@misc{BorndoerferEgererKarbsteinetal., author = {Bornd{\"o}rfer, Ralf and Egerer, Ascan and Karbstein, Marika and Messerschmidt, Ralf and Perez, Marc and Pfisterer, Steven and Strauß, Petra}, title = {Kombil{\"o}sung: Optimierung des Liniennetzes in Karlsruhe}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-69677}, abstract = {Wir beschreiben die Optimierung des Nahverkehrsnetzes der Stadt Karlsruhe im Zusammmenhang mit den Baumaßnahmen der sogenannten Kombil{\"o}sung.}, language = {de} } @misc{BorndoerferKarbstein, author = {Bornd{\"o}rfer, Ralf and Karbstein, Marika}, title = {A Note on Menger's Theorem for Hypergraphs}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-14471}, number = {12-03}, abstract = {We prove the companion Theorem to Menger's Theorem for hypergraphs. This result gives rise to a new class of blocking pairs of ideal matrices, that generalize the incidence matrices of cuts and paths.}, language = {en} } @misc{BorndoerferFriedowKarbstein, author = {Bornd{\"o}rfer, Ralf and Friedow, Isabel and Karbstein, Marika}, title = {Optimierung des Linienplans 2010 in Potsdam}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-14486}, number = {12-04}, abstract = {Im Zuge der {\"U}bernahme von 6 Linien der Havelbus Verkehrsgesellschaft mbH durch die ViP Verkehr in Potsdam GmbH ergab sich 2009 die Notwendigkeit der Entwicklung eines neuen Linien- und Taktplans f{\"u}r das Jahr 2010. Das Konrad-Zuse-Zentrum f{\"u}r Informationstechnik Berlin (ZIB) entwickelt in einem Projekt des DFG-Forschungszentrums Matheon ein Verfahren zur mathematischen Linienoptimierung. Dieses Tool wurde bei der Optimierung des ViP Linienplans 2010 in einer projektbegleitenden Studie eingesetzt, um Alternativen bei verschiedenen Planungs- und Zielvorgaben auszuloten. In dem Artikel wird eine Auswertung der Ergebnisse mit dem Verkehrsanalysesystem Visum der PTV AG beschrieben. Die Auswertungen best{\"a}tigen, dass mit Hilfe von mathematischer Optimierung eine weitere Verk{\"u}rzung der Reisezeit um 1\%, eine als um 6\% verk{\"u}rzt empfundene Reisezeit, 10\% weniger Fahrzeit im Fahrzeug und eine gleichzeitige Kostenreduktion um 5\% m{\"o}glich sind.}, language = {de} } @inproceedings{BorndoerferHoppmannKarbstein, author = {Bornd{\"o}rfer, Ralf and Hoppmann, Heide and Karbstein, Marika}, title = {A Configuration Model for the Line Planning Problem}, series = {ATMOS 2013 - 13th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems}, volume = {33}, booktitle = {ATMOS 2013 - 13th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems}, editor = {Frigioni, Daniele and Stiller, Sebastian}, publisher = {Schloss Dagstuhl--Leibniz-Zentrum f{\"u}r Informatik}, doi = {10.4230/OASIcs.ATMOS.2013.68}, pages = {68 -- 79}, language = {en} } @incollection{BorndoerferHoangKarbsteinetal., author = {Bornd{\"o}rfer, Ralf and Hoang, Nam-Dung and Karbstein, Marika and Koch, Thorsten and Martin, Alexander}, title = {How many Steiner terminals can you connect in 20 years?}, series = {Facets of Combinatorial Optimization; Festschrift for Martin Gr{\"o}tschel}, booktitle = {Facets of Combinatorial Optimization; Festschrift for Martin Gr{\"o}tschel}, editor = {J{\"u}nger, Michael and Reinelt, Gerhard}, publisher = {Springer}, doi = {10.1007/978-3-642-38189-8_10}, pages = {215 -- 244}, language = {en} } @inproceedings{BorndoerferKarbstein, author = {Bornd{\"o}rfer, Ralf and Karbstein, Marika}, title = {A Direct Connection Approach to Integrated Line Planning and Passenger Routing}, series = {ATMOS 2012 - 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems}, volume = {25}, booktitle = {ATMOS 2012 - 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems}, editor = {Delling, Daniel and Liberti, Leo}, doi = {http://dx.doi.org/10.4230/OASIcs.ATMOS.2012.47}, pages = {47 -- 57}, language = {en} } @article{BorndoerferFriedowKarbstein, author = {Bornd{\"o}rfer, Ralf and Friedow, Isabel and Karbstein, Marika}, title = {Optimierung des Linienplans 2010 in Potsdam}, series = {Der Nahverkehr}, volume = {30}, journal = {Der Nahverkehr}, number = {4}, pages = {34 -- 39}, language = {de} } @inproceedings{BorndoerferKarbsteinMehrgahrdtetal., author = {Bornd{\"o}rfer, Ralf and Karbstein, Marika and Mehrgahrdt, Julika and Reuther, Markus and Schlechte, Thomas}, title = {The Cycle Embedding Problem}, series = {Operations Research Proceedings 2014}, booktitle = {Operations Research Proceedings 2014}, doi = {10.1007/978-3-319-28697-6_65}, pages = {465 -- 472}, abstract = {Given two hypergraphs, representing a fine and a coarse "layer", and a cycle cover of the nodes of the coarse layer, the cycle embedding problem (CEP) asks for an embedding of the coarse cycles into the fine layer. The CEP is NP-hard for general hypergraphs, but it can be solved in polynomial time for graphs. We propose an integer rogramming formulation for the CEP that provides a complete escription of the CEP polytope for the graphical case. The CEP comes up in railway vehicle rotation scheduling. We present computational results for problem instances of DB Fernverkehr AG that justify a sequential coarse-first-fine-second planning approach.}, language = {en} } @article{BorndoerferHoppmannKarbstein, author = {Bornd{\"o}rfer, Ralf and Hoppmann, Heide and Karbstein, Marika}, title = {Passenger routing for periodic timetable optimization}, series = {Public Transport}, journal = {Public Transport}, publisher = {Springer-Verlag Berlin Heidelberg}, doi = {10.1007/s12469-016-0132-0}, abstract = {The task of periodic timetabling is to determine trip arrival and departure times in a public transport system such that travel and transfer times are minimized. This paper investigates periodic timetabling models with integrated passenger routing. We show that different routing models can have a huge influence on the quality of the entire system: Whatever metric is applied, the performance ratios of timetables w.r.t. different routing models can be arbitrarily large. Computations on a real-world instance for the city of Wuppertal substantiate the theoretical findings. These results indicate the existence of untapped optimization potentials that can be used to improve the efficiency of public transport systems by integrating passenger routing.}, language = {en} } @inproceedings{BorndoerferHoppmannKarbstein, author = {Bornd{\"o}rfer, Ralf and Hoppmann, Heide and Karbstein, Marika}, title = {Separation of Cycle Inequalities for the Periodic Timetabling Problem}, series = {24th Annual European Symposium on Algorithms (ESA 2016)}, volume = {57}, booktitle = {24th Annual European Symposium on Algorithms (ESA 2016)}, doi = {10.4230/LIPIcs.ESA.2016.21}, abstract = {Cycle inequalities play an important role in the polyhedral study of the periodic timetabling problem. We give the first pseudo-polynomial time separation algorithm for cycle inequalities, and we give a rigorous proof for the pseudo-polynomial time separability of the change-cycle inequalities. The efficiency of these cutting planes is demonstrated on real-world instances of the periodic timetabling problem.}, language = {en} }