@misc{BeisegelChiarelliKoehleretal., author = {Beisegel, Jesse and Chiarelli, Nina and K{\"o}hler, Ekkehard and Krnc, Matjaž and Milanič, Martin and Pivač, Nevena and Scheffler, Robert and Strehler, Martin}, title = {Edge Elimination and Weighted Graph Classes}, series = {Graph-Theoretic Concepts in Computer Science - 46th International Workshop, {WG} 2020, Leeds, UK, June 24-26, 2020}, journal = {Graph-Theoretic Concepts in Computer Science - 46th International Workshop, {WG} 2020, Leeds, UK, June 24-26, 2020}, editor = {Adler, Isolde and M{\"u}ller, Haiko}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-60439-4}, issn = {1611-3349}, doi = {10.1007/978-3-030-60440-0_11}, pages = {134 -- 147}, language = {en} } @inproceedings{StrehlerDressler, author = {Strehler, Martin and Dressler, Daniel}, title = {Capacitated Confluent Flows: Complexity and Algorithms}, series = {Algorithms and Complexity, 7th International Conference, CIAC 2010, Rome, 2010}, booktitle = {Algorithms and Complexity, 7th International Conference, CIAC 2010, Rome, 2010}, publisher = {Berlin}, address = {Springer}, isbn = {978-3-642-13073-1}, pages = {347 -- 358}, 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} } @misc{DresslerStrehler, author = {Dressler, Daniel and Strehler, Martin}, title = {Polynomial-Time Algorithms for Special Cases of the Maximum Confluent Flow Problem}, series = {Discrete Applied Mathematics}, volume = {163}, journal = {Discrete Applied Mathematics}, number = {2}, issn = {0166-218X}, pages = {142 -- 154}, language = {en} } @phdthesis{Strehler, author = {Strehler, Martin}, title = {Signalized Flows - optimizing traffic signals and guideposts and related network flow problems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-23637}, pages = {182}, 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} } @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} } @inproceedings{MertingSchwanStrehler, author = {Merting, S{\"o}ren and Schwan, Christian and Strehler, Martin}, title = {Routing of Electric Vehicles: Constrained Shortest Path Problems with Resource Recovering Nodes}, series = {15th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2015)}, booktitle = {15th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2015)}, editor = {Italiano, Giuseppe F. and Schmidt, Marie}, publisher = {Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik}, address = {Dagstuhl, Germany}, isbn = {978-3-939897-99-6}, doi = {10.4230/OASIcs.ATMOS.2015.29}, url = {http://nbn-resolving.de/urn:nbn:de:0030-drops-54559}, pages = {29 -- 41}, abstract = {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.}, language = {en} } @misc{SchwanStrehler, author = {Schwan, Christian and Strehler, Martin}, title = {Energy-efficient Routing of Hybrid Vehicles}, series = {arXiv.org}, journal = {arXiv.org}, pages = {11}, abstract = {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.}, language = {en} }