What is OPUS?

Siegen University Library provides a free of charge repository named OPUS Siegen (OPUS = Online PUblication Server) with the purpose to publish, archive and retrieve electronical documents produced at the University of Siegen.

What will you find here?

You will find Open-Access-Publications from all faculties of Siegen University and from the "universi" publishing house. The University Library applies acknowledged quality standards and offers support for publishing your documents.

How to participate?

For uploading documents, sign on to OPUS via Shibboleth using your ZIMT-Account.

Recently published
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    „hot auf Zerstörung“? Rezos Medienkritik aus diskurslinguistischer Perspektive
    Die vorliegende Arbeit widmet sich der linguistischen Analyse von Medienkritik im digitalen Zeitalter am Beispiel des YouTubers Rezo. Im Fokus steht das im Jahr 2020 veröffentlichte Video „Die Zerstörung der Presse“, in dem Rezo etablierte deutsche Printmedien einer kritischen Betrachtung unterzieht. Auf Basis eines qualitativen Analyseansatzes werden drei Videos betrachtet: das Ursprungsvideo Rezos, die Reaktion der FAZ („Unsere Antwort auf Rezos „Zerstörung der Presse““) sowie Rezos Reaktionsvideo („Die dümmsten und lustigsten Reaktionen“). Die Analyse demonstriert, wie sich Rezo durch den Einsatz sprachlicher Kreativität und bewusster Inszenierung zwischen journalistischer Kritik und Politainment befindet. Im Rahmen der Analyse werden verschiedene Aspekte der Videos untersucht, darunter der Aufbau, die Verwendung von Anglizismen sowie der Pronomina-Gebrauch als Index einer adressatengerechten Gestaltung. Rezos Medienkritik ist gekennzeichnet durch jugendsprachliche Elemente, eine direkte Adressierung und diskursive Strategien, die auf eine junge Zielgruppe zugeschnitten sind. Die kontrastive Analyse mit dem FAZ-Video offenbart zudem Diskrepanzen in der sprachlichen Darstellung von Glaubwürdigkeit. Die vorliegende Arbeit leistet somit einen Beitrag zur Erforschung digitaler politischer Kommunikation aus sprachwissenschaftlicher Perspektive.
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    Thin-Film Device Development and Technologies - Sensing Principles and Application-Specific Examples
    Advanced on-chip integrated photonic and electronic devices, such as hyperspectral photodetectors, depth sensors or memristors, obtain significant drawbacks with respect to performance and/or the technological integration effort. To overcome such limitations, optimized materials and innovative device concepts were developed to maximize performance and integration densities for specific applications. The selected thin and ultra-thin film material examples can obtain significant advantages and exhibit fundamentally different and adjustable material properties compared to their bulk monocrystalline counterparts. Exploiting the benefitial properties of two dimensional (2D) and amorphous semiconducting materials allows the development of high-performance optoelectronic devices, especially for sensing applications. The aim of this work is to demonstrate how novel 2D-material and conventional thin-film semiconductor processing platforms and technologies can be combined to enable a heterogenous device integration on top of chip electronics with enhanced performance. As device examples, 2D-material heterostructure photodetectors for enhanced sensing applications, nonlinear amorphous silicon and graphene photodetectors for depth sensing as well as thin-film memristors for the development of neuro-inspired “smart” cameras are presented, discussed and compared with the state-of-the-art.
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    Dynamic Reconfiguration and Fault Diagnosis in Time-Triggered Multi-Core Architectures
    The growing complexity of modern System-on-Chip (SoC) designs, coupled with their application in safety-critical domains, requires significant advancements in fault tolerance and energy efficiency. Safety-critical systems, where failures can result in catastrophic consequences, demand reliable and efficient communication frameworks. Despite considerable advancements, challenges persist in achieving accurate fault localization, ensuring adaptability in real-time fault scenarios, and maintaining energy-efficient operation across diverse Network-on-Chip(NoC) topologies. The first part of the thesis introduces an adaptive communication service for time-triggered NoCs, which dynamically adjusts schedules in response to events such as slack, battery depletion, and faults. This approach enhances energy efficiency by employing techniques such as Dynamic Voltage and Frequency Scaling (DVFS) and clock gating, and it supports timely communication while maintaining fault isolation. The second part focuses on fault detection, localization within time-triggered and event-triggered NoCs. A diagnostic architecture incorporating deterministic behavior and source-based routing enables precise identification and localization of faults. The Fault Monitor Unit plays a key role in detecting errors at run-time through real-time monitoring of message validity and timing. Once detected, faults are localized using techniques such as Cyclic Redundancy Code (CRC) checks and time-stamp analysis. Recovery is achieved by isolating the affected component and dynamically rerouting messages or reallocating tasks to healthy nodes using predefined schedule, minimizing system disruption. These solutions are validated through simulations and experimental scenarios across various NoC topologies, demonstrating significant improvements in fault tolerance and system adaptability. The experimental results validate the proposed architectures across a range of scenarios, including both synthetic and real-world avionics configurations. Latency tests conducted on 2x2, 3x3, and 4x4 mesh topologies exhibit predictable delay patterns across varying packet sizes. Additionally, memory optimization techniques, which focus on storing only the differences in schedules, effectively reduce storage requirements. Fault detection achieved a 100% rate for single faults in routers, tiles, and links across various network topologies such as mesh, torus, and ring, with accurate localization in most cases. The results emphasize the scalability, robustness, and adaptability of the proposed methods, demonstrating their suitability for deployment in safety-critical domains such as automotive, aerospace, and industrial automation.
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    Smart Speaker im Dialog. Sprachliche Praktiken mit Voice User Interfaces
    The monograph researches linguistic practices in the use of stationary voice-controlled digital assistants (smart speakers) such as Amazon’s Alexa, Google Home, or Apple’s Siri – all of which operate through so-called Voice User Interfaces (VUIs), i.e., voice-based interfaces between humans and machines. Empirically, the study draws on video and audio recordings from real households, documenting both the initial setup and everyday use of smart speakers. Methodologically, the work is grounded in conversation analysis and enriched by multimodal video-based interaction analysis and ethnographic perspectives. The analysis focuses on both dyadic dialogues between humans and VUIs and more complex multi-party interactions. A praxeological understanding of language and media is central: language is conceptualized as an integral part of social practices, while interfaces are understood as situationally constituted between users and digital infrastructures. Drawing on domestication theory, the study also explores how users interact with these devices linguistically, how they integrate them into everyday routines, adapt to them—and how, in turn, the devices shape user practices. The study’s key findings show that users orient themselves to established conversational routines when interacting with smart speakers. However, specific variations emerge: rigid sequential structures often need to be followed for successful execution of commands, which impacts how users address the device, manage turn-taking, and perform repairs. Users adapt to these structures—linguistic practices thus become interface practices. Nevertheless, especially in multi-party interactions, users frequently treat VUIs at the surface level as if they were conversational participants. Yet this attribution proves unstable and can shift from moment to moment. At times, linguistic cues directed at the smart speaker may instead target human participants. The users studied demonstrate linguistic competence in distinguishing between addressing a human and addressing a machine.
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    Adaptation of Distributed Safety-Critical Time-Triggered Systems using Machine Learning
    (2025-08-18)
    Adaptation can be achieved by adjusting schedules to change the distribution of tasks among the available resources, avoiding failed resources, or accounting for slack within schedules. Metascheduling can be utilised in Time-Triggered Systems (TTS) to realise adaptation. However, metaschedulers encounter the problems of state explosion, storage limitations, and runtime issues when dealing with a high number of tasks. The objective of this thesis is to introduce a metascheduling model that utilises Machine Learning (ML) to generate modified schedules in real-time. Consequently, there is no longer a need to store the extensive collections of schedules produced by a meta-scheduler. Furthermore, real-time adaptation is enhanced by producing compact, compatible models for run-time execution. This thesis conducts a study, analysis, modelling, comparison, and implementation of Machine Learning (ML) based meta-scheduling algorithms focusing on multi-core safety-critical TTS. The motivation for adaptation in TTS is to achieve enhanced energy efficiency, perform fault recovery, and adjust to varying environmental conditions. This study examined different types of machine learning models. The models used in this study include Graph Neural Networks (GNN), Encoder/Decoder Neural Networks (E/D NN), Artificial Neural Networks (ANN), Random Forest Classifiers (RFC), and Reinforcement Learning (RL) algorithms. The performance and complexity of the previously mentioned ML algorithms were tested in assigning temporal and spatial allocation aspects of the meta-scheduling problem. Additionally, comparisons were made with heuristic algorithms commonly used in literature for the purpose of comparison. The significance of this study is that the suggested method offers a way to balance the storage capacity of the multi-core safety-critical TTS with the number of schedules for each adaptation scenario. This is achieved by utilising a conventional meta-scheduler with a Genetic Algorithm (GA) to generate appropriate datasets for training. Three datasets were primarily produced with an emphasis on workload (operation load across processing units), makespan, and energy usage. The suggested ML architecture has the capability to handle a wide range of scenarios without requiring the storage of schedules. In addition to increasing adaptation capacity, as ML models are capable of adjusting to new situations that were not part of the training dataset. Moreover, permitting online operation (real-time execution) of the RL algorithm provides an extra layer for adaptation as it continues to enhance the decision making process of allocating resources with time. The thesis is part of a research project that targets a solution to the conventional metaschedulers' problems: state-space explosion and runtime inefficiency by implementing the previously mentioned ML models in a hardware simulated environment designed to mimic the hardware difficulties of a multi-core safety-critical TTS. It compares the performance parameters of several algorithms as well, enabling the selection of the ideal model for each certain case depending on the required performance and hardware resource consumption. The results indicated that the GNN-based model exhibited superior accuracy and performance in predicting temporal allocations. The RL-based approach demonstrated remarkable adaptability and continuous improvement in real-time scheduling scenarios. The ANN and RFC models also performed robustly, offering substantial computational efficiency and reduced energy consumption compared to traditional heuristic methods. The integration of the GA for dataset generation enhanced the training process, resulting in highly optimised and reliable models. Additionally, the experimental results highlighted that the ML models effectively balance the trade-offs between workload, makespan, and energy consumption, providing a versatile solution adaptable to various operational demands. Overall, the proposed framework not only addresses the limitations of traditional metaschedulers but also sets a new standard for adaptive, efficient, and scalable scheduling in multi-core safety-critical TTS.
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