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Schatten im Diskurs. Anknüpfungspunkte zur Integration einer kritischen Genderperspektive in die Nachhaltigkeitsforschung
Full text linkDie Dissertation untersucht Anknüpfungspunkte für die Integration einer kritischen Genderperspektive in die Nachhaltigkeitsforschung. Hierzu erfolgt die kritische Reflexion und Analyse von Nachhaltigkeitsverständnissen in Forschungsförderprogrammen und Forschungsprojekten im Themenfeld Nachhaltigkeit in Deutschland anhand einer qualitativen Analyse von Dokumenten der Forschungsförderung und Expert*inneninterviews in Forschungsprojekten. Durch die Nutzung einer kritischen Genderperspektive als sensibilisierendes Konzept können so die Schatten im Diskurs der Nachhaltigkeitsforschung, wie die Reproduktion von gesellschaftlichen Strukturen der Ungerechtigkeit, aufgedeckt werden. Die Ergebnisse weisen Anknüpfungspunkte auf inhaltlicher und struktureller Ebene der inter- und transdisziplinären Nachhaltigkeitsforschung auf, um die Integration einer kritischen Genderperspektive und damit ihre Relevanz für eine gesellschaftliche Transformation zu bestärken
Phase Transitions in Robust Networks: From Theoretical Insights to an Ecological Application
Full text linkTo better understand the coexistence of species through network structure, I propose a framework for modeling competitive ecological systems via network robustness. First, I refine network robustness by analyzing regular and star networks under random, targeted, and viral attacks. Using generating functions, I show that regular networks resist minor random attacks but collapse under larger ones, while star networks resist random but not targeted and viral attacks. Then, I identify network structures that maximize the giant component after random attacks. With a fixed mean degree and constrained degrees, I show (dis)continuous phase transitions based on (link) node maximization. To finalize, I explore coexistence in competitive networks with two dispersal strategies, showing that random networks support broader coexistence regions while regular networks exhibit higher patch occupancy
A computational neuroscience approach to studying the mechanisms of magnetic orientation and navigation in birds
Full text linkIt is widely accepted that birds possess two systems for orientation and navigation: a compass and a map. One hypothesis for these mechanisms is that birds possess tiny magnets (magnetite particles) that respond to the magnetic field. The existence of this particles can be tested by a strong but brief magnetic field pulse. Thus, we performed simulated pulse studies where we were able to reproduce some results from literature and make some predictions for future experiments. Also, we tested the bird’s navigational ability using the inclination compass in a reinforcement learning setting. In these studies, the learning agent was able to successfully navigate and show experimentally discovered properties of navigation, such as extrapolation
Entwicklung einer Methode zur Evaluation der Effizienz von Sprachsteuerung als industrielles Human-Machine Interface in der Produktion
Full text linkSprache bietet als natürlichste Form der Kommunikation das Potenzial, die Kollaboration zwischen Mensch und Maschine in Produktionsabläufen effizienter zu gestalten. Obwohl die Steuerung von technischen Systemen im Consumer-Bereich wie bei Fahrzeugen, Smartphones und Hausautomatisierungen bereits seit Jahren standardmäßig als HMI-Modalität zur Verfügung steht, ist die Steuerung von Maschinen per Sprache aktuell noch die Ausnahme. Für den zielgerichteten Einsatz einer Sprachsteuerung als industrielles HMI werden objektive Einflussfaktoren und davon abgeleitete quantitative Parameter benötigt, um das Effizienzpotenzial zu prognostizieren. In dieser Arbeit wird auf Basis der drei Einflussfaktoren Menükomplexität, Art und Anzahl von Laufwegen sowie der Anzahl simultan zu bedienender Maschinen eine allgemeingültige Methode zur Evaluation der Effizienz einer Sprachsteuerung als industrielles HMI in der Produktion entwickelt. Diese ermöglicht es Herstellern von Produktionsmaschinen und Endanwendern, ihre vorhandenen oder neu einzuführenden Produktionsabläufe hinsichtlich der Effizienz einer Sprachsteuerung als Ergänzung oder Austausch zu einem konventionellen HMI zu bewerten. Durch die systematische Identifikation von Anwendungsszenarien, die von einer Sprachsteuerung hinsichtlich ihrer Effizienz profitieren, werden Produktionsunternehmen in die Lage versetzt, sicher eine Investitionsentscheidung treffen zu können
Causal dynamic modeling with Bayesian methods
Full text linkRoot cause analysis is essential in industrial settings. Counterfactual formulations from causal inference assess whether failures would occur under different conditions, enabling system improvements via hypothetical interventions. However, the hypothetical nature of counterfactual distributions makes them inherently ambiguous, which is particularly challenging in continuous settings. If the underlying system is dynamic, as it is typically the case in industrial processes, this increases complexity, particularly with regard to scalability.
This work tackles three challenges: uncertainties in counterfactual estimation, root cause identification in dynamic systems, and unobserved variables. To address uncertainties, we propose a Bayesian approach for improved reliability. For automatic root cause identification from a single faulty observation, we present an auto-regressive model with sampling-based estimation. Additionally, we sketch deconfounding techniques for unobserved variables. These methods enhance counterfactual reasoning, enabling faster, more accurate root cause identification and simplifying quality control
A Systematic Analysis of Electricity Markets on Smart Grid Performance
Full text linkToday’s electric power system is facing several challenges to achieve the energy transition and to comply with a fully sustainable and clean power sector. Renewable energies and
smart grid technologies are key contributors in supporting this transformation. Smart grid technologies refer to a supply network that uses digital communication technologies
to provide information on resource availability, enable controllability, and encourage a more dynamic operation of the power system. Electricity markets nowadays face the
challenge of evolving since new market products and services are emerging, such as flexibility services. However, in liberalized energy systems, changes in market dynamics
require thorough evaluation, especially if their objective is the achievement of a more sustainable power system.
This research aims to explore how smart grid technologies influence power system performance, thereby promoting sustainability of the electricity market through the
development of new market rules. To achieve this goal, this thesis employs a combination of methodologies to categorize different electricity market designs, identify gaps for new
market rules, and, through a systematic analysis of the literature, select relevant Key Performance Indicators (KPIs). These KPIs are used to assess intended sustainability goals considering the market characteristics of its original design. A bibliometric analysis
was implemented to develop a set of performance indicators for smart grid markets. These indicators are used to evaluate the economic, social, environmental, and policy
dimensions of sustainability in power systems. To develop this set of indicators and visualize their relationships among dimensions, tools such as science mapping and coword analysis are employed. These tools support the construction of relationships based on semantics analysis.
As a result, a first set of KPIs is proposed for the evaluation of sustainability aspects based on changes in electricity market designs and rules. A use case for evaluating the sustainability implications of different payment mechanisms for flexibility services in
distribution systems was considered. The evaluation of relationships between the KPIs supported the visualization of the dynamics of the aspects in power systems and the
implications of changes in the market payment scheme over different dimensions.
Finally, expert interviews are conducted to evaluate the process. The objective is to generate knowledge through an understanding of the market, its relationship withsustainability, and the assessment methods implemented across different regions. Content
analysis and data mining are employed to identify patterns within expert opinions, thereby supporting the connections between the market and evaluation methods. The
process enables the clustering and mapping of market-related KPIs. The relationship among market concepts clarifies how changes in the electricity market can promote a
more sustainable energy system. This approach offers a systematic and multidimensional analysis of electricity markets which allows to bridge the gap between the market design framework and its practical evaluation method. The thesis aims to provide a foundation for policymakers and industry stakeholders, assisting them in measuring progress towards sustainable goals in electricity markets
Axiomatic profit and loss decomposition of path-independent instruments in continuous time and numerical approximations
Full text linkIn the first section of this paper, we construct a class of time-continuous decompositions of path-independent financial instruments that takes into account the whole information of the paths and is consistent for different time grids. We show that there is a unique decomposition by demanding the three properties exactness, symmetry and normalization. We analyze suitable approximations, convergence types and conditions for efficient computation.
For the efficient pricing of financial instruments, we analyze the COS method in the second section. We introduce the damped COS method, prove its convergence and analyze its order of convergence. To apply the method, we derive formulas for the truncation range of the density and the number of terms for the approximation by a cosine series for a predefined error tolerance. In the last section, we analyze machine learning methods to quickly evaluate the formulas
Traumatisierte Kinder und Jugendliche im Drehtüreffekt zwischen den Systemen
Full text linkDie Dissertation untersucht das Phänomen des Drehtüreffekts bei sogenannten „Systemsprengern“ aus der subjektiven Perspektive betroffener Jugendlicher. In einer qualitativen Interviewstudie mit 21 Jugendlichen werden Muster von Abbrüchen, Gewalt, Beziehungslosigkeit und mangelnder Partizipation sichtbar. Die Analyse zeigt, dass unzureichende Kommunikation und fehlende Einbindung zentrale Faktoren für Eskalationen sind. Die Studie plädiert für mehr Beziehung, Menschlichkeit und Partizipation in der pädagogischen Arbeit, um systemisches Scheitern zu verhindern
Different therapeutic approaches to Zenker diverticulum: A retrospective comparative study between the flexible endoscopic method using needle knife and the rigid endoscopic method using laser in terms of effectiveness, complications and recurrence rates
Full text linkZenker’s diverticulum is an outpouching at the pharyngoesophageal junction causing dysphagia, regurgitation and aspiration. Myotomy may be performed by open, rigid or flexible endoscopy. This retrospective study compared flexible needle‑knife endoscopy (gastroenterology) and rigid laser myotomy (ENT). From 2009–2021, 136 patients were treated (88 flexible, 48 rigid). Flexible endoscopy showed shorter procedure time and hospitalization (p < 0.05). Complication and recurrence rates were similar, but subjective symptom improvement was higher (88.7% vs. 65.5%; p < 0.05). Flexible endoscopy may provide greater effectiveness with comparable safety
Lock-ins in Climate Change Adaptation: Comparative Evidence from German States and European Neighbors
Full text linkClimate change impacts are increasing globally and with them the need for climate adaptation. Dynamics of stability and change within established governance systems determine the extent to which societies adapt to growing risks. With the aim of exploring how patterns of action and inaction within German climate adaptation governance can be characterized and explained, this dissertation research adds to the greater understanding of how governance responses for adaptation are developed, maintained, or altered over time. The papers identify adaptation gaps or policies that are suboptimal for overcoming long-term risks; include the first nationwide analysis of state adaptation strategies and clusters three different policy approaches; and highlight specific problem domains: coastal risks, water scarcity, and mental health. The case studies reveal evidence of policy stability in adaptation governance that is, more or less, subject to lock-in dynamics inhibiting transformative adaptation