TY - GEN A1 - Fügenschuh, Armin T1 - Optimale Schulanfangszeiten Y1 - 2006 PB - Bild der Wissenschaft 11/2006, Sonderbeilage zum Klaus-Tschira-Preis ER - TY - JOUR A1 - Fügenschuh, Armin T1 - Optimal verknüpft - Schulanfangszeiten und öffentlicher Personennahverkehr JF - thema forschung Y1 - 2006 VL - 1 SP - 82 EP - 85 ER - TY - JOUR A1 - Fügenschuh, Armin T1 - Mathematische Modelle zur betrieblichen Optimierung JF - Z! - das Zukunftsmagazin Y1 - 2006 VL - 1 SP - 3 ER - TY - CHAP A1 - Eisenblätter, Andreas A1 - Koch, Thorsten A1 - Martin, Alexander A1 - Achterberg, Tobias A1 - Fügenschuh, Armin A1 - Koster, Arie M.C.A. A1 - Wegel, Oliver A1 - Wessäly, Roland ED - Anandalingam, G. ED - Raghavan, S. T1 - Modelling Feasible Network Configurations for UMTS T2 - Telecommunications Network Design and Management Y1 - 2003 UR - http://opus.kobv.de/zib/volltexte/2002/684/ PB - Kluver ER - TY - CHAP A1 - Eisenblätter, Andreas A1 - Fügenschuh, Armin A1 - Geerdes, Hans-Florian A1 - Junglas, Daniel A1 - Koch, Thorsten A1 - Martin, Alexander ED - Ahr, Dino ED - Fahrion, Roland ED - Oswald, Marcus ED - Reinelt, Gerhard T1 - Optimisation Methods for UMTS Radio Network Planning T2 - Operation Research Proceedings 2003 Y1 - 2003 U6 - https://doi.org/10.1007/978-3-642-17022-5_5 SP - 31 EP - 38 PB - Springer ER - TY - JOUR A1 - Eisenblätter, Andreas A1 - Fügenschuh, Armin A1 - Fledderus, E. A1 - Geerdes, Hans-Florian A1 - Heideck, B. A1 - Junglas, Daniel A1 - Koch, Thorsten A1 - Kürner, T. A1 - Martin, Alexander ED - Martin, Alexander T1 - Mathematical Methods for Automatic Optimization of UMTS Radio Networks Y1 - 2003 UR - http://momentum.zib.de/paper/momentum-d43.pdf IS - D4.3 PB - IST-2000-28088 MOMENTUM ER - TY - CHAP A1 - Fügenschuh, Armin A1 - Homfeld, Henning A1 - Martin, Alexander T1 - Leitwegeplanung T2 - Mathematik für Innovationen in Industrie und Dienstleistungen Y1 - 2007 ER - TY - CHAP A1 - Vierhaus, Ingmar A1 - Fügenschuh, Armin T1 - A Global Approach to the Optimal Control of System Dynamics Models T2 - Proceedings of the 31st International Conference of the System Dynamics Society N2 - The System Dynamics (SD) methodology is a framework for modeling and simulating the dynamic behavior of socioeconomic systems. Characteristic for the description of such systems is the occurrence of feedback loops together with stocks and flows. The mathematical equations that describe the system are usually ordinary differential equations and nonlinear algebraic constraints. Seemingly simple systems can show a nonintuitive, unpredictable behavior over time. Controlling a dynamical system means to specify potential interventions from outside that should keep the system on the desired track, and to define an evaluation schema to compare different controls among each other, so that a ``best'' control can be defined in a meaningful way. The central question is how to compute such globally optimal control for a given SD model, that allows the transition of the system into a desired state with minimum effort. We propose a mixed-integer nonlinear programming (MINLP) reformulation of the System Dynamics Optimization (SDO) problem. MINLP problems can be solved by linear programming based branch-and-bound approach. We demonstrate that standard MINLP solvers are not able to solve SDO problem. To overcome this obstacle, we introduce a special-tailored bound propagation method. Numerical results for these test cases are presented. Y1 - 2013 ER - TY - CHAP A1 - Vierhaus, Ingmar A1 - Fügenschuh, Armin A1 - Gottwald, Robert Lion A1 - Grösser, Stefan T1 - Modern Nonlinear Optimization Techniques for an Optimal Control of System Dynamics Models T2 - Proceedings of the 32nd International Conference of the System Dynamics Society N2 - We study System Dynamics models with several free parameters that can be altered by the user. We assume that the user's goal is to achieve a certain dynamic behavior of the model by varying these parameters. In order to find best possible combination of parameter settings, several automatic parameter tuning methods are described in the literature and readily available within existing System Dynamic software packages. We give a survey on the available techniques in the market and describe their theoretical background. Some of these methods are already six decades old, and meanwhile newer and more powerful optimization methods have emerged in the mathematical literature. One major obstacle for their direct use are tabled data in System Dynamics models, which are usually interpreted as piecewise linear functions. However, modern optimization methods usually require smooth functions which are twice continuously differentiable. We overcome this problem by a smooth spline interpolation of the tabled data. We use a test set of three complex System Dynamic models from the literature, describe their individual transition into optimization problems, and demonstrate the applicability of modern optimization algorithms to these System Dynamics Optimization problems. Y1 - 2014 ER - TY - CHAP A1 - Humpola, Jesco A1 - Fügenschuh, Armin A1 - Hiller, Benjamin A1 - Koch, Thorsten A1 - Lehmann, Thomas A1 - Lenz, Ralf A1 - Schwarz, Robert A1 - Schweiger, Jonas T1 - The Specialized MINLP Approach T2 - Evaluating Gas Network Capacities N2 - We propose an approach to solve the validation of nominations problem using mixed-integer nonlinear programming (MINLP) methods. Our approach handles both the discrete settings and the nonlinear aspects of gas physics. Our main contribution is an innovative coupling of mixed-integer (linear) programming (MILP) methods with nonlinear programming (NLP) that exploits the special structure of a suitable approximation of gas physics, resulting in a global optimization method for this type of problem. Y1 - 2015 SN - 9781611973686 VL - SIAM-MOS series on Optimization ER -