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Volume

OASIcs, Volume 20

11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems

ATMOS 2011, September 8, 2011, Saarbrücken, Germany

Editors: Alberto Caprara and Spyros Kontogiannis

Document

DOI: 10.4230/OASIcs.ATMOS.2012.1

A Fast Heuristic Algorithm for the Train Unit Assignment Problem

Authors: Valentina Cacchiani, Alberto Caprara, and Paolo Toth

Published in: OASIcs, Volume 25, 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2012)

Abstract

In this paper we study a railway optimization problem known as the Train Unit Assignment Problem. A train unit consists of a self-contained train with an engine and a set of wagons with passenger seats. Given a set of timetabled train trips, each with a required number of passenger seats, and a set of train units, each with a given number of available seats, the problem calls for the best assignment of the train units to the trips, possibly combining more than one train unit for a given trip, that fulfills the seat requests. We propose a heuristic algorithm based on the computation of a lower bound obtained by solving an Integer Linear Programming model that gives the optimal solution in a "peak period" of the day. The performance of the heuristic algorithm is computationally evaluated on real-world instances provided by a regional Italian Train Operator. The results are compared with those of existing methods from the literature, showing that the new method is able to obtain solutions of good quality in much shorter computing times.

Cite as

Valentina Cacchiani, Alberto Caprara, and Paolo Toth. A Fast Heuristic Algorithm for the Train Unit Assignment Problem. In 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 25, pp. 1-9, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{cacchiani_et_al:OASIcs.ATMOS.2012.1,
  author =	{Cacchiani, Valentina and Caprara, Alberto and Toth, Paolo},
  title =	{{A Fast Heuristic Algorithm for the Train Unit Assignment Problem}},
  booktitle =	{12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{1--9},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-45-3},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{25},
  editor =	{Delling, Daniel and Liberti, Leo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2012.1},
  URN =		{urn:nbn:de:0030-drops-36971},
  doi =		{10.4230/OASIcs.ATMOS.2012.1},
  annote =	{Keywords: Train Unit Assignment, Heuristic Algorithm, ILP model, Real-world instances}
}

Document

Complete Volume

DOI: 10.4230/OASIcs.ATMOS.2011

OASIcs, Volume 20, ATMOS'11, Complete Volume

Authors: Alberto Caprara and Spyros Kontogiannis

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

OASIcs, Volume 20, ATMOS'11, Complete Volume

Cite as

11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@Proceedings{caprara_et_al:OASIcs.ATMOS.2011,
  title =	{{OASIcs, Volume 20, ATMOS'11, Complete Volume}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011},
  URN =		{urn:nbn:de:0030-drops-35824},
  doi =		{10.4230/OASIcs.ATMOS.2011},
  annote =	{Keywords: Analysis of Algorithms and Problem Complexity, Optimization, Graph Theory, Applications}
}

Document

Front Matter

DOI: 10.4230/OASIcs.ATMOS.2011.i

Frontmatter, Table of Contents, Preface, Workshop Organization

Authors: Alberto Caprara and Spyros Kontogiannis

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

Frontmatter, Table of contents, Preface, Workshop Organization

Cite as

11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. i-ix, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{caprara_et_al:OASIcs.ATMOS.2011.i,
  author =	{Caprara, Alberto and Kontogiannis, Spyros},
  title =	{{Frontmatter, Table of Contents, Preface, Workshop Organization}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{i--ix},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.i},
  URN =		{urn:nbn:de:0030-drops-32618},
  doi =		{10.4230/OASIcs.ATMOS.2011.i},
  annote =	{Keywords: Frontmatter, Table of contents, Preface, Workshop Organization}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.1

Real-time traffic control in railway systems

Authors: Carlo Mannino

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

Despite the constantly increasing demand of passengers and goods transport in Europe, the share of railway traffic is decreasing. One major reason appears to be congestion, which in turn results in frequent delays and in a general unreliability of the system. This fact has triggered the study of efficient ways to manage railway traffic, both off-line and real-time, by means of optimization and mathematical programming techniques. And yet, to our knowledge, there are only a few fully automated real-time traffic control systems which are actually in operation in the European railway system; in most cases such systems only control very simple lines and actually they only support the activity of human dispatchers. We describe here two recent optimization based applications to real-time traffic control which have actually been put into operation in the Italian railways. One such system has been able to fully control the trains in the terminal stations of Milano metro system. The other one will be fully operative by the end of 2012, when it will control the trains on several Italian single-track railways. Both systems heavily rely on mixed integer programming techniques to elaborate good quality timetables in real time.

Cite as

Carlo Mannino. Real-time traffic control in railway systems. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 1-14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{mannino:OASIcs.ATMOS.2011.1,
  author =	{Mannino, Carlo},
  title =	{{Real-time traffic control in railway systems}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{1--14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.1},
  URN =		{urn:nbn:de:0030-drops-32623},
  doi =		{10.4230/OASIcs.ATMOS.2011.1},
  annote =	{Keywords: Railway systems, traffic control}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.15

A bilevel rescheduling framework for optimal inter-area train coordination

Authors: Francesco Corman, Andrea D'Ariano, Dario Pacciarelli, and Marco Pranzo

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

Railway dispatchers reschedule trains in real-time in order to limit the propagation of disturbances and to regulate traffic in their respective dispatching areas by minimizing the deviation from the off-line timetable. However, the decisions taken in one area may influence the quality and even the feasibility of train schedules in the other areas. Regional control centers coordinate the dispatchers' work for multiple areas in order to regulate traffic at the global level and to avoid situations of global infeasibility. Differently from the dispatcher problem, the coordination activity of regional control centers is still underinvestigated, even if this activity is a key factor for effective traffic management. This paper studies the problem of coordinating several dispatchers with the objective of driving their behavior towards globally optimal solutions. With our model, a coordinator may impose constraints at the border of each dispatching area. Each dispatcher must then schedule trains in its area by producing a locally feasible solution compliant with the border constraints imposed by the coordinator. The problem faced by the coordinator is therefore a bilevel programming problem in which the variables controlled by the coordinator are the border constraints. We demonstrate that the coordinator problem can be solved to optimality with a branch and bound procedure. The coordination algorithm has been tested on a large real railway network in the Netherlands with busy traffic conditions. Our experimental results show that a proven optimal solution is frequently found for various network divisions within computation times compatible with real-time operations.

Cite as

Francesco Corman, Andrea D'Ariano, Dario Pacciarelli, and Marco Pranzo. A bilevel rescheduling framework for optimal inter-area train coordination. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 15-26, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{corman_et_al:OASIcs.ATMOS.2011.15,
  author =	{Corman, Francesco and D'Ariano, Andrea and Pacciarelli, Dario and Pranzo, Marco},
  title =	{{A bilevel rescheduling framework for optimal inter-area train coordination}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{15--26},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.15},
  URN =		{urn:nbn:de:0030-drops-32636},
  doi =		{10.4230/OASIcs.ATMOS.2011.15},
  annote =	{Keywords: Train Delay Minimization, Schedule Coordination, Bilevel Programming}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.27

The Lockmaster's problem

Authors: Sofie Coene and Frits C. R. Spieksma

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

Inland waterways form a natural network that is an existing, congestion free infrastructure with capacity for more traffic. The European commission promotes the transportation of goods by ship as it is a reliable, efficient and environmental friendly way of transport. A bottleneck for transportation over water are the locks that manage the water level. The lockmaster's problem concerns the optimal strategy for operating such a lock. In the lockmaster's problem we are given a lock, a set of ships coming from downstream that want to go upstream, and another set of ships coming from upstream that want to go downstream. We are given the arrival times of the ships and a constant lockage time; the goal is to minimize total waiting time of the ships. In this paper a dynamic programming algorithm (DP) is proposed that solves the lockmaster's problem in polynomial time. We extend this DP to different generalizations that consider weights, water usage, capacity, and (a fixed number of) multiple chambers. Finally, we prove that the problem becomes strongly NP-hard when the number of chambers is part of the input.

Cite as

Sofie Coene and Frits C. R. Spieksma. The Lockmaster's problem. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 27-37, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{coene_et_al:OASIcs.ATMOS.2011.27,
  author =	{Coene, Sofie and Spieksma, Frits C. R.},
  title =	{{The Lockmaster's problem}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{27--37},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.27},
  URN =		{urn:nbn:de:0030-drops-32647},
  doi =		{10.4230/OASIcs.ATMOS.2011.27},
  annote =	{Keywords: lock scheduling, batch scheduling, dynamic programming, complexity}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.38

Track Allocation in Freight-Train Classification with Mixed Tracks

Authors: Markus Bohlin, Holger Flier, Jens Maue, and Matús Mihalák

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

We consider the process of forming outbound trains from cars of inbound trains at rail-freight hump yards. Given the arrival and departure times as well as the composition of the trains, we study the problem of allocating classification tracks to outbound trains such that every outbound train can be built on a separate classification track. We observe that the core problem can be formulated as a special list coloring problem in interval graphs, which is known to be NP-complete. We focus on an extension where individual cars of different trains can temporarily be stored on a special subset of the tracks. This problem induces several new variants of the list-coloring problem, in which the given intervals can be shortened by cutting off a prefix of the interval. We show that in case of uniform and sufficient track lengths, the corresponding coloring problem can be solved in polynomial time, if the goal is to minimize the total cost associated with cutting off prefixes of the intervals. Based on these results, we devise two heuristics as well as an integer program to tackle the problem. As a case study, we consider a real-world problem instance from the Hallsberg Rangerbangard hump yard in Sweden. Planning over horizons of seven days, we obtain feasible solutions from the integer program in all scenarios, and from the heuristics in most scenarios.

Cite as

Markus Bohlin, Holger Flier, Jens Maue, and Matús Mihalák. Track Allocation in Freight-Train Classification with Mixed Tracks. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 38-51, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{bohlin_et_al:OASIcs.ATMOS.2011.38,
  author =	{Bohlin, Markus and Flier, Holger and Maue, Jens and Mihal\'{a}k, Mat\'{u}s},
  title =	{{Track Allocation in Freight-Train Classification with Mixed Tracks}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{38--51},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.38},
  URN =		{urn:nbn:de:0030-drops-32658},
  doi =		{10.4230/OASIcs.ATMOS.2011.38},
  annote =	{Keywords: algorithms, complexity, graph theory, railways, scheduling, shunting, train classification, train marshalling, transportation}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.52

Faster Batched Shortest Paths in Road Networks

Authors: Daniel Delling, Andrew V. Goldberg, and Renato F. Werneck

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

We study the problem of computing batched shortest paths in road networks efficiently. Our focus is on computing paths from a single source to multiple targets (one-to-many queries). We perform a comprehensive experimental comparison of several approaches, including new ones. We conclude that a new extension of PHAST (a recent one-to-all algorithm), called RPHAST, has the best performance in most cases, often by orders of magnitude. When used to compute distance tables (many-to-many queries), RPHAST often outperforms all previous approaches.

Cite as

Daniel Delling, Andrew V. Goldberg, and Renato F. Werneck. Faster Batched Shortest Paths in Road Networks. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 52-63, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{delling_et_al:OASIcs.ATMOS.2011.52,
  author =	{Delling, Daniel and Goldberg, Andrew V. and Werneck, Renato F.},
  title =	{{Faster Batched Shortest Paths in Road Networks}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{52--63},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.52},
  URN =		{urn:nbn:de:0030-drops-32663},
  doi =		{10.4230/OASIcs.ATMOS.2011.52},
  annote =	{Keywords: shortest paths, contraction hierarchies, many-to-many, one-to-many}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.64

UniALT for regular language contrained shortest paths on a multi-modal transportation network

Authors: Dominik Kirchler, Leo Liberti, Thomas Pajor, and Roberto Wolfler Calvo

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

Shortest paths on road networks can be efficiently calculated using Dijkstra's algorithm (D). In addition to roads, multi-modal transportation networks include public transportation, bicycle lanes, etc. For paths on this type of network, further constraints, e.g., preferences in using certain modes of transportation, may arise. The regular language constrained shortest path problem deals with this kind of problem. It uses a regular language to model the constraints. The problem can be solved efficiently by using a generalization of Dijkstra's algorithm (D_RegLC). In this paper we propose an adaption of the speed-up technique uniALT, in order to accelerate D_RegLC. We call our algorithm SDALT. We provide experimental results on a realistic multi-modal public transportation network including time-dependent cost functions on arcs. The experiments show that our algorithm performs well, with speed-ups of a factor 2 to 20.

Cite as

Dominik Kirchler, Leo Liberti, Thomas Pajor, and Roberto Wolfler Calvo. UniALT for regular language contrained shortest paths on a multi-modal transportation network. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 64-75, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{kirchler_et_al:OASIcs.ATMOS.2011.64,
  author =	{Kirchler, Dominik and Liberti, Leo and Pajor, Thomas and Wolfler Calvo, Roberto},
  title =	{{UniALT for regular language contrained shortest paths on a multi-modal transportation network}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{64--75},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.64},
  URN =		{urn:nbn:de:0030-drops-32670},
  doi =		{10.4230/OASIcs.ATMOS.2011.64},
  annote =	{Keywords: time-dependency, ALT, regular language, shortest path, multi-modal}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.76

The Price of Robustness in Timetable Information

Authors: Marc Goerigk, Martin Knoth, Matthias Müller-Hannemann, Marie Schmidt, and Anita Schöbel

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

In timetable information in public transport the goal is to search for a good passenger's path between an origin and a destination. Usually, the travel time and the number of transfers shall be minimized. In this paper, we consider robust timetable information, i.e. we want to identify a path which will bring the passenger to the planned destination even in the case of delays. The classic notion of strict robustness leads to the problem of identifying those changing activities which will never break in any of the expected delay scenarios. We show that this is in general a strongly NP-hard problem. Therefore, we propose a conservative heuristic which identifies a large subset of these robust changing activities in polynomial time by dynamic programming and so allows us to find strictly robust paths efficiently. We also transfer the notion of light robustness, originally introduced for timetabling, to timetable information. In computational experiments we then study the price of strict and light robustness: How much longer is the travel time of a robust path than of a shortest one according to the published schedule? Based on the schedule of high-speed trains within Germany of 2011, we quantitatively explore the trade-off between the level of guaranteed robustness and the increase in travel time. Strict robustness turns out to be too conservative, while light robustness is promising: a modest level of guarantees is achievable at a reasonable price for the majority of passengers.

Cite as

Marc Goerigk, Martin Knoth, Matthias Müller-Hannemann, Marie Schmidt, and Anita Schöbel. The Price of Robustness in Timetable Information. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 76-87, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{goerigk_et_al:OASIcs.ATMOS.2011.76,
  author =	{Goerigk, Marc and Knoth, Martin and M\"{u}ller-Hannemann, Matthias and Schmidt, Marie and Sch\"{o}bel, Anita},
  title =	{{The Price of Robustness in Timetable Information}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{76--87},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.76},
  URN =		{urn:nbn:de:0030-drops-32680},
  doi =		{10.4230/OASIcs.ATMOS.2011.76},
  annote =	{Keywords: strict and light robustness, delay scenarios, experimental study}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.88

Delay Management including Capacities of Stations

Authors: Twan Dollevoet, Marie Schmidt, and Anita Schöbel

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

The question of delay management (DM) is whether trains should wait for delayed feeder trains or should depart on time. Solutions to this problem strongly depend on the capacity constraints of the tracks making sure that no two trains can use the same piece of track at the same time. While these capacity constraints have been included in integer programming formulations for DM, the capacity constraints of the stations (only offering a limited number of platforms) have been neglected so far. This can lead to highly infeasible solutions. In order to overcome this problem we suggest two new formulations for DM both including the stations' capacities. We present numerical results showing that the assignment-based formulation is clearly superior to the packing formulation. We furthermore propose an iterative algorithm in which we improve the platform assignment with respect to the current delays of the trains at each station in each step. We will show that this subproblem asks for coloring the nodes of a graph with a given number of colors while minimizing the weight of the conflicts. We show that the graph to be colored is an interval graph and that the problem can be solved in polynomial time by presenting a totally unimodular IP formulation.

Cite as

Twan Dollevoet, Marie Schmidt, and Anita Schöbel. Delay Management including Capacities of Stations. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 88-99, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{dollevoet_et_al:OASIcs.ATMOS.2011.88,
  author =	{Dollevoet, Twan and Schmidt, Marie and Sch\"{o}bel, Anita},
  title =	{{Delay Management including Capacities of Stations}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{88--99},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.88},
  URN =		{urn:nbn:de:0030-drops-32699},
  doi =		{10.4230/OASIcs.ATMOS.2011.88},
  annote =	{Keywords: Delay management, station capacities}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.100

Stochastic Delay Prediction in Large Train Networks

Authors: Annabell Berger, Andreas Gebhardt, Matthias Müller-Hannemann, and Martin Ostrowski

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

In daily operation, railway traffic always deviates from the planned schedule to a certain extent. Primary initial delays of trains may cause a whole cascade of secondary delays of other trains over the entire network. In this paper, we propose a stochastic model for delay propagation and forecasts of arrival and departure events which is applicable to all kind of public transport (not only to railway traffic). Our model is fairly realistic, it includes general waiting policies (how long do trains wait for delayed feeder trains), it uses driving time profiles (discrete distributions) on travel arcs which depend on the departure time, and it incorporates the catch-up potential of buffer times on driving sections and train stops. The model is suited for an online scenario where a massive stream of update messages on the current status of trains arrives which has to be propagated through the whole network. Efficient stochastic propagation of delays has important applications in online timetable information, in delay management and train disposition, and in stability analysis of timetables. The proposed approach has been implemented and evaluated on the German timetable of 2011 with waiting policies of Deutsche Bahn AG. A complete stochastic delay propagation for the whole German train network and a whole day can be performed in less than 14 seconds on a PC. We tested our propagation algorithm with artificial discrete travel time distributions which can be parametrized by the size of their fluctuations. Our forecasts are compared with real data. It turns out that stochastic propagation of delays is efficient enough to be applicable in practice, but the forecast quality requires further adjustments of our artificial travel time distributions to estimates from real data.

Cite as

Annabell Berger, Andreas Gebhardt, Matthias Müller-Hannemann, and Martin Ostrowski. Stochastic Delay Prediction in Large Train Networks. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 100-111, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{berger_et_al:OASIcs.ATMOS.2011.100,
  author =	{Berger, Annabell and Gebhardt, Andreas and M\"{u}ller-Hannemann, Matthias and Ostrowski, Martin},
  title =	{{Stochastic Delay Prediction in Large Train Networks}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{100--111},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.100},
  URN =		{urn:nbn:de:0030-drops-32705},
  doi =		{10.4230/OASIcs.ATMOS.2011.100},
  annote =	{Keywords: stochastic delay propagation, timetable information, delay management, train disposition, stability analysis}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.112

Comparison of discrete and continuous models for the pooling problem

Authors: Mohammed Alfaki and Dag Haugland

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

The pooling problem is an important global optimization problem which is encountered in many industrial settings. It is traditionally modeled as a bilinear, nonconvex optimization problem, and solved by branch-and-bound algorithms where the subproblems are convex. In some industrial applications, for instance in pipeline transportation of natural gas, a different modeling approach is often made. Rather than defining it as a bilinear problem, the range of qualities is discretized, and the complicating constraints are replaced by linear ones involving integer variables. Consequently, the pooling problem is approximated by a mixed-integer programming problem. With a coarse discretization, this approach represents a saving in computational effort, but may also lead to less accurate modeling. Justified guidelines for choosing between a bilinear and a discrete model seem to be scarce in the pooling problem literature. In the present work, we study discretized versions of models that have been proved to work well when formulated as bilinear programs. Through extensive numerical experiments, we compare the discrete models to their continuous ancestors. In particular, we study how the level of discretization must be chosen if a discrete model is going to be competitive in both running time and accuracy.

Cite as

Mohammed Alfaki and Dag Haugland. Comparison of discrete and continuous models for the pooling problem. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 112-121, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{alfaki_et_al:OASIcs.ATMOS.2011.112,
  author =	{Alfaki, Mohammed and Haugland, Dag},
  title =	{{Comparison of discrete and continuous models for the pooling problem}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{112--121},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.112},
  URN =		{urn:nbn:de:0030-drops-32719},
  doi =		{10.4230/OASIcs.ATMOS.2011.112},
  annote =	{Keywords: Global Optimization, Industrial Optimization, Graphs and Networks, Pooling problem}
}

Document

DOI: 10.4230/OASIcs.ATMOS.2011.122

On the Smoothed Price of Anarchy of the Traffic Assignment Problem

Authors: Luciana Buriol, Marcus Ritt, Felix Rodrigues, and Guido Schäfer

Published in: OASIcs, Volume 20, 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2011)

Abstract

We study the effect of perturbations on the Price of Anarchy for the Traffic Assignment Problem. Adopting the smoothed analysis approach, we randomly perturb the latency functions of the given network and estimate the expected Price of Anarchy on the perturbed instances. We provide both theoretical and experimental results that show that the Smoothed Price of Anarchy is of the same order of magnitude as the original one.

Cite as

Luciana Buriol, Marcus Ritt, Felix Rodrigues, and Guido Schäfer. On the Smoothed Price of Anarchy of the Traffic Assignment Problem. In 11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 20, pp. 122-133, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{buriol_et_al:OASIcs.ATMOS.2011.122,
  author =	{Buriol, Luciana and Ritt, Marcus and Rodrigues, Felix and Sch\"{a}fer, Guido},
  title =	{{On the Smoothed Price of Anarchy of the Traffic Assignment Problem}},
  booktitle =	{11th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{122--133},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-33-0},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{20},
  editor =	{Caprara, Alberto and Kontogiannis, Spyros},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2011.122},
  URN =		{urn:nbn:de:0030-drops-32727},
  doi =		{10.4230/OASIcs.ATMOS.2011.122},
  annote =	{Keywords: Traffic Assignment Problem, Smoothed Analysis, Price of Anarchy}
}

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