@techreport{BurtchenBaehr, author = {Burtchen, Angie and B{\"a}hr, Martin}, title = {Pseudospektralmethoden zur L{\"o}sung von Optimalsteuerungsproblemen mit unendlichem Zeithorizont : aus den Masterarbeiten von Martin B{\"a}hr und Angie Burtchen}, publisher = {Mathematisches Institut}, address = {Cottbus}, pages = {68, VI Blatt}, language = {de} } @inproceedings{BreussQueauBaehretal., author = {Breuß, Michael and Qu{\`e}au, Yvain and B{\"a}hr, Martin and Durou, Jean-Denis}, title = {Highly Efficient Surface Normal Integration}, series = {Proceedings of the Conference Algoritmy 2016, 20th Conference on Scientific Computing, Vysok{\´e} Tatry - Podbansk{\´e}, Slovakia, March 14 - 18}, booktitle = {Proceedings of the Conference Algoritmy 2016, 20th Conference on Scientific Computing, Vysok{\´e} Tatry - Podbansk{\´e}, Slovakia, March 14 - 18}, publisher = {Publishing House of Slovak University of Technology in Bratislava}, address = {Bratislava}, isbn = {978-80-227-4544-4}, pages = {204 -- 213}, language = {en} } @inproceedings{BaehrBreuss, author = {B{\"a}hr, Martin and Breuß, Michael}, title = {An Improved Eikonal Method for Surface Normal Integration}, series = {Pattern Recognition, 37th German Conference, GCPR 2015, Aachen, Germany, October 7-10, 2015, Proceedings}, booktitle = {Pattern Recognition, 37th German Conference, GCPR 2015, Aachen, Germany, October 7-10, 2015, Proceedings}, editor = {Gall, Juergen and Gehler, Peter and Leibe, Bastian}, publisher = {Springer International Publishing}, address = {Berlin}, isbn = {978-3-319-24946-9}, doi = {10.1007/978-3-319-24947-6_22}, pages = {274 -- 284}, language = {en} } @misc{BaehrBreussQueauetal., author = {B{\"a}hr, Martin and Breuß, Michael and Qu{\`e}au, Yvain and Sharifi Boroujerdi, Ali and Durou, Jean-Denis}, title = {Fast and accurate surface normal integration on non-rectangular domains}, series = {Computational Visual Media}, volume = {3}, journal = {Computational Visual Media}, number = {2}, issn = {2096-0433}, doi = {10.1007/s41095-016-0075-z}, pages = {107 -- 129}, abstract = {The integration of surface normals for the purpose of computing the shape of a surface in 3D space is a classic problem in computer vision. However, even nowadays it is still a challenging task to devise a method that is flexible enough to work on non-trivial computational domains with high accuracy, robustness, and computational efficiency. By uniting a classic approach for surface normal integration with modern computational techniques, we construct a solver that fulfils these requirements. Building upon the Poisson integration model, we use an iterative Krylov subspace solver as a core step in tackling the task. While such a method can be very efficient, it may only show its full potential when combined with suitable numerical preconditioning and problem-specific initialisation. We perform a thorough numerical study in order to identify an appropriate preconditioner for this purpose. To provide suitable initialisation, we compute this initial state using a recently developed fast marching integrator. Detailed numerical experiments illustrate the benefits of this novel combination. In addition, we show on real-world photometric stereo datasets that the developed numerical framework is flexible enough to tackle modern computer vision applications.}, language = {en} } @inproceedings{BaehrDachselBreuss, author = {B{\"a}hr, Martin and Dachsel, Robert and Breuß, Michael}, title = {Fast Solvers for Solving Shape Matching by Time Integration}, series = {Proceedings of the OAGM Workshop 2018 Medical Image Analysis, May 15 - 16, 2018, Hall/Tyrol, Austria}, booktitle = {Proceedings of the OAGM Workshop 2018 Medical Image Analysis, May 15 - 16, 2018, Hall/Tyrol, Austria}, editor = {Welk, Martin and Urschler, Martin and Roth, Peter M.}, publisher = {Verlag der TU Graz}, address = {Graz}, isbn = {978-3-85125-603-1}, doi = {10.3217/978-3-85125-603-1-14}, pages = {65 -- 72}, abstract = {The main task in three-dimensional non-rigid shape correspondence is to retrieve similarities between two or more similar three-dimensional objects. An important building block of many methods constructed to achieve this goal is a simplified shape representation called feature descriptor, which is invariant under almost isometric transformations. A recent feature descriptor relies on the full numerical integration of the geometric heat equation. This approach involves to solve a system of linear equations with multiple right-hand sides. To this end, it is necessary to find a fast and accurate numerical scheme in conjunction with the solution of a sparse linear system and many different right sides. In this paper we evaluate direct, iterative and model order reduction (MOR) methods and their influence to shape correspondence applications which will be validated on standard shape data sets with different resolutions.}, language = {en} } @misc{BaehrRadowBreussetal., author = {B{\"a}hr, Martin and Radow, Georg and Breuß, Michael and F{\"u}genschuh, Armin}, title = {Computation of Stable Honeycomb Structures for Additive Manufacturing}, series = {Operations Research Proceedings 2018, Selected Papers of the Annual International Conference of the German Operations Research Society (GOR), Brussels, Belgium, September 12-14, 2018}, journal = {Operations Research Proceedings 2018, Selected Papers of the Annual International Conference of the German Operations Research Society (GOR), Brussels, Belgium, September 12-14, 2018}, editor = {Fortz, Bernard and Labb{\´e}, Martine}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-18499-5}, issn = {978-3-030-18500-8}, doi = {10.1007/978-3-030-18500-8_45}, pages = {363 -- 369}, abstract = {In certain additive manufacturing processes of industrial interest, the task arises to build up structures layer-wise in a purely vertical manner. The question arises how to construct such a structure in a convenient way so that it is structurally as stable as possible. In this paper, we consider the automatic construction of a honeycomb structure, given the boundary of a shape of interest. In doing this we employ Lloyd's algorithm in two different realisations. For computing the incorporated Voronoi tessellation we consider the use of a Delaunay triangulation or the Eikonal equation. As a main point of our paper, we give a comparison of these two methods. We show that one can make use of the arising graph of the honeycomb structure as input for a specific routing scheme that enhances printability when the printing material stays soft for some time during the printing process.}, language = {en} } @misc{BaehrBuhlRadowetal., author = {B{\"a}hr, Martin and Buhl, Johannes and Radow, Georg and Schmidt, Johannes and Bambach, Markus and Breuß, Michael and F{\"u}genschuh, Armin}, title = {Stable honeycomb structures and temperature based trajectory optimization for wire-arc additive manufacturing}, series = {Optimization and Engineering}, volume = {22}, journal = {Optimization and Engineering}, number = {2}, issn = {1573-2924}, doi = {10.1007/s11081-020-09552-5}, pages = {913 -- 974}, abstract = {We consider two mathematical problems that are connected and occur in the layer-wise production process of a workpiece using wire-arc additive manufacturing. As the first task, we consider the automatic construction of a honeycomb structure, given the boundary of a shape of interest. In doing this, we employ Lloyd's algorithm in two different realizations. For computing the incorporated Voronoi tesselation we consider the use of a Delaunay triangulation or alternatively, the eikonal equation. We compare and modify these approaches with the aim of combining their respective advantages. Then in the second task, to find an optimal tool path guaranteeing minimal production time and high quality of the workpiece, a mixed-integer linear programming problem is derived. The model takes thermal conduction and radiation during the process into account and aims to minimize temperature gradients inside the material. Its solvability for standard mixed-integer solvers is demonstrated on several test-instances. The results are compared with manufactured workpieces.}, language = {en} } @book{BaehrBuhlRadowetal., author = {B{\"a}hr, Martin and Buhl, Johannes and Radow, Georg and Schmidt, Johannes and Bambach, Markus and Breuß, Michael and F{\"u}genschuh, Armin}, title = {Stable honeycomb structures and temperature based trajectory optimization for wire-arc additive manufacturing}, address = {Cottbus}, doi = {10.26127/btuopen-5079}, pages = {49}, language = {en} } @misc{BaehrBreuss, author = {B{\"a}hr, Martin and Breuß, Michael}, title = {Efficient Long-Term Simulation of the Heat Equation with Application in Geothermal Energy Storage}, series = {Mathematics}, volume = {10}, journal = {Mathematics}, number = {13}, issn = {2227-7390}, doi = {10.3390/math10132309}, abstract = {Long-term evolutions of parabolic partial differential equations, such as the heat equation, are the subject of interest in many applications. There are several numerical solvers marking the state-of-the-art in diverse scientific fields that may be used with benefit for the numerical simulation of such long-term scenarios. We show how to adapt some of the currently most efficient numerical approaches for solving the fundamental problem of long-term linear heat evolution with internal and external boundary conditions as well as source terms. Such long-term simulations are required for the optimal dimensioning of geothermal energy storages and their profitability assessment, for which we provide a comprehensive analytical and numerical model. Implicit methods are usually considered the best choice for resolving long-term simulations of linear parabolic problems; however, in practice the efficiency of such schemes in terms of the combination of computational load and obtained accuracy may be a delicate issue, as it depends very much on the properties of the underlying model. For example, one of the challenges in long-term simulation may arise by the presence of time-dependent boundary conditions, as in our application. In order to provide both a computationally efficient and accurate enough simulation, we give a thorough discussion of the various numerical solvers along with many technical details and own adaptations. By our investigation, we focus on two largely competitive approaches for our application, namely the fast explicit diffusion method originating in image processing and an adaptation of the Krylov subspace model order reduction method. We validate our numerical findings via several experiments using synthetic and real-world data. We show that we can obtain fast and accurate long-term simulations of typical geothermal energy storage facilities. We conjecture that our techniques can be highly useful for tackling long-term heat evolution in many applications.}, language = {en} } @misc{RapsBahrKarkossaetal., author = {Raps, Stefanie and Bahr, Laura and Karkossa, Isabel and Rossol, Manuela and Bergen, Martin von and Schubert, Kristin}, title = {Triclosan and its alternatives, especially chlorhexidine, modulate macrophage immune response with distinct modes of action}, series = {Science of The Total Environment}, volume = {914}, journal = {Science of The Total Environment}, publisher = {Elsevier BV}, issn = {0048-9697}, doi = {10.1016/j.scitotenv.2023.169650}, pages = {15}, abstract = {Since European regulators restricted the use of bacteriocidic triclosan (TCS), alternatives for TCS are emerging. Recently, TCS has been shown to reprogram immune metabolism, trigger the NLRP3 inflammasome, and subsequently the release of IL-1β in human macrophages, but data on substitutes is scarce. Hence, we aimed to examine the effects of TCS compared to its alternatives at the molecular level in human macrophages. LPS-stimulated THP-1 macrophages were exposed to TCS or its substitutes, including benzalkonium chloride, benzethonium chloride, chloroxylenol, chlorhexidine (CHX) and cetylpyridinium chloride, with the inhibitory concentration (IC10-value) of cell viability to decipher their mode of action. TCS induced the release of the pro-inflammatory cytokine TNF and high level of IL-1β, suggesting the activation of the NLRP3-inflammasome, which was confirmed by non-apparent IL-1β under the NLRP3-inhibitor MCC950 treatment d. While IL-6 release was reduced in all treatments, the alternative CHX completely abolished the release of all investigated cytokines. To unravel the underlying molecular mechanisms, we used untargeted LC-MS/MS-based proteomics. TCS and CHX showed the strongest cellular response at the protein and signalling pathway level, whereby pathways related to metabolism, translation, cellular stress and migration were mainly affected but to different proposed modes of action. TCS inhibited mitochondrial electron transfer and affected phagocytosis. In contrast, in CHX-treated cells, the translation was arrested due to stress conditions, resulting in the formation of stress granules. Mitochondrial (e.g. ATP5F1D, ATP5PB, UQCRQ) and ribosomal (e.g. RPL10, RPL35, RPS23) proteins were revealed as putative key drivers. Furthermore, we have demonstrated the formation of podosomes by CHX, potentially involved in ECM degradation. Our results exhibit modulation of the immune response in macrophages by TCS and its substitutes and illuminated underlying molecular effects. These results illustrate critical processes involved in the modulation of macrophages' immune response by TCS and its alternatives, providing information essential for hazard assessment.}, language = {en} } @misc{PillingBaehrWunderlich, author = {Pilling, Eric and B{\"a}hr, Martin and Wunderlich, Ralf}, title = {Stochastic optimal control of an industrial Power-to-Heat System with high-temperature heat pump and thermal energy storage}, series = {arXiv}, journal = {arXiv}, doi = {10.48550/arXiv.2411.02211}, pages = {1 -- 63}, abstract = {The optimal control of sustainable energy supply systems, including renewable energies and energy storage, takes a central role in the decarbonization of industrial systems. However, the use of fluctuating renewable energies leads to fluctuations in energy generation and requires a suitable control strategy for the complex systems in order to ensure energy supply. In this paper, we consider an electrified power-to-heat system which is designed to supply heat in form of superheated steam for industrial processes. The system consists of a high-temperature heat pump for heat supply, a wind turbine for power generation, a sensible thermal energy storage for storing excess heat and a steam generator for providing steam. If the system's energy demand cannot be covered by electricity from the wind turbine, additional electricity must be purchased from the power grid. For this system, we investigate the cost-optimal operation aiming to minimize the electricity cost from the grid by a suitable system control depending on the available wind power and the amount of stored thermal energy. This is a decision making problem under uncertainties about the future prices for electricity from the grid and the future generation of wind power. The resulting stochastic optimal control problem is treated as finite-horizon Markov decision process for a multi-dimensional controlled state process. We first consider the classical backward recursion techniques for solving the associated dynamic programming equation for the value function and compute the optimal decision rule. Since that approach suffers from the curse of dimensionality we also apply Q-learning techniques that are able to provide a good approximate solution to the optimization problem within reasonable time.}, language = {en} } @misc{RachevaBasaloLouridoGurdaletal., author = {Racheva, Miroslava and Basalo Lourido, Javier and Gurdal, Enise Ece and Herbst, Martin and Bayar, Seyhmus and Radzik, Daniela and B{\"a}hr, Elen and Zwies, Constanze and Neffe, Axel T. and Pietzsch, Markus and Lendlein, Andreas and Wischke, Christian}, title = {Tyrosinase cross-linked PEG hydrogels with DAT and DATT as artificial substrates : design, structure, and functions}, series = {Biomacromolecules}, volume = {27}, journal = {Biomacromolecules}, number = {2}, publisher = {American Chemical Society (ACS)}, address = {Washington, DC}, issn = {1525-7797}, doi = {10.1021/acs.biomac.5c01929}, pages = {1317 -- 1336}, abstract = {Enzymes such as oxidases are sustainable tools for hydrogel synthesis, but complex competing reactions have limited the mechanistic understanding and biomedical applications of these materials. Guided by molecular docking and MM-GBSA calculations, we identified two artificial substrates, desaminotyrosine (DAT) and desaminotyrosyltyrosine (DATT), that were experimentally more efficiently converted by mushroom tyrosinase (mTyr) than the natural substrate tyrosine. These substrates were used to synthesize hydrogels from DAT/DATT-functionalized star-shaped oligoethylene glycol (sOEG). Model reactions elucidated the chemical nature and functionality of the hydrogel netpoints. Material properties were systematically investigated depending on sOEG molecular weight (5, 10, 20 kDa), substrate type, and mTyr concentration. Functional mesh sizes and controlled release functions were investigated with fluorescent dextrans (4-500 kDa) and heparin. Cell culture studies with L929 fibroblasts and THP-1 monocytes suggested inertness of the material. These findings provide fundamental insight into mTyr-catalyzed hydrogel formation and support further exploration for in situ hydrogel synthesis.}, language = {en} }