@article{Fuegenschuh2007, author = {F{\"u}genschuh, Armin}, title = {Spalten am St{\"u}ck - Maschinenbauer, Materialwissenschaftler und Mathematiker erfinden die Blechbearbeitung neu}, series = {hoch\$^3\$}, volume = {2}, journal = {hoch\$^3\$}, pages = {19}, year = {2007}, language = {en} } @article{Fuegenschuh2007, author = {F{\"u}genschuh, Armin}, title = {Bestes Blech - Der hochkomplexe unsichtbare Weg zum pr{\"a}zisen und belastbaren Bauteil}, series = {hoch\$^3\$}, volume = {2}, journal = {hoch\$^3\$}, pages = {20}, year = {2007}, language = {en} } @article{Fuegenschuh2006, author = {F{\"u}genschuh, Armin}, title = {Optimierte Schulanfangszeiten}, series = {OR News}, volume = {28}, journal = {OR News}, pages = {25 -- 27}, year = {2006}, language = {en} } @article{DuerFuegenschuhHuhnetal.2006, author = {D{\"u}r, Mirjam and F{\"u}genschuh, Armin and Huhn, Petra and Klamroth, Kathrin and Saliba, Sleman and Tammer, Christiane}, title = {EURO Summer Institute 2006 in Wittenberg}, series = {OR News}, volume = {28}, journal = {OR News}, pages = {71 -- 72}, year = {2006}, language = {en} } @article{Fuegenschuh2006, author = {F{\"u}genschuh, Armin}, title = {Optimal verkn{\"u}pft - Schulanfangszeiten und {\"o}ffentlicher Personennahverkehr}, series = {thema forschung}, volume = {1}, journal = {thema forschung}, pages = {82 -- 85}, year = {2006}, language = {en} } @article{Fuegenschuh2006, author = {F{\"u}genschuh, Armin}, title = {Mathematische Modelle zur betrieblichen Optimierung}, series = {Z! - das Zukunftsmagazin}, volume = {1}, journal = {Z! - das Zukunftsmagazin}, pages = {3}, year = {2006}, language = {en} } @article{EisenblaetterFuegenschuhFledderusetal.2003, author = {Eisenbl{\"a}tter, Andreas and F{\"u}genschuh, Armin and Fledderus, E. and Geerdes, Hans-Florian and Heideck, B. and Junglas, Daniel and Koch, Thorsten and K{\"u}rner, T. and Martin, Alexander}, title = {Mathematical Methods for Automatic Optimization of UMTS Radio Networks}, number = {D4.3}, editor = {Martin, Alexander}, publisher = {IST-2000-28088 MOMENTUM}, year = {2003}, language = {en} } @article{HumpolaLehmannFuegenschuh, author = {Humpola, Jesco and Lehmann, Thomas and F{\"u}genschuh, Armin}, title = {A primal heuristic for optimizing the topology of gas networks based on dual information}, series = {EURO Journal on Computational Optimization}, volume = {3}, journal = {EURO Journal on Computational Optimization}, number = {1}, doi = {10.1007/s13675-014-0029-0}, pages = {53 -- 78}, abstract = {We present a novel heuristic to identify feasible solutions of a mixed-integer nonlinear programming problem arising in natural gas transportation: the selection of new pipelines to enhance the network's capacity to a desired level in a cost-efficient way. We solve this problem in a linear programming based branch-and-cut approach, where we deal with the nonlinearities by linear outer approximation and spatial branching. At certain nodes of the branching tree, we compute a KKT point of a nonlinear relaxation. Based on the information from the KKT point we alter some of the binary variables in a locally promising way exploiting our problem-specific structure. On a test set of real-world instances, we are able to increase the chance of identifying feasible solutions by some order of magnitude compared to standard MINLP heuristics that are already built in the general-purpose MINLP solver SCIP.}, language = {en} } @article{HumpolaFuegenschuh, author = {Humpola, Jesco and F{\"u}genschuh, Armin}, title = {Convex reformulations for solving a nonlinear network design problem}, series = {Computational Optimization and Applications}, volume = {62}, journal = {Computational Optimization and Applications}, number = {3}, publisher = {Springer US}, doi = {10.1007/s10589-015-9756-2}, pages = {717 -- 759}, abstract = {We consider a nonlinear nonconvex network design problem that arises, for example, in natural gas or water transmission networks. Given is such a network with active and passive components, that is, valves, compressors, control valves (active) and pipelines (passive), and a desired amount of flow at certain specified entry and exit nodes in the network. The active elements are associated with costs when used. Besides flow conservation constraints in the nodes, the flow must fulfill nonlinear nonconvex pressure loss constraints on the arcs subject to potential values (i.e., pressure levels) in both end nodes of each arc. The problem is to compute a cost minimal setting of the active components and numerical values for the flow and node potentials. We examine different (convex) relaxations for a subproblem of the design problem and benefit from them within a branch-and-bound approach. We compare different approaches based on nonlinear optimization numerically on a set of test instances.}, language = {en} } @article{HumpolaFuegenschuhKoch, author = {Humpola, Jesco and F{\"u}genschuh, Armin and Koch, Thorsten}, title = {Valid inequalities for the topology optimization problem in gas network design}, series = {OR Spectrum}, volume = {38}, journal = {OR Spectrum}, number = {3}, publisher = {Springer}, address = {Berlin Heidelberg}, doi = {https://doi.org/10.1007/s00291-015-0390-2}, pages = {597 -- 631}, abstract = {One quarter of Europe's energy demand is provided by natural gas distributed through a vast pipeline network covering the whole of Europe. At a cost of 1 million Euro per km extending the European pipeline network is already a multi-billion Euro business. Therefore, automatic planning tools that support the decision process are desired. Unfortunately, current mathematical methods are not capable of solving the arising network design problems due to their size and complexity. In this article, we will show how to apply optimization methods that can converge to a proven global optimal solution. By introducing a new class of valid inequalities that improve the relaxation of our mixed-integer nonlinear programming model, we are able to speed up the necessary computations substantially.}, language = {en} } @article{VierhausFuegenschuhGottwaldetal., author = {Vierhaus, Ingmar and F{\"u}genschuh, Armin and Gottwald, Robert Lion and Gr{\"o}sser, Stefan}, title = {Using white-box nonlinear optimization methods in system dynamics policy improvement}, series = {System Dynamics Review}, volume = {33}, journal = {System Dynamics Review}, number = {2}, doi = {10.1002/sdr.1583}, pages = {138 -- 168}, abstract = {We present a new strategy for the direct optimization of the values of policy functions. This approach is particularly well suited to model actors with a global perspective on the system and relies heavily on modern mathematical white-box optimization methods. We demonstrate our strategy on two classical models: market growth and World2. Each model is first transformed into an optimization problem by defining how the actor can influence the models' dynamics and by choosing objective functions to measure improvements. To improve comparability between different runs, we also introduce a comparison measure for possible interventions. We solve the optimization problems, discuss the resulting policies and compare them to the existing results from the literature. In particular, we present a run of the World2 model which significantly improves the published "towards a global equilibrium" run with equal cost of intervention.}, language = {en} }