@misc{HerzogMeyerWachsmuth, author = {Herzog, Roland and Meyer, Christian and Wachsmuth, Gerd}, title = {B- and Strong Stationarity for Optimal Control of Static Plasticity with Hardening}, series = {SIAM Journal on Optimization}, volume = {23}, journal = {SIAM Journal on Optimization}, number = {1}, issn = {1052-6234}, doi = {10.1137/110821147}, pages = {321 -- 352}, abstract = {Optimal control problems for the variational inequality of static elastoplasticity with linear kinematic hardening are considered. The control-to-state map is shown to be weakly directionally differentiable, and local optimal controls are proved to verify an optimality system of B-stationary type. For a modified problem, local minimizers are shown to even satisfy an optimality system of strongly stationary type.}, language = {en} } @misc{HerzogMeyerWachsmuth, author = {Herzog, Roland and Meyer, Christian and Wachsmuth, Gerd}, title = {C-Stationarity for Optimal Control of Static Plasticity with Linear Kinematic Hardening}, series = {SIAM Journal on Optimization}, volume = {50}, journal = {SIAM Journal on Optimization}, number = {5}, issn = {0363-0129}, doi = {10.1137/100809325}, pages = {3052 -- 3082}, abstract = {An optimal control problem is considered for the variational inequality representing the stress-based (dual) formulation of static elastoplasticity. The linear kinematic hardening model and the von Mises yield condition are used. Existence and uniqueness of the plastic multiplier is rigorously proved, which allows for the reformulation of the forward system using a complementarity condition. In order to derive necessary optimality conditions, a family of regularized optimal control problems is analyzed, wherein the static plasticity problems are replaced by their viscoplastic approximations. By passing to the limit in the optimality conditions for the regularized problems, necessary optimality conditions of C-stationarity type are obtained.}, language = {en} } @misc{HerzogMeyerWachsmuth, author = {Herzog, Roland and Meyer, Christian and Wachsmuth, Gerd}, title = {Integrability of displacement and stresses in linear and nonlinear elasticity with mixed boundary conditions}, series = {Journal of Mathematical Analysis and Applications}, volume = {382}, journal = {Journal of Mathematical Analysis and Applications}, number = {2}, issn = {0022-247X}, doi = {10.1016/j.jmaa.2011.04.074}, pages = {802 -- 813}, abstract = {Equations of linear and nonlinear infinitesimal elasticity with mixed boundary conditionsare considered. The bounded domain is assumed to have a Lipschitz boundary and to satisfy additional regularity assumptions. W^(1,p) regularity for the displacements and L^p regularity for the stresses are proved for some p>2.}, language = {en} } @misc{MahmoodinezhadMoralesNaumannetal., author = {Mahmoodinezhad, Ali and Morales, Carlos and Naumann, Franziska and Plate, Paul and Meyer, Robert and Janowitz, Christoph and Henkel, Karsten and Kot, Małgorzata and Z{\"o}llner, Marvin Hartwig and Wenger, Christian and Flege, Jan Ingo}, title = {Low-temperature atomic layer deposition of indium oxide thin films using trimethylindium and oxygen plasma}, series = {Journal of Vacuum Science and Technology A}, volume = {39}, journal = {Journal of Vacuum Science and Technology A}, number = {6}, issn = {0734-2101}, doi = {10.1116/6.0001375}, abstract = {Indium oxide (InxOy) thin films were deposited by plasma-enhanced atomic layer deposition (PEALD) using trimethylindium and oxygen plasma in a low-temperature range of 80-200 °C. The optical properties, chemical composition, crystallographic structure, and electrical characteristics of these layers were investigated by spectroscopic ellipsometry (SE), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), as well as current-voltage and capacitance-voltage measurements. The SE results yielded a nearly constant growth rate of 0.56 {\AA} per cycle and a thickness inhomogeneity of ≤1.2\% across 4-in. substrates in the temperature range of 100-150 °C. The refractive index (at 632.8 nm) was found to be 2.07 for the films deposited at 150 °C. The PEALD-InxOy layers exhibit a direct (3.3 ± 0.2 eV) and an indirect (2.8 ± 0.1 eV) bandgap with an uptrend for both with increasing substrate temperature. Based on XPS characterization, all InxOy samples are free of carbon impurities and show a temperature-dependent off-stoichiometry indicating oxygen vacancies. XRD diffraction patterns demonstrate an onset of crystallization at 150 °C. Consistent with the optical, XPS, and XRD data, the films deposited at ≥150 °C possess higher electrical conductivity. Our findings prove that a low-temperature PEALD process of InxOy is feasible and promising for a high-quality thin-film deposition without chemical impurities on thermally fragile substrates.}, language = {en} } @misc{HerzogMeyerWachsmuth, author = {Herzog, Roland and Meyer, Christian and Wachsmuth, Gerd}, title = {Existence and regularity of the plastic multiplier in static and quasistatic plasticity}, series = {GAMM-Mitteilungen}, volume = {34}, journal = {GAMM-Mitteilungen}, number = {1}, issn = {1522-2608}, doi = {10.1002/gamm.201110006}, pages = {39 -- 44}, abstract = {Existence of the plastic multiplier with L1 spatial regularity for quasistatic and static plasticity is proved for arbitrary continuous and convex yield functions and linear hardening laws. L2 regularity is shown in the particular cases of kinematic hardening, or combined kinematic and isotropic hardening}, language = {en} } @misc{SousaNazarenkoGrunewaldetal., author = {Sousa, Jo{\~a}o and Nazarenko, Artem A. and Grunewald, Christian and Psarommatis, Foivos and Fraile, Francisco and Meyer, Olga and Sarraipa, Jo{\~a}o}, title = {Zero-defect manufacturing terminology standardization: Definition, improvement, and harmonization}, series = {Frontiers in Manufacturing Technology}, volume = {2}, journal = {Frontiers in Manufacturing Technology}, issn = {2813-0359}, doi = {10.3389/fmtec.2022.947474}, abstract = {Zero-Defect Manufacturing (ZDM) is the next evolutionary step in quality management for manufacturing that makes use of Industry 4.0 technologies to support quality in manufacturing. These technologies help reduce the cost of inspection, allowing for more inspection points throughout the manufacturing process, reducing the size of quality feedback loops, and guaranteeing that no defective product is delivered to the customer. There are several ZDM-related initiatives, but still no harmonized terminology. This article describes the methodological approach to provide a common agreement on the ZDM concept and its associated terminology taking place within an open CEN-CENELEC Workshop. The methodology has the support of ISO standards for terminology work such as ISO 704, ISO 860, and ISO 10241-1/2. This work shows that the terminology for ZDM has a significant overlap with the terminology of quality management, metrology, dependability, statistics, non-destructive inspection, and condition monitoring. The proposed new terms and definitions can be used to further extend ISO's and IEC's already available terminologies and support present and future researchers in the field to conduct their research using a common vocabulary.}, language = {en} } @misc{MeyerKellerWolfersdorfetal., author = {Meyer, Bernd and Keller, Florian and Wolfersdorf, Christian and Lee, Roh Pin}, title = {Ein Konzept f{\"u}r die Kohlenstoffkreislaufwirtschaft : Sektorkopplung zwischen Energie, Chemie \& Abfall}, series = {Chemie Ingenieur Technik}, volume = {90}, journal = {Chemie Ingenieur Technik}, number = {1-2}, issn = {0009-286X}, doi = {10.1002/cite.201700088}, pages = {241 -- 248}, abstract = {Ein Konzept zur CO2-emissionsfreien Schließung des Kohlenstoffkreislaufes durch Kopplung von CO2-emissionsamer Kohlechemie, Abfallwirtschaft und Energiewirtschaft mithilfe der Co-Vergasung von Kohle und Abfall unter Einbindung von regenerativ erzeugtem Wasserstoff wird vorgestellt. Ziel ist die Erreichung der CO2-Emissionsfreiheit durch Einkopplung Erneuerbarer Energie. Am Beispiel der Olefinproduktion in Deutschland wird der daf{\"u}r erforderliche Bedarf ermittelt. Im Vergleich zeichnet sich die Vergasungsroute durch einen um etwa Faktor zwei geringeren Energiebedarf aus.}, language = {de} } @misc{LeeWolfersdorfKelleretal., author = {Lee, Roh Pin and Wolfersdorf, Christian and Keller, Florian and Meyer, Bernd}, title = {Towards a closed carbon cycle and achieving a circular economy for carbonaceous resources : Net zero emissions, resource efficiency and resource conservation through coupling of the energy, chemical and recycling sectors}, series = {Erd{\"o}l, Erdgas, Kohle}, volume = {6}, journal = {Erd{\"o}l, Erdgas, Kohle}, issn = {0179-3187}, doi = {10.19225/170603}, pages = {76 -- 80}, abstract = {Lignite and carbonaceous waste are valuable primary and secondary carbon carriers. The projected increased reduction in lignite for electricity production in Germany, the need to increase carbonaceous waste recycling as well as the anticipated availability of renewable electricity from Germany's energy transition all point to a high potential for closing the carbon cycle (C³) for the nation's carbon intensive industries. In this article, we present a concept for achieving net zero emissions, resource efficiency and conservation by coupling the energy, chemical and recycling sectors to support a circular carbon economy. To illustrate our concept, results from process model evaluations of domestic carbon feedstock (i.e. plastic waste and lignite) for olefins production in Germany are presented.}, language = {en} } @misc{BergerBellBartonetal., author = {Berger, Uta and Bell, Andrew and Barton, C. Michael and Chappin, Emile and Dreßler, Gunnar and Filatova, Tatiana and Fronville, Thibault and Lee, Allen and Loon, Emiel van and Lorscheid, Iris and Meyer, Matthias and M{\"u}ller, Birgit and Piou, Cyril and Radchuk, Viktoriia and Roxburgh, Nicholas and Sch{\"u}ler, Lennart and Troost, Christian and Wijermans, Nanda and Williams, Tim G. and Wimmler, Marie-Christin and Grimm, Volker}, title = {Towards reusable building blocks for agent-based modelling and theory development}, series = {Environmental Modelling \& Software}, volume = {175}, journal = {Environmental Modelling \& Software}, publisher = {Elsevier BV}, issn = {1364-8152}, doi = {10.1016/j.envsoft.2024.106003}, pages = {12}, language = {en} } @misc{HerglotzOchMeyeretal., author = {Herglotz, Christian and Och, Hannah and Meyer, Anna and Ramasubbu, Geetha and Eicherm{\"u}ller, Lena and Kr{\"a}nzler, Matthias and Brand, Fabian and Fischer, Kristian and Nguyen, Dat Thanh and Regensky, Andy and Kaup, Andr{\´e}}, title = {The Bj{\o}ntegaard Bible Why Your Way of Comparing Video Codecs May Be Wrong}, series = {IEEE Transactions on Image Processing}, journal = {IEEE Transactions on Image Processing}, number = {Volume 33}, issn = {1057-7149}, doi = {10.1109/TIP.2023.3346695}, pages = {987 -- 1001}, abstract = {In this paper, we provide an in-depth assessment on the Bj{\o}ntegaard Delta. We construct a large data set of video compression performance comparisons using a diverse set of metrics including PSNR, VMAF, bitrate, and processing energies. These metrics are evaluated for visual data types such as classic perspective video, 360° video, point clouds, and screen content. As compression technology, we consider multiple hybrid video codecs as well as state-of-the-art neural network based compression methods. Using additional supporting points in-between standard points defined by parameters such as the quantization parameter, we assess the interpolation error of the Bj{\o}ntegaard-Delta (BD) calculus and its impact on the final BD value. From the analysis, we find that the BD calculus is most accurate in the standard application of rate-distortion comparisons with mean errors below 0.5 percentage points. For other applications and special cases, e.g., VMAF quality, energy considerations, or inter-codec comparisons, the errors are higher (up to 5 percentage points), but can be halved by using a higher number of supporting points. We finally come up with recommendations on how to use the BD calculus such that the validity of the resulting BD-values is maximized. Main recommendations are as follows: First, relative curve differences should be plotted and analyzed. Second, the logarithmic domain should be used for saturating metrics such as SSIM and VMAF. Third, BD values below a certain threshold indicated by the subset error should not be used to draw recommendations. Fourth, using two supporting points is sufficient to obtain rough performance estimates.}, language = {en} }