Over the past decade, accelerating digital innovation has transformed how firms, consumers, and individuals interact. Digital transformation is a broad socioeconomic shift driven by the adoption of digital technologies, such as cloud computing, big data, artificial intelligence, and the Internet of Things. It has opened new avenues for value creation and shifted interactions from human-centered to technology-mediated. As digital transformation influences ecosystems rather than just individual organizations, I adopt a multi-level perspective to understand its impact on interrelated actors and systems. This dissertation examines how digital transformation shapes technology-mediated interactions at three levels: inter- and intra-firm relationships (macro level), consumer-firm touchpoints (meso level), and individual consumer identity (micro level). Despite a growing focus on digital technologies in marketing research, a comprehensive, multi-level understanding of how digital transformation influences technology-mediated interactions remains limited. This dissertation addresses this gap by answering the overarching research question: How do digital transformations shape technology-mediated interactions at the macro, meso, and micro levels? This question will be addressed across three independent essays. Essay 1 focuses on the macro level, examining how digital transformation affects technology-mediated intra- and inter-firm relationships between customer and provider firms. Essay 2 examines the meso level and explores how emerging technologies, such as AI-enabled agents, influence consumer perceptions and reactions. Essay 3 covers the micro level, exploring how digital transformation, particularly the use of avatars as consumer embodiments in technology-mediated spaces, affects consumers' individual identities. Together, these essays offer new theoretical and practical insights into the evolving nature of technology-mediated interactions, while highlighting the transformative role of digital innovation across organizational, relational, and individual contexts.

Dieser Best Practice Guide zeigt, wie kleine und mittlere Unternehmen (KMU) ihre Cyber-Resilienz umfassend stärken können, von der technischen Basis über Lieferketten und Unternehmenskultur bis hin zu Notfallmanagement und OT-Security. Da Cyberangriffe zunehmend komplexer werden und menschliches Verhalten weiterhin in über 80 % der Vorfälle eine entscheidende Rolle spielt, reicht technische Absicherung allein nicht aus. Entscheidend ist ein integrierter Ansatz, der Mindset (sicherheitsbewusste Haltung), Skillset (praktisches Wissen und regelmäßige Schulungen) und Toolset (adäquate technische Lösungen) miteinander verbindet. Der Cyber-Security Grundschutz vermittelt KMU praxisnahe Schritte zur Identifikation des IST-Zustands, zur Priorisierung von Schutzmaßnahmen und zur Einführung eines kontinuierlichen Verbesserungsprozesses nach dem PDCA-Modell. Das Supply Chain Cyber-Security Handbuch verdeutlicht, wie digital vernetzte Lieferketten zu kritischen Angriffspunkten werden können und unterstützt Unternehmen dabei, relevante Partner zu identifizieren, zu klassifizieren und risikobasierte Maßnahmen zu implementieren. Das Awareness- & Kultur-Handbuch zeigt, wie eine „Security-First“-Kultur entsteht, die Cybersicherheit als Teamaufgabe begreift und über Zero-Trust-Prinzipien, klare Verantwortlichkeiten und moderne Lernformate wie Serious Games nachhaltig verankert. Das Cyber-Notfallkonzept bietet KMU einen strukturierten Leitfaden zur Vorbereitung, Reaktion und Wiederherstellung bei Sicherheitsvorfällen - inklusive Checklisten, Rollenmodellen und Incident-Response-Plänen, um Ausfallzeiten zu minimieren und handlungsfähig zu bleiben. Ergänzend vermittelt das OT-Security Handbuch die Besonderheiten industrieller Systeme und zeigt, wie KMU ihre Produktionsumgebungen schützen können - von der Bewertung kritischer Anlagen über sichere Konfigurationen bis zur schrittweisen Umsetzung praxistauglicher OT-Security-Maßnahmen. Gemeinsam bilden die fünf Handbücher ein ganzheitliches Rahmenwerk, das KMU befähigt, Cybersicherheit als festen Bestandteil des Arbeitsalltags zu verankern, Risiken entlang der gesamten Wertschöpfungskette zu reduzieren und die eigene Widerstandsfähigkeit gegenüber Cyberbedrohungen systematisch zu erhöhen.

Cryptographic keys are fundamental components for ensuring security in digital systems. To ensure reliable key generation and management, various technical concepts have been developed, primarily based on dedicated hardware components such as Trusted Platform Modules (TPMs). However, many modern systems, especially small resource-constrained devices, typically lack hardware support for secure key generation and management. To address these limitations, Physical Unclonable Functions (PUFs) have proven to be an effective solution for key generation, device authentication, and identification tasks. PUFs leverage inherent variations in hardware components to produce unique, device-specific keys. For a well-designed PUF, these keys can be reproduced reliably on the same device but are practically impossible to clone. Various types of PUFs exist, including those that exploit slight delay differences in circuits with symmetric paths. Others rely on physical characteristics of components already present in the computing system, such as SRAM or DRAM. However, many of these constructions rely on technologies that could be replaced by emerging ones in the future. Such a replacement may involve a transition from traditional memory technologies, such as SRAM, DRAM, and flash memory, to emerging Non-Volatile Memories (NVMs), including Ferroelectric RAM (FRAM), Magnetoresistive RAM (MRAM), and Resistive RAM (ReRAM). These new technologies, in turn, necessitate innovative hardware security solutions for generating intrinsic hardware fingerprints, ensuring security for next-generation embedded devices. Furthermore, the integration of nanomaterials, such as carbon nanotubes, into processor architectures and the adoption of reconfigurable hardware platforms like Field-Programmable Gate Arrays (FPGAs) require the development of specifically tailored cybersecurity solutions. This dissertation aims to develop hardware-based security mechanisms for these types of devices by designing new PUF constructions and demonstrating their practical applications. One focus lies on PUFs extracted from nanomaterials and emerging circuit elements, particularly memristive devices and Carbon NanoTube Field-Effect Transistors (CNT-FETs). For memristive devices, which form the basis of ReRAM memory, this work analyzes methods ranging from simple binary quantization to advanced techniques exploiting device-specific response patterns. In the case of CNT-FETs, custom-fabricated wafers are developed to construct PUFs with optimal properties, such as high robustness, uniformity, and entropy, even under varying environmental conditions. These conditions include fluctuations in ambient temperature. Based on an analysis of fundamental system components, this work evaluates the feasibility of deriving PUFs from fully integrated circuits. A specific focus is placed on emerging non-volatile memory technologies, assessing their potential for PUF applications. To achieve PUF behavior in these memory devices, techniques such as intentional timing manipulation, induced bit flips through row hammering, and variations in supply voltage are examined. These resulting bit flips can be exploited as PUF responses. Additionally, transforming raw PUF responses into cryptographically usable keys and integrating specific PUFs into practical applications are core components of this work. The demonstrated practical applications include an innovative architecture for encrypting and binding data to non-volatile memory modules, implemented on Multiprocessor System-on-Chips (MPSoCs) incorporating FPGAs. This architecture enables the storage of confidential data on non-volatile memory while simultaneously using the same module as a PUF, without requiring separate memory partitions solely for the PUF functionality. Finally, practical applications of hardware fingerprints in the automotive sector are demonstrated, including an FPGA-based implementation to maintain security while preserving the temporal determinism of time-critical messages. These goals are met through the use of hardware-implemented cryptographic algorithms coupled with an FPGA-based ring oscillator PUF. To summarize, this work presents new types of PUF implementations, starting with nanomaterials and emerging circuit elements, extending to PUFs derived from integrated circuits, and demonstrates innovative solutions for their integration into MPSoC-based architectures.

This study reports the Intraclass Correlation Coefficients of feedback ratings produced by OpenAI's GPT-4, a large language model (LLM), across various iterations, time frames, and stylistic variations. The model was used to rate responses to tasks related to macroeconomics in higher education (HE), based on their content and style. Statistical analysis was performed to determine the absolute agreement and consistency of ratings in all iterations, and the correlation between the ratings in terms of content and style. The findings revealed high interrater reliability, with ICC scores ranging from 0.94 to 0.99 for different time periods, indicating that GPT-4 is capable of producing consistent ratings. The prompt used in this study is also presented and explained.

The Renewable Energy Sources Act (EEG) in Germany aims to transition the country to a sustainable energy system. This has led to a decentralization of the energy market and a shift toward community-focused energy supply systems. Municipal energy companies (MECs), deeply rooted in their communities, are crucial in facilitating this transition and promoting innovative technologies. Websites serve as important communication tools, facilitating interaction between companies and consumers. In our study, we conducted a quantitative content analysis to examine how MECs communicate issues related to the energy transition on their web pages (N = 300). In general, our results show that the energy transition was rarely mentioned on landing pages, and while companies are improving their sustainable electricity products, renewable gas and heating tariffs have received little attention. Additionally, we identified three communication types of MECs: The transitionalists (45 %), the traditionalists (35 %), and the pioneers (20 %), with the latter being the most innovative that emphasizes issues related to the energy transition. Overall, it can be said that the MECs have not yet fully exploited their potential to position themselves as pioneers of the energy transition in their website communications.