TY - CHAP A1 - Küchler, Andreas A1 - Hammer, F. A1 - Mäueler, G. T1 - Behaviour of Bushings with Silicone Rubber Sheds T2 - 6th ISH Int. Symp. on High Voltage Engineering Y1 - 1989 SP - 38 EP - 47 CY - New Orleans, LA, USA ER - TY - JOUR A1 - Holder, Marvin Alexander Samuel A1 - Eberspächer, Mark T1 - Systematic methods for the synthesis of equidistant MIMO arrays JF - Advances in Radio Science N2 - Finding a feasible antenna arrangement for multiple input multiple output (MIMO) arrays to serve a specific purpose is a first crucial step towards a successful MIMO radar system design. Design methods to synthesize uniformly weighted and equidistant MIMO arrays are proposed and investigated. The methods can be used to gain a design foundation for 1D or 2D arrays without software tools or programming effort. Since the presented approach does not consider electromagnetic fields, electromagnetic full-wave simulations might be required additionally. The method is based on sequentially copying and displacing antenna groups with the help of a number scheme. A nomenclature is proposed to classify the degrees of freedom in the design procedure. If the antennas are aligned to a uniform grid, a polynomial representation of the array can be chosen alternatively. This method is beneficial when redundancies of a produced array and where they appear must be analyzed. A new design problem arises when an array is to consist of only transceiving antennas, which can be analyzed with polynomial multiplication. One strategy to find a suitable MIMO array consisting of transceiver elements is given and evaluated. Y1 - 2023 UR - https://ars.copernicus.org/articles/21/15/2023/ U6 - https://doi.org/10.5194/ars-21-15-2023 VL - 21 SP - 15 EP - 23 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Stimpel, Bernhard A1 - Syben, Christopher A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Fully-automatic CT data preparation for interventional X-ray skin dose simulation JF - Bildverarbeitung für die Medizin 2020: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 15. bis 17. März 2020 in Berlin Y1 - 2020 U6 - https://doi.org/10.1007/978-3-658-29267-6_26 SP - 125 EP - 130 PB - Springer Fachmedien CY - Wiesbaden ER - TY - JOUR A1 - Busch, Erik A1 - Strobel, Norbert A1 - Nobach, Kai A1 - Bulitta, Clemens A1 - Hirshfeld, John W. A1 - Lin, Wu A1 - de Abreu, Marcel Gama T1 - Optimizing the innovation and development process of medical devices - a study based on angiographic equipment JF - Health and Technology Y1 - 2021 UR - https://link.springer.com/article/10.1007/s12553-021-00537-7 U6 - https://doi.org/doi.org/10.1007/s12553-021-00537-7 VL - 11 IS - 3 SP - 563 EP - 574 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Ochs, Philipp A1 - Stepina, Elizaveta A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - XDose: toward online cross-validation of experimental and computational X-ray dose estimation JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2020 U6 - https://doi.org/10.1007/s11548-020-02298-6 VL - 16 IS - 2 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Felsner, Lina A1 - Hoppe, Elisabeth A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - X-ray Scatter Estimation Using Deep Splines JF - IEEE Transactions on Medical Imaging Y1 - 2021 UR - https://arxiv.org/pdf/2101.09177.pdf VL - 40 IS - 9 SP - 2272 EP - 2283 ER - TY - JOUR A1 - Hariharan, Sai Gokul A1 - Strobel, Norbert A1 - Kaethner, Christian A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Data-driven estimation of noise variance stabilization parameters for low-dose x-ray images JF - Physics in Medicine and Biology Y1 - 2020 U6 - https://doi.org/10.1088/1361-6560/abbc82 VL - 65 IS - 22 ER - TY - JOUR A1 - Zhong, Xia A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - A machine learning pipeline for internal anatomical landmark embedding based on a patient surface model JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2019 U6 - https://doi.org/10.1007/s11548-018-1871-y VL - 14 IS - 1 SP - 53 EP - 61 ER - TY - JOUR A1 - Shetty, Karthik A1 - Birkhold, Annette A1 - Jaganathan, Srikrishna A1 - Strobel, Norbert A1 - Egger, Bernhard A1 - Kowarschik, Markus A1 - Maier, Andreas T1 - BOSS: Bones, organs and skin shape model JF - Computers in Biology and Medicine Y1 - 2023 UR - https://arxiv.org/pdf/2303.04923.pdf SN - 0010-4825 VL - 165 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part C: Grey Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 902 Y1 - 2023 SN - 978-2-8587-3607-2 SP - 1 EP - 102 ER - TY - JOUR A1 - Adamy, Jürgen A1 - Voutsas, Kyriakos A1 - Willert, Volker T1 - Ein binaurales Richtungshörsystem für mobile Roboter in echoarmer Umgebung JF - at - Automatisierungstechnik N2 - In diesem Beitrag wird ein binaurales Lokalisationsmodell für einen autonomen mobilen Roboter vorgestellt, das sich am menschlichen Hörsystem orientiert. Im Mittelpunkt steht die technische Umsetzung der neuronalen Verarbeitungsmechanismen der Olivenkerne des auditorischen Systems, die ein binaurales Richtungshören ermöglichen. Das System ist in der Lage, im Bereich des Sichtfeldes des Roboters eine Schallquelle in echoarmer, d.h. reflexionsarmer Umgebung anhand von Laufzeitunterschieden und Pegeldifferenzen zu lokalisieren. Die Möglichkeit des Richtungshörens verbessert die Wahrnehmung der unmittelbaren Umgebung des Roboters entscheidend und erlaubt z.B. die Ausrichtung des Roboterkopfes zur Schallquelle. Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-60022 SN - 2196-677X VL - 51 IS - 9 SP - 387 EP - 395 PB - Walter de Gruyter GmbH ER - TY - CHAP A1 - Holder, Marvin A1 - Eberspächer, Mark A1 - Waldschmidt, Christian T1 - Radar imaging device using prism shaped aperture T2 - 2024 Kleinheubach Conference Y1 - 2024 U6 - https://doi.org/10.23919/IEEECONF64570.2024.10738992 SP - 1 EP - 4 PB - IEEE ER - TY - THES A1 - Ziegler, Andreas ED - Montesinos-Miracle, Daniel ED - Ackva, Ansgar T1 - Possibilities and limitations of active battery management systems for lithium-ion batteries N2 - Lithium-Ion Batteries (LIBs) are being used in more and more areas of application. At the same time, their chemical composition and their designs are constantly evolving. Major developments are also taking place in the field of Battery Management Systems (BMSs), which are essential for the safe operation of LIBs. The focus is on intelligent charge redistribution between individual cells, called Active Balancing (AB). This thesis deals with the possibilities and limitations of AB. An empirical long-term experiment provides new insights into the ageing behaviour of batteries that are actively balanced during their entire service life. The main objective of this work is to to demonstrate influences on the ageing behaviour of batteries that are still unknown at present. A literature study shows that previous work in this area is often based on theoretical approaches and rarely has a functional proof through measurement results. Most significant statements from literature are examined. These include the increase in discharge capacity, energy efficiency and service life associated with AB, as well as lower parameter variation of the individual cells installed in the battery. Before starting the empirical experiment, the current state of the art is captured and a universal AB topology is selected from a large number of known systems. The operating behaviour as well as the balancing algorithms are explained in detail in order to be able to understand the influences occurring during the ageing of the batteries. The ageing experiment itself is a comparison test between commercial Passive Balancing (PB) and the novel AB. Two identical battery packs are aged under uniform conditions, but with the two different BMSs mentioned above. At the end of the ageing process, the battery packs are disassembled and the parameters of all individual cells are determined for further investigation. The main contribution of this work is the proof of effects through AB, especially with large battery loads. Both the increase in discharge capacity and the service life are demonstrated. The work shows how parameter variation of individual cells can be made visible during operation. It also presents diagnosis and calculation methods. The energetic efficiency of the batteries cannot be increased, since the self-consumption of the power electronics of the AB system is always higher than with PB. However, the overall efficiency of the battery increases due to an increase in capacity and an extension of the service life. The thesis also shows that with lower battery loads, the use of AB is not beneficial any more or may lead to negative effects. In such applications conventional PB is sufficient. The results obtained during pack ageing are additionally substantiated and extended by the measurement results of the individual cells. At the end of the thesis, all results and contributions are summarised. Suggestions for optimisation as well as further research ideas are presented as a possible starting point for further scientific studies. Y1 - 2023 UR - http://hdl.handle.net/10803/687388 ER - TY - JOUR A1 - Gensler, Marius A1 - Malkmus, Christoph A1 - Ockermann, Philipp A1 - Möllmann, Marc A1 - Hahn, Lukas A1 - Salehi, Sahar A1 - Luxenhofer, Robert A1 - Boccaccini, Aldo R. A1 - Hansmann, Jan T1 - Perfusable Tissue Bioprinted into a 3D-Printed Tailored Bioreactor System JF - Bioengineering N2 - Bioprinting provides a powerful tool for regenerative medicine, as it allows tissue construction with a patient’s specific geometry. However, tissue culture and maturation, commonly supported by dynamic bioreactors, are needed. We designed a workflow that creates an implant-specific bioreactor system, which is easily producible and customizable and supports cell cultivation and tissue maturation. First, a bioreactor was designed and different tissue geometries were simulated regarding shear stress and nutrient distribution to match cell culture requirements. These tissues were then directly bioprinted into the 3D-printed bioreactor. To prove the ability of cell maintenance, C2C12 cells in two bioinks were printed into the system and successfully cultured for two weeks. Next, human mesenchymal stem cells (hMSCs) were successfully differentiated toward an adipocyte lineage. As the last step of the presented strategy, we developed a prototype of an automated mobile docking station for the bioreactor. Overall, we present an open-source bioreactor system that is adaptable to a wound-specific geometry and allows cell culture and differentiation. This interdisciplinary roadmap is intended to close the gap between the lab and clinic and to integrate novel 3D-printing technologies for regenerative medicine. Y1 - 2024 U6 - https://doi.org/10.3390/bioengineering11010068 SN - 2306-5354 VL - 11 IS - 1 PB - MDPI ER - TY - JOUR A1 - Hein, Thiemo A1 - Oeser, David A1 - Ziegler, Andreas A1 - Montesinos-Miracle, Daniel A1 - Ackva, Ansgar T1 - Aging Determination of Series-Connected Lithium-Ion Cells Independent of Module Design JF - Batteries N2 - In this work, a battery consisting of eight commercial NMC/graphite cells connected in series was cycled to 60% of its initial capacity. During the test, special care was taken to ensure that the results were not influenced by either the module assembly or the module design. For this purpose, the cells were virtually connected in a laboratory environment with the help of the test device as if they were operated together in a battery. Extrinsic influences that affect cell aging were thus reduced to a minimum. Differential Voltage Analysis (DVA), Electrochemical Impedance Spectrum (EIS), and relaxation measurements were performed to analyze the aging behavior of each cell. The results show that despite a theoretically perfect module design, Cell-to-Cell Variations (CtCV) occurred during aging. The shifting Depth of Discharge (DoD) values among the cells further amplify CtCV. Lithium plating was also observed in the faster aging cells after cyclic aging, suggesting that this aging effect contributes significantly to the development of CtCV. After the aging test, the battery was equipped with an active balancing system that maximizes capacity utilization. More important, the balancing charges which are calculated iteratively within the used balancing algorithm show a strong correlation to the pure capacity losses and thus provide a new way to determine the capacity values of each cell individually without disassembling the battery. Y1 - 2023 U6 - https://doi.org/10.3390/batteries9030172 VL - 9 IS - 3 ER - TY - RPRT A1 - Ackva, Ansgar T1 - Hochdynamischer Umrichter in Hybridstruktur : Schlussbericht im Förderprogramm FHprofUnt : Laufzeit des Vorhabens: 01.10.2012 bis 30.09.3015 Y1 - 2016 U6 - https://doi.org/10.2314/gbv:876282885 PB - Hochschule für angewandte Wissenschaften Würzburg-Schweinfurt CY - Schweinfurt ER - TY - RPRT A1 - Ackva, Ansgar A1 - Küchler, Andreas T1 - Konvergenz elektrischer Energietechnologien : Akronym: KEE-TECH : Schlussbericht zur Erstellung des Strategiekonzepts Y1 - 2016 U6 - https://doi.org/10.2314/GBV:883086484 PB - Hochschule für angewandte Wissenschaften Würzburg-Schweinfurt CY - Würzburg ER - TY - RPRT A1 - Ackva, Ansgar T1 - Vorhabenbezeichnung: Bat-PA-40 : Schlussbericht : Berichtszeitraum: 01.02.2018 bis 31.01.2019 Y1 - 2019 U6 - https://doi.org/10.2314/kxp:1681868938 PB - Hochschule für Angewandte Wissenschaften Würzburg-Schweinfurt ER - TY - RPRT A1 - Ackva, Ansgar T1 - Multilevel-Umrichter Prüfsystem : Schlussbericht : Berichtszeitraum: 01.09.2014-31.08.2015 Y1 - 2016 U6 - https://doi.org/10.2314/gbv:872408639 PB - Hochschule für angewandte Wissenschaften Würzburg-Schweinfurt CY - Schweinfurt ER - TY - JOUR A1 - Holder, Marvin A1 - Eberspächer, Mark A1 - Waldschmidt, Christian T1 - A hybrid algorithm to process millimeter wave images with prism-shaped aperture JF - Advances in Radio Science N2 - To process images of a prism-shaped aperture in a radar imaging context, a hybrid algorithm is derived. This hybrid algorithm combines the benefits of backprojection and the Omega-K algorithm in terms of computational performance and flexibility. As a demonstration for an application of this algorithm, a 3D inspection system based on millimeter wave imaging is introduced. The system scans through the object, while it is passing on a conveyor belt. It comprises a curved antenna layout, which is able to synthesize the prism-shaped aperture. This aperture is shown to have superior resolution capabilities compared to a planar aperture. Some potential pitfalls when implementing the hybrid algorithm are assessed. Approximation formulae to estimate the achievable resolution are derived. The introduced algorithm is analyzed regarding its point spread function and compared to backprojection with the help of numerical simulations to demonstrate its potential. Y1 - 2025 U6 - https://doi.org/10.5194/ars-23-101-2025 SN - 1684-9973 VL - 25 IS - 23 SP - 101 EP - 111 PB - Copernicus GmbH ER - TY - JOUR A1 - Yükselen, Emir A1 - Rahimpour, Ebrahim T1 - An improvement in the design process of sustainable peak power rating transformer for solar utility JF - International Journal of Electrical Power & Energy Systems N2 - The transformer industry faces critical challenges, such as maintaining reliable production while meeting rising sustainability requirements. This paper introduces a significant advancement in the design and optimization of a transformer dedicated to a photovoltaic power plant, which exhibits a unique loading cycle distinct from standard power and distribution transformers. The main aim is to minimize the carbon footprint by enhancing the design process to improve operational performance, efficiency, and functional reliability. Such upgrades are essential for transitioning to a zero-emission electricity system and developing green energy projects. In this paper, a transformer has been studied using a combination of electrical design and 3D finite element method simulation to evaluate various design parameters. An optimization study has been conducted using an innovative multi-objective genetic algorithm utilizing a cost function that factors in size and material costs to identify the most efficient and cost-effective design solutions. The proposed design method was then validated through thermal model simulations and experimental tests based on the photovoltaic load cycle. A comparison of critical thermal parameters directly affecting the transformer’s lifetime and reliability was also drawn. The results were consistent with the expected outcomes, confirming the effectiveness and reliability of the proposed design methodology. KW - Transformer KW - Photovoltaic KW - Finite element method KW - Optimization KW - Genetic algorithm Y1 - 2025 U6 - https://doi.org/https://doi.org/10.1016/j.ijepes.2025.110928 SN - 0142-0615 VL - 170 SP - 1 EP - 13 PB - Elsevier BV ER - TY - CHAP A1 - Yükselen, Emir A1 - Rahimpour, Ebrahim T1 - An Optimization Approach for Sustainable Transformer Design in Photovoltaic Power Plants”, 4th IEEE International Conference on Power Electronics Smart Grid and Renewable Energy T2 - 4th IEEE International Conference on Power Electronics Smart Grid and Renewable Energy Y1 - 2025 ER -