This study investigates the aspects of resilience in the management strategies of the key stakeholders of flood risk management in the city of Accra, Ghana. The overall objective is to analyse the response capacity in the strategies of the key stakeholders in flood risk management for managing the unexpected course of flood disasters in addition to the expected features of flood risk. To achieve the set objective, the following research questions are addressed: Who are the key stakeholders of flood risk management in the city of Accra? How are these stakeholders dealing with the unexpected course of flood disasters in addition to the expected features of flood risk in their management strategies? How could the capacity of the strategies for responding to the unexpected course of flood disasters be advanced? The inductive case study design applies document analyses, semi-structured interviews as well as key stakeholder identification and validation methods. Scientific and policy documents about resilience and flood risk management were reviewed. The research participants were mainly directors and representatives of organisations in flood risk management of the study. Empirical findings include key stakeholders in flood risk management as well as aspects of resilience and anticipation in flood risk management strategies. The main finding on the key stakeholders of flood risk management are national, district, civil society, and private sector organisations as well as traditional authorities (local chiefs). Aspects of resilience in flood risk management strategies comprises omnivorousness, agile and timely flow of response resource, homoeostasis, flatness of the response structure and process, redundancy of the response resources and buffer capacity. Findings revealed resilience regarding diversity in sources of resource and responses for dealing with unexpected course of flood disasters. The aspects of anticipation are described as resistance to known risk, maintenance of boundary conditions of the management strategies and specialisation for dealing with specific flood risk within and among organisations. Regarding anticipation, results indicate that there are measures for resisting known flood risk but their implementation is ineffective. Based upon the findings, hypotheses are derived for advancement of resilience and anticipation in flood risk management strategies. Involvement of the local chiefs, Slum Union of Ghana, Local Development Associations of flood-prone communities and key private sector organisations in flood risk management strategies in the city of Accra would amend their response capacities in diversity of sources of response resources and allow for advanced resilience regarding their responses to the impacts of land-use changes and the waste disposal in watercourses. Recommendations refer to prospects to advance the response capacity of key stakeholders of flood risk management strategies by integrating traditional authorities and private organisations in flood risk management in the city of Accra.:Note on the commencement of the doctoral procedure i Declaration of conformity ii Acknowledgement iv Abstract vi Table of contents x List of figures xv List of tables xvi List of abbreviations xvii 1 Introduction 1 1.1 Background 1 1.2 Problem statement 2 1.3 Objectives and research questions 12 1.4 Justification of the study 16 1.5 Structure of this research 17 2 Conceptual framework 20 2.1 Basic concepts in flood risk management 20 2.1.1 Flood risk 21 2.1.2 Expected and unexpected course of flood disasters 24 2.1.3 Flood risk management 27 2.1.4 Flood risk management strategies 30 2.1.5 Stakeholders of flood risk management strategies 33 2.1.6 Risk governance beyond flood risk management strategies 39 2.2 Resilience in flood risk management strategies 42 2.2.1 Overview of resilience concepts 43 2.2.2 Resilience and flood risk management 49 2.2.3 Operationalisation of resilience in flood risk management strategies 54 3 Research design and methods 71 3.1 Research design 71 3.1.1 Overall design 71 3.1.2 Case study approach 72 3.1.3 Research ethics and access to data 73 3.2 Data collection methods 75 3.2.1 Sampling techniques 75 3.2.2 Documents analysis 75 3.2.3 Expert interviews 76 3.3. Data analysis 78 3.4 Methods for answering the research questions 79 3.4.1 Research question 1: Stakeholder analysis 79 3.4.2 Research question 2: Semi-structured interviews and content analysis 93 3.4.3 Research question 3: Derivation of hypotheses 95 4 Identification of potential key stakeholders and selection of key stakeholders 101 4.1 Principled stakeholders of flood risk management 101 4.2 Potential key stakeholders of flood risk management 104 4.2.1 Potential key stakeholders on international level 104 4.2.2 Potential key stakeholders in flood risk management at the national level 110 4.2.3 Potential key stakeholders of flood risk management from Accra Metropolitan Assembly 119 4.2.4 Potential key stakeholders from non-governmental organisations 123 4.2.5 Potential key stakeholders from business organisations 128 4.2.6 Potential key stakeholders from traditional authorities and opinion leaders 132 4.3 Selection of key stakeholders of flood risk management in the city of Accra 135 4.4 Description of the key stakeholders of flood risk management in the city of Accra 138 5 Resilience and anticipation in flood risk management strategies 143 5.1 Resilience aspects 143 5.1.1 Resilience aspect Omnivorousness of the flood risk management strategy 143 5.1.2 Resilience aspect Agile and timely flow of response rate of the flood risk management strategy 147 5.1.3 Resilience aspect Homeostasis of the flood risk management strategy 155 5.1.4 Resilience aspect Flatness of response process and structure of flood risk management strategy 162 5.1.5 Resilience aspect Redundancy of response resources for flood risk management of the organisations 165 5.1.6 Resilience aspect Buffer capacity of the flood risk management strategy 171 5.2 Aspects of Anticipation 173 5.2.1 Anticipation aspect Resistance to (known) flood risks 173 5.2.2 Anticipation aspect Maintenance of boundary conditions of flood risk management strategy 179 5.2.3 Anticipation aspect Specialisation in dealing with specific courses of flood disasters 182 6 Hypotheses for advancing resilience and anticipation in flood risk management strategies 184 6.1 Hypotheses on advancing resilience in flood risk management strategies 184 6.1.1 Hypotheses for resilience regarding Omnivorousness of the flood risk management strategy 184 6.1.2 Hypothesis for resilience regarding Homoeostasis of flood risk management strategy 186 6.1.3 Hypothesis for resilience regarding agile and timely flow of response rate of the flood risk management strategy 189 6.1.4 Hypothesis for resilience regarding flatness of flood risk management strategy 191 6.1.5 Hypothesis on resilience regarding Redundancy of flood risk management strategies 194 6.1.6 Hypothesis for resilience regarding Buffer capacity of flood risk management strategy 196 6.2 Hypothesis for advancement of anticipation in flood risk management strategies 197 6.2.1 Hypotheses for anticipation regarding Resistance to known flood risk in flood risk management strategy 197 6.2.2 Hypotheses for anticipation regarding maintenance in boundary conditions of flood risk management strategy 201 6.2.3 Hypothesis for anticipation regarding Specialisation for dealing with specific courses of flood disasters 203 7 Discussion of approach and key findings 206 7.1 Conceptual and methodological rigour of the study 206 7.2 Conceptual and empirical relevance for resilience and anticipation in flood risk management strategies 213 7.3 Accomplishment of the research objectives and answers to the research questions 217 7.4 Limitations of this research 226 7.5 Prospects and challenges for future research on resilience in FRM strategies 227 8 Conclusions and recommendations 229 8.1 Conclusions on main contributions of this study 229 8.2 Demand for future research 231 8.3 Recommendations for formulation and implementation of FRM strategies in the city of Accra 232 8.4 General concluding remarks 234 9 References 235 9.1 Literature 235 9.2 Other sources 252 10 Appendices 259 10.1 Appendix I Interview guide 259 10.2 Appendix II Selected interview codes and quotations 264 / Diese Arbeit untersucht Aspekte von Resilienz in den Strategien von Schlüsselakteuren des Hochwasserrisikomanagements in der Stadt Accra (Ghana). Das übergeordnete Ziel besteht darin, das Reaktionsvermögen dieser Akteure in ihren Management-Strategien nicht nur hinsichtlich des erwarteten, sondern vor allem hinsichtlich des unerwarteten Verlaufs von Hochwasserkatastrophen zu untersuchen. Die folgenden drei Forschungsfragen werden untersucht: Wer sind die Schlüsselakteure des Hochwasserrisikomanagements in der Stadt Accra? Wie berücksichtigen diese Akteure in ihren Management-Strategien den unerwarteten Verlauf von Hochwasserkatastrophen zusätzlich zu dem erwarteten Verlauf? Wie könnte das Reaktionsvermögen bezüglich des Umgangs mit dem unerwarteten Verlauf von Hochwasserkatastrophen in diesen Strategien ausgeweitet werden? Im Rahmen des induktiven Fallstudiendesigns werden Dokumentenanalysen, halbstandardisierte Interviews und Gruppendiskussionen eingesetzt. Die daraus resultierenden empirischen Befunde beziehen sich neben der Identifikation der Schlüsselakteure des Hochwasserrisikomanagements auch auf die Aspekte von Resilienz und Antizipation in ihren Management-Strategien. Zu den Schlüsselakteuren zählen nationale und lokale Organisationen, aber auch solche aus der Zivilgesellschaft, dem privaten Sektor und traditionelle Autoritäten. Bei den Aspekten von Resilienz in den Hochwasserrisikomanagement-Strategien handelt es sich um ganzheitliche Herangehensweisen, regen und zeitnahen Einsatz von Ressourcen zur Ereignisbewältigung sowie Pufferkapazitäten. Die Ergebnisse zeigten Widerstandsfähigkeit in Bezug auf die Vielfalt in den Quellen von Ressourcen und Antworten auf den unerwarteten Verlauf von Hochwasserkatastrophen. Die Ergebnisse hinsichtlich der Antizipation von Hochwasserrisikomanagement-Strategien umfassen den Widerstand gegen das bekannte Risiko, die Aufrechterhaltung von Rahmenbedingungen der Management-Strategien und die Spezialisierung auf bestimmte Hochwasserrisiken. Auf den Erkenntnissen über die Aspekte von Resilienz und Antizipation in den Hochwasserrisikomanagement-Strategien aufbauend werden Hypothesen abgeleitet. In den Handlungsempfehlungen werden die Chancen einer Integration traditioneller Autoritäten und anderer Interessensgruppen in das Hochwasserrisikomanagement der Stadt Accra aufgezeigt, wodurch eine Weiterentwicklung der Resilienz in den Hochwasserrisikomanagement-Strategien für die Zukunft erreicht werden kann.:Note on the commencement of the doctoral procedure i Declaration of conformity ii Acknowledgement iv Abstract vi Table of contents x List of figures xv List of tables xvi List of abbreviations xvii 1 Introduction 1 1.1 Background 1 1.2 Problem statement 2 1.3 Objectives and research questions 12 1.4 Justification of the study 16 1.5 Structure of this research 17 2 Conceptual framework 20 2.1 Basic concepts in flood risk management 20 2.1.1 Flood risk 21 2.1.2 Expected and unexpected course of flood disasters 24 2.1.3 Flood risk management 27 2.1.4 Flood risk management strategies 30 2.1.5 Stakeholders of flood risk management strategies 33 2.1.6 Risk governance beyond flood risk management strategies 39 2.2 Resilience in flood risk management strategies 42 2.2.1 Overview of resilience concepts 43 2.2.2 Resilience and flood risk management 49 2.2.3 Operationalisation of resilience in flood risk management strategies 54 3 Research design and methods 71 3.1 Research design 71 3.1.1 Overall design 71 3.1.2 Case study approach 72 3.1.3 Research ethics and access to data 73 3.2 Data collection methods 75 3.2.1 Sampling techniques 75 3.2.2 Documents analysis 75 3.2.3 Expert interviews 76 3.3. Data analysis 78 3.4 Methods for answering the research questions 79 3.4.1 Research question 1: Stakeholder analysis 79 3.4.2 Research question 2: Semi-structured interviews and content analysis 93 3.4.3 Research question 3: Derivation of hypotheses 95 4 Identification of potential key stakeholders and selection of key stakeholders 101 4.1 Principled stakeholders of flood risk management 101 4.2 Potential key stakeholders of flood risk management 104 4.2.1 Potential key stakeholders on international level 104 4.2.2 Potential key stakeholders in flood risk management at the national level 110 4.2.3 Potential key stakeholders of flood risk management from Accra Metropolitan Assembly 119 4.2.4 Potential key stakeholders from non-governmental organisations 123 4.2.5 Potential key stakeholders from business organisations 128 4.2.6 Potential key stakeholders from traditional authorities and opinion leaders 132 4.3 Selection of key stakeholders of flood risk management in the city of Accra 135 4.4 Description of the key stakeholders of flood risk management in the city of Accra 138 5 Resilience and anticipation in flood risk management strategies 143 5.1 Resilience aspects 143 5.1.1 Resilience aspect Omnivorousness of the flood risk management strategy 143 5.1.2 Resilience aspect Agile and timely flow of response rate of the flood risk management strategy 147 5.1.3 Resilience aspect Homeostasis of the flood risk management strategy 155 5.1.4 Resilience aspect Flatness of response process and structure of flood risk management strategy 162 5.1.5 Resilience aspect Redundancy of response resources for flood risk management of the organisations 165 5.1.6 Resilience aspect Buffer capacity of the flood risk management strategy 171 5.2 Aspects of Anticipation 173 5.2.1 Anticipation aspect Resistance to (known) flood risks 173 5.2.2 Anticipation aspect Maintenance of boundary conditions of flood risk management strategy 179 5.2.3 Anticipation aspect Specialisation in dealing with specific courses of flood disasters 182 6 Hypotheses for advancing resilience and anticipation in flood risk management strategies 184 6.1 Hypotheses on advancing resilience in flood risk management strategies 184 6.1.1 Hypotheses for resilience regarding Omnivorousness of the flood risk management strategy 184 6.1.2 Hypothesis for resilience regarding Homoeostasis of flood risk management strategy 186 6.1.3 Hypothesis for resilience regarding agile and timely flow of response rate of the flood risk management strategy 189 6.1.4 Hypothesis for resilience regarding flatness of flood risk management strategy 191 6.1.5 Hypothesis on resilience regarding Redundancy of flood risk management strategies 194 6.1.6 Hypothesis for resilience regarding Buffer capacity of flood risk management strategy 196 6.2 Hypothesis for advancement of anticipation in flood risk management strategies 197 6.2.1 Hypotheses for anticipation regarding Resistance to known flood risk in flood risk management strategy 197 6.2.2 Hypotheses for anticipation regarding maintenance in boundary conditions of flood risk management strategy 201 6.2.3 Hypothesis for anticipation regarding Specialisation for dealing with specific courses of flood disasters 203 7 Discussion of approach and key findings 206 7.1 Conceptual and methodological rigour of the study 206 7.2 Conceptual and empirical relevance for resilience and anticipation in flood risk management strategies 213 7.3 Accomplishment of the research objectives and answers to the research questions 217 7.4 Limitations of this research 226 7.5 Prospects and challenges for future research on resilience in FRM strategies 227 8 Conclusions and recommendations 229 8.1 Conclusions on main contributions of this study 229 8.2 Demand for future research 231 8.3 Recommendations for formulation and implementation of FRM strategies in the city of Accra 232 8.4 General concluding remarks 234 9 References 235 9.1 Literature 235 9.2 Other sources 252 10 Appendices 259 10.1 Appendix I Interview guide 259 10.2 Appendix II Selected interview codes and quotations 264

A backbone network is the central part of the communication network, which provides connectivity within the various systems across large distances. Disruptions in a backbone network would cause severe consequences which could manifest in the service outage on a large scale. Depending on the size and the importance of the network, its failure could leave a substantial impact on the area it is associated with. The failures of the network services could lead to a significant disturbance of human activities. Therefore, making backbone communication networks more resilient directly affects the resilience of the area. Contemporary urban and regional development overwhelmingly converges with the communication infrastructure expansion and their obvious mutual interconnections become more reciprocal. Spreading failures are of particular interest. They usually originate in a single network segment and then spread to the rest of network often causing a global collapse. Two types of spreading failures are given focus, namely: epidemics and cascading failures. How to make backbone networks more resilient against spreading failures? How to tune the topology or additionally protect nodes or links in order to mitigate an effect of the potential failure? Those are the main questions addressed in this thesis. First, the epidemic phenomena are discussed. The subjects of epidemic modeling and identification of the most influential spreaders are addressed using a proposed Linear Time-Invariant (LTI) system approach. Throughout the years, LTI system theory has been used mostly to describe electrical circuits and networks. LTI is suitable to characterize the behavior of the system consisting of numerous interconnected components. The results presented in this thesis show that the same mathematical toolbox could be used for the complex network analysis. Then, cascading failures are discussed. Like any system which can be modeled using an interdependence graph with limited capacity of either nodes or edges, backbone networks are prone to cascades. Numerical simulations are used to model such failures. The resilience of European National Research and Education Networks (NREN) is assessed, weak points and critical areas of the network are identified and the suggestions for its modification are proposed.

Bit flips are known to be a source of strange system behavior, failures, and crashes. They can cause dramatic financial loss, security breaches, or even harm human life. Caused by energized particles arising from, e.g., cosmic rays or heat, they are hardly avoidable. Due to transistor sizes becoming smaller and smaller, modern hardware becomes more and more prone to bit flips. This yields a high scientific interest, and many techniques to make systems more resilient against bit flips are developed. Fault-tolerance techniques are techniques that detect and react to bit flips or their effects. Before using these techniques, they typically need to be configured for the particular system they shall protect, the grade of resilience that shall be achieved, and the environment. State-of-the-art configuration approaches have a high risk of being imprecise, of being affected by undesired side effects, and of yielding questionable resilience measures. In this thesis we encourage the usage of formal methods for resiliency configuration, point out advantages and investigate difficulties. We exemplarily investigate two systems that are equipped with fault-tolerance techniques, and we apply parametric variants of probabilistic model checking to obtain optimal configurations for pre-defined resilience criteria. Probabilistic model checking is an automated formal method that operates on Markov models, i.e., state-based models with probabilistic transitions, where costs or rewards can be assigned to states and transitions. Probabilistic model checking can be used to compute, e.g., the probability of having a failure, the conditional probability of detecting an error in case of bit-flip occurrence, or the overhead that arises due to error detection and correction. Parametric variants of probabilistic model checking allow parameters in the transition probabilities and in the costs and rewards. Instead of computing values for probabilities and overhead, parametric variants compute rational functions. These functions can then be analyzed for optimality. The considered fault-tolerant systems are inspired by the work of project partners. The first system is an inter-process communication protocol as it is used in the Fiasco.OC microkernel. The communication structures provided by the kernel are protected against bit flips by a fault-tolerance technique. The second system is inspired by the redo-based fault-tolerance technique \haft. This technique protects an application against bit flips by partitioning the application's instruction flow into transaction, adding redundance, and redoing single transactions in case of error detection. Driven by these examples, we study challenges when using probabilistic model checking for fault-tolerance configuration and present solutions. We show that small transition probabilities, as they arise in error models, can be a cause of previously known accuracy issues, when using numeric solver in probabilistic model checking. We argue that the use of non-iterative methods is an acceptable alternative. We debate on the usability of the rational functions for finding optimal configurations, and show that for relatively short rational functions the usage of mathematical methods is appropriate. The redo-based fault-tolerance model suffers from the well-known state-explosion problem. We present a new technique, counter-based factorization, that tackles this problem for system models that do not scale because of a counter, as it is the case for this fault-tolerance model. This technique utilizes the chain-like structure that arises from the counter, splits the model into several parts, and computes local characteristics (in terms of rational functions) for these parts. These local characteristics can then be combined to retrieve global resiliency and overhead measures. The rational functions retrieved for the redo-based fault-tolerance model are huge - for small model instances they already have the size of more than one gigabyte. We therefor can not apply precise mathematic methods to these functions. Instead, we use the short, matrix-based representation, that arises from factorization, to point-wise evaluate the functions. Using this approach, we systematically explore the design space of the redo-based fault-tolerance model and retrieve sweet-spot configurations.

Diese Arbeit beschäftigt sich mit dem Thema Resilienzförderung im Hochschulkontext vor dem Hintergrund der Bologna-Zielsetzung 'Beschäftigungsfähigkeit'. Resilienz als notwendige Kompetenz von Fach- und Führungskräften und deren Entwicklung dient im Verständnis der Autorin der Erhöhung der Beschäftigungsfähigkeit von Absolvent*innen. Die Resilienzforschung im Hochschulkontext ist ein sehr junges Forschungsfeld, es finden sich Studien über Resilienzfaktoren im nationalen und internationalen Kontext, ein Schutzfaktorenmodell fehlte bislang. Diese Dissertation beschäftigt sich mit der Entwicklung eines solchen Schutzfaktorenmodells für die Hochschulausbildung. Hierzu wurde im Rahmen einer mehrphasigen Mixed-Methods-Studie ein konzeptuelles Modell entwickelt und überprüft. Die Modellierung erfolgte mittels PLS-Strukturgleichungsmodellierung. Die Ergebnisse zeigen die Bedeutung einzelner Faktoren als individuelle und hochschulseitige Schutzfaktoren auf. Zusammenhänge zwischen individuellen und hochschulseitigen Schutzfaktoren, personalen, sozialen und methodischen Kompetenzen und der Resilienz werden deutlich. Es zeigt sich die Bedeutung von personalen, sozialen und methodischen Kompetenzen als Mediator zur Resilienzentwicklung. Die Ergebnisse ermöglichen eine Systematisierung der Resilienzförderung im Hochschulkontext mit Schwerpunkt Wirtschaftswissenschaften.:DANKSAGUNG III EXTENDED ABSTRACT IV ABKÜRZUNGSVERZEICHNIS ALLGEMEIN VIII ABKÜRZUNGSVERZEICHNIS HCM IX ABBILDUNGSVERZEICHNIS XI TABELLENVERZEICHNIS XII 1 EINLEITUNG 1 1.1 Kontext und Problemstellung 1 1.2 Motivation 2 1.3 Zielsetzung und forschungsleitende Fragen 3 2 RESILIENZFORSCHUNG IM HOCHSCHULKONTEXT 7 2.1 Bologna-Erklärung, Employability und die Bedeutung von Resilienz 7 2.2 Resilienz und das Modell der Risiko- und Schutzfaktoren 11 2.3 Überblick über die Resilienzforschung im Hochschulkontext 14 3 EMPIRISCHE STUDIE IM SEQUENZIELLEN MIXED METHODS DESIGN ZUR ENTWICKLUNG EINES SCHUTZFAKTORENMODELLS IM HOCHSCHULKONTEXT 17 3.1 Forschungsparadigma und Forschungsdesigns 17 3.2 Datenerhebung und Datenauswertung der Teilstudien 21 3.2.1 Stichprobenbildung 21 3.2.2 Studien qual I und qual II 23 3.2.3 Studie QUANT 26 3.3 Zusammenführung der Ergebnisse 29 3.3.1 Beitrag A: Systematischer Literaturüberblick und initiales Schutzfaktorenmodell 30 3.3.2 Beitrag B: Ergänzende Schutzfaktoren aus dem Hochschulkontext 31 3.3.3 Beitrag C: Ergänzende Schutzfaktoren aus dem Arbeitskontext 33 3.3.4 Beitrag D: Entwicklung des Schutzfaktorenmodells mittels PLS-SEM 35 4 ZUSAMMENFASSUNG 45 4.1 Kritische Würdigung 45 4.2 Implikationen 47 4.3 Ausblick und Forschungsbedarf 49 CHRONOLOGIE DER PUBLIKATIONEN 52 Beitrag A 54 Beitrag B 69 Beitrag C 96 Beitrag D 114 LITERATURVERZEICHNIS XIII

Die Corona-Pandemie hat den Alltag Studierender in den vergangenen zwei Jahren geprägt, stark verändert und einhergehend damit auch die Voraussetzungen, unter welchen sich Erfolg und Gesundheit im Studium entwickeln können. Widerstands- sowie Anpassungsfähigkeit scheinen im Zuge weitreichender Veränderungen in der akademischen Hochschullehre bedeutsamer geworden zu sein. Gleichzeitig besteht schon seit Längerem die Notwendigkeit, das Forschungsdesiderat in Bezug auf Resilienz und (Hochschul-)Bildung, deren Voraussetzungen sowie Interventionsansätze von Bewältigungsstrategien in Studierenden zu untersuchen. Dieses Forschungsprojekt hat davon ausgehend, akademische Resilienz unter Studierenden in der Zeit der Corona-Krise quantitativ erhoben und analysiert. Mit einem ressourcenbasierten Blick auf personale, soziale, institutionelle sowie finanzielle Dimensionen sozialer Ungleichheit an der Technischen Universität Dresden wurden dabei sowohl Herkunfts- und Kontexteffekte in Bezug auf akademische Resilienz als auch Ressourcen, welche diese beeinflussen bzw. in spezifischen Gruppen moderieren, untersucht. Akademische Resilienz wurde dabei anhand von Resilienz, Lebenszufriedenheit sowie Betroffenheit Studierender abgebildet, welche jeweils als abhängige Variable in moderierte Regressionsmodelle einbezogen wurden. Studierende mit Kind(ern), Migrationshintergrund, physischen und psychischen Beeinträchtigungen bzw. Lernschwächen sowie der ersten Hochschulgeneration wurden als Risikogruppen im Vergleich zu Studierenden ohne diese Merkmale in Hinblick auf akademische Resilienz analysiert. Im Zuge dessen wurde ebenso die Bedeutung spezifischer Ressourcen innerhalb der studentischen Risikogruppen mit Hilfe von Interaktionsvariablen geprüft. Dabei konnten Studierende mit Beeinträchtigung, Studienanfänger:innen sowie sozial isolierte Studierende der TU Dresden als vulnerabel und damit als spezifische Zielgruppen von Interventionsangeboten identifiziert werden. Darüber hinaus konnte die Bedeutung sozialer Ressourcen, insbesondere sozialer Unterstützung und Netzwerke sowie die Erfahrung von Selbstwirksamkeit und Kontrolle, herausgestellt werden. Dadurch, dass die Studierenden zwar eine eher hohe Betroffenheit äußerten, jedoch gleichzeitig eher resilient und zufrieden waren, bekräftigt die Studie die Bedeutung akademischer Resilienz und die Notwendigkeit, diese kontinuierlich in Studierenden zu sichern. / The Covid-19 pandemic has had massive influence and brought enormous change in the everyday life of students in the past two years. Under these circumstances also, the requirements for the development and preservation of success and mental health in the field of university education have altered. Resistance and adaptability seem to be much more important in the face of profound changes and insecurity. Universities should develop intervention programs tailored to these capabilities. Simultaneously, a knowledge gap exists relating to resilience and higher education, their preconditions and intervention measures of coping strategies researched and analysed in university students. From this point of view, this research project has surveyed data under students of the Technical University Dresden to display their academic resilience during the Covid-19 Pandemic. The quantitative data set got analysed with a resource theoretically view on personal, social, institutional and financial dimensions of social inequality. In terms of that, origin and context effects relating to academic resilience as well as resources which influence or rather interact with it just within risk groups of students, got analysed. Academic resilience as the process of positive adaption in the face of a personal as well as a professional crisis got depicted by resilience, Well-being and consternation which were used as dependent variables in multiple linear regression models. Students with child(ren), migration background, physical, psychological or learning disabilities as well as students of the first generation in higher academic education got defined as risk groups along the research status and analysed in comparison with students without these characteristics. In terms of that also the influence of specific resources for students got proofed by integrating them as predictors as well as in building and involving interaction variables relating to the risk factors and predictor resources for making possible differences between promotive resources in general and protective resources, which may influence the academic resilience of the risk groups significant stronger, visible. Significant interactions also got plotted for interpreting the effects more precise. The results show, that students with psychological, physical or learning disabilities are significant less resilient during the pandemic situation, but they are not showing significantly less well-being or higher consternation. The other risk groups show no significant differences to students without risk characteristics beside students with child(ren) which show even a better well-being than all the other students. The results clearly point out the importance of personal and social resources, self-efficacy, an internal Locus of control and a reliable social network in particular which should also be supported by the university itself. Further risk groups which can be found in the data are social isolated students and university entrants, which should also be focused on intervention programs of the university. Over all Students of TUD show high scores of resilience and a good well-being even though they express strong consternation of the crisis at the same time which underlines the importance and utility of academic resilience in students which should be continuously secured and developed broader.

Diese Dissertation ist motiviert durch die Finanzkrise im Jahre 2007-2009 und das Versagen der ökonomischen Methodologie die gestiegene Fragilität des Finanzsystems vor der Krise zu erkennen. Ich untersuche die Nützlichkeit von alternativen Ansätzen und fokussiere dabei auf methodologischen Defizite des Standardansatzes, die sich im Zuge der Finanzkrise offenbart haben. Insbesondere fokussiere ich auf ökologische Ansätze, da die Ökonomie und die Ökologie ähnliche phänomenologische Gemeinsamkeiten haben und dennoch viele gegensätzliche methodologische Doktrinen beherbergen, so dass sie sich ergänzen können. Die erste Studie betrachtet die Verbindungen zwischen Ökologie und Ökonomie und setzt sich mit der historischen Fragestellung auseinander wie Analogie-Modelle, inspiriert durch unterschiedliche Forschungsparadigmen, zu einer Entwicklung von zwei gegensätzlichen methodologischen Sichtweisen innerhalb der Ökonomie geführt haben. Dabei finde ich, dass die Finanzkrise eine Veränderung in der ökonomischen Methodologie in Richtung von Ansätzen aus den Lebenswissenschaften verursacht hat. In den letzten zwei Studien wende ich ökologische Modelle auf die Finanzwissenschaft an, indem ich Netzwerk-Ansätze mit Agenten-basierten Simulationen kombiniere, um Contangion-Effekte in Bankensystemen zu studieren. In der ersten Simulationsstudie untersuche ich den Einfluss von Unsicherheit auf die Stabilität von Bankensystemen und finde, dass Informationsasymmetrien zu einem erstaunlichen Anstieg des Risikos eines Systemkollapses nach einem Finanzschock führen können. In der zweiten Simulationsstudie untersuche ich den Zusammenhang zwischen Konzentration und Resilienz von Bankensystemen. Ich finde, kontraintuitiv, dass ein Anstieg an Konzentration, wenn von Ungleichheit entkoppelt, die Systemresilienz erhöhen kann. Zusammengefasst, zeige ich in dieser Arbeit, dass ökologische Ansätze fruchtbar gemacht werden können, um ökonomische Probleme zu beleuchten. / This dissertation is motivated by the 2007-2009 financial crisis and the failure of the mainstream economic methodology to detect the increased fragility of the pre-crisis financial system. I explore the viability of alternative approaches focusing on the methodological blind spots that were revealed by the financial crisis. In particular, I focus on ecological approaches since economics and ecology share many phenomenological similarities but harbor many opposing methodological doctrines, which make them complementary. The collection of projects presented here is my attempt at facilitating crosspollination between the two disciplines dealing with similar problems. The first project considers the connections between ecology and economics, and provides a historical account of how analogical models inspired by different research paradigms led to the development of two contrasting methodological perspectives in economics, the classical physics worldview and the life sciences worldview. I find that the recent financial crisis precipitated a shift in economic methodology towards approaches inspired by life sciences. In the remaining two projects I apply ecological models to finance by combining network approaches with agent-based simulations to study contagion in banking systems. In the first simulation study I explore the impact of uncertainty on the stability of banking networks and show that information asymmetries lead to a striking increase in the risk of system collapse after a financial shock. In the second simulation study I investigate the relationship between concentration and resilience in banking systems. I find, counterintuitively, that an increase in concentration can be beneficial for system stability in certain conditions. Specifically, when concentration is decoupled from inequality, its increase can improve system resilience. Taken together, this thesis shows that ecological approaches can be fruitfully used to illuminate economic problems.

Das erste Ziel dieser Arbeit ist eine umfassende Analyse der Wasserflüsse durchzuführen und Quellen und Senken des kontinentalen Niederschlags zu identifizieren. Als Analysemethode werden komplexe Netzwerke verwendet, ein Ansatz, mit dessen Hilfe das neuartige Konzept des “cascading moisture recycling'''' (CMR) eingeführt wird. CMR wird als vielfache Verdunstung von Niederschlag während des Feuchtigkeitstransports über bewaldeten Gebieten definiert. Dieses Verfahren ermöglicht es, den Anteil von CMR an der Menge des regionalen Niederschlags zu quantifizieren und Schlüsselregionen des CMR zu identifizieren. Die Analyse zeigt, dass der südliche Bereich des Amazonasbeckens nicht nur eine direkte Quelle für Niederschlag im La-Plata Becken ist, sondern auch als ``Brückenregion'''' dient, über die die verdunstete Feuchtigkeit des ganzen Amazonasbeckens auf dem Weg in die Subtropen transportiert wird. Die Ergebnisse zeigen, dass eine Neubewertung der Vulnerabilität des Amazonasregenwalds unter Umweltveränderungen unabdingbar ist. Dies ist das zweite Ziel der vorliegenden Arbeit. Durch diese Veränderungen könnten große Teile des Regenwaldes in eine Savanne umgewandelt werden. Dies würde wiederum den Niederschlag reduzieren, was sich negativ auf die Stabilität der verbleibenden Waldgebiete auswirken und ein Waldsterben verursachen kann. Für die Analyse dieser Zusammenhänge werden ebenfalls komplexe Netzwerke verwendet, um das Konzept der Ökosystem-Resilienz und CMR basierend auf Beobachtungsdaten zu kombinieren. Es werden die Schlüsselregionen, in denen Entwaldung zu einer Destabilisierung der verbleibenden Wald führt, identifiziert und die Möglichkeit eines großflächigen Absterben des Regenwaldes aufgrund von verlängerter Trockenzeit untersucht. Die Ergebnisse zeigen, dass die Diversität des Regenwaldes und die durch den Feuchtigkeitstransport gegebene Konnektivität der Waldgebiete eine wichtige Rolle für die Stabilität und ökologische Integrität dieses Ökosystems spielen. / The first aim of this thesis is to improve the understanding of vegetation-atmosphere interactions by means of complex network analysis of water fluxes from the sources to the sinks of rainfall in South America. This novel approach allows to introduce the concept of “cascading moisture recycling” defined as moisture recycling on the continent involving re-evaporation cycles along the way. A methodological framework is developed to quantify the importance of cascading moisture recycling and to identify key regions that sustain this process. It reveals, for instance, that the southern part of the Amazon basin is not only a direct source of rainfall for the La Plata basin as previously thought but also an intermediary region that re-distribute moisture evaporating from the entire Amazon basin towards the subtropics. This new concept lays the foundation for evaluating the vulnerability of the Amazon forest to environmental perturbations, which is the second aim of this thesis. Land-use and rainfall variability are expected to be intensified at the end of the twenty-first century and may push the south-eastern part of the Amazon forest towards a grass-dominated ecosystem. Such a forest loss would reduce local dry-season evapotranspiration and the resulting moisture supply for down-wind rainfall. In turn, this might erode the resilience of the remaining forest and lead to further forest losses. Using a complex network approach, the concepts of forest resilience and cascading moisture recycling are combined in a data-driven modeling framework. Key regions are identified where deforestation would greatly destabilize the remaining forest, as well as tipping points in dry-season intensification for large-scale self-amplified Amazon forest loss. The findings highlight the need to maintain the diversity and connectivity of forest patches in order to sustain the ecological integrity of the largest remaining tropical forest on Earth.

An der Schnittstelle von Quartiers- und Wohnungsmarktforschung wurde im Rahmen dieser Arbeit der Beitrag von Wohnungseigentümern zu einer resilienten Quartiersentwicklung in Berlin untersucht. Die Verknüpfung des Quartiers als Untersuchungsraum mit dem Konzept der Resilienz stellt aus raumwissenschaftlicher Perspektive eine weitgehende Neuerung im akademischen Diskurs dar. Aufgrund der massiven Transformation des deutschen Mietwohnungsmarktes hinsichtlich dessen Eigentümerstruktur seit Ende der 1990er, standen die beiden zentralen Akteure dieses Prozesses - kommunale Wohnungsunternehmen sowie private Finanzinvestoren - im Fokus der Analyse. Der Beitrag der Wohnungseigentümer zu resilienter Quartiersentwicklung wurde sowohl in Hinblick auf deren Bestandsbewirtschaftung als auch hinsichtlich des Engagements in einem weiteren Quartierskontext untersucht und bewertet. Die Ergebnisse der Untersuchung belegen, dass Wohnungseigentümern insgesamt eine sehr bedeutende Rolle für die Resilienz von Quartieren zukommt, da sie diese auf vielfältige Weise beeinflussen - sowohl über ihre Bestandsbewirtschaftung als auch darüber hinaus. Das Engagement im weiteren Quartiersumfeld sowie der daraus resultierende Beitrag zur Quartiersresilienz sind dabei sehr divers, wobei Engagement von den Wohnungseigentümern in verschiedenen Quartieren sehr selektiv erbracht wird. Während in (Groß)Wohnsiedlungen das Engagement recht aktiv war, konnten in Altbauquartieren kaum Aktivitäten der Eigentümer identifiziert werden. Dabei war die Erbringung des Quartiersengagements sowie der Beitrag zur Resilienz von einer Reihe verschiedener Faktoren abhängig (quartiers- und unternehmensspezifische sowie institutionelle). Der Beitrag zur Resilienz von Quartieren konnte für die kommunalen Wohnungsunternehmen im Vergleich zu den privaten Finanzinvestoren insgesamt als positiver charakterisiert werden, wobei eine Pauschalisierung nicht erfolgen kann. So konnte zum einen auch für private Investoren vereinzelt ein durchaus positiver Beitrag zur Quartiersresilienz herausgearbeitet werden, zum anderen wurde auch in einer Reihe von Quartieren ein Ausbleiben des Engagements der kommunalen Wohnungsunternehmen beobachtet. / At the interface of neighborhood and housing market research, the presented study examines the contribution of housing owners to a resilient neighborhood development in Berlin. The link between the neighborhood as an area of research and the concept of resilience is a scientific advancement from a spatial science perspective. Due to the massive transformation of the German rental housing market in terms of its ownership structure since the end of the 1990s, the two central actors of this process, municipal housing companies as well as private financial investors, have been in the center of the analysis. The housing owners’ contribution to resilient neighborhood development was analyzed and assessed both with regard to their stock management and particularly their commitment in the neighborhood. The results of the study reveal that housing owners are of major importance for neighborhood resilience as they influence it in various ways, by their stock management and beyond. The commitment in a broader neighborhood setting as well as the resulting contribution to neighborhood resilience are very diverse. However, housing owners render their activities in various neighborhoods very selectively. While in (large) housing estates the commitment was fairly active, hardly any activities could be identified in old building stock neighborhoods. The performance of neighborhood commitment and the contribution to resilience was dependent on a number of factors (neighborhood and company-specific as well as institutional). The contribution to neighborhood resilience can be characterized as more positively for the municipal housing companies compared to the private investors. A generalization, however, should not be deduced since a positive contribution to neighborhood resilience could be identified for private investors occasionally. Furthermore, an absence of commitment could also be observed for the municipal housing companies in several neighborhoods.

Eine Untersuchung über den Zusammenhang zwischen sozialer Lage und dem Gesundheitsstatus bei Kindern und Jugendlichen.

Eine Untersuchung über den Zusammenhang zwischen sozialer Lage und dem Gesundheitsstatus bei Kindern und Jugendlichen.