8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems ATMOS 2008, September 18, 2008, Karlsruhe, Germany Edited by Matteo Fischetti Peter Widmayer OASIcs – Vol. 9 – ATMOS2008 www.dagstuhl.de/oasics Editors Matteo Fischetti Peter Widmayer DEI, Dipartimento di Ingegneria dell’Informazione Institut für Theoretische Informatik University of Padova Universitätstrasse 6 via Gradenigo 6/A 8092 Zürich, Switzerland 35131 Padova, Italy [email protected] [email protected] ACM Classification 1998 F.2 Analysis of Algorithms and Problem Complexity, G.1.6 Optimization, G.2.2 Graph Theory, G.2.3 Applications ISBN 978-3-939897-07-1 Published online and open access by Schloss Dagstuhl – Leibniz-Center for Informatics GmbH, Dagstuhl Publishing, Saarbrücken/Wadern, Germany. Publication date October, 2008. Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available in the Internet at http://dnb.d-nb.de. License This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works license: http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. In brief, this license authorizes each and everybody to share (to copy, distribute and transmit) the work under the following conditions, without impairing or restricting the author’s moral rights: Attribution: The work must be attributed to its authors. Noncommercial: The work may not be used for commercial purposes. No derivation: It is not allowed to alter or transform this work. The copyright is retained by the corresponding authors. Digital Object Identifier: 10.4230/OASIcs.ATMOS.2008.i ISBN 978-3-939897-07-1 ISSN 2190-6807 http://www.dagstuhl.de/oasics OASIcs – OpenAccess Series in Informatics OASIcs aims at a suitable publication venue to publish peer-reviewed collections of papers emerging from a scientific event. OASIcs volumes are published according to the principle of Open Access, i.e., they are available online and free of charge. ISSN 2190-6807 www.dagstuhl.de/oasics ATMOS 2008 Preface: Algorithmic Approaches for Transportation Modeling, Optimization, and Systems Matteo Fischetti1 and Peter Widmayer2 DEI, Dipartimento di Ingegneria dell’Informazione, University of Padova, Italy [email protected] Institute of Theoretical Computer Science, ETH Z¨urich, Switzerland [email protected] The 8th ATMOS workshop was held in Karlsruhe, September 18, 2008, within ALGO, a set of meetings related to algorithms. The se- ries of ATMOS workshops, starting in Heraklion in 2001, continuing in Malaga in 2002, Budapest in 2003, Bergen in 2004, Palma de Mallorca in 2005, Z¨urich in 2006, and Sevilla in 2007 is by now an established series of meetings between algorithms researchers dealing with transportation problems, and practitioners, mainly from railways. The focus of ATMOS is on complex and large-scale network optimization problems that require new solution techniques and ideas from mathematical optimization and theoretical computer science. Tools and concepts are rooted in graph and network algorithms, combinatorial optimization, approximation and on- line algorithms, stochastic and robust optimization. Of particular interest are – Infrastructure Planning – Line Planning – Timetable Generation – Routing and Platform Assignment – Vehicle Scheduling – Crew and Duty Scheduling – Rostering – Demand Forecasting – Design of TariffSystems – Maintenance and Shunting of Rolling Stock – Delay Management – Rolling Stock Rescheduling – Simulation Tools for Railway Operations – Timetable Information More generally, ATMOS aims at the successful integration of sev- eral of these subproblems or planning stages, algorithms operating in an ATMOS 2008 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems http://drops.dagstuhl.de/opus/volltexte/2008/1593 2 Matteo Fischetti and Peter Widmayer online/realtime or stochastic setting and heuristic or approximate algo- rithms for real-world instances. We received 15 submissions, out of which 12 were selected for pre- sentation and inclusion in this volume, in a thorough reviewing process guided by the program committee consisting of – Cynthia Barnhart, MIT – Ralf Bornd¨orfer, Zuse Institute Berlin – Alberto Caprara, University of Bologna – Jens Clausen, Technical University of Denmark – Guy Desaulniers, GERAD, Ecole Polytechnique Montr´eal – Matteo Fischetti, University of Padova (Co-Chair) – Leo Kroon RSM Erasmus University and Netherlands Railways – Marc Nunkesser, ETH Z¨urich – Anita Sch¨obel, University of G¨ottingen – Dorothea Wagner, University of Karlsruhe – Peter Widmayer, ETH Z¨urich (Co-Chair) In addition, Rolf M¨ohring gave an invited talk on “Timetabling and Robustness: Computing Good and Delay-Resistant Timetables”. We sincerely thank the program committee for the competent work in selecting the best papers and the external referees for their help, the organizer Marc Nunkesser for taking care of all arrangements, the ALGO organizing committee for embedding ATMOS so smoothly into the ALGO programme, the editors of the Dagstuhl Seminar Proceedings for accept- ing the publication of this volume within DROPS, and, last but not least, the participants for the lively interaction that is the ultimate goal of the meeting. Padova and Z¨urich, October 2008 Matteo Fischetti and Peter Widmayer ATMOS 2008 - Abstracts Collection Selected Papers from the 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems Matteo Fischetti1 and Peter Widmayer2 University of Padova, IT and ETH Zürich, CH Abstract. Proceedings of the 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems, held on Sept- meber 18 in Karlsruhe, Germany. ATMOS 2008 Preface 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems The 8th ATMOS workshop was held in Karlsruhe, September 18, 2008, within ALGO, a set of meetings related to algorithms. The series of ATMOS workshops, starting in Heraklion in 2001, continuing in Malaga in 2002, Budapest in 2003, Bergen in 2004, Palma de Mallorca in 2005, Zürich in 2006, and Sevilla in 2007 is by now an established series of meetings between algorithms researchers dealing with transportation problems, and practitioners, mainly from railways. Joint work of: Fischetti, Matteo; Widmayer, Peter Extended Abstract: http://drops.dagstuhl.de/opus/volltexte/2008/1593 Dynamic Algorithms for Recoverable Robustness Problems Recently, the recoverable robustness model has been introduced in the optimiza- tion area. This model allows to consider disruptions (input data changes) in a unied way, that is, during both the strategic planning phase and the operational phase. Although the model represents a signicant improvement, it has the fol- lowing drawback: we are typically not facing only one disruption, but many of them might appear one after another. In this case, the solutions provided in the context of the recoverable robustness are not satisfying. In this paper we extend the concept of recoverable robustness to deal not only with one single recovery step, but with arbitrarily many recovery steps. To this aim, we introduce the notion of dynamic recoverable robustness problems. We apply the new model in the context of timetabling and delay management problems. We are interested in nding ecient dynamic robust algorithms for solving the timetabling problem and in evaluating the price of robustness of the proposed solutions. ATMOS 2008 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems http://drops.dagstuhl.de/opus/volltexte/2008/1592 2 M. Fischetti, P. Widmayer Keywords: Robustness, optimization problems, dynamic algorithms, timetabling, delay management Joint work of: Cicerone, Serano; Di Stefano, Gabriele; Schachtebeck, Michael; Schöbel, Anita Full Paper: http://drops.dagstuhl.de/opus/volltexte/2008/1587 Ecient On-Trip Timetable Information in the Presence of Delays The search for train connections in state-of-the-art commercial timetable infor- mation systems is based on a static schedule. Unfortunately, public transporta- tion systems suer from delays for various reasons. Thus, dynamic changes of the planned schedule have to be taken into account. A system that has access to delay information of trains (and uses this information within search queries) can provide valid alternatives in case a train change breaks. Additionally, it can be used to actively guide passengers as these alternatives may be presented before the passenger is already stranded at a station due to a broken transfer. In this work we present an approach which takes a stream of delay information and schedule changes on short notice (partial train cancellations, extra trains) into account. Primary delays of trains may cause a cascade of so-called secondary delays of other trains which have to wait according to certain waiting policies between connecting trains. We introduce the concept of a dependency graph to eciently calculate and update all primary and secondary delays. This delay in- formation is then incorporated into a time-expanded search graph which has to be updated dynamically. These update operations are quite complex, but turn out to be not time-critical in a fully realistic scenario. We nally present a case study with data provided by Deutsche Bahn AG showing that this approach has been