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Documents authored by Schnee, Mathias


Document
Reliability and Delay Distributions of Train Connections

Authors: Mohammad H. Keyhani, Mathias Schnee, Karsten Weihe, and Hans-Peter Zorn

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


Abstract
Finding reliable train connections is a considerable issue in timetable information since train delays perturb the timetable daily. We present an effective probabilistic approach for estimating the reliability of connections in a large train network. Experiments on real customer queries and real timetables for all trains in Germany show that our approach can be implemented to deliver good results at the expense of only little processing time. Based on probability distributions for train events in connections, we estimate the reliability of connections. We have analyzed our computed reliability ratings by validating our predictions against real delay data from German Railways. This study shows that we are able to predict the feasibility of connections very well. In essence, our predictions are slightly optimistic for connections with a high rating and pretty accurate for connections with a medium rating. Only for the rare cases of a very low rating, we are too pessimistic. Our probabilistic approach already delivers good results, still has improvement potential, and offers a new perspective in the search for more reliable connections in order to bring passengers safely to their destinations even in case of delays.

Cite as

Mohammad H. Keyhani, Mathias Schnee, Karsten Weihe, and Hans-Peter Zorn. Reliability and Delay Distributions of Train Connections. In 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 25, pp. 35-46, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)


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@InProceedings{keyhani_et_al:OASIcs.ATMOS.2012.35,
  author =	{Keyhani, Mohammad H. and Schnee, Mathias and Weihe, Karsten and Zorn, Hans-Peter},
  title =	{{Reliability and Delay Distributions of Train Connections}},
  booktitle =	{12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{35--46},
  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.2012.35},
  URN =		{urn:nbn:de:0030-drops-37014},
  doi =		{10.4230/OASIcs.ATMOS.2012.35},
  annote =	{Keywords: Stochastic Delay Propagation, Timetable Information, Connection Reliability}
}
Document
Efficient On-Trip Timetable Information in the Presence of Delays

Authors: Lennart Frede, Matthias Müller-Hannemann, and Mathias Schnee

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


Abstract
The search for train connections in state-of-the-art commercial timetable information systems is based on a static schedule. Unfortunately, public transportation systems suffer 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 efficiently calculate and update all primary and secondary delays. This delay information 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 finally present a case study with data provided by Deutsche Bahn AG showing that this approach has been successfully integrated into our multi-criteria timetable information system MOTIS and can handle massive delay data streams instantly.

Cite as

Lennart Frede, Matthias Müller-Hannemann, and Mathias Schnee. Efficient On-Trip Timetable Information in the Presence of Delays. In 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'08). Open Access Series in Informatics (OASIcs), Volume 9, pp. 1-16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


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@InProceedings{frede_et_al:OASIcs.ATMOS.2008.1584,
  author =	{Frede, Lennart and M\"{u}ller-Hannemann, Matthias and Schnee, Mathias},
  title =	{{Efficient On-Trip Timetable Information in the Presence of Delays}},
  booktitle =	{8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'08)},
  pages =	{1--16},
  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.2008.1584},
  URN =		{urn:nbn:de:0030-drops-15843},
  doi =		{10.4230/OASIcs.ATMOS.2008.1584},
  annote =	{Keywords: Timetable information system, primary and secondary delays dependency graph, dynamic graph update}
}
Document
16. Improved Search for Night Train Connections

Authors: Thorsten Gunkel, Matthias Müller-Hannemann, and Mathias Schnee

Published in: OASIcs, Volume 7, 7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07) (2007)


Abstract
The search for attractive night train connections is fundamentally different from ordinary search: the primary objective of a costumer of a night train is to have a reasonably long sleeping period without interruptions due to train changes. For most passenger it is also undesired to reach the final destination too early in the morning. These objectives are in sharp contrast to standard information systems which focus on minimizing the total travel time. In this paper we present and compare two new approaches to support queries for night train connections. These approaches have been integrated into the Multi-Objective Traffic Information System (MOTIS) which is currently developed by our group. Its purpose is to find all train connections which are attractive from a costumer point of view. With a computational study we demonstrate that our specialized algorithms for night train connections are able to satisfy costumer queries much better than standard methods. This can be achieved with reasonable computational costs: a specialized night train search requires only a few seconds of CPU time.

Cite as

Thorsten Gunkel, Matthias Müller-Hannemann, and Mathias Schnee. 16. Improved Search for Night Train Connections. In 7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07). Open Access Series in Informatics (OASIcs), Volume 7, pp. 243-258, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{gunkel_et_al:OASIcs.ATMOS.2007.1178,
  author =	{Gunkel, Thorsten and M\"{u}ller-Hannemann, Matthias and Schnee, Mathias},
  title =	{{16. Improved Search for Night Train Connections}},
  booktitle =	{7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07)},
  pages =	{243--258},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-04-0},
  ISSN =	{2190-6807},
  year =	{2007},
  volume =	{7},
  editor =	{Ahuja, Ravindra K. and Liebchen, Christian and Mesa, Juan A.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2007.1178},
  URN =		{urn:nbn:de:0030-drops-11781},
  doi =		{10.4230/OASIcs.ATMOS.2007.1178},
  annote =	{Keywords: Timetable information system, multi-criteria optimization, night trains, computational study}
}
Document
Paying Less for Train Connections with MOTIS

Authors: Matthias Müller-Hannemann and Mathias Schnee

Published in: OASIcs, Volume 2, 5th Workshop on Algorithmic Methods and Models for Optimization of Railways (ATMOS'05) (2006)


Abstract
Finding cheap train connections for long-distance traffic is algorithmically a hard task due to very complex tariff regulations. Several new tariff options have been developed in recent years, partly to react on the stronger competition with low-cost airline carriers. In such an environment, it becomes more and more important that search engines for travel connections are able to find special offers efficiently. We have developed a multi-objective traffic information system (MOTIS) which finds all attractive train connections with respect to travel time, number of interchanges, and ticket costs. In contrast, most servers for timetable information as well as the theoretical literature on this subject focus only on travel time as the primary objective, and secondary objectives like the number of interchanges are treated only heuristically. The purpose of this paper is to show by means of a case study how several of the most common tariff rules (including special offers) can be embedded into a general multi-objective search tool. Computational results show that a multi-objective search with a mixture of tariff rules can be done almost as fast as just with one regular tariff. For the train schedule of Germany, a query can be answered within 1.9s on average on a standard PC.

Cite as

Matthias Müller-Hannemann and Mathias Schnee. Paying Less for Train Connections with MOTIS. In 5th Workshop on Algorithmic Methods and Models for Optimization of Railways (ATMOS'05). Open Access Series in Informatics (OASIcs), Volume 2, pp. 1-19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2006)


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@InProceedings{mullerhannemann_et_al:OASIcs.ATMOS.2005.657,
  author =	{M\"{u}ller-Hannemann, Matthias and Schnee, Mathias},
  title =	{{Paying Less for Train Connections with MOTIS}},
  booktitle =	{5th Workshop on Algorithmic Methods and Models for Optimization of Railways (ATMOS'05)},
  pages =	{1--19},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-00-2},
  ISSN =	{2190-6807},
  year =	{2006},
  volume =	{2},
  editor =	{Kroon, Leo G. and M\"{o}hring, Rolf H.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2005.657},
  URN =		{urn:nbn:de:0030-drops-6572},
  doi =		{10.4230/OASIcs.ATMOS.2005.657},
  annote =	{Keywords: Timetable information system, multi-criteria optimization, shortest paths, fares, special offers, long-distance traffic}
}
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