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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Publication Open Access Abschlussbericht des DFG-Projekts "Landesgeschichte im Radio. Der Herstellungsprozess und der intermediale Transfer von landesgeschichtlichen Narrativen der WDR-Landesredaktion um Walter Först (1960 – Anfang der 1990er Jahre)"(2026-02-17)The final report of the DFG-funded project ‘State History on the Radio: The Production Process and the intermedial Transfer of Regional Historical Narratives by the WDR Regional Editorial Office under Walter Först (1960–early 1990s)’ briefly summarises the results of the historical research. Using North Rhine-Westphalia as an example, the project analyses narratives of state history distributed by mass media between 1960 and the early 1990s and traces practices of "doing history". In a symbiosis of public history and media and state historical perspective, the intermedial transfer of historical contributions as building modules of historical culture will be examined exemplarily on the basis of the WDR-Hörfunk-Landesredaktion (WDR radio editorial office dealing with state affairs) around the journalistic NRW history expert Walter Först (1920-1993). The editorial team has actively produced and anchored formative historical images for North Rhine-Westphalia. On the basis of intensive archival research, it analyses how the journalistic actors located the state in the field of tension of a diverse region, the Federal Republic of Germany and its European neighbours and how they promoted historical processes of meaning and identity formation. It is examined how the editor-in-chief established a network with other institutions and persons working in the fields of politics, culture and history, transferred this into institutional forms beyond broadcasting and thus created an additional communication basis for negotiated narratives.Source Type:2 1 - Some of the metrics are blocked by yourconsent settings
Publication Open Access „The Amazon for Drone Warfare“: Zur Plattformisierung der Drohnenkriegsführung im Russisch-Ukrainischen Krieg(2026); Russia’s war in Ukraine has been marked by both parties’ extensive use of drones. While the early phases of the war saw the development of what we have called Consumer Drone Warfare, that is, the use of off-the-shelf or ready-to-fly drones provided by large manufacturers like DJI or Autel, there has been a notable shift towards locally assembled First-Person-View or FPV Drones in recent times. We argue that this development is made possible by – and in turn fuels – the platformization of warfare by the Ukrainian military. In this article, we trace three distinct but interwoven sites of platformization: 1) the modular FPV drone itself, understood as a military platform for sensor and weapon systems; 2) the Delta System, an ecosystem of applications for planning and cooperatively executing drone strikes; 3) and the Brave1 Market, a logistics platform connecting military units to equipment and weapon manufacturers which has been dubbed “the Amazon for Drone Warfare.” In doing so, we will show that platformized drone warfare reshapes and economizes processes of military organization and procurement according to the logics of markets and gamification. As they render the chain of operations from drone development to battlefield deployment (ac)countable, Delta and Brave1 are designed to facilitate quality control and self-organization vis-a-vis an increasing number of military tech start-ups and heterogenous hardware parts. We posit that the infrastructures for drone development and data collection established by platformized FPV drone warfare act as stepping stones towards (semi-)autonomous forms of drone warfare powered by machine learning and AI systems.9 5 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Essays on Inequality, Digitalization, and the Environment(2025)This thesis consists of five thematically related chapters on inequality, digitalization, and the environment. Two recurring themes are (i) who captures rents under shocks and how institutions shape income distribution, and (ii) how inequality and digital technologies alter emissions with policy-relevant trade-offs. The first chapter decomposes Germany’s 2021-2023 inflation across 11 sectors using Gross Value Added deflators, showing that profits - not wages - captured 57.6% of price growth in high-inflation sectors, with implications for competition and fiscal policy to countermeasure inflation and distributional impacts. Chapter 2 constructs Ecuador’s first Distributional National Accounts (1990-2022) from survey-tax microdata, finding persistent top-end concentration (top one percent: 25% of pretax income) and a fragile move from extractive to weakly inclusive institutions during the commodity boom that eroded post-COVID. Chapter 3 integrates tax registers and machine learning-based consumption to account for the carbon emissions of the "missing rich": the top ten percent share of disposable income rises from 30% (survey) to 46% (integrated) and their emissions share from 26% to 31%. However, full redistribution would raise emissions by 26% versus 6% in survey-only estimates - highlighting needs for the design of emission-mitigating in combination with income redistributional policies. Chapter 4 estimates the net climate effect of digitalization across industrialized countries: digitalization in firms and households generally lowers carbon dioxide emissions, but the optimum differs - lower-income industrialized countries lie above its potential emission-reducing level of digitalization while higher-income ones remain below efficiency-enhancing levels. Chapter 5 investigates digitalization in the agricultural sector: adopting digital yield monitoring in 28 states in the United States (1996-2010) reduces nitrous oxide per unit of output and per hectare; production expands, yet efficiency gains dominate, delivering net emission cuts and provide evidence for climate-smart agriculture.Source Type:15 5 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Variational L0 Regularization for Enhanced Depth Image Analysis(2025)Mathematical optimization is fundamental in computational imaging, where problems often center on minimizing an objective function under various constraints. An important class of optimization problems involves minimal partitioning, which aims to segment data into partitions which meet certain criteria, such as photometric or geometric similarity. This class of problems is computationally demanding as it is has a NP-Hard complexity, which means that the computational effort required to estimate a solution increases exponentially with the size of the data. Consequently, finding (nearly) optimal solutions within a reasonable amount of time is often infeasible. This dissertation presents an analysis of the efficient and effective utilization of minimal partitioning techniques in RGB-D image processing. This is achieved by constraining the underlying optimization problems with the L0 “norm”, which enforces piecewise constant solutions. The first case study analyses the utilization of the L0 “norm” for scene flow estimation, where 3D motions are modeled as rigid transformations and constrained to be piece-wise constant. By substituting the L0 “norm” with the truncated quadratic “norm”, this approach achieves both high accuracy as well as real-time performance. The next focus is on the estimation of geometric models on RGB-D images, specifically to obtain denoised depth and normal values. The novel geometric model definition along with the Cut Pursuit optimization leads to a higher accuracy compared to other model based methods. The third and final enhancement addresses the high computational demands of the preceding Cut Pursuit based method by introducing a stochastic optimization technique. It improves the convergence rate and also the overall runtime efficiency.Source Type:11 9 - Some of the metrics are blocked by yourconsent settings
Publication Open Access On p-adic regulators of number fields(2026)In this thesis, we study the p-adic regulator of number fields, which is an arithmetic invariant introduced by Leopoldt. We aim to derive conjectural results regarding the distribution of p-adic regulators for families of number fields, which until now has been exclusively done for number fields of odd prime degree. Furthermore, we investigate the existence of formulas for p-adic regulators of number fields in terms of subfields, which supplements previous research for other arithmetic invariants. We obtain conjectures for families of quadratic number fields by computing images of logarithm maps. More generally, for a family of number fields, we establish a principle that states that the distribution of the valuations of p-adic regulators equals the distribution of specific random modules. We provide principles for normal (extensions of) number fields and non-normal number fields. One of the main results, and foundation for the principles, grants for every prime number p and for every number field the existence of a finite module that has an order linked to the p-adic regulator. Additionally, we prove formulas for expected distributions of p-adic regulators for a range of normal number fields, e.g., with cyclic Galois group. The formulas are derived by utilizing an approach that involves random matrices and group determinants. Moreover, we obtain formulas for the valuation of the p-adic regulator for normal number fields in terms of subfields and a generalization for normal extensions of number fields. To show these formulas, we use the concepts of scalar norm relations, or rather Brauer relations, and cohomological Mackey functors. Additionally, we derive a formula for p-adic L-functions of a number field and its subfields. Lastly, we discuss open questions concerning distributions of p-adic regulators and provide computational data that supports the formulated principles for a range of examples. In conclusion, the principles extend previous conjectures on distributions of p-adic regulators, and the proven formulas for the valuation of the p-adic regulator for normal number fields allow more efficient computations by exploiting subfields.Source Type:5 5
