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 - TY - GEN A1 - Dragan, Feodor F. A1 - Köhler, Ekkehard A1 - Leitert, Arne T1 - Line-distortion, Bandwidth and Path-length of a graph T2 - Algorithmica Y1 - 2017 U6 - https://doi.org/10.1007/s00453-015-0094-7 SN - 0178-4617 SN - 1432-0541 VL - 77 IS - 3 SP - 686 EP - 713 ER -