@misc{PetkovicKochZittel2021, author = {Petkovic, Milena and Koch, Thorsten and Zittel, Janina}, title = {Deep learning for spatio-temporal supply and demand forecasting in natural gas transmission networks}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-81221}, year = {2021}, abstract = {Germany is the largest market for natural gas in the European Union, with an annual consumption of approx. 95 billion cubic meters. Germany's high-pressure gas pipeline network is roughly 40,000 km long, which enables highly fluctuating quantities of gas to be transported safely over long distances. Considering that similar amounts of gas are also transshipped through Germany to other EU states, it is clear that Germany's gas transport system is essential to the European energy supply. Since the average velocity of gas in a pipeline is only 25km/h, an adequate high-precision, high-frequency forecasting of supply and demand is crucial for efficient control and operation of such a transmission network. We propose a deep learning model based on spatio-temporal convolutional neural networks (DLST) to tackle the problem of gas flow forecasting in a complex high-pressure transmission network. Experiments show that our model effectively captures comprehensive spatio-temporal correlations through modeling gas networks and consistently outperforms state-of-the-art benchmarks on real-world data sets by at least 21\$\\%\$. The results demonstrate that the proposed model can deal with complex nonlinear gas network flow forecasting with high accuracy and effectiveness.}, language = {en} } @article{LeKoch2021, author = {Le, Thi Thai and Koch, Thorsten}, title = {Instability of a tangential discontinuity surface in a three-dimensional compressible medium}, volume = {33}, journal = {Physics of Fluids}, number = {1}, doi = {10.1063/5.0033753}, pages = {016106}, year = {2021}, abstract = {Compressible flows appear in many natural and technological processes, for instance, the flow of natural gases in a pipe system. Thus, a detailed study of the stability of tangential velocity discontinuity in compressible media is relevant and necessary. The first early investigation in two-dimensional (2D) media was given more than 70 years ago. In this article, we continue investigating the stability in three-dimensional (3D) media. The idealized statement of this problem in an infinite spatial space was studied by Syrovatskii in 1954. However, the omission of the absolute sign of cos θ with θ being the angle between vectors of velocity and wave number in a certain inequality produced the inaccurate conclusion that the flow is always unstable for entire values of the Mach number M. First, we revisit this case to arrive at the correct conclusion, namely that the discontinuity surface is stabilized for a large Mach number with a given value of the angle θ. Next, we introduce a real finite spatial system such that it is bounded by solid walls along the flow direction. We show that the discontinuity surface is stable if and only if the dispersion relation equation has only real roots, with a large value of the Mach number; otherwise, the surface is always unstable. In particular, we show that a smaller critical value of the Mach number is required to make the flow in a narrow channel stable.}, language = {en} } @article{HoppmannBaumHenningsZitteletal.2021, author = {Hoppmann-Baum, Kai and Hennings, Felix and Zittel, Janina and Gotzes, Uwe and Spreckelsen, Eva-Maria and Spreckelsen, Klaus and Koch, Thorsten}, title = {An Optimization Approach for the Transient Control of Hydrogen Transport Networks}, journal = {Mathematical Methods of Operations Research}, number = {Special Issue on Energy Networks}, year = {2021}, language = {en} } @article{HoppmannBaumHenningsLenzetal.2021, author = {Hoppmann-Baum, Kai and Hennings, Felix and Lenz, Ralf and Gotzes, Uwe and Heinecke, Nina and Spreckelsen, Klaus and Koch, Thorsten}, title = {Optimal Operation of Transient Gas Transport Networks}, volume = {22}, journal = {Optimization and Engineering}, doi = {10.1007/s11081-020-09584-x}, pages = {735 -- 781}, year = {2021}, abstract = {In this paper, we describe an algorithmic framework for the optimal operation of transient gas transport networks consisting of a hierarchical MILP formulation together with a sequential linear programming inspired post-processing routine. Its implementation is part of the KOMPASS decision support system, which is currently used in an industrial setting. Real-world gas transport networks are controlled by operating complex pipeline intersection areas, which comprise multiple compressor units, regulators, and valves. In the following, we introduce the concept of network stations to model them. Thereby, we represent the technical capabilities of a station by hand-tailored artificial arcs and add them to network. Furthermore, we choose from a predefined set of flow directions for each network station and time step, which determines where the gas enters and leaves the station. Additionally, we have to select a supported simple state, which consists of two subsets of artificial arcs: Arcs that must and arcs that cannot be used. The goal is to determine a stable control of the network satisfying all supplies and demands. The pipeline intersections, that are represented by the network stations, were initially built centuries ago. Subsequently, due to updates, changes, and extensions, they evolved into highly complex and involved topologies. To extract their basic properties and to model them using computer-readable and optimizable descriptions took several years of effort. To support the dispatchers in controlling the network, we need to compute a continuously updated list of recommended measures. Our motivation for the model presented here is to make fast decisions on important transient global control parameters, i.e., how to route the flow and where to compress the gas. Detailed continuous and discrete technical control measures realizing them, which take all hardware details into account, are determined in a subsequent step. In this paper, we present computational results from the KOMPASS project using detailed real-world data.}, language = {en} } @article{PrauseHoppmannBaumDefournyetal.2021, author = {Prause, Felix and Hoppmann-Baum, Kai and Defourny, Boris and Koch, Thorsten}, title = {The maximum diversity assortment selection problem}, volume = {93}, journal = {Mathematical Methods of Operations Research}, publisher = {Mathematical Methods of Operations Research}, doi = {https://doi.org/10.1007/s00186-021-00740-2}, pages = {521 -- 554}, year = {2021}, abstract = {In this article, we introduce the Maximum Diversity Assortment Selection Problem (MDASP), which is a generalization of the two-dimensional Knapsack Problem (2D-KP). Given a set of rectangles and a rectangular container, the goal of 2D-KP is to determine a subset of rectangles that can be placed in the container without overlapping, i.e., a feasible assortment, such that a maximum area is covered. MDASP is to determine a set of feasible assortments, each of them covering a certain minimum threshold of the container, such that the diversity among them is maximized. Thereby, diversity is defined as the minimum or average normalized Hamming distance of all assortment pairs. MDASP was the topic of the 11th AIMMS-MOPTA Competition in 2019. The methods described in this article and the resulting computational results won the contest. In the following, we give a definition of the problem, introduce a mathematical model and solution approaches, determine upper bounds on the diversity, and conclude with computational experiments conducted on test instances derived from the 2D-KP literature.}, language = {en} } @misc{CharoussetBrignolvanAckooijOudjaneetal.2021, author = {Charousset-Brignol, Sandrine and van Ackooij, Wim and Oudjane, Nadia and Daniel, Dominique and Noceir, Slimane and Haus, Utz-Uwe and Lazzaro, Alfio and Frangioni, Antonio and Lobato, Rafael and Ghezelsoflu, Ali and Iardella, Niccol{\`o} and Galli, Laura and Gorgone, Enrico and dell'Amico, Mauro and Giannelos, Spyros and Moreira, Alex and Strbac, Goran and Borozan, Stefan and Falugi, Paula and Pudjianto, Danny and Wyrwoll, Lothar and Schmitt, Carlo and Franken, Marco and Beulertz, Daniel and Schwaeppe, Henrik and Most, Dieter and Y{\"u}ksel-Erg{\"u}n, Inci and Zittel, Janina and Koch, Thorsten}, title = {Synergistic approach of multi-energy models for a European optimal energy system management tool}, volume = {9}, journal = {The Project Repository Journal}, pages = {113 -- 116}, year = {2021}, language = {en} } @misc{RuschPetersKottigBoltzeetal.2021, author = {Rusch, Beate and Peters-Kottig, Wolfgang and Boltze, Julia and Brandtner, Andreas and Degkwitz, Andreas and Kirsch, Simona and Koch, Thorsten and Lohrum, Stefan and M{\"u}ller, Anja and Mutter, Moritz and Seeliger, Frank and Stanek, Ursula}, title = {KOBV Jahresbericht 2019-2020}, address = {Berlin}, organization = {Kooperativer Bibliotheksverbund Berlin-Brandenburg}, issn = {1438-0064}, doi = {10.12752/8247}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-82474}, pages = {84}, year = {2021}, abstract = {Der aktuelle KOBV-Jahresbericht informiert dar{\"u}ber, was in den Mitgliedsbibliotheken und Partnerprojekten in den letzten beiden Jahren passiert ist und was sich in der Verbundzentrale und in der Bibliothekslandschaft {\"a}ndert. Die Ausgabe 2019/2020 enth{\"a}lt den Schwerpunktteil »Digitalisierung« mit verschiedenen Perspektiven auf die digitale Arbeitswelt.}, language = {de} } @misc{BertelmannBoltzeCeynowaetal.2021, author = {Bertelmann, Roland and Boltze, Julia and Ceynowa, Klaus and Christof, J{\"u}rgen and Faensen, Katja and Groß, Matthias and Hoffmann, Cornelia and Koch, Thorsten and Kuberek, Monika and Lohrum, Stefan and Pampel, Heinz and Putnings, Markus and Retter, Regina and Rusch, Beate and Sch{\"a}ffler, Hildegard and S{\"o}llner, Konstanze and Steffen, Ronald and Wannick, Eike}, title = {DeepGreen: Open-Access-Transformation in der Informationsinfrastruktur - Anforderungen und Empfehlungen, Version 1.0}, issn = {1438-0064}, doi = {10.12752/8150}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-81503}, year = {2021}, abstract = {DeepGreen ist ein Service, der es teilnehmenden institutionellen Open-Access-Repositorien,Open-Access-Fachrepositorien und Forschungsinformationssystemen erleichtert, f{\"u}r sie relevante Verlagspublikationen in zyklischer Abfolge mithilfe von Schnittstellen Open Access zur Verf{\"u}gung zu stellen. Die entsprechende Bandbreite an Relationen zwischen den Akteuren, diverse lizenzrechtliche Rahmenbedingungen sowie technische Anforderungen gestalten das Thema komplex. Ziel dieser Handreichung ist es, neben all diesen Themen, die begleitend beleuchtet werden, im Besonderen Empfehlungen f{\"u}r die reibungslose Nutzung der Daten{\"u}bertragung zu liefern. Außerdem werden mithilfe einer vorangestellten Workflow- Evaluierung Unterschiede und Besonderheiten in den Arbeitsschritten bei institutionellen Open-Access-Repositorien und Open-Access-Fachrepositorien aufgezeigt und ebenfalls mit Empfehlungen angereichert.}, language = {de} } @misc{BestuzhevaBesanconChenetal.2021, author = {Bestuzheva, Ksenia and Besan{\c{c}}on, Mathieu and Chen, Wei-Kun and Chmiela, Antonia and Donkiewicz, Tim and van Doornmalen, Jasper and Eifler, Leon and Gaul, Oliver and Gamrath, Gerald and Gleixner, Ambros and Gottwald, Leona and Graczyk, Christoph and Halbig, Katrin and Hoen, Alexander and Hojny, Christopher and van der Hulst, Rolf and Koch, Thorsten and L{\"u}bbecke, Marco and Maher, Stephen J. and Matter, Frederic and M{\"u}hmer, Erik and M{\"u}ller, Benjamin and Pfetsch, Marc E. and Rehfeldt, Daniel and Schlein, Steffan and Schl{\"o}sser, Franziska and Serrano, Felipe and Shinano, Yuji and Sofranac, Boro and Turner, Mark and Vigerske, Stefan and Wegscheider, Fabian and Wellner, Philipp and Weninger, Dieter and Witzig, Jakob}, title = {The SCIP Optimization Suite 8.0}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-85309}, year = {2021}, abstract = {The SCIP Optimization Suite provides a collection of software packages for mathematical optimization centered around the constraint integer programming framework SCIP. This paper discusses enhancements and extensions contained in version 8.0 of the SCIP Optimization Suite. Major updates in SCIP include improvements in symmetry handling and decomposition algorithms, new cutting planes, a new plugin type for cut selection, and a complete rework of the way nonlinear constraints are handled. Additionally, SCIP 8.0 now supports interfaces for Julia as well as Matlab. Further, UG now includes a unified framework to parallelize all solvers, a utility to analyze computational experiments has been added to GCG, dual solutions can be postsolved by PaPILO, new heuristics and presolving methods were added to SCIP-SDP, and additional problem classes and major performance improvements are available in SCIP-Jack.}, language = {en} }