114 Search Results for "Zaroliagis, Christos"


Volume

OASIcs, Volume 85

20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)

ATMOS 2020, September 7-8, 2020, Pisa, Italy (Virtual Conference)

Editors: Dennis Huisman and Christos D. Zaroliagis

Volume

LIPIcs, Volume 57

24th Annual European Symposium on Algorithms (ESA 2016)

ESA 2016, August 22-24, 2016, Aarhus, Denmark

Editors: Piotr Sankowski and Christos Zaroliagis

Document
REX: A Realistic Time-Dependent Model for Multimodal Public Transport

Authors: Spyros Kontogiannis, Paraskevi-Maria-Malevi Machaira, Andreas Paraskevopoulos, and Christos Zaroliagis

Published in: OASIcs, Volume 106, 22nd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2022)


Abstract
We present the non-FIFO time-dependent graph model with REalistic vehicle eXchange times (REX) for schedule-based multimodal public transport, along with a novel query algorithm called TRIP-based LAbel-correction propagation (TRIPLA) algorithm that efficiently solves the realistic earliest-arrival routing problem. The REX model possesses all strong features of previous time-dependent graph models without suffering from their deficiencies. It handles non-negligible exchanges from one vehicle to another, as well as supports non-FIFO instances which are typical in public transport, without compromising space efficiency. We conduct a thorough experimental evaluation with real-world data which demonstrates that TRIPLA significantly outperforms all state-of-the-art query algorithms for multimodal earliest-arrival routing in schedule-based public transport.

Cite as

Spyros Kontogiannis, Paraskevi-Maria-Malevi Machaira, Andreas Paraskevopoulos, and Christos Zaroliagis. REX: A Realistic Time-Dependent Model for Multimodal Public Transport. In 22nd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2022). Open Access Series in Informatics (OASIcs), Volume 106, pp. 12:1-12:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2022)


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@InProceedings{kontogiannis_et_al:OASIcs.ATMOS.2022.12,
  author =	{Kontogiannis, Spyros and Machaira, Paraskevi-Maria-Malevi and Paraskevopoulos, Andreas and Zaroliagis, Christos},
  title =	{{REX: A Realistic Time-Dependent Model for Multimodal Public Transport}},
  booktitle =	{22nd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2022)},
  pages =	{12:1--12:16},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-259-4},
  ISSN =	{2190-6807},
  year =	{2022},
  volume =	{106},
  editor =	{D'Emidio, Mattia and Lindner, Niels},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2022.12},
  URN =		{urn:nbn:de:0030-drops-171164},
  doi =		{10.4230/OASIcs.ATMOS.2022.12},
  annote =	{Keywords: multimodal journey planning, REX model, TRIPLA query algorithm, schedule-based timetables}
}
Document
Complete Volume
OASIcs, Volume 85, ATMOS 2020, Complete Volume

Authors: Dennis Huisman and Christos D. Zaroliagis

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
OASIcs, Volume 85, ATMOS 2020, Complete Volume

Cite as

Dennis Huisman and Christos D. Zaroliagis. OASIcs, Volume 85, ATMOS 2020, Complete Volume. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 1-272, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@Proceedings{huisman_et_al:OASIcs.ATMOS.2020,
  title =	{{OASIcs, Volume 85, ATMOS 2020, Complete Volume}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{1--272},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020},
  URN =		{urn:nbn:de:0030-drops-131356},
  doi =		{10.4230/OASIcs.ATMOS.2020},
  annote =	{Keywords: OASIcs, Volume 85, ATMOS 2020, Complete Volume}
}
Document
Front Matter
Front Matter, Table of Contents, Preface, Conference Organization

Authors: Dennis Huisman and Christos D. Zaroliagis

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
Front Matter, Table of Contents, Preface, Conference Organization

Cite as

Dennis Huisman and Christos D. Zaroliagis. Front Matter, Table of Contents, Preface, Conference Organization. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 0:i-0:x, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{huisman_et_al:OASIcs.ATMOS.2020.0,
  author =	{Huisman, Dennis and Zaroliagis, Christos D.},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{0:i--0:x},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.0},
  URN =		{urn:nbn:de:0030-drops-131363},
  doi =		{10.4230/OASIcs.ATMOS.2020.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
An Efficient Solution for One-To-Many Multi-Modal Journey Planning

Authors: Jonas Sauer, Dorothea Wagner, and Tobias Zündorf

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
We study the one-to-many journey planning problem in multi-modal transportation networks consisting of a public transit network and an additional, non-schedule-based mode of transport. Given a departure time and a single source vertex, we aim to compute optimal journeys to all vertices in a set of targets, optimizing both travel time and the number of transfers used. Solving this problem yields a crucial component in many other problems, such as efficient point-of-interest queries, computation of isochrones, or multi-modal traffic assignments. While many algorithms for multi-modal journey planning exist, none of them are applicable to one-to-many scenarios. Our solution is based on the combination of two state-of-the-art approaches: ULTRA, which enables efficient journey planning in multi-modal networks, but only for one-to-one queries, and (R)PHAST, which enables efficient one-to-many queries, but only in time-independent networks. Similarly to ULTRA, our new approach can be combined with any existing public transit algorithm that allows a search to all stops, which we demonstrate for CSA and RAPTOR. For small to moderately sized target sets, the resulting algorithms are nearly as fast as the pure public transit algorithms they are based on. For large target sets, we achieve a speedup of up to 7 compared to a naive one-to-many extension of a state-of-the-art multi-modal approach.

Cite as

Jonas Sauer, Dorothea Wagner, and Tobias Zündorf. An Efficient Solution for One-To-Many Multi-Modal Journey Planning. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 1:1-1:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{sauer_et_al:OASIcs.ATMOS.2020.1,
  author =	{Sauer, Jonas and Wagner, Dorothea and Z\"{u}ndorf, Tobias},
  title =	{{An Efficient Solution for One-To-Many Multi-Modal Journey Planning}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{1:1--1:15},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.1},
  URN =		{urn:nbn:de:0030-drops-131371},
  doi =		{10.4230/OASIcs.ATMOS.2020.1},
  annote =	{Keywords: Algorithm Engineering, Route Planning, Public Transit, One-to-Many}
}
Document
On the Multi-Kind BahnCard Problem

Authors: Mike Timm and Sabine Storandt

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
The BahnCard problem is an important problem in the realm of online decision making. In its original form, there is one kind of BahnCard associated with a certain price, which upon purchase reduces the ticket price of train journeys for a certain factor over a certain period of time. The problem consists of deciding on which dates BahnCards should be purchased such that the overall cost, that is, BahnCard prices plus (reduced) ticket prices, is minimized without having knowledge about the number and prices of future journeys. In this paper, we extend the problem such that multiple kinds of BahnCards are available for purchase. We provide an optimal offline algorithm, as well as online strategies with provable competitiveness factors. Furthermore, we describe and implement several heuristic online strategies and compare their competitiveness in realistic scenarios.

Cite as

Mike Timm and Sabine Storandt. On the Multi-Kind BahnCard Problem. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 2:1-2:13, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{timm_et_al:OASIcs.ATMOS.2020.2,
  author =	{Timm, Mike and Storandt, Sabine},
  title =	{{On the Multi-Kind BahnCard Problem}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{2:1--2:13},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.2},
  URN =		{urn:nbn:de:0030-drops-131382},
  doi =		{10.4230/OASIcs.ATMOS.2020.2},
  annote =	{Keywords: offline solution, competitiveness, traveller profiles}
}
Document
Faster Preprocessing for the Trip-Based Public Transit Routing Algorithm

Authors: Vassilissa Lehoux and Christelle Loiodice

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
We propose an additional preprocessing step for the Trip-Based Public Transit Routing algorithm, an exact state-of-the art algorithm for bi-criteria min cost path problems in public transit networks. This additional step reduces significantly the preprocessing time, while preserving the correctness and the computation times of the queries. We test our approach on three large scale networks and show that the improved preprocessing is compatible with frequent real-time updates, even on the larger data set. The experiments also indicate that it is possible, if preprocessing time is an issue, to use the proposed preprocessing step on its own to obtain already a significant reduction of the query times compared to the no pruning scenario.

Cite as

Vassilissa Lehoux and Christelle Loiodice. Faster Preprocessing for the Trip-Based Public Transit Routing Algorithm. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 3:1-3:12, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{lehoux_et_al:OASIcs.ATMOS.2020.3,
  author =	{Lehoux, Vassilissa and Loiodice, Christelle},
  title =	{{Faster Preprocessing for the Trip-Based Public Transit Routing Algorithm}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{3:1--3:12},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.3},
  URN =		{urn:nbn:de:0030-drops-131395},
  doi =		{10.4230/OASIcs.ATMOS.2020.3},
  annote =	{Keywords: Public transit, Route planning, Algorithms, Preprocessing}
}
Document
Integrating ULTRA and Trip-Based Routing

Authors: Jonas Sauer, Dorothea Wagner, and Tobias Zündorf

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
We study a bi-modal journey planning scenario consisting of a public transit network and a transfer graph representing a secondary transportation mode (e.g., walking or cycling). Given a pair of source and target locations, the objective is to find a Pareto set of journeys optimizing arrival time and the number of required transfers. For public transit networks with a restricted, transitively closed transfer graph, one of the fastest known algorithms solving this bi-criteria problem is Trip-Based Routing [Witt, 2015]. However, this algorithm cannot be trivially extended to unrestricted transfer graphs. In this work, we combine Trip-Based Routing with ULTRA [Baum et al., 2019], a preprocessing technique that allows any public transit algorithm that requires transitive transfers to handle an unrestricted transfer graph. Since both ULTRA and Trip-Based Routing precompute transfer shortcuts in a preprocessing phase, a naive combination of the two leads to a three-phase algorithm that performs redundant work and produces superfluous shortcuts. We therefore propose a new, integrated preprocessing phase that combines the advantages of both and reduces the number of computed shortcuts by up to a factor of 9 compared to a naive combination. The resulting query algorithm, ULTRA-Trip-Based is the fastest known algorithm for the considered problem setting, achieving a speedup of up to 4 compared to the fastest previously known approach, ULTRA-RAPTOR.

Cite as

Jonas Sauer, Dorothea Wagner, and Tobias Zündorf. Integrating ULTRA and Trip-Based Routing. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 4:1-4:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{sauer_et_al:OASIcs.ATMOS.2020.4,
  author =	{Sauer, Jonas and Wagner, Dorothea and Z\"{u}ndorf, Tobias},
  title =	{{Integrating ULTRA and Trip-Based Routing}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{4:1--4:15},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.4},
  URN =		{urn:nbn:de:0030-drops-131408},
  doi =		{10.4230/OASIcs.ATMOS.2020.4},
  annote =	{Keywords: Algorithms, Journey Planning, Multi-Modal, Public Transportation}
}
Document
Determining All Integer Vertices of the PESP Polytope by Flipping Arcs

Authors: Niels Lindner and Christian Liebchen

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
We investigate polyhedral aspects of the Periodic Event Scheduling Problem (PESP), the mathematical basis for periodic timetabling problems in public transport. Flipping the orientation of arcs, we obtain a new class of valid inequalities, the flip inequalities, comprising both the known cycle and change-cycle inequalities. For a point of the LP relaxation, a violated flip inequality can be found in pseudo-polynomial time, and even in linear time for a spanning tree solution. Our main result is that the integer vertices of the polytope described by the flip inequalities are exactly the vertices of the PESP polytope, i.e., the convex hull of all feasible periodic slacks with corresponding modulo parameters. Moreover, we show that this flip polytope equals the PESP polytope in some special cases. On the computational side, we devise several heuristic approaches concerning the separation of cutting planes from flip inequalities. We finally present better dual bounds for the smallest and largest instance of the benchmarking library PESPlib.

Cite as

Niels Lindner and Christian Liebchen. Determining All Integer Vertices of the PESP Polytope by Flipping Arcs. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 5:1-5:18, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{lindner_et_al:OASIcs.ATMOS.2020.5,
  author =	{Lindner, Niels and Liebchen, Christian},
  title =	{{Determining All Integer Vertices of the PESP Polytope by Flipping Arcs}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{5:1--5:18},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.5},
  URN =		{urn:nbn:de:0030-drops-131411},
  doi =		{10.4230/OASIcs.ATMOS.2020.5},
  annote =	{Keywords: Periodic Event Scheduling Problem, Periodic Timetabling, Mixed Integer Programming}
}
Document
A New Sequential Approach to Periodic Vehicle Scheduling and Timetabling

Authors: Paul Bouman, Alexander Schiewe, and Philine Schiewe

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
When evaluating the operational costs of a public transport system, the most important factor is the number of vehicles needed for operation. In contrast to the canonical sequential approach of first fixing a timetable and then adding a vehicle schedule, we consider a sequential approach where a vehicle schedule is determined for a given line plan and only afterwards a timetable is fixed. We compare this new sequential approach to a model that integrates both steps. To represent various operational requirements, we consider multiple possibilities to restrict the vehicle circulations to be short, as this can provide operational benefits. The sequential approach can efficiently determine public transport plans with a low number of vehicles. This is evaluated theoretically and empirically demonstrated for two close-to real-world instances.

Cite as

Paul Bouman, Alexander Schiewe, and Philine Schiewe. A New Sequential Approach to Periodic Vehicle Scheduling and Timetabling. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 6:1-6:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{bouman_et_al:OASIcs.ATMOS.2020.6,
  author =	{Bouman, Paul and Schiewe, Alexander and Schiewe, Philine},
  title =	{{A New Sequential Approach to Periodic Vehicle Scheduling and Timetabling}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{6:1--6:16},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.6},
  URN =		{urn:nbn:de:0030-drops-131422},
  doi =		{10.4230/OASIcs.ATMOS.2020.6},
  annote =	{Keywords: Vehicle Scheduling, Timetabling, Integrated Planning}
}
Document
Analyzing a Family of Formulations for Cyclic Crew Rostering

Authors: Thomas Breugem, Twan Dollevoet, and Dennis Huisman

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
In this paper, we analyze a family of formulations for the Cyclic Crew Rostering Problem (CCRP), in which a cyclic roster has to be constructed for a group of employees. Each formulation in the family is based on a partition of the roster. Intuitively, finer partitions give rise to a formulation with fewer variables, but possibly more constraints. Coarser partitions lead to more variables, but might allow to incorporate many of the constraints implicitly. We derive analytical results regarding the relative strength of the different formulations, which can serve as a guideline for formulating a given problem instance. Furthermore, we propose a column generation approach, and use it to compare the strength of the formulations empirically. Both the theoretical and computational results demonstrate the importance of choosing a suitable formulation. In particular, for practical instances of Netherlands Railways, stronger lower bounds are obtained, and more than 90% of the roster constraints can be modeled implicitly.

Cite as

Thomas Breugem, Twan Dollevoet, and Dennis Huisman. Analyzing a Family of Formulations for Cyclic Crew Rostering. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 7:1-7:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{breugem_et_al:OASIcs.ATMOS.2020.7,
  author =	{Breugem, Thomas and Dollevoet, Twan and Huisman, Dennis},
  title =	{{Analyzing a Family of Formulations for Cyclic Crew Rostering}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{7:1--7:16},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.7},
  URN =		{urn:nbn:de:0030-drops-131438},
  doi =		{10.4230/OASIcs.ATMOS.2020.7},
  annote =	{Keywords: Crew Planning, Roster Sequence, Column Generation, Railway Optimization}
}
Document
Time-Dependent Alternative Route Planning

Authors: Spyros Kontogiannis, Andreas Paraskevopoulos, and Christos D. Zaroliagis

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
We present a new method for computing a set of alternative origin-to-destination routes in road networks with an underlying time-dependent metric. The resulting set is aggregated in the form of a time-dependent alternative graph and is characterized by minimum route overlap, small stretch factor, small size and low complexity. To our knowledge, this is the first work that deals with the time-dependent setting in the framework of alternative routes. Based on preprocessed minimum travel-time information between a small set of nodes and all other nodes in the graph, our algorithm carries out a collection phase for candidate alternative routes, followed by a pruning phase that cautiously discards uninteresting or low-quality routes from the candidate set. Our experimental evaluation on real time-dependent road networks demonstrates that the new algorithm performs much better (by one or two orders of magnitude) than existing baseline approaches. In particular, the entire alternative graph can be computed in less than 0.384sec for the road network of Germany, and in less than 1.24sec for that of Europe. Our approach provides also "quick-and-dirty" results of decent quality, in about 1/300 of the above mentioned query times for continental-size instances.

Cite as

Spyros Kontogiannis, Andreas Paraskevopoulos, and Christos D. Zaroliagis. Time-Dependent Alternative Route Planning. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 8:1-8:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{kontogiannis_et_al:OASIcs.ATMOS.2020.8,
  author =	{Kontogiannis, Spyros and Paraskevopoulos, Andreas and Zaroliagis, Christos D.},
  title =	{{Time-Dependent Alternative Route Planning}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{8:1--8:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.8},
  URN =		{urn:nbn:de:0030-drops-131441},
  doi =		{10.4230/OASIcs.ATMOS.2020.8},
  annote =	{Keywords: time-dependent shortest path, alternative routes, travel-time oracle, plateau and penalty methods}
}
Document
Customizable Contraction Hierarchies with Turn Costs

Authors: Valentin Buchhold, Dorothea Wagner, Tim Zeitz, and Michael Zündorf

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
We incorporate turn restrictions and turn costs into the route planning algorithm customizable contraction hierarchies (CCH). There are two common ways to represent turn costs and restrictions. The edge-based model expands the network so that road segments become vertices and allowed turns become edges. The compact model keeps intersections as vertices, but associates a turn table with each vertex. Although CCH can be used as is on the edge-based model, the performance of preprocessing and customization is severely affected. While the expanded network is only three times larger, both preprocessing and customization time increase by up to an order of magnitude. In this work, we carefully engineer CCH to exploit different properties of the expanded graph. We reduce the increase in customization time from up to an order of magnitude to a factor of about 3. The increase in preprocessing time is reduced even further. Moreover, we present a CCH variant that works on the compact model, and show that it performs worse than the variant on the edge-based model. Surprisingly, the variant on the edge-based model even uses less space than the one on the compact model, although the compact model was developed to keep the space requirement low.

Cite as

Valentin Buchhold, Dorothea Wagner, Tim Zeitz, and Michael Zündorf. Customizable Contraction Hierarchies with Turn Costs. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 9:1-9:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


Copy BibTex To Clipboard

@InProceedings{buchhold_et_al:OASIcs.ATMOS.2020.9,
  author =	{Buchhold, Valentin and Wagner, Dorothea and Zeitz, Tim and Z\"{u}ndorf, Michael},
  title =	{{Customizable Contraction Hierarchies with Turn Costs}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{9:1--9:15},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.9},
  URN =		{urn:nbn:de:0030-drops-131453},
  doi =		{10.4230/OASIcs.ATMOS.2020.9},
  annote =	{Keywords: Turn costs, realistic road networks, customizable contraction hierarchies, route planning, shortest paths}
}
Document
A Strategic Routing Framework and Algorithms for Computing Alternative Paths

Authors: Thomas Bläsius, Maximilian Böther, Philipp Fischbeck, Tobias Friedrich, Alina Gries, Falk Hüffner, Otto Kißig, Pascal Lenzner, Louise Molitor, Leon Schiller, Armin Wells, and Simon Wietheger

Published in: OASIcs, Volume 85, 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)


Abstract
Traditional navigation services find the fastest route for a single driver. Though always using the fastest route seems desirable for every individual, selfish behavior can have undesirable effects such as higher energy consumption and avoidable congestion, even leading to higher overall and individual travel times. In contrast, strategic routing aims at optimizing the traffic for all agents regarding a global optimization goal. We introduce a framework to formalize real-world strategic routing scenarios as algorithmic problems and study one of them, which we call Single Alternative Path (SAP), in detail. There, we are given an original route between a single origin-destination pair. The goal is to suggest an alternative route to all agents that optimizes the overall travel time under the assumption that the agents distribute among both routes according to a psychological model, for which we introduce the concept of Pareto-conformity. We show that the SAP problem is NP-complete, even for such models. Nonetheless, assuming Pareto-conformity, we give multiple algorithms for different variants of SAP, using multi-criteria shortest path algorithms as subroutines. Moreover, we prove that several natural models are in fact Pareto-conform. The implementation and evaluation of our algorithms serve as a proof of concept, showing that SAP can be solved in reasonable time even though the algorithms have exponential running time in the worst case.

Cite as

Thomas Bläsius, Maximilian Böther, Philipp Fischbeck, Tobias Friedrich, Alina Gries, Falk Hüffner, Otto Kißig, Pascal Lenzner, Louise Molitor, Leon Schiller, Armin Wells, and Simon Wietheger. A Strategic Routing Framework and Algorithms for Computing Alternative Paths. In 20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020). Open Access Series in Informatics (OASIcs), Volume 85, pp. 10:1-10:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


Copy BibTex To Clipboard

@InProceedings{blasius_et_al:OASIcs.ATMOS.2020.10,
  author =	{Bl\"{a}sius, Thomas and B\"{o}ther, Maximilian and Fischbeck, Philipp and Friedrich, Tobias and Gries, Alina and H\"{u}ffner, Falk and Ki{\ss}ig, Otto and Lenzner, Pascal and Molitor, Louise and Schiller, Leon and Wells, Armin and Wietheger, Simon},
  title =	{{A Strategic Routing Framework and Algorithms for Computing Alternative Paths}},
  booktitle =	{20th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2020)},
  pages =	{10:1--10:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-170-2},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{85},
  editor =	{Huisman, Dennis and Zaroliagis, Christos D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2020.10},
  URN =		{urn:nbn:de:0030-drops-131469},
  doi =		{10.4230/OASIcs.ATMOS.2020.10},
  annote =	{Keywords: Routing, Strategic Routing, Selfish Routing, Route Planning, Network Flow, Algorithm Design}
}
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