@phdthesis{Frikel, author = {Frikel, J{\"u}rgen}, title = {Reconstructions in limited angle x-ray tomography: Characterization of classical reconstructions and adapted curvelet sparse regularization}, publisher = {Technische Universit{\"a}t M{\"u}nchen}, address = {M{\"u}nchen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20130328-1115037-0-3}, abstract = {This thesis is devoted to the problem of tomographic reconstruction at limited angular range. In the first part, we prove a characterization of filtered backprojection reconstructions from limited angle data. Moreover, we develop a strategy for artifact reduction and stabilization. In the second part, we introduce a new edge-preserving reconstruction algorithm for limited angle tomography and analyze this algorithm mathematically. Some numerical experiments are also presented.}, language = {en} } @phdthesis{Raptis, author = {Raptis, Georgios}, title = {Vertraulichkeit von medizinischen Daten in der Telematik-Infrastruktur - Sicherheitsanalyse unter Ber{\"u}cksichtigung von Aspekten der langfristigen Sicherheit}, address = {Heidelberg}, subject = {Medizinische Dokumentation}, language = {de} } @phdthesis{Ramsauer, author = {Ramsauer, Ralf}, title = {OSS Architecture for Mixed-Criticality Systems}, publisher = {Leibniz Universit{\"a}t Hannover}, pages = {188}, abstract = {Computer-based automation in industrial appliances led to a growing number of logically dependent, but physically separated embedded control units per appliance. Many of those components are safety-critical systems, and require adherence to safety standards, which is inconsonant with the relentless demand for features in those appliances. Features lead to a growing amount of control units per appliance, and to a increasing complexity of the overall software stack, being unfavourable for safety certifications. Modern CPUs provide means to revise traditional separation of concerns design primitives: the consolidation of systems, which yields new engineering challenges that concern the entire software and system stack. Multi-core CPUs favour economic consolidation of formerly separated systems with one efficient single hardware unit. Nonetheless, the system architecture must provide means to guarantee the freedom from interference between domains of different criticality. System consolidation demands for architectural and engineering strategies to fulfil requirements (e.g., real-time or certifiability criteria) in safety-critical environments. In parallel, there is an ongoing trend to substitute ordinary proprietary base platform software components by mature OSS variants for economic and engineering reasons. There are fundamental differences of processual properties in development processes of OSS and proprietary software. OSS in safety-critical systems requires development process assessment techniques to build an evidence-based fundament for certification efforts that is based upon empirical software engineering methods. In this thesis, I will approach from both sides: the software and system engineering perspective. In the first part of this thesis, I focus on the assessment of OSS components: I develop software engineering techniques that allow to quantify characteristics of distributed OSS development processes. I show that ex-post analyses of software development processes can be used to serve as a foundation for certification efforts, as it is required for safety-critical systems. In the second part of this thesis, I present a system architecture based on OSS components that allows for consolidation of mixed-criticality systems on a single platform. Therefore, I exploit virtualisation extensions of modern CPUs to strictly isolate domains of different criticality. The proposed architecture shall eradicate any remaining hypervisor activity in order to preserve realtime capabilities of the hardware by design, while guaranteeing strict isolation across domains.}, language = {en} } @phdthesis{ZInner, author = {ZInner, Helge}, title = {Vernetzung heterogener Feldbusse auf Basis des Standards Ethernet Audio Video Bridging}, address = {Ilmenau}, pages = {III, 191 S.}, language = {de} } @phdthesis{Stadler, author = {Stadler, Sebastian Rudolf Johann}, title = {The integration of virtual reality into the design process}, url = {http://nbn-resolving.de/https://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:91-diss-20211103-1612177-1-3}, pages = {VIII, 205}, abstract = {Technological advances strive towards automation and digitalization with the aim to increase efficiency in terms of decreased costs and product development time, resulting in shorter product life cycles. As this causes industries to release products more frequently and more quickly, industrial designers face problems in developing more complex systems in a decreased amount of time while aiming to meet individualized user requirements and stakeholder demands. If prototypes are infeasible or unaffordable, a successful market implementation of products is jeopardized. As design history proves, the introduction of new technologies to the profession of design has the potential to revolutionize the way of working for industrial designers. Virtual Reality may be one of these revolutions, as Computer-Aid Design has been in the 1980s. The present dissertation investigates the integration of Virtual Reality and its impact on the design process, the respective design method, but also the designer and design as a profession. After defining industrial design and Virtual Reality, a basic framework is proposed that describes a design process consensus model, the transfer of conventional design methods into VR, as well as a preliminary set of criteria for evaluating design studies. Based on this framework, four research questions are defined that initiate the investigation of how Virtual Reality can impact the design process, design methods, the role of designers, and design as a profession. To allow this, a refined set of criteria for evaluating design studies is developed and a benchmark study is conducted that proves the suitability for using Virtual Reality in the chosen context. Subsequently, five design studies are conducted in the field of autonomous mobility for public transport in Singapore to investigate the previously defined questions. The five design methods that are combined with Virtual Reality are heuristic evaluation, surveys, Computer-Aided Design prototyping, usability testing, and product presentation. For each design study, the development of the VR apparatus as well as the data collection and test of the method is explained. Additionally, two conventional design methods are consulted for a subsequent comparative analysis of each VR methods. Beyond the definition of the refined evaluation criteria, consisting of safety, validity, time and cost, variability, interactivity, immersion, and effort, the suitability of using VR for behavioural observation in the present application domain is confirmed. Based on the present investigations, the Virtual Design Toolbox is presented. The toolbox consists of five method cards that explain the usage of Virtual Reality for industrial designers throughout the product development and function as support for successfully developing and applying design methods utilizing this technology. The case studies prove that the usage of Virtual Reality has the potential to impact the design process, as divergent thinking and convergent thinking is fostered through valid data collection, decreased time- and cost- involvement, and increased variability. The roles of the involved designers throughout all design studies shifted from being concept creators towards coordinators and facilitators. Implications are derived on different levels, starting with the technology of Virtual Reality that could be a future game changer for research and design, followed by increased motivation to participate in design studies, the need for interdisciplinary teams to establish the required expertise, and lastly integration of Virtual Reality in design education. The usage of Virtual Reality in design will not replace conventional design methods but has the potential to lead to a paradigm shift for the whole profession of design.}, language = {en} } @phdthesis{Lalo, author = {Lalo, Erjola}, title = {Deployment designs for multi-core-real time systems}, edition = {1. Auflage}, publisher = {Universit{\"a}tsverlag Regensburg}, address = {Regensburg}, isbn = {978-3-86845-181-8}, doi = {10.21268/20240712-0}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:104-20240712-00000-7}, pages = {iii, 371}, abstract = {In modern embedded automotive systems, multi-core processors are used to provide higher execution performance and more computing capacity. However, they influence the way these systems are designed. Each change of the platform and application software results in an effort required to ensure and validate the functional correctness and timing requirements of these systems in a multi-core platform. For this reason, the use of the Logical Execution Time (LET) paradigm is advantageous for multi-core systems, as it satisfies these requirements by providing time and dataflow determinism, thereby reducing the development cycle and the impact of the platform in the design of such systems. To integrate LET into these systems, special mechanisms are required to satisfy its semantics. Therefore, this work focuses on buffering and scheduling techniques for resource efficient integration of LET in automotive systems. A buffering mechanism and an automatic schedule synthesis are proposed to guarantee functional correctness, timing requirements, and LET semantics and to reduce the increased demands of LET for memory and processor resources. A static and global buffering protocol is proposed, which compared to lock-based protocols has plausible memory needs and zero-communication overheads at the boundaries of LET intervals. The automatic schedule synthesis considers the Operating System (OS) overheads such that scheduling is optimized with respect to context-switching overheads caused by preemption. Buffering implements most of the LET semantics, but it provides no guarantee that tasks execute within their LET intervals. If scheduling is not designed to ensure that all tasks execute within their LET intervals, then functional correctness and LET semantics are violated. The manual design of a feasible schedule that satisfies the semantics and additional requirements of the application is inefficient and requires a significant amount of effort. Therefore, an automatic schedule generation approach for the Fixed-Priority Scheduling (FPS) and Time-Triggered Scheduling (TTS) is proposed. FPS is the widely used mechanism in the automotive domain because of its flexibility to handle dynamic changes of highly event-driven applications. Recently, TTS has attracted considerable attention in this domain to increase deterministic execution of tasks and efficient planning of processor resources. Therefore, schedule synthesis of FPS and TTS is provided to identify the efficiency, practicality, and resource optimization abilities of each approach for LET systems. To show the practicality of LET for industrial automotive systems, its integration into the software architecture of the classic platform of AUTomotive Open System Architecture (AUTOSAR) is described and a case study is conducted using a real world system.}, language = {en} } @phdthesis{Renner, author = {Renner, Sebastian}, title = {Secure Lightweight Authenticated Encryption for Critical Infrastructures in the Internet of Things}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20230922-1703211-1-0}, pages = {xix, 135}, abstract = {The cryptographic protection of transmitted data on resource-constraint IoT devices presents a difficult challenge. In this thesis, a benchmarking framework for the performance evaluation of lightweight encryption algorithms is introduced. It is analyzed, if and when novel encryption algorithms are more suitable for IoT use cases than the current standard. Besides comparing the sole performance, the cost for hardening the algorithms against side-channel analysis is discussed.}, language = {en} } @phdthesis{Wulf, author = {Wulf, Frederik}, title = {Essays on cloud computing adoption, post-adoption, and security}, pages = {166}, language = {en} } @phdthesis{Weiss, author = {Weiß, Nils}, title = {Security testing in safety-critical networks}, pages = {xiv, 126}, abstract = {The evolution of cars from mechanical systems to rolling computers creates new requirements for safety and security engineering. Nowadays, every vehicle contains a safety-critical real-time communication network to fulfill its function. Especially the increasing connectivity of automotive systems enlarged the attack surface for cyber-attacks. Safety engineering in this area is well understood and studied for decades, though the security engineering of these systems needs further research. This thesis introduces a black-box investigation process to analyze existing auto-motive systems and components and identifies security vulnerabilities in four different ECUs. Combined with a survey of published security research, vehicle-internal networks are identified as an extraordinary threat to the vehicle's safety and security. The outstanding automation capabilities of security tests for these networks are leveraged in the second part of this thesis. In order to create automated tools for automotive networks, a software foundation is necessary. As part of this thesis, a comprehensive open-source software framework for security testing in vehicular networks was developed and published. This aims to support further security research based on open and free software. Novel tools for the automated identification and exploration of attack surfaces in automotive diagnostic protocol implementations are created and evaluated. These tools allow the creation of comparable attack surface metrics through black-box scans of arbitrary ECUs. Automata learning and system state reverse-engineering techniques highly increase the exploration capabilities of the presented tools. The exploration algorithm is tested on thirteen different ECUs from independent OEMs. All gathered results are evaluated and discussed in the final part of this thesis. Finally, open issues and further research based on this contribution are discussed.}, language = {en} } @phdthesis{Schedlbauer, author = {Schedlbauer, J{\"u}rgen}, title = {Anforderungsorientierte Optimierung, Evaluation und Validierung der praktischen Inhalte der Lehre in der Medizinischen Informatik in Hochschulen f{\"u}r Angewandte Wissenschaften (HAW)}, isbn = {978-3-88246-461-0}, doi = {10.5283/epub.47750}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-477509}, pages = {xvi, 253}, abstract = {Die European University Association (EUA) definiert „Besch{\"a}ftigungsf{\"a}higkeit" als ein Hauptziel der Hochschulausbildung. Der zentrale Aspekt dieser Arbeit ist, kompetenzorientierte Lehre in der praktischen Ausbildung der medizinischen Informatik an Hochschulen f{\"u}r angewandte Wissenschaft(HAW) durch Analyse der Kompetenzanforderungen des Marktes und der Hochschulen zu optimieren. Als Erstes wird dazu ein Berufsbild der Medizinischen Informatik erarbeitet, indem mit Hilfe von Webcrawling, Webextraktion und Text Mining Begriffe von Stellenanzeigen, anhand einer Inhaltsanalyse, die Kompetenzen im Bereich Fachwissen und Soft Skills (Gesch{\"a}ftsprozessmanagement, Teamwork, Prozesse, Lern- und Probleml{\"o}sungsf{\"a}higkeiten) ermittelt werden. Als N{\"a}chstes wird untersucht, inwiefern HAWs diese Kompetenzen in ihren Modulhandb{\"u}chern als Lernziele definieren. Um die Vermittlung der praktischen Inhalte der Ausbildung entsprechend dem Berufsbild zu optimieren wurde - basierend auf der Methodik des Design-based Research - die Lehrmethodik „INstall" entwickelt und evaluiert um die Arbeitsmarktf{\"a}higkeit der Studierenden zu verbessern. Die Eignung der Lehrmethodik wurde anhand einer Fremd- und Selbsteinsch{\"a}tzung der Studierenden untersucht. Die Ergebnisse der Stellenanalyse zeigen, dass nur 45\% der Begriffe der Kategorie Fachwissen und 55\% der Kategorie Soft Skills zuzuordnen sind. Die vorherrschenden Begriffe waren Programmierung, Erfahrung, Projekt und Server. Die Auswertung der Modulhandb{\"u}cher zur Kompetenzorientierung hat große Unterschiede offengelegt, da in zwei Dritteln der Modulhandb{\"u}cher keine Soft Skills als Lernergebnisse formuliert wurden. Anhand eines Zyklus {\"u}ber drei Vorlesungen wurde nachgewiesen, dass die Erweiterung der Lernziele auf Soft Skills durch die Methode „INstall", in der Fremd- und Selbsteinsch{\"a}tzung der Studierenden einen starken Zugewinn an Kompetenzen im fachlichen Wissen, bei der Teamarbeit, im Gesch{\"a}ftsprozessmanagement, beim Lernen, in der Kommunikation und der Probleml{\"o}sung gebracht hat. Die Arbeit legt den Schluss nahe, dass Hard- und Soft Skills bei den Arbeitnehmeranforderungen zur Medizinischen Informatik gleich gewichtet sind. Daraus kann abgeleitet werden, dass die Vorgaben der Berufsverb{\"a}nde zum Kompetenzprofil {\"u}berdacht werden sollten. Fraglich erscheint, ob ein großer Teil der Modulhandb{\"u}cher den Vorgaben der EUA (Besch{\"a}ftigungsf{\"a}higkeit) entsprechen, da die Lernziele ein Defizit an Soft Skills aufweisen. Insgesamt bleibt festzuhalten: Eine gezielte Ausrichtung der Lernziele von {\"U}bungen auf die Anforderungen des Arbeitsmarktes durch die neue Lehrmethode „INstall" hat zu einer von den Studierenden selbst best{\"a}tigten sp{\"u}rbaren Steigerung der ben{\"o}tigten Kompetenzen gef{\"u}hrt.}, language = {de} } @phdthesis{Schmid, author = {Schmid, Isabel}, title = {Weiterentwicklung von Methoden und Ans{\"a}tzen zur automatisierten Informationsextraktion aus Social Networks}, doi = {10.5283/epub.53491}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-534918}, pages = {VII, 192}, abstract = {Ob Werbebotschaften effektiv in einem sozialen Netzwerk verbreitet werden k{\"o}nnen, ist abh{\"a}ngig von der Person, die dabei als Multiplikator eingesetzt wird (Deng et al., 2016). Der Einsatz eines einflussreichen Nutzers kann nicht nur die Reichweite der Marketingbotschaft deutlich erh{\"o}hen, sondern auch in den Bereichen Innovations- und Produktmanagement wirken. Neben der großen praktischen Relevanz des Themengebiets hat dieses auch in der Wissenschaft eine Vielzahl an Publikationen hervorgebracht. Eine klare Definition und Abgrenzung einflussreicher Nutzertypen wie z.B. Influencer, Key User oder Lead User fehlt bislang und soll mit Hilfe eines ausf{\"u}hrlichen Literatur{\"u}berblicks angefertigt werden (Ver{\"o}ffentlichung 1). Außerdem wird im Rahmen der Dissertation die Identifikation von Lead User weiterentwickelt, indem verschiedene Analyseformen wie z.B. die SNA, die Sentimentanalyse und das Topic Modeling miteinander kombiniert werden. Das Thema der Sentimentanalyse wird zudem in einer weiteren Ver{\"o}ffentlichung n{\"a}her betrachtet, insbesondere im Zuge der Analyse langer und unstrukturierter Texte. Jedoch lassen sich Vorteile von sozialen Netzwerken nicht nur in Bezug auf die Verbindung zwischen Kunde und Unternehmen feststellen, sondern auch im Bereich ESN. ESN werden mit dem Ziel angewandt, die organisationale Effektivit{\"a}t sowie die Effizienz im Unternehmen zu verbessern (Stei et al., 2016). Zentral dabei ist, dass die Mitarbeiter dazu motiviert werden, aktiv Inhalte zu erzeugen und ihr Wissen mit anderen zu teilen (G{\"u}nther and Spath, 2010). Hierbei lassen sich auch unter den Mitarbeitern unterschiedliche Nutzergruppen erkennen. So k{\"o}nnen u.a. aufgrund von Aktivit{\"a}t und Zentralit{\"a}t im Netzwerk Nutzertypen voneinander unterschieden werden. Zentrale Personen im Netzwerk m{\"u}ssen gef{\"o}rdert werden, um Kommunikation und Kollaboration zu sichern. Deshalb stehen die sog. „value-adding user" im Zentrum der Analyse einer weiteren Publikation.}, language = {de} }