina was hindered by the pores. The change of porosity during cooling is comparatively low.