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Documents authored by Pajor, Thomas

Document
DOI: 10.4230/OASIcs.ATMOS.2017.8
Faster Transit Routing by Hyper Partitioning

Authors: Daniel Delling, Julian Dibbelt, Thomas Pajor, and Tobias Zündorf

Published in: OASIcs, Volume 59, 17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017)

Abstract
We present a preprocessing-based acceleration technique for computing bi-criteria Pareto-optimal journeys in public transit networks, based on the well-known RAPTOR algorithm [Delling et al 2015]. Our key idea is to first partition a hypergraph into cells, in which vertices correspond to routes (e.g., bus lines) and hyperedges to stops, and to then mark routes sufficient for optimal travel across cells. The query can then be restricted to marked routes and those in the source and target cells. This results in a practical approach, suitable for networks that are too large to be efficiently handled by the basic RAPTOR algorithm.
Cite as

Daniel Delling, Julian Dibbelt, Thomas Pajor, and Tobias Zündorf. Faster Transit Routing by Hyper Partitioning. In 17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017). Open Access Series in Informatics (OASIcs), Volume 59, pp. 8:1-8:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@InProceedings{delling_et_al:OASIcs.ATMOS.2017.8,
  author =	{Delling, Daniel and Dibbelt, Julian and Pajor, Thomas and Z\"{u}ndorf, Tobias},
  title =	{{Faster Transit Routing by Hyper Partitioning}},
  booktitle =	{17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017)},
  pages =	{8:1--8:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-042-2},
  ISSN =	{2190-6807},
  year =	{2017},
  volume =	{59},
  editor =	{D'Angelo, Gianlorenzo and Dollevoet, Twan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2017.8},
  URN =		{urn:nbn:de:0030-drops-78962},
  doi =		{10.4230/OASIcs.ATMOS.2017.8},
  annote =	{Keywords: Routing, speed-up techniques, public transport, partitioning}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2015.1
Towards Realistic Pedestrian Route Planning

Authors: Simeon Andreev, Julian Dibbelt, Martin Nöllenburg, Thomas Pajor, and Dorothea Wagner

Published in: OASIcs, Volume 48, 15th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2015)

Abstract
Pedestrian routing has its specific set of challenges, which are often neglected by state-of-the-art route planners. For instance, the lack of detailed sidewalk data and the inability to traverse plazas and parks in a natural way often leads to unappealing and suboptimal routes. In this work, we first propose to augment the network by generating sidewalks based on the street geometry and adding edges for routing over plazas and squares. Using this and further information, our query algorithm seamlessly handles node-to-node queries and queries whose origin or destination is an arbitrary location on a plaza or inside a park. Our experiments show that we are able to compute appealing pedestrian routes at negligible overhead over standard routing algorithms.
Cite as

Simeon Andreev, Julian Dibbelt, Martin Nöllenburg, Thomas Pajor, and Dorothea Wagner. Towards Realistic Pedestrian Route Planning. In 15th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2015). Open Access Series in Informatics (OASIcs), Volume 48, pp. 1-15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{andreev_et_al:OASIcs.ATMOS.2015.1,
  author =	{Andreev, Simeon and Dibbelt, Julian and N\"{o}llenburg, Martin and Pajor, Thomas and Wagner, Dorothea},
  title =	{{Towards Realistic Pedestrian Route Planning}},
  booktitle =	{15th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2015)},
  pages =	{1--15},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-99-6},
  ISSN =	{2190-6807},
  year =	{2015},
  volume =	{48},
  editor =	{Italiano, Giuseppe F. and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2015.1},
  URN =		{urn:nbn:de:0030-drops-54592},
  doi =		{10.4230/OASIcs.ATMOS.2015.1},
  annote =	{Keywords: pedestrian routing, realistic model, shortest paths, speed-up technique}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2014.138
Speed-Consumption Tradeoff for Electric Vehicle Route Planning

Authors: Moritz Baum, Julian Dibbelt, Lorenz Hübschle-Schneider, Thomas Pajor, and Dorothea Wagner

Published in: OASIcs, Volume 42, 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2014)

Abstract
We study the problem of computing routes for electric vehicles (EVs) in road networks. Since their battery capacity is limited, and consumed energy per distance increases with velocity, driving the fastest route is often not desirable and may even be infeasible. On the other hand, the energy-optimal route may be too conservative in that it contains unnecessary detours or simply takes too long. In this work, we propose to use multicriteria optimization to obtain Pareto sets of routes that trade energy consumption for speed. In particular, we exploit the fact that the same road segment can be driven at different speeds within reasonable intervals. As a result, we are able to provide routes with low energy consumption that still follow major roads, such as freeways. Unfortunately, the size of the resulting Pareto sets can be too large to be practical. We therefore also propose several nontrivial techniques that can be applied on-line at query time in order to speed up computation and filter insignificant solutions from the Pareto sets. Our extensive experimental study, which uses a real-world energy consumption model, reveals that we are able to compute diverse sets of alternative routes on continental networks that closely resemble the exact Pareto set in just under a second---several orders of magnitude faster than the exhaustive algorithm.
Cite as

Moritz Baum, Julian Dibbelt, Lorenz Hübschle-Schneider, Thomas Pajor, and Dorothea Wagner. Speed-Consumption Tradeoff for Electric Vehicle Route Planning. In 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 42, pp. 138-151, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)

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@InProceedings{baum_et_al:OASIcs.ATMOS.2014.138,
  author =	{Baum, Moritz and Dibbelt, Julian and H\"{u}bschle-Schneider, Lorenz and Pajor, Thomas and Wagner, Dorothea},
  title =	{{Speed-Consumption Tradeoff for Electric Vehicle Route Planning}},
  booktitle =	{14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{138--151},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-75-0},
  ISSN =	{2190-6807},
  year =	{2014},
  volume =	{42},
  editor =	{Funke, Stefan and Mihal\'{a}k, Mat\'{u}s},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2014.138},
  URN =		{urn:nbn:de:0030-drops-47583},
  doi =		{10.4230/OASIcs.ATMOS.2014.138},
  annote =	{Keywords: electric vehicles, shortest paths, route planning, bicriteria optimization, algorithm engineering}
}
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.2009.2145
Efficient Route Planning in Flight Networks

Authors: Daniel Delling, Thomas Pajor, Dorothea Wagner, and Christos Zaroliagis

Published in: OASIcs, Volume 12, 9th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'09) (2009)

Abstract
We present a set of three new time-dependent models with increasing flexibility for realistic route planning in flight networks. By these means, we obtain small graph sizes while modeling airport procedures in a realistic way. With these graphs, we are able to efficiently compute a set of best connections with multiple criteria over a full day. It even turns out that due to the very limited graph sizes it is feasible to precompute full distance tables between all airports. As a result, best connections can be retrieved in a few microseconds on real world data.
Cite as

Daniel Delling, Thomas Pajor, Dorothea Wagner, and Christos Zaroliagis. Efficient Route Planning in Flight Networks. In 9th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'09). Open Access Series in Informatics (OASIcs), Volume 12, pp. 1-17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)

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@InProceedings{delling_et_al:OASIcs.ATMOS.2009.2145,
  author =	{Delling, Daniel and Pajor, Thomas and Wagner, Dorothea and Zaroliagis, Christos},
  title =	{{Efficient Route Planning in Flight Networks}},
  booktitle =	{9th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'09)},
  pages =	{1--17},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-11-8},
  ISSN =	{2190-6807},
  year =	{2009},
  volume =	{12},
  editor =	{Clausen, Jens and Di Stefano, Gabriele},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2009.2145},
  URN =		{urn:nbn:de:0030-drops-21450},
  doi =		{10.4230/OASIcs.ATMOS.2009.2145},
  annote =	{Keywords: Timetable information, flight modeling, shortest paths, multi criteria, table lookups Timetable information, flight modeling, shortest paths, multi criteria, table lookups}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2008.1582
Engineering Time-Expanded Graphs for Faster Timetable Information

Authors: Daniel Delling, Thomas Pajor, and Dorothea Wagner

Published in: OASIcs, Volume 9, 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'08) (2008)

Abstract
We present an extension of the well-known time-expanded approach for timetable information. By remodeling unimportant stations, we are able to obtain faster query times with less space consumption than the original model. Moreover, we show that our extensions harmonize well with speed-up techniques whose adaption to timetable networks is more challenging than one might expect.
Cite as

Daniel Delling, Thomas Pajor, and Dorothea Wagner. Engineering Time-Expanded Graphs for Faster Timetable Information. In 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'08). Open Access Series in Informatics (OASIcs), Volume 9, pp. 1-20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)

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@InProceedings{delling_et_al:OASIcs.ATMOS.2008.1582,
  author =	{Delling, Daniel and Pajor, Thomas and Wagner, Dorothea},
  title =	{{Engineering Time-Expanded Graphs for Faster Timetable Information}},
  booktitle =	{8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'08)},
  pages =	{1--20},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-07-1},
  ISSN =	{2190-6807},
  year =	{2008},
  volume =	{9},
  editor =	{Fischetti, Matteo and Widmayer, Peter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2008.1582},
  URN =		{urn:nbn:de:0030-drops-15826},
  doi =		{10.4230/OASIcs.ATMOS.2008.1582},
  annote =	{Keywords: Timetable information, shortest path, modeling}
}
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