@incollection{ButenwegThierauf1999, author = {Butenweg, Christoph and Thierauf, G.}, title = {Automatic design of reinforced concrete structures with parallel computing}, series = {Innovative computational methods for structural mechanics}, booktitle = {Innovative computational methods for structural mechanics}, editor = {Papadrakakis, M. and Topping, B.H.V.}, publisher = {Saxe-Coburg Publication}, address = {Edinburgh}, isbn = {1-874672-05-9}, doi = {10.4203/csets.1.14}, pages = {305 -- 318}, year = {1999}, abstract = {A concept for the analysis and optimal design of reinforced concrete structures is described. It is based on a nonlinear optimization algorithm and a finite element program for linear and nonlinear analysis of structures. With the aim of minimal cost design a two stage optimization using efficient gradient algorithm is developed. The optimization problems on global (structural) and local (crosssectional) level are formulated. A parallelization concept for solving the two stage optimization problem in minimal time is presented. Examples are included to illustrate the practical use and the effectively of the parallelization in the area of engineering design.}, language = {en} } @inproceedings{SildatkeKarwanniKraftetal.2020, author = {Sildatke, Michael and Karwanni, Hendrik and Kraft, Bodo and Schmidts, Oliver and Z{\"u}ndorf, Albert}, title = {Automated Software Quality Monitoring in Research Collaboration Projects}, series = {ICSEW'20: Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops}, booktitle = {ICSEW'20: Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops}, publisher = {IEEE}, address = {New York, NY}, doi = {10.1145/3387940.3391478}, pages = {603 -- 610}, year = {2020}, abstract = {In collaborative research projects, both researchers and practitioners work together solving business-critical challenges. These projects often deal with ETL processes, in which humans extract information from non-machine-readable documents by hand. AI-based machine learning models can help to solve this problem. Since machine learning approaches are not deterministic, their quality of output may decrease over time. This fact leads to an overall quality loss of the application which embeds machine learning models. Hence, the software qualities in development and production may differ. Machine learning models are black boxes. That makes practitioners skeptical and increases the inhibition threshold for early productive use of research prototypes. Continuous monitoring of software quality in production offers an early response capability on quality loss and encourages the use of machine learning approaches. Furthermore, experts have to ensure that they integrate possible new inputs into the model training as quickly as possible. In this paper, we introduce an architecture pattern with a reference implementation that extends the concept of Metrics Driven Research Collaboration with an automated software quality monitoring in productive use and a possibility to auto-generate new test data coming from processed documents in production. Through automated monitoring of the software quality and auto-generated test data, this approach ensures that the software quality meets and keeps requested thresholds in productive use, even during further continuous deployment and changing input data.}, language = {en} } @article{FoersterRosenauerRemmele1997, author = {F{\"o}rster, Arnold and Rosenauer, A. and Remmele, T.}, title = {Atomic scale strain measurements by the digital analysis of transmission electron microscopic lattice images / A. Rosenauer ; T. Remmele ; D. Gerthsen ... A. F{\"o}rster}, series = {Optik : international journal for light and electron optics. 105 (1997), H. 3}, journal = {Optik : international journal for light and electron optics. 105 (1997), H. 3}, isbn = {0030-4026}, pages = {99 -- 107}, year = {1997}, language = {en} } @article{FoersterRosenauerOberstetal.1999, author = {F{\"o}rster, Arnold and Rosenauer, A. and Oberst, W. and Gerthsen, D.}, title = {Atomic scale analysis of the indium distribution in InGaAs/GaAs (001) heterostructures: segregation, lateral indium redistribution and the effect of growth interruptions. Rosenauer, A. ; Oberst, W. ; Gerthsen, D. ; F{\"o}rster, A.}, series = {Thin Solid Films. 357 (1999)}, journal = {Thin Solid Films. 357 (1999)}, isbn = {0040-6090}, pages = {18 -- 21}, year = {1999}, language = {en} } @misc{FrauenrathdeGeyerd'OrthNiendorf2011, author = {Frauenrath, Tobias and de Geyer d'Orth, Thibaut and Niendorf, Thoralf}, title = {Assessment of Accuracy \& Reproducibility of ECG, Pulse Oximetry \& Phonocardiogram Gating of Cardiac MRI at 7T}, series = {2011 ISMRM Annual Meeting Proceedings}, journal = {2011 ISMRM Annual Meeting Proceedings}, issn = {1545-4428}, year = {2011}, abstract = {At (ultra)high magnetic fields the artifact sensitivity of ECG recordings increases. This bears the risk of R-wave mis-registration which has been consistently reported for ECG triggered CMR at 7.0T. Realizing the constraints of conventional ECG, acoustic cardiac triggering (ACT) has been proposed. The clinical ACT has not been carefully examined yet. For this reason, this work scrutinizes the suitability, accuracy and reproducibility of ACT for CMR at 7.0T. For this purpose, the trigger reliability and trigger detection variance are examined together with an qualitative and quantitative assessment of image quality of the heart at 7.0T.}, language = {en} } @article{FoersterSchaeferLondschien1988, author = {F{\"o}rster, Arnold and Sch{\"a}fer, B.-J. and Londschien, M.}, title = {Arsenic passivation of MOMBE grown GaAs surfaces / B. -J. Sch{\"a}fer ; A. F{\"o}rster ; M. Londschien ...}, series = {Surface Science. 204 (1988), H. 3}, journal = {Surface Science. 204 (1988), H. 3}, isbn = {0039-6028}, pages = {485 -- 490}, year = {1988}, language = {en} } @article{FoersterReschEsseraetal.1992, author = {F{\"o}rster, Arnold and Resch, U. and Essera, N. and Raptis, Y. S.}, title = {Arsenic passivation of MBE grown GaAs(100): structural and electronic properties of the decapped surfaces / U. Resch ; N. Essera ; Y. S. Raptis ... A. F{\"o}rster ...}, series = {Surface Science. 269-270 (1992)}, journal = {Surface Science. 269-270 (1992)}, isbn = {0039-6028}, pages = {797 -- 803}, year = {1992}, language = {en} } @article{PieperKlein2012, author = {Pieper, Martin and Klein, Peter}, title = {Application of simple, periodic homogenization techniques to non-linear heat conduction problems in non-periodic, porous media}, series = {Heat mass transfer}, volume = {48}, journal = {Heat mass transfer}, number = {2}, publisher = {Springer}, address = {Berlin}, issn = {0947-7411}, doi = {10.1007/s00231-011-0879-4}, pages = {291 -- 300}, year = {2012}, abstract = {Often, detailed simulations of heat conduction in complicated, porous media have large runtimes. Then homogenization is a powerful tool to speed up the calculations by preserving accurate solutions at the same time. Unfortunately real structures are generally non-periodic, which requires unpractical, complicated homogenization techniques. We demonstrate in this paper, that the application of simple, periodic techniques to realistic media, that are just close to periodic, gives accurate, approximative solutions. In order to obtain effective parameters for the homogenized heat equation, we have to solve a so called "cell problem". In contrast to periodic structures it is not trivial to determine a suitable unit cell, which represents a non-periodic media. To overcome this problem, we give a rule of thumb on how to choose a good cell. Finally we demonstrate the efficiency of our method for virtually generated foams as well as real foams and compare these results to periodic structures.}, language = {en} } @article{HelsperNiessnerRoenicke1984, author = {Helsper, Christoph and Nießner, R. and R{\"o}nicke, G.}, title = {Application of a Multistep Condensation Nuclei Counter as a Detector for Particle Surface Composition / Nießner, R.; Helsper, C.; R{\"o}nicke, G.}, series = {Aerosols : science, technology, and industr. applications of airborne particles ; proceedings of the 1. Internat. Aerosol Conference held Sept. 17-21, 1984, Minneapolis, Minn., U.S.A / ed.: Benjamin Y. H. Liu}, journal = {Aerosols : science, technology, and industr. applications of airborne particles ; proceedings of the 1. Internat. Aerosol Conference held Sept. 17-21, 1984, Minneapolis, Minn., U.S.A / ed.: Benjamin Y. H. Liu}, publisher = {Elsevier}, address = {New York [u.a.]}, isbn = {0444009477}, pages = {63 -- 66}, year = {1984}, language = {en} } @article{HelsperNiessner1985, author = {Helsper, Christoph and Nießner, R.}, title = {Application of a Multistep Condensation Nuclei Counter as a Detector for Particle Surface Composition / Nießner, R. ; Helsper, C.}, series = {Journal of Aerosol Science. 16 (1985), H. 3}, journal = {Journal of Aerosol Science. 16 (1985), H. 3}, isbn = {0021-8502}, pages = {201 -- 209}, year = {1985}, language = {en} } @article{FoersterDarmoDubeckyetal.1998, author = {F{\"o}rster, Arnold and Darmo, J. and Dubecky, F. and Kordos, P.}, title = {Annealing effect on concentration of EL6-like deep-level state in low-temperature-grown molecular beam epitaxial GaAs. Darmo, J.; Dubecky, F.; Kordos, P.; F{\"o}rster, A.}, series = {Applied Physics Letters. 72 (1998), H. 5}, journal = {Applied Physics Letters. 72 (1998), H. 5}, isbn = {1077-3118}, pages = {590 -- 592}, year = {1998}, language = {en} } @article{FoersterDarmoDubeckyetal.1996, author = {F{\"o}rster, Arnold and Darmo, J. and Dubeck{\´y}, F. and Kordos, P.}, title = {Annealing characteristics of native defects in low-temperature-grown MBE GaAs / J. Darmo ; F. Dubecky ; P. Kordos ; A. F{\"o}rster}, series = {Semiconducting and insulating materials 1996 : proceedings of the 9th Conference on Semiconducting and Insulating Materials (SIMC '9), April 29 - May 3, 1996, Toulouse, France / [IEEE]}, journal = {Semiconducting and insulating materials 1996 : proceedings of the 9th Conference on Semiconducting and Insulating Materials (SIMC '9), April 29 - May 3, 1996, Toulouse, France / [IEEE]}, address = {Piscataway, NJ [u.a.]}, isbn = {0-7803-3095-1}, pages = {67 -- ff.}, year = {1996}, language = {en} } @article{BarsovBechstedtHardt2001, author = {Barsov, S. and Bechstedt, U. and Hardt, Arno}, title = {ANKE, a new facility for medium energy hadron physics at COSY-J{\"u}lich / S. Barsov [u.a.]}, series = {Nuclear instruments and methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Vol. 462, iss. 3}, journal = {Nuclear instruments and methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Vol. 462, iss. 3}, issn = {0167-5087 (Print) ; 0168-9002 (E-journal)}, pages = {364 -- 381}, year = {2001}, language = {en} } @inproceedings{BreitbachAlexopoulosMayetal.2019, author = {Breitbach, Gerd and Alexopoulos, Spiros and May, Martin and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf}, title = {Analysis of volumetric solar radiation absorbers made of wire meshes}, series = {AIP Conference Proceedings}, volume = {2126}, booktitle = {AIP Conference Proceedings}, issn = {0094243X}, doi = {10.1063/1.5117521}, pages = {030009-1 -- 030009-6}, year = {2019}, language = {en} } @article{ButenwegRosinHoller2017, author = {Butenweg, Christoph and Rosin, Julia and Holler, Stefan}, title = {Analysis of cylindrical granular material silos under seismic excitation}, series = {Buildings}, volume = {7}, journal = {Buildings}, number = {3}, publisher = {MDPI}, address = {Basel}, issn = {2075-5309}, doi = {10.3390/buildings7030061}, pages = {1 -- 12}, year = {2017}, abstract = {Silos generally work as storage structures between supply and demand for various goods, and their structural safety has long been of interest to the civil engineering profession. This is especially true for dynamically loaded silos, e.g., in case of seismic excitation. Particularly thin-walled cylindrical silos are highly vulnerable to seismic induced pressures, which can cause critical buckling phenomena of the silo shell. The analysis of silos can be carried out in two different ways. In the first, the seismic loading is modeled through statically equivalent loads acting on the shell. Alternatively, a time history analysis might be carried out, in which nonlinear phenomena due to the filling as well as the interaction between the shell and the granular material are taken into account. The paper presents a comparison of these approaches. The model used for the nonlinear time history analysis considers the granular material by means of the intergranular strain approach for hypoplasticity theory. The interaction effects between the granular material and the shell is represented by contact elements. Additionally, soil-structure interaction effects are taken into account.}, language = {en} } @inproceedings{RosinMykoniouButenweg2017, author = {Rosin, J. and Mykoniou, K. and Butenweg, Christoph}, title = {Analysis Of Base Isolated Liquid Storage Tanks With 3D Fsi-Analysis As Well As Simplified Approaches}, series = {16th World Conference on Earthquake Engineering, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017}, booktitle = {16th World Conference on Earthquake Engineering, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017}, publisher = {Chilean Association on Seismology and Earthquake Engineering (ACHISINA)}, pages = {1 -- 14}, year = {2017}, abstract = {Tanks are preferably designed, for cost-saving reasons, as circular, cylindrical, thin-walled shells. In case of seismic excitation, these constructions are highly vulnerable to stability failures. An earthquake-resistant design of rigidly supported tanks for high seismic loading demands, however, uneconomic wall thicknesses. A cost-effective alternative can be provided by base isolation systems. In this paper, a simplified seismic design procedure for base isolated tanks is introduced, by appropriately modifying the standard mechanical model for flexible, rigidly supported tanks. The non-linear behavior of conventional base isolation systems becomes an integral part of a proposed simplified process, which enables the assessment of the reduced hydrodynamic forces acting on the tank walls and the corresponding stress distribution. The impulsive and convective actions of the liquid are taken into account. The validity of this approach is evaluated by employing a non-linear fluid-structure interaction algorithm of finite element method. Special focus is placed on the boundary conditions imposed from the base isolation and the resulting hydrodynamic pressures. Both horizontal and vertical component of ground motion are considered in order to study the principal effects of the base isolation on the pressure distribution of the tank walls. The induced rocking effects associated with elastomeric bearings are discussed. The results manifest that base isolated tanks can be designed for seismic loads by means of the proposed procedure with sufficient accuracy, allowing to dispense with numerically expensive techniques.}, language = {en} } @inproceedings{GedleSchmitzGielenetal.2022, author = {Gedle, Yibekal and Schmitz, Mark and Gielen, Hans and Schmitz, Pascal and Herrmann, Ulf and Teixeira Boura, Cristiano Jos{\´e} and Mahdi, Zahra and Chico Caminos, Ricardo Alexander and Dersch, J{\"u}rgen}, title = {Analysis of an integrated CSP-PV hybrid power plant}, series = {SOLARPACES 2020}, booktitle = {SOLARPACES 2020}, number = {2445 / 1}, publisher = {AIP conference proceedings / American Institute of Physics}, address = {Melville, NY}, isbn = {978-0-7354-4195-8}, issn = {1551-7616 (online)}, doi = {10.1063/5.0086236}, pages = {9 Seiten}, year = {2022}, abstract = {In the past, CSP and PV have been seen as competing technologies. Despite massive reductions in the electricity generation costs of CSP plants, PV power generation is - at least during sunshine hours - significantly cheaper. If electricity is required not only during the daytime, but around the clock, CSP with its inherent thermal energy storage gets an advantage in terms of LEC. There are a few examples of projects in which CSP plants and PV plants have been co-located, meaning that they feed into the same grid connection point and ideally optimize their operation strategy to yield an overall benefit. In the past eight years, TSK Flagsol has developed a plant concept, which merges both solar technologies into one highly Integrated CSP-PV-Hybrid (ICPH) power plant. Here, unlike in simply co-located concepts, as analyzed e.g. in [1] - [4], excess PV power that would have to be dumped is used in electric molten salt heaters to increase the storage temperature, improving storage and conversion efficiency. The authors demonstrate the electricity cost sensitivity to subsystem sizing for various market scenarios, and compare the resulting optimized ICPH plants with co-located hybrid plants. Independent of the three feed-in tariffs that have been assumed, the ICPH plant shows an electricity cost advantage of almost 20\% while maintaining a high degree of flexibility in power dispatch as it is characteristic for CSP power plants. As all components of such an innovative concept are well proven, the system is ready for commercial market implementation. A first project is already contracted and in early engineering execution.}, language = {en} } @article{BlockViebahnJungbluth2024, author = {Block, Simon and Viebahn, Peter and Jungbluth, Christian}, title = {Analysing direct air capture for enabling negative emissions in Germany: an assessment of the resource requirements and costs of a potential rollout in 2045}, series = {Frontiers in Climate}, volume = {6}, journal = {Frontiers in Climate}, publisher = {Frontiers}, address = {Lausanne}, issn = {2624-9553}, doi = {10.3389/fclim.2024.1353939}, pages = {18 Seiten}, year = {2024}, abstract = {Direct air capture (DAC) combined with subsequent storage (DACCS) is discussed as one promising carbon dioxide removal option. The aim of this paper is to analyse and comparatively classify the resource consumption (land use, renewable energy and water) and costs of possible DAC implementation pathways for Germany. The paths are based on a selected, existing climate neutrality scenario that requires the removal of 20 Mt of carbon dioxide (CO2) per year by DACCS from 2045. The analysis focuses on the so-called "low-temperature" DAC process, which might be more advantageous for Germany than the "high-temperature" one. In four case studies, we examine potential sites in northern, central and southern Germany, thereby using the most suitable renewable energies for electricity and heat generation. We show that the deployment of DAC results in large-scale land use and high energy needs. The land use in the range of 167-353 km2 results mainly from the area required for renewable energy generation. The total electrical energy demand of 14.4 TWh per year, of which 46\% is needed to operate heat pumps to supply the heat demand of the DAC process, corresponds to around 1.4\% of Germany's envisaged electricity demand in 2045. 20 Mt of water are provided yearly, corresponding to 40\% of the city of Cologne's water demand (1.1 million inhabitants). The capture of CO2 (DAC) incurs levelised costs of 125-138 EUR per tonne of CO2, whereby the provision of the required energy via photovoltaics in southern Germany represents the lowest value of the four case studies. This does not include the costs associated with balancing its volatility. Taking into account transporting the CO2 via pipeline to the port of Wilhelmshaven, followed by transporting and sequestering the CO2 in geological storage sites in the Norwegian North Sea (DACCS), the levelised costs increase to 161-176 EUR/tCO2. Due to the longer transport distances from southern and central Germany, a northern German site using wind turbines would be the most favourable.}, language = {en} } @article{FoersterVergheseZamdmeretal.1996, author = {F{\"o}rster, Arnold and Verghese, S. and Zamdmer, N. and Hu, Qing}, title = {An optical correlator using a low-temperature-grown GaAs photoconductor / S. Verghese ; N. Zamdmer ; Qing Hu .... A. F{\"o}rster}, series = {Applied physics letters. 69 (1996), H. 6}, journal = {Applied physics letters. 69 (1996), H. 6}, isbn = {0003-6951}, pages = {842 -- 844}, year = {1996}, language = {en} } @inproceedings{PuetzBaierBrauneretal.2022, author = {P{\"u}tz, Sebastian and Baier, Ralph and Brauner, Philipp and Brillowski, Florian and Dammers, Hannah and Liehner, Luca and Mertens, Alexander and Rodemann, Niklas and Schneider, Sebastian and Schollemann, Alexander and Steuer-Dankert, Linda and Vervier, Luisa and Gries, Thomas and Leicht-Scholten, Carmen and Nagel, Saskia K. and Piller, Frank T. and Schuh, G{\"u}nther and Ziefle, Martina and Nitsch, Verena}, title = {An interdisciplinary view on humane interfaces for digital shadows in the internet of production}, series = {2022 15th International Conference on Human System Interaction (HSI)}, booktitle = {2022 15th International Conference on Human System Interaction (HSI)}, publisher = {IEEE}, isbn = {978-1-6654-6823-7 (Print)}, issn = {2158-2246 (Print)}, doi = {10.1109/HSI55341.2022.9869467}, pages = {8 Seiten}, year = {2022}, abstract = {Digital shadows play a central role for the next generation industrial internet, also known as Internet of Production (IoP). However, prior research has not considered systematically how human actors interact with digital shadows, shaping their potential for success. To address this research gap, we assembled an interdisciplinary team of authors from diverse areas of human-centered research to propose and discuss design and research recommendations for the implementation of industrial user interfaces for digital shadows, as they are currently conceptualized for the IoP. Based on the four use cases of decision support systems, knowledge sharing in global production networks, human-robot collaboration, and monitoring employee workload, we derive recommendations for interface design and enhancing workers' capabilities. This analysis is extended by introducing requirements from the higher-level perspectives of governance and organization.}, language = {en} }