TY - JOUR A1 - Ziegler, Günter M. A1 - Hege, Hans-Christian A1 - Duda, Georg T1 - Neue Bilder für die Medizin? JF - DFN-Mitteilungen Y1 - 2005 VL - 13(3) SP - 163 EP - 167 ER - TY - GEN A1 - Ziegler, Günter M. A1 - Zivaljevic, R. T. T1 - Homotopy Types of Subspace Arrangements via Diagrams of Spaces. N2 - We prove combinatorial formulas for the homotopy type of the union of the subspaces in an (affine, compactified affine, spherical or projective) subspace arrangement. From these formulas we derive results of Goresky & MacPherson on the homology of the arrangement and the cohomology of its complement. The union of an arrangement can be interpreted as the direct limit of a diagram of spaces over the intersection poset. A closely related space is obtained by taking the homotopy direct limit of this diagram. Our method consists in constructing a combinatorial model diagram over the same poset, whose homotopy limit can be compared to the original one by usual homotopy comparison results for diagrams of spaces. T3 - ZIB-Report - SC-91-15 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-658 ER - TY - JOUR A1 - Ziesche, Ralf F. A1 - Arlt, Tobias A1 - Finegan, Donal P. A1 - Heenan, Thomas M.M. A1 - Tengattini, Alessandro A1 - Baum, Daniel A1 - Kardjilov, Nikolay A1 - Markötter, Henning A1 - Manke, Ingo A1 - Kockelmann, Winfried A1 - Brett, Dan J.L. A1 - Shearing, Paul R. T1 - 4D imaging of lithium-batteries using correlative neutron and X-ray tomography with a virtual unrolling technique JF - Nature Communications N2 - The temporally and spatially resolved tracking of lithium intercalation and electrode degradation processes are crucial for detecting and understanding performance losses during the operation of lithium-batteries. Here, high-throughput X-ray computed tomography has enabled the identification of mechanical degradation processes in a commercial Li/MnO2 primary battery and the indirect tracking of lithium diffusion; furthermore, complementary neutron computed tomography has identified the direct lithium diffusion process and the electrode wetting by the electrolyte. Virtual electrode unrolling techniques provide a deeper view inside the electrode layers and are used to detect minor fluctuations which are difficult to observe using conventional three dimensional rendering tools. Moreover, the ‘unrolling’ provides a platform for correlating multi-modal image data which is expected to find wider application in battery science and engineering to study diverse effects e.g. electrode degradation or lithium diffusion blocking during battery cycling. Y1 - 2020 U6 - https://doi.org/10.1038/s41467-019-13943-3 VL - 11 SP - 777 ER - TY - THES A1 - Zilske, Michael T1 - Adaptives Remeshing von nicht-mannigfaltigen Dreiecksnetzen T1 - Adaptive remeshing of non-manifold triangle meshes N2 - In dieser Arbeit wird eine Serie von Remeshing-Verfahren um die Berücksichtigung von nicht-mannigfaltigen Dreiecksvernetzungen und Merkmalskantenzügen erweitert. Die betrachteten Verfahren arbeiten im Wesentlichen lokal. Daher können die im Rahmen dieser Arbeit entwickelten Erweiterungen, die nicht-mannigfaltige Kantenzüge und Merkmalskantenzüge betreffen, separat beschrieben werden. Dabei wird ein Ansatz verfolgt, beide Arten von besonderen Kantenzügen aufgrund ihrer Gemeinsamkeiten einheitlich zu behandeln. Dieser besteht zum einen darin, eine Korrespondenz zwischen Kantenzügen auf der Eingabe- und der Ausgabefläche zu erhalten, indem die Remeshing-Operationen auf den Kantenzügen in entsprechend eingeschränkter Weise verwendet werden. Zum anderen wird beschrieben, wie die Abtastdichte der Kantenzüge dynamisch an die Abtastdichte der Umgebung angepasst werden kann, um für weitgehende Isotropie in der Nähe von Merkmalskantenzügen zu sorgen. N2 - A unified approach for consistent remeshing of arbitrary non-manifold triangle meshes with additional user-defined feature lines is presented. The method is based on local operations only and produces meshes of high regularity and triangle quality while preserving the geometry as well as topology of the feature lines as well as the input mesh. KW - Vernetzung KW - Merkmalslinien KW - Knotendichte KW - Topologie KW - Dreiecksqualität KW - meshing KW - feature lines KW - node density KW - topology KW - triangle quality Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-474 ER - TY - THES A1 - Zilske, Michael T1 - Adaptive remeshing of non-manifold triangulations T2 - Adaptives Remeshing von nicht-mannigfaltigen Dreicksnetzen Y1 - 2007 ER - TY - CHAP A1 - Zilske, Michael A1 - Lamecker, Hans A1 - Zachow, Stefan T1 - Adaptive Remeshing of Non-Manifold Surfaces T2 - Eurographics 2008 Annex to the Conf. Proc. Y1 - 2008 SP - 207 EP - 211 ER - TY - GEN A1 - Zilske, Michael A1 - Lamecker, Hans A1 - Zachow, Stefan T1 - Adaptive Remeshing of Non-Manifold Surfaces N2 - We present a unified approach for consistent remeshing of arbitrary non-manifold triangle meshes with additional user-defined feature lines, which together form a feature skeleton. Our method is based on local operations only and produces meshes of high regularity and triangle quality while preserving the geometry as well as topology of the feature skeleton and the input mesh. T3 - ZIB-Report - 07-01 KW - remeshing KW - non-manifold KW - mesh quality optimization Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9445 ER - TY - CHAP A1 - Zimmer, Max A1 - Spiegel, Christoph A1 - Pokutta, Sebastian T1 - How I Learned to Stop Worrying and Love Retraining T2 - Proceedings of International Conference on Learning Representations Y1 - 2023 ER - TY - CHAP A1 - Zimmer, Max A1 - Spiegel, Christoph A1 - Pokutta, Sebastian T1 - Sparse Model Soups T2 - Proceedings of International Conference on Learning Representations Y1 - 2024 ER - TY - CHAP A1 - Zink, Christof A1 - Ekterai, Michael A1 - Martin, Dominik A1 - Clemens, William A1 - Maennel, Angela A1 - Mundinger, Konrad A1 - Richter, Lorenz A1 - Crump, Paul A1 - Knigge, Andrea T1 - Deep-learning-based visual inspection of facets and p-sides for efficient quality control of diode lasers T2 - High-Power Diode Laser Technology XXI N2 - The optical inspection of the surfaces of diode lasers, especially the p-sides and facets, is an essential part of the quality control in the laser fabrication procedure. With reliable, fast, and flexible optical inspection processes, it is possible to identify and eliminate defects, accelerate device selection, reduce production costs, and shorten the cycle time for product development. Due to a vast range of rapidly changing designs, structures, and coatings, however, it is impossible to realize a practical inspection with conventional software. In this work, we therefore suggest a deep learning based defect detection algorithm that builds on a Faster Regional Convolutional Neural Network (Faster R-CNN) as a core component. While for related, more general object detection problems, the application of such models is straightforward, it turns out that our task exhibits some additional challenges. On the one hand, a sophisticated pre- and postprocessing of the data has to be deployed to make the application of the deep learning model feasible. On the other hand, we find that creating labeled training data is not a trivial task in our scenario, and one has to be extra careful with model evaluation. We can demonstrate in multiple empirical assessments that our algorithm can detect defects in diode lasers accurately and reliably in most cases. We analyze the results of our production-ready pipeline in detail, discuss its limitations and provide some proposals for further improvements. Y1 - 2023 U6 - https://doi.org/10.1117/12.2648691 VL - 12403 SP - 94 EP - 112 PB - SPIE ER - TY - JOUR A1 - Zinser, Max A1 - Zachow, Stefan A1 - Sailer, Hermann T1 - Bimaxillary "rotation advancement" procedures in patients with obstructive sleep apnea: A 3-dimensional airway analysis of morphological changes JF - International Journal of Oral & Maxillofacial Surgery Y1 - 2013 U6 - https://doi.org/10.1016/j.ijom.2012.08.002 VL - 42 IS - 5 SP - 569 EP - 578 ER - TY - CHAP A1 - Zittel, Janina A1 - Clarner, Jan-Patrick A1 - Tawfik, Christine A1 - Dykes, Maxwell A1 - Rivetta, Fabian A1 - Riedmüller, Stephanie T1 - A multi-objective optimization strategy for district heating production portfolio planning. T2 - Proceedings of the 37th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems – ECOS 2024 N2 - The imperative to decarbonize energy systems has intensified the need for efficient transformations within the heating sector, with a particular focus on district heating networks. This study addresses this challenge by proposing a comprehensive optimization approach evaluated on the district heating network of the Märkisches Viertel of Berlin. Our objective is to simultaneously optimize heat production with three targets: minimizing costs, minimizing CO2-emissions, and maximizing heat generation from Combined Heat and Power (CHP) plants for enhanced efficiency. To tackle this optimization problem, we employed a Mixed-Integer Linear Program (MILP) that encompasses the conversion of various fuels into heat and power, integration with relevant markets, and considerations for technical constraints on power plant operation. These constraints include startup and minimum downtime, activation costs, and storage limits. The ultimate goal is to delineate the Pareto front, representing the optimal trade-offs between the three targets. We evaluate variants of the 𝜖-constraint algorithm for their effectiveness in coordinating these objectives, with a simultaneous focus on the quality of the estimated Pareto front and computational efficiency. One algorithm explores solutions on an evenly spaced grid in the objective space, while another dynamically adjusts the grid based on identified solutions. Initial findings highlight the strengths and limitations of each algorithm, providing guidance on algorithm selection depending on desired outcomes and computational constraints. Our study emphasizes that the optimal choice of algorithm hinges on the density and distribution of solutions in the feasible space. Whether solutions are clustered or evenly distributed significantly influences algorithm performance. These insights contribute to a nuanced understanding of algorithm selection for multi-objective multi-energy system optimization, offering valuable guidance for future research and practical applications for planning sustainable district heating networks. Y1 - 2024 ER - TY - THES A1 - Zobel, Valentin T1 - Spectral Analysis of the Hodge Laplacian on Discrete Manifolds Y1 - 2010 ER - TY - GEN A1 - Zobel, Valentin A1 - Reininghaus, Jan A1 - Hotz, Ingrid T1 - Visualization of Two-Dimensional Symmetric Tensor Fields Using the Heat Kernel Signature T2 - Topological Methods in Data Analysis and Visualization III Y1 - 2013 SP - 249 EP - 262 CY - Davis, CA, USA ER - TY - JOUR A1 - Zobel, Valentin A1 - Reininghaus, Jan A1 - Hotz, Ingrid T1 - Generalized Heat Kernel Signature JF - Journal of WSCG, International Conference on Computer Graphics, Visualization and Computer Vision Y1 - 2011 SP - 93 EP - 100target ER - TY - THES A1 - Zonker, Johannes T1 - Coarse Graining of Agent-Based Models and Spatio-Temporal Modeling of Spreading Processes Y1 - 2023 UR - http://dx.doi.org/10.17169/refubium-41220 ER - TY - JOUR A1 - Zonker, Johannes A1 - Padilla-Iglesias, Cecilia A1 - Djurdjevac Conrad, Natasa T1 - Insights into drivers of mobility and cultural dynamics of African hunter-gatherers over the past 120 000 years JF - Royal Society Open Science N2 - Humans have a unique capacity to innovate, transmit and rely on complex, cumulative culture for survival. While an important body of work has attempted to explore the role of changes in the size and interconnectedness of populations in determining the persistence, diversity and complexity of material culture, results have achieved limited success in explaining the emergence and spatial distribution of cumulative culture over our evolutionary trajectory. Here, we develop a spatio-temporally explicit agent-based model to explore the role of environmentally driven changes in the population dynamics of hunter–gatherer communities in allowing the development, transmission and accumulation of complex culture. By modelling separately demography- and mobility-driven changes in interaction networks, we can assess the extent to which cultural change is driven by different types of population dynamics. We create and validate our model using empirical data from Central Africa spanning 120 000 years. We find that populations would have been able to maintain diverse and elaborate cultural repertoires despite abrupt environmental changes and demographic collapses by preventing isolation through mobility. However, we also reveal that the function of cultural features was also an essential determinant of the effects of environmental or demographic changes on their dynamics. Our work can therefore offer important insights into the role of a foraging lifestyle on the evolution of cumulative culture. Y1 - 2023 U6 - https://doi.org/10.1098/rsos.230495 VL - 10 IS - 11 ER - TY - GEN A1 - Zonker, Johannes A1 - Padilla-Iglesias, Cecilia A1 - Djurdjevac Conrad, Natasa T1 - Supplementary code and data for Royal Society Open Science Manuscript rsos.230495 N2 - In this repository are all files necessary to run the agent-based model of the paper "Insights into drivers of mobility and cultural dynamics of African hunter–gatherers over the past 120 000 years", Royal Society Open Science, 10(11), 2023. Y1 - 2023 U6 - https://doi.org/10.12752/9254 ER - TY - THES A1 - Zoufahl, Andre T1 - Explorative Analysis of Vortex Structures in 2D Flows KW - Flow Visualization Y1 - 2012 ER - TY - THES A1 - Zschiedrich, Lin T1 - Transparent boundary conditions for Maxwell's equations: Numerical concepts beyond the PML method N2 - Optical technologies are ubiquitously used in hi-tech devices. As a common feature of such devices one finds structures with dimensions in the order of the wavelength of the used light. To design and produce such devices, the wave nature of light must be taken into account. Accordingly, robust simulation tools are required which are based on rigorously solving Maxwell's equations, the governing equations of light propagation within macroscopic media. This thesis contributes to the modeling and the numerical computation of light scattering problems: Light scattering problems are typically posed on the entire space. The Perfectly-Matched -Layer method (PML) is widely used to restrict the simulation problem onto a bounded computational domain. We propose an adaptive PML method which exhibits a good convergence even for critical problems where standard PML implementations fail. Besides the computation of the near field, that is the electromagnetic field within the computational domain, it is of major interest to evaluate the electromagnetic field in the exterior domain and to compute the far field. So far, this was numerically only possible for simple geometries such as homogeneous exterior domains or layered media. To deal with more complicated devices, for example with waveguide inhomogeneities, we develop an evaluation formula based on the PML solution which allows for an exterior domain field evaluation in a half space above the device. Finally, we generalize the PML method to problems with multiply structured exterior domains. The term “multiply structured exterior domain” is defined in this thesis and means that the exterior domain exhibits several half-infinite structures. Mathematically, this gives rise to various complications. For example, no analytical solutions to Maxwell's equations for standard light sources are available in the exterior domain, which are needed to describe the incoming field in a light scattering problem. To tackle this we propose a new light scattering problem formulation which fits well into the PML method framework and which may be regarded as an extension of classical contributions by Sommerfeld, Wiener and Hopf. An exterior domain evaluation formula for multiply structured exterior domains with an extended illumination is derived as well. KW - transparent boundary conditions KW - electromagnetic scattering KW - Maxwell's equations KW - perfectly matched layers KW - PML KW - Wiener-Hopf techniques Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:188-fudissthesis000000013994-8 ER -