@incollection{HilgerKoehlerMoehringetal., author = {Hilger, Moritz and K{\"o}hler, Ekkehard and M{\"o}hring, Rolf H. and Schilling, Heiko}, title = {Fast Point-to-Point Shortest Path Computations with Arc-Flags}, language = {en} } @misc{BrandstaedtDraganKoehler, author = {Brandst{\"a}dt, Andreas and Dragan, Feodor F. and K{\"o}hler, Ekkehard}, title = {Linear time algorithms for Hamiltonian problems on (claw,net)-free graphs}, series = {SIAM journal on computing}, volume = {30}, journal = {SIAM journal on computing}, number = {5}, issn = {0097-5397}, pages = {1662 -- 1677}, language = {en} } @inproceedings{BaierErlebachHalletal., author = {Baier, Georg and Erlebach, Thomas and Hall, Alexander and K{\"o}hler, Ekkehard and Schilling, Heiko and Skutella, Martin}, title = {Length-bounded cuts and flows}, language = {en} } @misc{BaierKoehlerSkutella, author = {Baier, Georg and K{\"o}hler, Ekkehard and Skutella, Martin}, title = {The k-Splittable Flow Problem}, language = {en} } @inproceedings{CorneilDraganKoehler, author = {Corneil, Derek G. and Dragan, Feodor F. and K{\"o}hler, Ekkehard}, title = {On the power of BFS to determine a graphs diameter}, series = {LATIN 2002, theoretical informatics, proceedings, 5th Latin American Symposium, Cancun, Mexico, April 3 - 6, 2002}, booktitle = {LATIN 2002, theoretical informatics, proceedings, 5th Latin American Symposium, Cancun, Mexico, April 3 - 6, 2002}, editor = {Rajsbaum, Sergio}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {3-540-43400-3}, pages = {209 -- 223}, language = {en} } @inproceedings{CorneilDraganKoehleretal., author = {Corneil, Derek G. and Dragan, Feodor F. and K{\"o}hler, Ekkehard and Yan, Chenyu}, title = {Collective tree 1-spanners for interval graphs}, series = {Graph theoretic concepts in computer science, 31st international workshop, WG 2005, Metz, France, June 23 - 25, 2005}, booktitle = {Graph theoretic concepts in computer science, 31st international workshop, WG 2005, Metz, France, June 23 - 25, 2005}, editor = {Kratsch, Dieter}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {3-540-31000-2}, pages = {151 -- 162}, language = {en} } @incollection{KoehlerMoehringNoekeletal., author = {K{\"o}hler, Ekkehard and M{\"o}hring, Rolf H. and N{\"o}kel, K. and W{\"u}nsch, Gregor}, title = {Optimization of signalized traffic networks}, language = {en} } @incollection{KoehlerMoehringSkutella, author = {K{\"o}hler, Ekkehard and M{\"o}hring, Rolf H. and Skutella, Martin}, title = {Traffic networks and flows over time}, language = {en} } @misc{BaumannKoehler, author = {Baumann, Nadine and K{\"o}hler, Ekkehard}, title = {Approximating earliest arrival flows with flow-dependent transit times}, language = {en} } @inproceedings{BaumannKoehler, author = {Baumann, Nadine and K{\"o}hler, Ekkehard}, title = {Approximating earliest arrival flows with flow-dependent transit times}, language = {en} } @inproceedings{FeketeHallKoehleretal., author = {Fekete, S{\´a}ndor P. and Hall, Alexander and K{\"o}hler, Ekkehard and Kr{\"o}ller, Alexander}, title = {The Maximum Energy-Constrained Dynamic Flow Problem}, language = {en} } @misc{CorneilKoehlerOlariuetal., author = {Corneil, Derek G. and K{\"o}hler, Ekkehard and Olariu, Stephan and Stewart, Lorna}, title = {Linear Orderings of Subfamilies of AT-Free Graphs}, language = {en} } @misc{FeketeKoehlerTeich, author = {Fekete, S{\´a}ndor P. and K{\"o}hler, Ekkehard and Teich, J{\"u}rgen}, title = {Higher-Dimensional Packing with Order Constraints}, language = {en} } @misc{FeketeKoehlerTeich, author = {Fekete, S{\´a}ndor P. and K{\"o}hler, Ekkehard and Teich, J{\"u}rgen}, title = {Extending Partial Suborders}, language = {en} } @inproceedings{FeketeKoehlerTeich, author = {Fekete, S{\´a}ndor P. and K{\"o}hler, Ekkehard and Teich, J{\"u}rgen}, title = {Higher-Dimensional Packing with Order Constraints}, language = {en} } @incollection{GawrilowKoehlerMoehringetal., author = {Gawrilow, Ewgenij and K{\"o}hler, Ekkehard and M{\"o}hring, Rolf H. and Stenzel, Bj{\"o}rn}, title = {Dynamic Routing of Automated Guided Vehicles in Real-time}, language = {en} } @inproceedings{KoehlerCorneilOlariuetal., author = {K{\"o}hler, Ekkehard and Corneil, Derek G. and Olariu, Stephan and Stewart, Lorna}, title = {On subfamilies of AT-free graphs}, language = {en} } @article{Koehler, author = {K{\"o}hler, Ekkehard}, title = {Recognizing graphs without asteroidal triples}, language = {en} } @inproceedings{KoehlerSkutella, author = {K{\"o}hler, Ekkehard and Skutella, Martin}, title = {Flows over Time with Load-Dependent Transit Times}, language = {en} } @article{KoehlerSkutella, author = {K{\"o}hler, Ekkehard and Skutella, Martin}, title = {Flows over Time with Load-Dependent Transit Times}, language = {en} } @inproceedings{KoehlerLangkauSkutella, author = {K{\"o}hler, Ekkehard and Langkau, Katharina and Skutella, Martin}, title = {Time-Expanded Graphs for Flow-Dependent Transit Times}, language = {en} } @inproceedings{KoehlerMoehringSchilling, author = {K{\"o}hler, Ekkehard and M{\"o}hring, Rolf H. and Schilling, Heiko}, title = {Acceleration of shortest path and constrained shortest path computation}, language = {en} } @inproceedings{KoehlerMoehringWuensch, author = {K{\"o}hler, Ekkehard and M{\"o}hring, Rolf H. and W{\"u}nsch, Gregor}, title = {Minimizing Total Delay in Fixed-Time Controlled Traffic Networks}, language = {en} } @inproceedings{LiebchenWuenschKoehleretal., author = {Liebchen, Christian and W{\"u}nsch, Gregor and K{\"o}hler, Ekkehard and Reich, Alexander and Rizzi, Romeo}, title = {Benchmarks for strictly fundamental cycle bases}, language = {en} } @misc{PrzuljCorneilKoehler, author = {Przulj, Natasha and Corneil, Derek G. and K{\"o}hler, Ekkehard}, title = {Hereditary dominating pair graphs}, language = {en} } @misc{BaierErlebachHalletal., author = {Baier, Georg and Erlebach, Thomas and Hall, Alexander and K{\"o}hler, Ekkehard and Schilling, Heiko and Skutella, Martin}, title = {Length-bounded cuts and flows}, language = {en} } @article{KoehlerCorneilDragan, author = {K{\"o}hler, Ekkehard and Corneil, Derek G. and Dragan, Feodor F.}, title = {On the power of BFS to determine a graph's diameter}, language = {en} } @inproceedings{FeketeKoehlerTeich, author = {Fekete, S{\´a}ndor P. and K{\"o}hler, Ekkehard and Teich, J{\"u}rgen}, title = {Optimal FPGA module placement with temporal precedence constraints}, series = {Proceedings, Design, Automation and Test in Europe Conference and Exhibition 2001, Munich, Germany, March 13 - 16, 2001}, booktitle = {Proceedings, Design, Automation and Test in Europe Conference and Exhibition 2001, Munich, Germany, March 13 - 16, 2001}, editor = {Nebel, Wolfgang}, publisher = {Computer Society Press}, address = {Los Alamitos [u.a.]}, isbn = {0-7695-0993-2}, pages = {658 -- 665}, language = {en} } @article{Koehler, author = {K{\"o}hler, Ekkehard}, title = {Connected domination and dominating clique in trapezoid graphs}, language = {en} } @inproceedings{BaierKoehlerSkutella, author = {Baier, Georg and K{\"o}hler, Ekkehard and Skutella, Martin}, title = {On the k-Splittable Flow Problem}, language = {en} } @inproceedings{DraganKoehler, author = {Dragan, Feodor F. and K{\"o}hler, Ekkehard}, title = {An approximation algorithm for the tree t-spanner problem on unweighted graphs via generalized chordal graphs}, series = {Approximation, Randomization and Combinatorial Optimization, Algorithms and Techniques, 14th International Workshop, APPROX 2011, and 15th International Workshop, RANDOM 2011, Princeton, NJ, USA}, booktitle = {Approximation, Randomization and Combinatorial Optimization, Algorithms and Techniques, 14th International Workshop, APPROX 2011, and 15th International Workshop, RANDOM 2011, Princeton, NJ, USA}, publisher = {Springer}, address = {Heidelberg [u.a.]}, isbn = {978-3-642-22934-3}, pages = {171 -- 183}, language = {en} } @inproceedings{KoehlerStrehler, author = {K{\"o}hler, Ekkehard and Strehler, Martin}, title = {Traffic signal optimization using cyclically expanded networks}, series = {10th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS'10), September 9, 2010, Liverpool, United Kingdom}, booktitle = {10th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS'10), September 9, 2010, Liverpool, United Kingdom}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum f{\"u}r Informatik GmbH}, address = {Wadern}, isbn = {978-3-939897-20-0}, pages = {114 -- 129}, language = {en} } @inproceedings{KoehlerStrehler, author = {K{\"o}hler, Ekkehard and Strehler, Martin}, title = {Signalanlagenoptimierung mit zyklisch expandierten Netzwerken}, series = {Optimierung in Verkehr und Transport, 16./17. 03. 2011, Stuttgart, Tagungsband Heureka '11}, booktitle = {Optimierung in Verkehr und Transport, 16./17. 03. 2011, Stuttgart, Tagungsband Heureka '11}, publisher = {FGSV-Verlag}, address = {K{\"o}ln}, isbn = {978-3-941790-72-8}, pages = {314 -- 333}, language = {de} } @misc{KoehlerStrehler, author = {K{\"o}hler, Ekkehard and Strehler, Martin}, title = {Combining Static and Dynamic Models for Traffic Signal Optimization Inherent Load-dependent Travel Times in a Cyclically Time-expanded Network Model}, series = {Procedia - Social and Behavioral Science}, volume = {54}, journal = {Procedia - Social and Behavioral Science}, issn = {1877-0428}, doi = {10.1016/j.sbspro.2012.09.827}, pages = {1125 -- 1134}, language = {en} } @inproceedings{KoehlerMouatadid, author = {K{\"o}hler, Ekkehard and Mouatadid, Lalla}, title = {Linear Time LexDFS on Cocomparability Graphs}, series = {Algorithm Theory - SWAT 2014, 14th Scandinavian Symposium and Workshops, Copenhagen, Denmark, July 2-4, 2014}, booktitle = {Algorithm Theory - SWAT 2014, 14th Scandinavian Symposium and Workshops, Copenhagen, Denmark, July 2-4, 2014}, editor = {Ravi, R. and Gortz, Inge Li}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-08404-6}, doi = {10.1007/978-3-319-08404-6_28}, pages = {319 -- 330}, language = {en} } @misc{CorneilKoehlerLanlignel, author = {Corneil, Derek G. and K{\"o}hler, Ekkehard and Lanlignel, Jean-Marc}, title = {On end-vertices of Lexicographic Breadth First Searches}, series = {Discrete Applied Mathematics}, volume = {158}, journal = {Discrete Applied Mathematics}, number = {5}, issn = {0166-218X}, doi = {10.1016/j.dam.2009.10.001}, pages = {434 -- 443}, language = {en} } @inproceedings{DraganKoehlerLeitert, author = {Dragan, Feodor F. and K{\"o}hler, Ekkehard and Leitert, Arne}, title = {Line-Distortion, Bandwidth and Path-Length of a Graph}, series = {Algorithm Theory - SWAT 2014 - 14th Scandinavian Symposium and Workshops, Copenhagen, Denmark, July 2-4, 2014}, booktitle = {Algorithm Theory - SWAT 2014 - 14th Scandinavian Symposium and Workshops, Copenhagen, Denmark, July 2-4, 2014}, publisher = {Springer International Publ.}, isbn = {978-3-319-08404-6}, doi = {10.1007/978-3-319-08404-6_14}, pages = {158 -- 169}, language = {en} } @inproceedings{DraganKoehler, author = {Dragan, Feodor F. and K{\"o}hler, Ekkehard}, title = {An Approximation Algorithm for the Tree t-Spanner Problem on Unweighted Graphs via Generalized Chordal Graphs}, series = {Approximation, Randomization and Combinatorial Optimization, Algorithms and Techniques - 14th International Workshop, APPROX 2011 and 15th International Workshop, RANDOM 2011, Princeton, NJ, USA, August 17-19, 2011, Proceedings}, booktitle = {Approximation, Randomization and Combinatorial Optimization, Algorithms and Techniques - 14th International Workshop, APPROX 2011 and 15th International Workshop, RANDOM 2011, Princeton, NJ, USA, August 17-19, 2011, Proceedings}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-642-22934-3}, doi = {10.1007/978-3-642-22935-0_15}, pages = {171 -- 183}, language = {en} } @inproceedings{DraganCorneilKoehleretal., author = {Dragan, Feodor F. and Corneil, Derek G. and K{\"o}hler, Ekkehard and Xiang, Yang}, title = {Additive Spanners for Circle Graphs and Polygonal Graphs}, series = {Graph-Theoretic Concepts in Computer Science, 34th International Workshop, WG 2008, Durham, UK, June 30 - July 2, 2008}, booktitle = {Graph-Theoretic Concepts in Computer Science, 34th International Workshop, WG 2008, Durham, UK, June 30 - July 2, 2008}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-540-92247-6}, doi = {10.1007/978-3-540-92248-3_11}, pages = {110 -- 121}, language = {en} } @misc{DraganKoehler, author = {Dragan, Feodor F. and K{\"o}hler, Ekkehard}, title = {An Approximation Algorithm for the Tree t-Spanner Problem on Unweighted Graphs via Generalized Chordal Graphs}, series = {Algorithmica}, volume = {69}, journal = {Algorithmica}, number = {4}, doi = {10.1007/s00453-013-9765-4}, pages = {884 -- 905}, language = {en} } @misc{DraganCorneilKoehleretal., author = {Dragan, Feodor F. and Corneil, Derek G. and K{\"o}hler, Ekkehard and Xiang, Yang}, title = {Collective additive tree spanners for circle graphs and polygonal graphs}, series = {Discrete Applied Mathematics}, volume = {160}, journal = {Discrete Applied Mathematics}, number = {12}, doi = {10.1016/j.dam.2012.03.036}, pages = {1717 -- 1729}, language = {en} } @misc{CorneilDusartHabibetal., author = {Corneil, Derek G. and Dusart, J{\´e}r{\´e}mie and Habib, Michel and K{\"o}hler, Ekkehard}, title = {On the Power of Graph Searching for Cocomparability Graphs}, series = {SIAM Journal on Discrete Mathematics (SIDMA)}, volume = {30}, journal = {SIAM Journal on Discrete Mathematics (SIDMA)}, number = {1}, issn = {1095-7146}, doi = {10.1137/15M1012396}, pages = {569 -- 591}, language = {en} } @misc{KoehlerStrehler, author = {K{\"o}hler, Ekkehard and Strehler, Martin}, title = {Traffic signal optimization using cyclically expanded networks}, series = {Networks}, volume = {65}, journal = {Networks}, number = {3}, doi = {10.1002/net.21601}, pages = {244 -- 261}, language = {en} } @inproceedings{Koehler, author = {K{\"o}hler, Ekkehard}, title = {Recognizing Graphs without Asteroidal Triples}, series = {Graph-Theoretic Concepts in Computer Science, 26th International Workshop, WG 2000 Konstanz, Germany, June 15-17, 2000 Proceedings (Ulrik Brandes and Dorothea Wagner, eds.), LNCS 1928, Springer, 2000}, booktitle = {Graph-Theoretic Concepts in Computer Science, 26th International Workshop, WG 2000 Konstanz, Germany, June 15-17, 2000 Proceedings (Ulrik Brandes and Dorothea Wagner, eds.), LNCS 1928, Springer, 2000}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-540-41183-3}, doi = {10.1007/3-540-40064-8_24}, pages = {255 -- 266}, language = {en} } @inproceedings{KoehlerSkutella, author = {K{\"o}hler, Ekkehard and Skutella, Martin}, title = {Flows over time with load-dependent transit times}, series = {Proceeding SODA '02 Proceedings of the thirteenth annual ACM-SIAM symposium on Discrete algorithms}, booktitle = {Proceeding SODA '02 Proceedings of the thirteenth annual ACM-SIAM symposium on Discrete algorithms}, publisher = {ACM Press [u.a.]}, address = {New York [u.a.]}, isbn = {0-89871-513-X}, pages = {174 -- 183}, language = {en} } @inproceedings{MoehringKoehlerGawrilowetal., author = {M{\"o}hring, Rolf H. and K{\"o}hler, Ekkehard and Gawrilow, Ewgenij and Stenzel, Bj{\"o}rn}, title = {Conflict-free Real-time AGV Routing}, series = {Operations Research Proceedings 2004, Selected Papers of the Annual International Conference of the German Operations Research Society (GOR), Jointly Organized with the Netherlands Society for Operations Research (NGB) Tilburg, September 1-3, 2004}, booktitle = {Operations Research Proceedings 2004, Selected Papers of the Annual International Conference of the German Operations Research Society (GOR), Jointly Organized with the Netherlands Society for Operations Research (NGB) Tilburg, September 1-3, 2004}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-540-24274-1}, doi = {10.1007/3-540-27679-3_3}, pages = {18 -- 24}, language = {en} } @misc{KoehlerLiebchenWuenschetal., author = {K{\"o}hler, Ekkehard and Liebchen, Christian and W{\"u}nsch, Gregor and Rizzi, Romeo}, title = {Lower bounds for strictly fundamental cycle bases in grid graphs}, series = {Networks : an international journal}, volume = {53}, journal = {Networks : an international journal}, number = {2}, issn = {1097-0037}, doi = {10.1002/net.20283}, pages = {191 -- 205}, language = {en} } @misc{KoehlerMouatadid, author = {K{\"o}hler, Ekkehard and Mouatadid, Lalla}, title = {A linear time algorithm to compute a maximum weighted independent set on cocomparability graphs}, series = {Information Processing Letters}, volume = {116}, journal = {Information Processing Letters}, number = {6}, issn = {0020-0190}, doi = {10.1016/j.ipl.2015.12.001}, pages = {391 -- 395}, language = {en} } @misc{KoehlerStrehler, author = {K{\"o}hler, Ekkehard and Strehler, Martin}, title = {Traffic signal optimization: combining static and dynamic models}, series = {arXiv.org}, journal = {arXiv.org}, pages = {29}, abstract = {In this paper, we present a cyclically time-expanded network model for simultaneous optimization of traffic assignment and traffic signal parameters, in particular offsets, split times, and phase orders. Since travel times are of great importance for developing realistic solutions for traffic assignment and traffic signal coordination in urban road networks, we perform an extensive analysis of the model. We show that a linear time-expanded model can reproduce realistic travel times especially for use with traffic signals and we verify this by simulation. Furthermore, we show how exact mathematical programming techniques can be used for optimizing the control of traffic signals. We provide computational results for real world instances and demonstrate the capabilities of the cyclically time-expanded by simulation results obtained with state-of-the-art traffic simulation tools.}, language = {en} } @misc{SchnellenbachKoehler, author = {Schnellenbach, Jan and K{\"o}hler, Ekkehard}, title = {Zur{\"u}ck zum Rubikon: Wie der Primat der Politik in der Eurozone wieder dauerhaft hergestellt werden kann}, series = {Badische Zeitung}, journal = {Badische Zeitung}, number = {23.08.2012}, language = {de} }