TY - CHAP A1 - Hilger, Moritz A1 - Köhler, Ekkehard A1 - Möhring, Rolf H. A1 - Schilling, Heiko T1 - Fast Point-to-Point Shortest Path Computations with Arc-Flags Y1 - 2009 ER - TY - GEN A1 - Brandstädt, Andreas A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard T1 - Linear time algorithms for Hamiltonian problems on (claw,net)-free graphs T2 - SIAM journal on computing Y1 - 2000 SN - 0097-5397 VL - 30 IS - 5 SP - 1662 EP - 1677 ER - TY - CHAP A1 - Baier, Georg A1 - Erlebach, Thomas A1 - Hall, Alexander A1 - Köhler, Ekkehard A1 - Schilling, Heiko A1 - Skutella, Martin T1 - Length-bounded cuts and flows Y1 - 2006 ER - TY - GEN A1 - Baier, Georg A1 - Köhler, Ekkehard A1 - Skutella, Martin T1 - The k-Splittable Flow Problem Y1 - 2005 ER - TY - CHAP A1 - Corneil, Derek G. A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard ED - Rajsbaum, Sergio T1 - On the power of BFS to determine a graphs diameter T2 - LATIN 2002, theoretical informatics, proceedings, 5th Latin American Symposium, Cancun, Mexico, April 3 - 6, 2002 Y1 - 2002 SN - 3-540-43400-3 SP - 209 EP - 223 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Corneil, Derek G. A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard A1 - Yan, Chenyu ED - Kratsch, Dieter T1 - Collective tree 1-spanners for interval graphs T2 - Graph theoretic concepts in computer science, 31st international workshop, WG 2005, Metz, France, June 23 - 25, 2005 Y1 - 2005 SN - 3-540-31000-2 SN - 978-3-540-31000-6 SP - 151 EP - 162 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Möhring, Rolf H. A1 - Nökel, K. A1 - Wünsch, Gregor T1 - Optimization of signalized traffic networks Y1 - 2008 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Möhring, Rolf H. A1 - Skutella, Martin T1 - Traffic networks and flows over time Y1 - 2009 ER - TY - GEN A1 - Baumann, Nadine A1 - Köhler, Ekkehard T1 - Approximating earliest arrival flows with flow-dependent transit times Y1 - 2007 ER - TY - CHAP A1 - Baumann, Nadine A1 - Köhler, Ekkehard T1 - Approximating earliest arrival flows with flow-dependent transit times Y1 - 2004 ER - TY - CHAP A1 - Fekete, Sándor P. A1 - Hall, Alexander A1 - Köhler, Ekkehard A1 - Kröller, Alexander T1 - The Maximum Energy-Constrained Dynamic Flow Problem Y1 - 2008 ER - TY - GEN A1 - Corneil, Derek G. A1 - Köhler, Ekkehard A1 - Olariu, Stephan A1 - Stewart, Lorna T1 - Linear Orderings of Subfamilies of AT-Free Graphs Y1 - 2006 ER - TY - GEN A1 - Fekete, Sándor P. A1 - Köhler, Ekkehard A1 - Teich, Jürgen T1 - Higher-Dimensional Packing with Order Constraints Y1 - 2006 ER - TY - GEN A1 - Fekete, Sándor P. A1 - Köhler, Ekkehard A1 - Teich, Jürgen T1 - Extending Partial Suborders Y1 - 2001 ER - TY - CHAP A1 - Fekete, Sándor P. A1 - Köhler, Ekkehard A1 - Teich, Jürgen T1 - Higher-Dimensional Packing with Order Constraints Y1 - 2001 ER - TY - CHAP A1 - Gawrilow, Ewgenij A1 - Köhler, Ekkehard A1 - Möhring, Rolf H. A1 - Stenzel, Björn T1 - Dynamic Routing of Automated Guided Vehicles in Real-time Y1 - 2008 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Corneil, Derek G. A1 - Olariu, Stephan A1 - Stewart, Lorna T1 - On subfamilies of AT-free graphs Y1 - 2001 ER - TY - JOUR A1 - Köhler, Ekkehard T1 - Recognizing graphs without asteroidal triples Y1 - 2004 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Skutella, Martin T1 - Flows over Time with Load-Dependent Transit Times Y1 - 2003 ER - TY - JOUR A1 - Köhler, Ekkehard A1 - Skutella, Martin T1 - Flows over Time with Load-Dependent Transit Times Y1 - 2005 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Langkau, Katharina A1 - Skutella, Martin T1 - Time-Expanded Graphs for Flow-Dependent Transit Times Y1 - 2002 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Möhring, Rolf H. A1 - Schilling, Heiko T1 - Acceleration of shortest path and constrained shortest path computation Y1 - 2005 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Möhring, Rolf H. A1 - Wünsch, Gregor T1 - Minimizing Total Delay in Fixed-Time Controlled Traffic Networks Y1 - 2004 ER - TY - CHAP A1 - Liebchen, Christian A1 - Wünsch, Gregor A1 - Köhler, Ekkehard A1 - Reich, Alexander A1 - Rizzi, Romeo T1 - Benchmarks for strictly fundamental cycle bases Y1 - 2007 ER - TY - GEN A1 - Przulj, Natasha A1 - Corneil, Derek G. A1 - Köhler, Ekkehard T1 - Hereditary dominating pair graphs Y1 - 2004 ER - TY - GEN A1 - Baier, Georg A1 - Erlebach, Thomas A1 - Hall, Alexander A1 - Köhler, Ekkehard A1 - Schilling, Heiko A1 - Skutella, Martin T1 - Length-bounded cuts and flows Y1 - 2010 ER - TY - JOUR A1 - Köhler, Ekkehard A1 - Corneil, Derek G. A1 - Dragan, Feodor F. T1 - On the power of BFS to determine a graph's diameter Y1 - 2003 ER - TY - CHAP A1 - Fekete, Sándor P. A1 - Köhler, Ekkehard A1 - Teich, Jürgen ED - Nebel, Wolfgang T1 - Optimal FPGA module placement with temporal precedence constraints T2 - Proceedings, Design, Automation and Test in Europe Conference and Exhibition 2001, Munich, Germany, March 13 - 16, 2001 Y1 - 2001 SN - 0-7695-0993-2 SP - 658 EP - 665 PB - Computer Society Press CY - Los Alamitos [u.a.] ER - TY - JOUR A1 - Köhler, Ekkehard T1 - Connected domination and dominating clique in trapezoid graphs Y1 - 2000 ER - TY - CHAP A1 - Baier, Georg A1 - Köhler, Ekkehard A1 - Skutella, Martin T1 - On the k-Splittable Flow Problem Y1 - 2002 ER - TY - CHAP A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard T1 - An approximation algorithm for the tree t-spanner problem on unweighted graphs via generalized chordal graphs T2 - Approximation, Randomization and Combinatorial Optimization, Algorithms and Techniques, 14th International Workshop, APPROX 2011, and 15th International Workshop, RANDOM 2011, Princeton, NJ, USA Y1 - 2011 SN - 978-3-642-22934-3 SP - 171 EP - 183 PB - Springer CY - Heidelberg [u.a.] ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Strehler, Martin T1 - Traffic signal optimization using cyclically expanded networks T2 - 10th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS'10), September 9, 2010, Liverpool, United Kingdom Y1 - 2010 SN - 978-3-939897-20-0 SP - 114 EP - 129 PB - Schloss Dagstuhl - Leibniz-Zentrum für Informatik GmbH CY - Wadern ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Strehler, Martin T1 - Signalanlagenoptimierung mit zyklisch expandierten Netzwerken T2 - Optimierung in Verkehr und Transport, 16./17. 03. 2011, Stuttgart, Tagungsband Heureka '11 Y1 - 2011 SN - 978-3-941790-72-8 SP - 314 EP - 333 PB - FGSV-Verlag CY - Köln ER - TY - GEN A1 - Köhler, Ekkehard A1 - Strehler, Martin T1 - Combining Static and Dynamic Models for Traffic Signal Optimization Inherent Load-dependent Travel Times in a Cyclically Time-expanded Network Model T2 - Procedia - Social and Behavioral Science Y1 - 2012 UR - http://www.sciencedirect.com/science/article/pii/S1877042812042899 U6 - https://doi.org/10.1016/j.sbspro.2012.09.827 SN - 1877-0428 VL - 54 SP - 1125 EP - 1134 ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Mouatadid, Lalla ED - Ravi, R. ED - Gortz, Inge Li T1 - Linear Time LexDFS on Cocomparability Graphs T2 - Algorithm Theory – SWAT 2014, 14th Scandinavian Symposium and Workshops, Copenhagen, Denmark, July 2-4, 2014 Y1 - 2014 UR - http://link.springer.com/chapter/10.1007%2F978-3-319-08404-6_28 SN - 978-3-319-08404-6 U6 - https://doi.org/10.1007/978-3-319-08404-6_28 SP - 319 EP - 330 PB - Springer CY - Cham ER - TY - GEN A1 - Corneil, Derek G. A1 - Köhler, Ekkehard A1 - Lanlignel, Jean-Marc T1 - On end-vertices of Lexicographic Breadth First Searches T2 - Discrete Applied Mathematics Y1 - 2010 U6 - https://doi.org/10.1016/j.dam.2009.10.001 SN - 0166-218X VL - 158 IS - 5 SP - 434 EP - 443 ER - TY - CHAP A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard A1 - Leitert, Arne T1 - Line-Distortion, Bandwidth and Path-Length of a Graph T2 - Algorithm Theory - SWAT 2014 - 14th Scandinavian Symposium and Workshops, Copenhagen, Denmark, July 2-4, 2014 Y1 - 2014 SN - 978-3-319-08404-6 SN - 978-3-319-08403-9 U6 - https://doi.org/10.1007/978-3-319-08404-6_14 SP - 158 EP - 169 PB - Springer International Publ. ER - TY - CHAP A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard T1 - An Approximation Algorithm for the Tree t-Spanner Problem on Unweighted Graphs via Generalized Chordal Graphs T2 - 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 Y1 - 2012 SN - 978-3-642-22934-3 SN - 978-3-642-22935-0 U6 - https://doi.org/10.1007/978-3-642-22935-0_15 SP - 171 EP - 183 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Dragan, Feodor F. A1 - Corneil, Derek G. A1 - Köhler, Ekkehard A1 - Xiang, Yang T1 - Additive Spanners for Circle Graphs and Polygonal Graphs T2 - Graph-Theoretic Concepts in Computer Science, 34th International Workshop, WG 2008, Durham, UK, June 30 - July 2, 2008 Y1 - 2008 SN - 978-3-540-92247-6 U6 - https://doi.org/10.1007/978-3-540-92248-3_11 SP - 110 EP - 121 PB - Springer CY - Berlin [u.a.] ER - TY - GEN A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard T1 - An Approximation Algorithm for the Tree t-Spanner Problem on Unweighted Graphs via Generalized Chordal Graphs T2 - Algorithmica Y1 - 2014 U6 - https://doi.org/10.1007/s00453-013-9765-4 VL - 69 IS - 4 SP - 884 EP - 905 ER - TY - GEN A1 - Dragan, Feodor F. A1 - Corneil, Derek G. A1 - Köhler, Ekkehard A1 - Xiang, Yang T1 - Collective additive tree spanners for circle graphs and polygonal graphs T2 - Discrete Applied Mathematics Y1 - 2012 U6 - https://doi.org/10.1016/j.dam.2012.03.036 VL - 160 IS - 12 SP - 1717 EP - 1729 ER - TY - GEN A1 - Corneil, Derek G. A1 - Dusart, Jérémie A1 - Habib, Michel A1 - Köhler, Ekkehard T1 - On the Power of Graph Searching for Cocomparability Graphs T2 - SIAM Journal on Discrete Mathematics (SIDMA) Y1 - 2016 U6 - https://doi.org/10.1137/15M1012396 SN - 1095-7146 SN - 0895-4801 VL - 30 IS - 1 SP - 569 EP - 591 ER - TY - GEN A1 - Köhler, Ekkehard A1 - Strehler, Martin T1 - Traffic signal optimization using cyclically expanded networks T2 - Networks Y1 - 2015 U6 - https://doi.org/10.1002/net.21601 VL - 65 IS - 3 SP - 244 EP - 261 ER - TY - CHAP A1 - Köhler, Ekkehard T1 - Recognizing Graphs without Asteroidal Triples T2 - 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 Y1 - 2000 SN - 978-3-540-41183-3 SN - 978-3-540-40064-6 U6 - https://doi.org/10.1007/3-540-40064-8_24 SP - 255 EP - 266 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Köhler, Ekkehard A1 - Skutella, Martin T1 - Flows over time with load-dependent transit times T2 - Proceeding SODA '02 Proceedings of the thirteenth annual ACM-SIAM symposium on Discrete algorithms Y1 - 2002 SN - 0-89871-513-X SP - 174 EP - 183 PB - ACM Press [u.a.] CY - New York [u.a.] ER - TY - CHAP A1 - Möhring, Rolf H. A1 - Köhler, Ekkehard A1 - Gawrilow, Ewgenij A1 - Stenzel, Björn T1 - Conflict-free Real-time AGV Routing T2 - 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 Y1 - 2005 SN - 978-3-540-24274-1 SN - 978-3-540-27679-1 U6 - https://doi.org/10.1007/3-540-27679-3_3 SP - 18 EP - 24 PB - Springer CY - Berlin [u.a.] ER - TY - GEN A1 - Köhler, Ekkehard A1 - Liebchen, Christian A1 - Wünsch, Gregor A1 - Rizzi, Romeo T1 - Lower bounds for strictly fundamental cycle bases in grid graphs T2 - Networks : an international journal Y1 - 2009 U6 - https://doi.org/10.1002/net.20283 SN - 1097-0037 VL - 53 IS - 2 SP - 191 EP - 205 ER - TY - GEN A1 - Köhler, Ekkehard A1 - Mouatadid, Lalla T1 - A linear time algorithm to compute a maximum weighted independent set on cocomparability graphs T2 - Information Processing Letters Y1 - 2015 U6 - https://doi.org/10.1016/j.ipl.2015.12.001 SN - 0020-0190 VL - 116 IS - 6 SP - 391 EP - 395 ER - TY - GEN A1 - Köhler, Ekkehard A1 - Strehler, Martin T1 - Traffic signal optimization: combining static and dynamic models T2 - arXiv.org N2 - 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. KW - Discrete Mathematics Y1 - 2015 UR - http://arxiv.org/abs/1509.08709 ER - TY - GEN A1 - Schnellenbach, Jan A1 - Köhler, Ekkehard T1 - Zurück zum Rubikon: Wie der Primat der Politik in der Eurozone wieder dauerhaft hergestellt werden kann T2 - Badische Zeitung Y1 - 2012 IS - 23.08.2012 ER -