3 Search Results for "Lemnian, Martin"


Document
Sensitivity Analysis and Coupled Decisions in Passenger Flow-Based Train Dispatching

Authors: Martin Lemnian, Matthias Müller-Hannemann, and Ralf Rückert

Published in: OASIcs, Volume 54, 16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016)


Abstract
Frequent train delays make passenger-oriented train dispatching a task of high practical relevance. In case of delays, dispatchers have to decide whether trains should wait for one or several delayed feeder trains or should depart on time. To support dispatchers, we have recently introduced the train dispatching framework PANDA (CASPT 2015). In this paper, we present and evaluate two enhancements which are also of general interest. First, we study the sensitivity of waiting decisions with respect to the accuracy of passenger flow data. More specifically, we develop an integer linear programming formulation for the following optimization problem: Given a critical transfer, what is the minimum number of passengers we have to add or to subtract from the given passenger flow such that the decision would change from waiting to non-waiting or vice versa? Based on experiments with realistic passenger flows and delay data from 2015 in Germany, an important empirical finding is that a significant fraction of all decisions is highly sensitive to small changes in passenger flow composition. Hence, very accurate passenger flows are needed in these cases. Second, we investigate the practical value of more sophisticated simulations. A simple strategy evaluates the effect of a waiting decision of some critical transfer on passenger delay subject to the assumption that all subsequent decisions are taken according to standard waiting time rules, as usually employed by railway companies like Deutsche Bahn. Here we analyze the impact of a higher level of simulation where waiting decisions for a critical transfer are considered jointly with one or more other decisions for subsequent transfers. We learn that such "coupled decisions" lead to improved solution in about 6.3% of all considered cases.

Cite as

Martin Lemnian, Matthias Müller-Hannemann, and Ralf Rückert. Sensitivity Analysis and Coupled Decisions in Passenger Flow-Based Train Dispatching. In 16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016). Open Access Series in Informatics (OASIcs), Volume 54, pp. 2:1-2:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{lemnian_et_al:OASIcs.ATMOS.2016.2,
  author =	{Lemnian, Martin and M\"{u}ller-Hannemann, Matthias and R\"{u}ckert, Ralf},
  title =	{{Sensitivity Analysis and Coupled Decisions in Passenger Flow-Based Train Dispatching}},
  booktitle =	{16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016)},
  pages =	{2:1--2:15},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-021-7},
  ISSN =	{2190-6807},
  year =	{2016},
  volume =	{54},
  editor =	{Goerigk, Marc and Werneck, Renato F.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2016.2},
  URN =		{urn:nbn:de:0030-drops-65264},
  doi =		{10.4230/OASIcs.ATMOS.2016.2},
  annote =	{Keywords: train delays, event-activity model, multi-criteria decisions, passenger flows, sensitivity analysis}
}
Document
Timing of Train Disposition: Towards Early Passenger Rerouting in Case of Delays

Authors: Martin Lemnian, Ralf Rückert, Steffen Rechner, Christoph Blendinger, and Matthias Müller-Hannemann

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


Abstract
Passenger-friendly train disposition is a challenging, highly complex online optimization problem with uncertain and incomplete information about future delays. In this paper we focus on the timing within the disposition process. We introduce three different classification schemes to predict as early as possible the status of a transfer: whether it will almost surely break, is so critically delayed that it requires manual disposition, or can be regarded as only slightly uncertain or as being safe. The three approaches use lower bounds on travel times, historical distributions of delay data, and fuzzy logic, respectively. In experiments with real delay data we achieve an excellent classification rate. Furthermore, using realistic passenger flows we observe that there is a significant potential to reduce the passenger delay if an early rerouting strategy is applied.

Cite as

Martin Lemnian, Ralf Rückert, Steffen Rechner, Christoph Blendinger, and Matthias Müller-Hannemann. Timing of Train Disposition: Towards Early Passenger Rerouting in Case of Delays. In 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 42, pp. 122-137, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)


Copy BibTex To Clipboard

@InProceedings{lemnian_et_al:OASIcs.ATMOS.2014.122,
  author =	{Lemnian, Martin and R\"{u}ckert, Ralf and Rechner, Steffen and Blendinger, Christoph and M\"{u}ller-Hannemann, Matthias},
  title =	{{Timing of Train Disposition: Towards Early Passenger Rerouting in Case of Delays}},
  booktitle =	{14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{122--137},
  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-dev.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2014.122},
  URN =		{urn:nbn:de:0030-drops-47576},
  doi =		{10.4230/OASIcs.ATMOS.2014.122},
  annote =	{Keywords: train delays, event-activity model, timing of decisions, passenger flows, passenger rerouting}
}
Document
Extended Sunflower Hidden Markov Models for the recognition of homotypic cis-regulatory modules}

Authors: Ioana M. Lemnian, Ralf Eggeling, and Ivo Grosse

Published in: OASIcs, Volume 34, German Conference on Bioinformatics 2013


Abstract
The transcription of genes is often regulated not only by transcription factors binding at single sites per promoter, but by the interplay of multiple copies of one or more transcription factors binding at multiple sites forming a cis-regulatory module. The computational recognition of cis-regulatory modules from ChIP-seq or other high-throughput data is crucial in modern life and medical sciences. A common type of cis-regulatory modules are homotypic clusters of binding sites, i.e., clusters of binding sites of one transcription factor. For their recognition the homotypic Sunflower Hidden Markov Model is a promising statistical model. However, this model neglects statistical dependences among nucleotides within binding sites and flanking regions, which makes it not well suited for de-novo motif discovery. Here, we propose an extension of this model that allows statistical dependences within binding sites, their reverse complements, and flanking regions. We study the efficacy of this extended homotypic Sunflower Hidden Markov Model based on ChIP-seq data from the Human ENCODE Project and find that it often outperforms the traditional homotypic Sunflower Hidden Markov Model.

Cite as

Ioana M. Lemnian, Ralf Eggeling, and Ivo Grosse. Extended Sunflower Hidden Markov Models for the recognition of homotypic cis-regulatory modules}. In German Conference on Bioinformatics 2013. Open Access Series in Informatics (OASIcs), Volume 34, pp. 101-109, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


Copy BibTex To Clipboard

@InProceedings{lemnian_et_al:OASIcs.GCB.2013.101,
  author =	{Lemnian, Ioana M. and Eggeling, Ralf and Grosse, Ivo},
  title =	{{Extended Sunflower Hidden Markov Models for the recognition of homotypic cis-regulatory modules\}}},
  booktitle =	{German Conference on Bioinformatics 2013},
  pages =	{101--109},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-59-0},
  ISSN =	{2190-6807},
  year =	{2013},
  volume =	{34},
  editor =	{Bei{\ss}barth, Tim and Kollmar, Martin and Leha, Andreas and Morgenstern, Burkhard and Schultz, Anne-Kathrin and Waack, Stephan and Wingender, Edgar},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.GCB.2013.101},
  URN =		{urn:nbn:de:0030-drops-42361},
  doi =		{10.4230/OASIcs.GCB.2013.101},
  annote =	{Keywords: Hidden Markov Models, cis-regulatory modules, de-novo motif discovery}
}
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