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 - GEN A1 - Dressler, Daniel A1 - Strehler, Martin T1 - Polynomial-Time Algorithms for Special Cases of the Maximum Confluent Flow Problem T2 - Discrete Applied Mathematics Y1 - 2014 SN - 0166-218X VL - 163 IS - 2 SP - 142 EP - 154 ER - TY - THES A1 - Strehler, Martin T1 - Signalized Flows – optimizing traffic signals and guideposts and related network flow problems Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus-23637 N1 - Auszeichnung „Beste Dissertation der BTU Cottbus“ 2012 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 - 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 - CHAP A1 - Merting, Sören A1 - Schwan, Christian A1 - Strehler, Martin ED - Italiano, Giuseppe F. ED - Schmidt, Marie T1 - Routing of Electric Vehicles: Constrained Shortest Path Problems with Resource Recovering Nodes T2 - 15th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2015) N2 - We consider a constrained shortest path problem with the possibility to refill the resource at certain nodes. This problem is motivated by routing electric vehicles with a comparatively short cruising range due to the limited battery capacity. Thus, for longer distances the battery has to be recharged on the way. Furthermore, electric vehicles can recuperate energy during downhill drive. We extend the common constrained shortest path problem to arbitrary costs on edges and we allow regaining resources at the cost of higher travel time. We show that this yields not shortest paths but shortest walks that may contain an arbitrary number of cycles. We study the structure of optimal solutions and develop approximation algorithms for finding short walks under mild assumptions on charging functions. We also address a corresponding network flow problem that generalizes these walks. KW - routing of electric vehicles, constrained shortest paths, FPTAS, con- strained network flow Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0030-drops-54559 UR - http://drops.dagstuhl.de/opus/volltexte/2015/5455 SN - 978-3-939897-99-6 SP - 29 EP - 41 PB - Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik CY - Dagstuhl, Germany ER - TY - GEN A1 - Schwan, Christian A1 - Strehler, Martin T1 - Energy-efficient Routing of Hybrid Vehicles T2 - arXiv.org N2 - We consider a constrained shortest path problem with two resources. These two resources can be converted into each other in a particular manner. Our practical application is the energy optimal routing of hybrid vehicles. Due to the possibility of converting fuel into electric energy this setting adds new characteristics and new combinatorial possibilities to the common constrained shortest path problem (CSP). We formulate the resulting problem as a generalization of CSP. We show that optimal paths in this model may contain cycles and we state conditions to prevent them. The main contribution is a polynomial-time approximation scheme and a simpler approximation algorithm for computing energy-optimal paths in graphs. KW - Discrete Mathematics Y1 - 2016 UR - http://arxiv.org/abs/1601.02371 ER - TY - CHAP A1 - Scheffler, Robert A1 - Strehler, Martin ED - Goerigk, Marc ED - Werneck, Renato T1 - Optimizing Traffic Signal Timings for Mega Events T2 - 16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016), ATMOS’16, August 25, 2016, Aarhus, Denmark Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0030-drops-66724 UR - http://drops.dagstuhl.de/opus/volltexte/2016/6532 SN - 978-3-95977-021-7 SP - 8,1 EP - 8,16 PB - Schloss Dagstuhl-Leibniz-Zentrum fuer Informatik CY - Dagstuhl, Germany ER - TY - CHAP A1 - Schade, Stanley A1 - Strehler, Martin ED - Goerigk, Marc ED - Werneck, Renato T1 - The Maximum Flow Problem for Oriented Flows T2 - 16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016) N2 - In several applications of network flows, additional constraints have to be considered. In this paper, we study flows, where the flow particles have an orientation. For example, cargo containers with doors only on one side and train coaches with 1st and 2nd class compartments have such an orientation. If the end position has a mandatory orientation, not every path from source to sink is feasible for routing or additional transposition maneuvers have to be made. As a result, a source-sink path may visit a certain vertex several times. We describe structural properties of optimal solutions, determine the computational complexity, and present an approach for approximating such flows. KW - network flow with orientation, graph expansion, approximation, container logistics, train routing Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0030-drops-65318 UR - http://drops.dagstuhl.de/opus/volltexte/2016/6531 SN - 978-3-95977-021-7 SP - 1 EP - 13 PB - Schloss Dagstuhl-Leibniz-Zentrum fuer Informatik CY - Dagstuhl, Germany ER - TY - GEN A1 - Strehler, Martin A1 - Merting, Sören A1 - Schwan, Christian T1 - Energy-efficient shortest routes for electric and hybrid vehicles T2 - Transportation Research Part B: Methodological Y1 - 2017 U6 - https://doi.org/10.1016/j.trb.2017.03.007 SN - 0191-2615 VL - Vol. 103 SP - 111 EP - 135 ER - TY - CHAP A1 - Strehler, Martin A1 - Scheffler, Robert ED - D'Angelo, Gianlorenzo ED - Dollevoet, Twan T1 - Optimizing Traffic Signal Settings for Public Transport Priority T2 - 17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017), September 7–8, 2017, Vienna, Austria KW - transit signal priority KW - traffic flow KW - traffic signal optimization KW - cyclically time-expanded network KW - public transport Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0030-drops-79109 UR - http://www.dagstuhl.de/dagpub/978-3-95977-042-2 SN - 978-3-95977-042-2 SP - 9-1 EP - 9-15 PB - Schloss Dagstuhl - Leibniz-Zentrum für Informatik GmbH CY - Wadern ER - TY - CHAP A1 - Schwan, Christian A1 - Strehler, Martin ED - Bock, Hans Georg ED - Phu, Hoang Xuan ED - Rannacher, Rolf ED - Schlöder, Johannes T1 - Two FPTAS for the Constrained Shortest Path Problem Applied to Hybrid Vehicle Routing T2 - Proceedings of the Sixth International Conference on High Performance Scientific Computing, March 16-20, 2015, Hanoi, Vietnam Y1 - 2017 SN - 978-3-319-67167-3 U6 - https://doi.org/10.1007/978-3-319-67168-0 SP - 223 EP - 234 PB - Springer International Publishing ET - 1. Auflage ER - TY - CHAP A1 - Scheffler, Robert A1 - Strehler, Martin A1 - Vargas Koch, Laura ED - Christodoulou, George ED - Harks, Tobias T1 - Equilibria in Routing Games with Edge Priorities T2 - 14th International Conference, WINE 2018, Oxford, UK, December 15–17, 2018, Proceedings Y1 - 2018 SN - 978-3-030-04612-5 U6 - https://doi.org/10.1007/978-3-030-04612-5_27 SP - 408 EP - 422 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Beisegel, Jesse A1 - Denkert, Carolin A1 - Köhler, Ekkehard A1 - Krnc, Matjaž A1 - Pivač, Nevena A1 - Scheffler, Robert A1 - Strehler, Martin T1 - Recognizing Graph Search Trees T2 - arXiv.org Y1 - 2018 UR - https://arxiv.org/abs/1811.09249v2 ER - TY - GEN A1 - Beisegel, Jesse A1 - Denkert, Carolin A1 - Köhler, Ekkehard A1 - Krnc, Matjaž A1 - Pivač, Nevena A1 - Scheffler, Robert A1 - Strehler, Martin T1 - On the End-Vertex Problem of Graph Searches T2 - Discrete Mathematics & Theoretical Computer Science Y1 - 2019 SN - 1365-8050 SN - 1462-7264 VL - 21 IS - 1 ER - TY - GEN A1 - Thunig, Theresa A1 - Scheffler, Robert A1 - Strehler, Martin A1 - Nagel, Kai T1 - Optimization and simulation of fixed-time traffic signal control in real-world applications T2 - 8th International Workshop on Agent-based Mobility, Traffic and Transportation Models, Methodologies and Applications ABMTRANS'19 Y1 - 2019 U6 - https://doi.org/10.1016/j.procs.2019.04.113 SN - 1877-0509 SP - 826 EP - 833 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Beisegel, Jesse A1 - Köhler, Ekkehard A1 - Scheffler, Robert A1 - Strehler, Martin T1 - Linear Time LexDFS on Chordal Graphs T2 - 28th Annual European Symposium on Algorithms (ESA) 2020, September 7-9, 2020, Pisa, Italy) Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0030-drops-128790 UR - https://drops.dagstuhl.de/opus/volltexte/2020/12879 VL - 173 SP - 13:1 EP - 13:13 PB - Schloss Dagstuhl, Leibnitz Zentrum für Informatik ER - TY - GEN A1 - Beisegel, Jesse A1 - Denkert, Carolin A1 - Köhler, Ekkehard A1 - Krnc, Matjaž A1 - Pivač, Nevena A1 - Scheffler, Robert A1 - Strehler, Martin ED - Coutinho, Gabriel ED - Kohayakawa, Yoshiharu ED - dos Santos, Vinicius ED - Urrutia, Sebastián T1 - Recognizing Graph Search Trees T2 - The proceedings of Lagos 2019, the tenth Latin and American Algorithms, Graphs and Optimization Symposium (LAGOS 2019) 2-7 June 2019, Belo Horizonte, Brazil Y1 - 2019 U6 - https://doi.org/10.1016/j.entcs.2019.08.010 SN - 1571-0661 SP - 99 EP - 110 PB - Elsevier ER - TY - GEN A1 - Köhler, Ekkehard A1 - Strehler, Martin T1 - Traffic Signal Optimization: Combining Static and Dynamic Models T2 - Transportation Science Y1 - 2019 U6 - https://doi.org/10.1287/trsc.2017.0760 SN - 1526-5447 VL - 53 IS - 1 SP - 21 EP - 41 ER - TY - GEN A1 - Beisegel, Jesse A1 - Denkert, Carolin A1 - Köhler, Ekkehard A1 - Krnc, Matjaž A1 - Pivač, Nevena A1 - Scheffler, Robert A1 - Strehler, Martin T1 - The Recognition Problem of Graph Search Trees T2 - SIAM Journal on Discrete Mathematics Y1 - 2021 U6 - https://doi.org/10.1137/20M1313301 SN - 1095-7146 SN - 0895-4801 VL - 35 IS - 2 SP - 1418 EP - 1446 ER - TY - GEN A1 - Köhler, Ekkehard A1 - Rogge, Markus A1 - Scheffler, Robert A1 - Strehler, Martin T1 - Optimal Bicycle Routes with Few Signal Stops T2 - 23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023) Y1 - 2023 U6 - https://doi.org/10.4230/OASIcs.ATMOS.2023.1 SN - 978-3-95977-302-7 VL - OASIcs - Open Access Series in Informatics; Band 115 SP - 1:1 EP - 1:14 PB - Schloss Dagstuhl – Leibniz-Zentrum für Informatik CY - Dagstuhl ER -