TY - JOUR A1 - Deuflhard, Peter A1 - Weiser, Martin A1 - Seebaß, Martin T1 - A New Nonlinear Elliptic Multilevel FEM Applied to Regional Hyperthermia JF - Comput. Visual. Sci. Y1 - 2000 U6 - https://doi.org/10.1007/PL00013546 VL - 3 SP - 1 EP - 6 ER - TY - JOUR A1 - Hammerschmidt, Martin A1 - Schneider, Philipp-Immanuel A1 - Santiago, Xavier Garcia A1 - Zschiedrich, Lin A1 - Weiser, Martin A1 - Burger, Sven T1 - Solving inverse problems appearing in design and metrology of diffractive optical elements by using Bayesian optimization JF - Proc. SPIE Y1 - 2018 U6 - https://doi.org/10.1117/12.2315468 VL - 10694 SP - 1069407 ER - TY - GEN A1 - Deuflhard, Peter A1 - Weiser, Martin A1 - Seebass, Martin T1 - A New Nonlinear Elliptic Multilevel FEM Applied to Regional Hyperthermia N2 - In the clinical cancer therapy of regional hyperthermia nonlinear perfusion effects inside and outside the tumor seem to play a not negligible role. A stationary model of such effects leads to a nonlinear Helmholtz term within an elliptic boundary value problem. The present paper reports about the application of a recently designed adaptive multilevel FEM to this problem. For several 3D virtual patients, nonlinear versus linear model is studied. Moreover, the numerical efficiency of the new algorithm is compared with a former application of an adaptive FEM to the corresponding instationary model PDE. T3 - ZIB-Report - SC-98-35 KW - hyperthermia KW - nonlinear elliptic KW - multilevel FEM Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-3785 ER - TY - JOUR A1 - Deuflhard, Peter A1 - Weiser, Martin A1 - Seebass, Martin T1 - A new nonlinear elliptic multilevel FEM in clinical cancer therapy planning JF - Comput. Vis. Sci. Y1 - 2000 VL - 3 SP - 115 EP - 120 ER - TY - GEN A1 - Hammerschmidt, Martin A1 - Weiser, Martin A1 - Santiago, Xavier Garcia A1 - Zschiedrich, Lin A1 - Bodermann, Bernd A1 - Burger, Sven T1 - Quantifying parameter uncertainties in optical scatterometry using Bayesian inversion N2 - We present a Newton-like method to solve inverse problems and to quantify parameter uncertainties. We apply the method to parameter reconstruction in optical scatterometry, where we take into account a priori information and measurement uncertainties using a Bayesian approach. Further, we discuss the influence of numerical accuracy on the reconstruction result. T3 - ZIB-Report - 17-37 KW - computational metrology KW - optical metrology KW - computational lithography KW - nanolithography KW - finite- element methods KW - nanooptics Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-64704 SN - 1438-0064 ER - TY - JOUR A1 - Hammerschmidt, Martin A1 - Weiser, Martin A1 - Santiago, Xavier Garcia A1 - Zschiedrich, Lin A1 - Bodermann, Bernd A1 - Burger, Sven T1 - Quantifying parameter uncertainties in optical scatterometry using Bayesian inversion JF - Proc. SPIE Y1 - 2017 U6 - https://doi.org/10.1117/12.2270596 VL - 10330 SP - 1033004 ER - TY - JOUR A1 - Becks, Henrik A1 - Lippold, Lukas A1 - Winkler, Paul A1 - Rohrer, Maximilian A1 - Leusmann, Thorsten A1 - Anton, David A1 - Sprenger, Bjarne A1 - Kähler, Philipp A1 - Rudenko, Iryna A1 - Andrés Arcones, Daniel A1 - Koutsourelakis, Phaedon-Stelios A1 - Unger, Jörg F. A1 - Weiser, Martin A1 - Petryna, Yuri A1 - Schnellenbach-Held, Martina A1 - Lowke, Dirk A1 - Wessels, Henning A1 - Lenzen, Armin A1 - Zabel, Volkmar A1 - Könke, Carsten A1 - Claßen, Martin A1 - Hegger, Josef T1 - Neuartige Konzepte für die Zustandsüberwachung und -analyse von Brückenbauwerken – Einblicke in das Forschungsvorhaben SPP100+ JF - Bauingenieur N2 - Die Brückeninfrastruktur in Deutschland und Europa steht aufgrund steigender Verkehrslasten und alternder Bauwerke vor erheblichen Herausforderungen. Das DFG-Schwerpunktprogramm 2388 „Hundert plus – Verlängerung der Lebensdauer komplexer Baustrukturen durch intelligente Digitalisierung“ (SPP100+) strebt an, durch digitale Innovationen und prädiktive Instandhaltungsstrategien die Nutzungsdauer bestehender Brückenbauwerke zu verlängern. Der vorliegende Beitrag fokussiert sich auf das SPP100+ zugehörige Cluster „Monitoring und Simulation“, das sieben Teilprojekte umfasst. Die Projekte entwickeln fortschrittliche Methoden zur Überwachung und Zustandsbewertung von Brücken mittels Digitaler Zwillinge, hochauflösender Sensortechnik und numerischer Simulationen. Innovative Ansätze wie nichtlineare Modellanpassungen, stochastische Methoden und künstliche Intelligenz ermöglichen eine präzise und frühzeitige Identifizierung potenzieller Schäden. Die Kombination aus kontinuierlichem Bauwerksmonitoring und effizienter Datenauswertung ist entscheidend für die langfristige Sicherheit und Langlebigkeit bestehender Brücken und trägt darüber hinaus zur Ressourcenschonung bei. N2 - Bridges in Germany and across Europe face significant challenges due to increasing traffic loads and aging structures. The DFG Priority Programme 2388 “Hundred Plus – Extending the Lifetime of Complex Engineering Structures through Intelligent Digitalization” (SPP100+) aims to extend the lifespan of existing bridge structures through digital innovations and predictive maintenance strategies. This paper focuses on the SPP100+ affiliated cluster “Monitoring and Simulation,” which encompasses seven sub-projects. These projects develop advanced methods for monitoring and assessing the condition of bridge structures using digital twins, high-resolution sensor technology, and numerical simulations. Innovative approaches such as nonlinear model adjustments, stochastic methods, and artificial intelligence facilitate precise and early identification of potential damages. The combination of continuous structural monitoring and efficient data evaluation is crucial for the long-term reliability and durability of existing bridges and contributes to resource conservation. T2 - Novel Concepts for the Condition Monitoring and Analysis of Bridge Structures – Insights into the SPP100+ Research Project Y1 - 2024 U6 - https://doi.org/10.37544/0005-6650-2024-10-63 VL - 99 IS - 10 SP - 327 EP - 338 ER - TY - GEN A1 - Weiser, Martin T1 - On goal-oriented adaptivity for elliptic optimal control problems N2 - The paper proposes goal-oriented error estimation and mesh refinement for optimal control problems with elliptic PDE constraints using the value of the reduced cost functional as quantity of interest. Error representation, hierarchical error estimators, and greedy-style error indicators are derived and compared to their counterparts when using the all-at-once cost functional as quantity of interest. Finally, the efficiency of the error estimator and generated meshes are demonstrated on numerical examples. T3 - ZIB-Report - 09-08 KW - optimal control KW - error estimation KW - adaptive mesh refinement Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11192 SN - 1438-0064 ER - TY - GEN A1 - Schiela, Anton A1 - Weiser, Martin T1 - Barrier methods for a control problem from hyperthermia treatment planning N2 - We consider an optimal control problem from hyperthermia treatment planning and its barrier regularization. We derive basic results, which lay the groundwork for the computation of optimal solutions via an interior point path-following method. Further, we report on a numerical implementation of such a method and its performance at an example problem. T3 - ZIB-Report - 09-36 KW - hyperthermia treatment planning KW - optimal control KW - barrier methods Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11567 SN - 1438-0064 ER - TY - GEN A1 - Weiser, Martin T1 - Optimization and Identification in Regional Hyperthermia N2 - Regional hyperthermia is a cancer therapy aiming at heating tumors using phased array applicators. This article provides an overview over current mathematical challenges of delivering individually optimal treatments. The focus is on therapy planning and identification of technical as well as physiological quantities from MR thermometry measurements. T3 - ZIB-Report - 08-40 KW - Hyperthermie-Therapieplanung KW - Identifizierung KW - MR-Thermometrie KW - Innere-Punkte-Methoden KW - hyperthermia treatment planning KW - identification KW - MR thermometry KW - interior point methods Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-10916 SN - 1438-0064 ER -