12 Search Results for "Urban, Christian"

Document
Short Paper
DOI: 10.4230/LIPIcs.GIScience.2023.83
Betweenness Centrality in Spatial Networks: A Spatially Normalised Approach (Short Paper)

Authors: Christian Werner and Martin Loidl

Published in: LIPIcs, Volume 277, 12th International Conference on Geographic Information Science (GIScience 2023)

Abstract
Centrality metrics are essential to network analysis. They reveal important morphological properties of networks, indicating e.g. node or edge importance. Applications are manifold, ranging from biology to transport planning. However, while being commonly applied in spatial contexts such as urban analytics, the implications of the spatial configuration of network elements on these metrics are widely neglected. As a consequence, a systematic bias is introduced into spatial network analyses. When applied to real-world problems, unintended side effects and wrong conclusions might be the result. In this paper, we assess the impact of node density on betweenness centrality. Furthermore, we propose a method for computing spatially normalised betweenness centrality. We apply it to a theoretical case as well as real-world transport networks. Results show that spatial normalisation mitigates the prevalent bias of node density.
Cite as

Christian Werner and Martin Loidl. Betweenness Centrality in Spatial Networks: A Spatially Normalised Approach (Short Paper). In 12th International Conference on Geographic Information Science (GIScience 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 277, pp. 83:1-83:6, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2023)

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@InProceedings{werner_et_al:LIPIcs.GIScience.2023.83,
  author =	{Werner, Christian and Loidl, Martin},
  title =	{{Betweenness Centrality in Spatial Networks: A Spatially Normalised Approach}},
  booktitle =	{12th International Conference on Geographic Information Science (GIScience 2023)},
  pages =	{83:1--83:6},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-288-4},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{277},
  editor =	{Beecham, Roger and Long, Jed A. and Smith, Dianna and Zhao, Qunshan and Wise, Sarah},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GIScience.2023.83},
  URN =		{urn:nbn:de:0030-drops-189781},
  doi =		{10.4230/LIPIcs.GIScience.2023.83},
  annote =	{Keywords: spatial network analysis, edge betweenness centrality, flow estimation, SIBC, spatial interaction, spatial centrality, urban analytics}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2023.5
Integrating Line Planning for Construction Sites into Periodic Timetabling via Track Choice

Authors: Berenike Masing, Niels Lindner, and Christian Liebchen

Published in: OASIcs, Volume 115, 23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023)

Abstract
We consider maintenance sites for urban rail systems, where unavailable tracks typically require changes to the regular timetable, and often even to the line plan. In this paper, we present an integrated mixed-integer linear optimization model to compute an optimal line plan that makes best use of the available tracks, together with a periodic timetable, including its detailed routing on the tracks within the stations. The key component is a flexible, turn-sensitive event-activity network that allows to integrate line planning and train routing using a track choice extension of the Periodic Event Scheduling Problem (PESP). Major goals are to maintain as much of the regular service as possible, and to keep the necessary changes rather local. Moreover, we present computational results on real construction site scenarios on the S-Bahn Berlin network. We demonstrate that this integrated problem is indeed solvable on practically relevant instances.
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Berenike Masing, Niels Lindner, and Christian Liebchen. Integrating Line Planning for Construction Sites into Periodic Timetabling via Track Choice. In 23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023). Open Access Series in Informatics (OASIcs), Volume 115, pp. 5:1-5:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2023)

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@InProceedings{masing_et_al:OASIcs.ATMOS.2023.5,
  author =	{Masing, Berenike and Lindner, Niels and Liebchen, Christian},
  title =	{{Integrating Line Planning for Construction Sites into Periodic Timetabling via Track Choice}},
  booktitle =	{23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023)},
  pages =	{5:1--5:15},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-302-7},
  ISSN =	{2190-6807},
  year =	{2023},
  volume =	{115},
  editor =	{Frigioni, Daniele and Schiewe, Philine},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2023.5},
  URN =		{urn:nbn:de:0030-drops-187669},
  doi =		{10.4230/OASIcs.ATMOS.2023.5},
  annote =	{Keywords: Periodic Timetabling, Line Planning, Track Choice, Mixed-Integer Programming, Construction Sites, Railway Rescheduling}
}
Document
DOI: 10.4230/LIPIcs.ITP.2023.27
POSIX Lexing with Bitcoded Derivatives

Authors: Chengsong Tan and Christian Urban

Published in: LIPIcs, Volume 268, 14th International Conference on Interactive Theorem Proving (ITP 2023)

Abstract
Sulzmann and Lu describe a lexing algorithm that calculates Brzozowski derivatives using bitcodes annotated to regular expressions. Their algorithm generates POSIX values which encode the information of how a regular expression matches a string - that is, which part of the string is matched by which part of the regular expression. This information is needed in the context of lexing in order to extract and to classify tokens. The purpose of the bitcodes is to generate POSIX values incrementally while derivatives are calculated. They also help with designing an "aggressive" simplification function that keeps the size of derivatives finitely bounded. Without simplification the size of some derivatives can grow arbitrarily big, resulting in an extremely slow lexing algorithm. In this paper we describe a variant of Sulzmann and Lu’s algorithm: Our variant is a recursive functional program, whereas Sulzmann and Lu’s version involves a fixpoint construction. We (i) prove in Isabelle/HOL that our variant is correct and generates unique POSIX values (no such proof has been given for the original algorithm by Sulzmann and Lu); we also (ii) establish finite bounds for the size of our derivatives.
Cite as

Chengsong Tan and Christian Urban. POSIX Lexing with Bitcoded Derivatives. In 14th International Conference on Interactive Theorem Proving (ITP 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 268, pp. 27:1-27:18, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2023)

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@InProceedings{tan_et_al:LIPIcs.ITP.2023.27,
  author =	{Tan, Chengsong and Urban, Christian},
  title =	{{POSIX Lexing with Bitcoded Derivatives}},
  booktitle =	{14th International Conference on Interactive Theorem Proving (ITP 2023)},
  pages =	{27:1--27:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-284-6},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{268},
  editor =	{Naumowicz, Adam and Thiemann, Ren\'{e}},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITP.2023.27},
  URN =		{urn:nbn:de:0030-drops-184027},
  doi =		{10.4230/LIPIcs.ITP.2023.27},
  annote =	{Keywords: POSIX matching and lexing, derivatives of regular expressions, Isabelle/HOL}
}
Document
DOI: 10.4230/LITES.8.1.2
Micro- and Macroscopic Road Traffic Analysis using Drone Image Data

Authors: Friedrich Kruber, Eduardo Sánchez Morales, Robin Egolf, Jonas Wurst, Samarjit Chakraborty, and Michael Botsch

Published in: LITES, Volume 8, Issue 1 (2022): Special Issue on Embedded Systems for Computer Vision. Leibniz Transactions on Embedded Systems, Volume 8, Issue 1

Abstract
The current development in the drone technology, alongside with machine learning based image processing, open new possibilities for various applications. Thus, the market volume is expected to grow rapidly over the next years. The goal of this paper is to demonstrate the capabilities and limitations of drone based image data processing for the purpose of road traffic analysis. In the first part a method for generating microscopic traffic data is proposed. More precisely, the state of vehicles and the resulting trajectories are estimated. The method is validated by conducting experiments with reference sensors and proofs to achieve precise vehicle state estimation results. It is also shown, how the computational effort can be reduced by incorporating the tracking information into a neural network. A discussion on current limitations supplements the findings. By collecting a large number of vehicle trajectories, macroscopic statistics, such as traffic flow and density can be obtained from the data. In the second part, a publicly available drone based data set is analyzed to evaluate the suitability for macroscopic traffic modeling. The results show that the method is well suited for gaining detailed information about macroscopic statistics, such as traffic flow dependent time headway or lane change occurrences. In conclusion, this paper presents methods to exploit the remarkable opportunities of drone based image processing for joint macro- and microscopic traffic analysis.
Cite as

Friedrich Kruber, Eduardo Sánchez Morales, Robin Egolf, Jonas Wurst, Samarjit Chakraborty, and Michael Botsch. Micro- and Macroscopic Road Traffic Analysis using Drone Image Data. In LITES, Volume 8, Issue 1 (2022): Special Issue on Embedded Systems for Computer Vision. Leibniz Transactions on Embedded Systems, Volume 8, Issue 1, pp. 02:1-02:27, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2022)

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@Article{kruber_et_al:LITES.8.1.2,
  author =	{Kruber, Friedrich and S\'{a}nchez Morales, Eduardo and Egolf, Robin and Wurst, Jonas and Chakraborty, Samarjit and Botsch, Michael},
  title =	{{Micro- and Macroscopic Road Traffic Analysis using Drone Image Data}},
  booktitle =	{LITES, Volume 8, Issue 1 (2022): Special Issue on Embedded Systems for Computer Vision},
  pages =	{02:1--02:27},
  journal =	{Leibniz Transactions on Embedded Systems},
  ISSN =	{2199-2002},
  year =	{2022},
  volume =	{8},
  number =	{1},
  editor =	{Kruber, Friedrich and S\'{a}nchez Morales, Eduardo and Egolf, Robin and Wurst, Jonas and Chakraborty, Samarjit and Botsch, Michael},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LITES.8.1.2},
  doi =		{10.4230/LITES.8.1.2},
  annote =	{Keywords: traffic data analysis, trajectory data, drone image data}
}
Document
DOI: 10.4230/LITES.8.1.3
HW-Flow: A Multi-Abstraction Level HW-CNN Codesign Pruning Methodology

Authors: Manoj-Rohit Vemparala, Nael Fasfous, Alexander Frickenstein, Emanuele Valpreda, Manfredi Camalleri, Qi Zhao, Christian Unger, Naveen-Shankar Nagaraja, Maurizio Martina, and Walter Stechele

Published in: LITES, Volume 8, Issue 1 (2022): Special Issue on Embedded Systems for Computer Vision. Leibniz Transactions on Embedded Systems, Volume 8, Issue 1

Abstract
Convolutional neural networks (CNNs) have produced unprecedented accuracy for many computer vision problems in the recent past. In power and compute-constrained embedded platforms, deploying modern CNNs can present many challenges. Most CNN architectures do not run in real-time due to the high number of computational operations involved during the inference phase. This emphasizes the role of CNN optimization techniques in early design space exploration. To estimate their efficacy in satisfying the target constraints, existing techniques are either hardware (HW) agnostic, pseudo-HW-aware by considering parameter and operation counts, or HW-aware through inflexible hardware-in-the-loop (HIL) setups. In this work, we introduce HW-Flow, a framework for optimizing and exploring CNN models based on three levels of hardware abstraction: Coarse, Mid and Fine. Through these levels, CNN design and optimization can be iteratively refined towards efficient execution on the target hardware platform. We present HW-Flow in the context of CNN pruning by augmenting a reinforcement learning agent with key metrics to understand the influence of its pruning actions on the inference hardware. With 2× reduction in energy and latency, we prune ResNet56, ResNet50, and DeepLabv3 with minimal accuracy degradation on the CIFAR-10, ImageNet, and CityScapes datasets, respectively.
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Manoj-Rohit Vemparala, Nael Fasfous, Alexander Frickenstein, Emanuele Valpreda, Manfredi Camalleri, Qi Zhao, Christian Unger, Naveen-Shankar Nagaraja, Maurizio Martina, and Walter Stechele. HW-Flow: A Multi-Abstraction Level HW-CNN Codesign Pruning Methodology. In LITES, Volume 8, Issue 1 (2022): Special Issue on Embedded Systems for Computer Vision. Leibniz Transactions on Embedded Systems, Volume 8, Issue 1, pp. 03:1-03:30, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2022)

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@Article{vemparala_et_al:LITES.8.1.3,
  author =	{Vemparala, Manoj-Rohit and Fasfous, Nael and Frickenstein, Alexander and Valpreda, Emanuele and Camalleri, Manfredi and Zhao, Qi and Unger, Christian and Nagaraja, Naveen-Shankar and Martina, Maurizio and Stechele, Walter},
  title =	{{HW-Flow: A Multi-Abstraction Level HW-CNN Codesign Pruning Methodology}},
  booktitle =	{LITES, Volume 8, Issue 1 (2022): Special Issue on Embedded Systems for Computer Vision},
  pages =	{03:1--03:30},
  journal =	{Leibniz Transactions on Embedded Systems},
  ISSN =	{2199-2002},
  year =	{2022},
  volume =	{8},
  number =	{1},
  editor =	{Vemparala, Manoj-Rohit and Fasfous, Nael and Frickenstein, Alexander and Valpreda, Emanuele and Camalleri, Manfredi and Zhao, Qi and Unger, Christian and Nagaraja, Naveen-Shankar and Martina, Maurizio and Stechele, Walter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LITES.8.1.3},
  doi =		{10.4230/LITES.8.1.3},
  annote =	{Keywords: Convolutional Neural Networks, Optimization, Hardware Modeling, Pruning}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2020.6
Don't Panic! Better, Fewer, Syntax Errors for LR Parsers

Authors: Lukas Diekmann and Laurence Tratt

Published in: LIPIcs, Volume 166, 34th European Conference on Object-Oriented Programming (ECOOP 2020)

Abstract
Syntax errors are generally easy to fix for humans, but not for parsers in general nor LR parsers in particular. Traditional "panic mode" error recovery, though easy to implement and applicable to any grammar, often leads to a cascading chain of errors that drown out the original. More advanced error recovery techniques suffer less from this problem but have seen little practical use because their typical performance was seen as poor, their worst case unbounded, and the repairs they reported arbitrary. In this paper we introduce the CPCT+ algorithm, and an implementation of that algorithm, that address these issues. First, CPCT+ reports the complete set of minimum cost repair sequences for a given location, allowing programmers to select the one that best fits their intention. Second, on a corpus of 200,000 real-world syntactically invalid Java programs, CPCT+ is able to repair 98.37%±0.017% of files within a timeout of 0.5s. Finally, CPCT+ uses the complete set of minimum cost repair sequences to reduce the cascading error problem, where incorrect error recovery causes further spurious syntax errors to be identified. Across the test corpus, CPCT+ reports 435,812±473 error locations to the user, reducing the cascading error problem substantially relative to the 981,628±0 error locations reported by panic mode.
Cite as

Lukas Diekmann and Laurence Tratt. Don't Panic! Better, Fewer, Syntax Errors for LR Parsers. In 34th European Conference on Object-Oriented Programming (ECOOP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 166, pp. 6:1-6:32, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)

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@InProceedings{diekmann_et_al:LIPIcs.ECOOP.2020.6,
  author =	{Diekmann, Lukas and Tratt, Laurence},
  title =	{{Don't Panic! Better, Fewer, Syntax Errors for LR Parsers}},
  booktitle =	{34th European Conference on Object-Oriented Programming (ECOOP 2020)},
  pages =	{6:1--6:32},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-154-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{166},
  editor =	{Hirschfeld, Robert and Pape, Tobias},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2020.6},
  URN =		{urn:nbn:de:0030-drops-131630},
  doi =		{10.4230/LIPIcs.ECOOP.2020.6},
  annote =	{Keywords: Parsing, error recovery, programming languages}
}
Document
DOI: 10.4230/LIPIcs.COSIT.2017.6
Urban Artefacts and Their Social Roles: Towards an Ontology of Social Practices

Authors: Alessia Calafiore, Guido Boella, Stefano Borgo, and Nicola Guarino

Published in: LIPIcs, Volume 86, 13th International Conference on Spatial Information Theory (COSIT 2017)

Abstract
Cities can be seen as systems of urban artefacts interacting with human activities. Since cities in this sense need to be organized and coordinated, convergences and divergences between the "planned" and the "lived" city have always been of paramount interest in urban planning. The increasing amount of geo big data and the growing impact of Internet of Things (IoT) in contemporary smart city is pushing toward a re-conceptualization of urban systems taking into consideration the complexity of human behaviors. This work contributes to this view by proposing an ontological analysis of urban artefacts and their roles, focusing in particular on the difference between social roles and functional roles through the prism of social practices.
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Alessia Calafiore, Guido Boella, Stefano Borgo, and Nicola Guarino. Urban Artefacts and Their Social Roles: Towards an Ontology of Social Practices. In 13th International Conference on Spatial Information Theory (COSIT 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 86, pp. 6:1-6:13, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)

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@InProceedings{calafiore_et_al:LIPIcs.COSIT.2017.6,
  author =	{Calafiore, Alessia and Boella, Guido and Borgo, Stefano and Guarino, Nicola},
  title =	{{Urban Artefacts and Their Social Roles: Towards an Ontology of Social Practices}},
  booktitle =	{13th International Conference on Spatial Information Theory (COSIT 2017)},
  pages =	{6:1--6:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-043-9},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{86},
  editor =	{Clementini, Eliseo and Donnelly, Maureen and Yuan, May and Kray, Christian and Fogliaroni, Paolo and Ballatore, Andrea},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.COSIT.2017.6},
  URN =		{urn:nbn:de:0030-drops-77642},
  doi =		{10.4230/LIPIcs.COSIT.2017.6},
  annote =	{Keywords: urban artefact, ontology, social practice, urban planning}
}
Document
DOI: 10.4230/LIPIcs.COSIT.2017.16
Timing of Pedestrian Navigation Instructions

Authors: Ioannis Giannopoulos, David Jonietz, Martin Raubal, Georgios Sarlas, and Lisa Stähli

Published in: LIPIcs, Volume 86, 13th International Conference on Spatial Information Theory (COSIT 2017)

Abstract
During pedestrian navigation in outdoor urban environments we often utilize assistance systems to support decision-making. These systems help wayfinders by providing relevant information withing the context of their surroundings, e.g., landmark-based instructions of the type "turn left at the church". Next to the instruction type and content, also the timing of the instruction must be considered in order to facilitate the wayfinding process. In this work we present our findings concerning the user and environmental factors that have an impact on the timing of instructions. We applied a survival analysis on data collected through an experiment in a realistic virtual environment in order to analyze the expected distance to the decision point until instructions are needed. The presented results can be used by navigation systems for instruction timing based on the characteristics of the current wayfinder and environment.
Cite as

Ioannis Giannopoulos, David Jonietz, Martin Raubal, Georgios Sarlas, and Lisa Stähli. Timing of Pedestrian Navigation Instructions. In 13th International Conference on Spatial Information Theory (COSIT 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 86, pp. 16:1-16:13, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)

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@InProceedings{giannopoulos_et_al:LIPIcs.COSIT.2017.16,
  author =	{Giannopoulos, Ioannis and Jonietz, David and Raubal, Martin and Sarlas, Georgios and St\"{a}hli, Lisa},
  title =	{{Timing of Pedestrian Navigation Instructions}},
  booktitle =	{13th International Conference on Spatial Information Theory (COSIT 2017)},
  pages =	{16:1--16:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-043-9},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{86},
  editor =	{Clementini, Eliseo and Donnelly, Maureen and Yuan, May and Kray, Christian and Fogliaroni, Paolo and Ballatore, Andrea},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.COSIT.2017.16},
  URN =		{urn:nbn:de:0030-drops-77606},
  doi =		{10.4230/LIPIcs.COSIT.2017.16},
  annote =	{Keywords: navigation, wayfinding, instructions, timing, survival analysis}
}
Document
DOI: 10.4230/LIPIcs.COSIT.2017.17
On Avoiding Traffic Jams with Dynamic Self-Organizing Trip Planning

Authors: Thomas Liebig and Maurice Sotzny

Published in: LIPIcs, Volume 86, 13th International Conference on Spatial Information Theory (COSIT 2017)

Abstract
Urban areas are increasingly subject to congestions. Most navigation systems and algorithms that avoid these congestions consider drivers independently and can, thus, cause novel congestions at unexpected places. Pre-computation of optimal trips (Nash equilibrium) could be a solution to the problem but is due to its static nature of no practical relevance. In contrast, the paper at-hand provides an approach to avoid traffic jams with dynamic self-organizing trip planning. We apply reinforcement learning to learn dynamic weights for routing from the decisions and feedback logs of the vehicles. In order to compare our routing regime against others, we validate our approach in an open simulation environment (LuST) that allows reproduction of the traffic in Luxembourg for a particular day. Additionally, in two realistic scenarios: (1) usage of stationary sensors and (2) deployment in a mobile navigation system, we perform experiments with varying penetration rates. All our experiments reveal that performance of the traffic network is increased and occurrence of traffic jams are reduced by application of our routing regime.
Cite as

Thomas Liebig and Maurice Sotzny. On Avoiding Traffic Jams with Dynamic Self-Organizing Trip Planning. In 13th International Conference on Spatial Information Theory (COSIT 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 86, pp. 17:1-17:12, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)

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@InProceedings{liebig_et_al:LIPIcs.COSIT.2017.17,
  author =	{Liebig, Thomas and Sotzny, Maurice},
  title =	{{On Avoiding Traffic Jams with Dynamic Self-Organizing Trip Planning}},
  booktitle =	{13th International Conference on Spatial Information Theory (COSIT 2017)},
  pages =	{17:1--17:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-043-9},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{86},
  editor =	{Clementini, Eliseo and Donnelly, Maureen and Yuan, May and Kray, Christian and Fogliaroni, Paolo and Ballatore, Andrea},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.COSIT.2017.17},
  URN =		{urn:nbn:de:0030-drops-77615},
  doi =		{10.4230/LIPIcs.COSIT.2017.17},
  annote =	{Keywords: situation-aware trip planning, self-organizing traffic, reinforcement learning}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2017.5
Modelling Homogeneous Generative Meta-Programming

Authors: Martin Berger, Laurence Tratt, and Christian Urban

Published in: LIPIcs, Volume 74, 31st European Conference on Object-Oriented Programming (ECOOP 2017)

Abstract
Homogeneous generative meta-programming (HGMP) enables the generation of program fragments at compile-time or run-time. We present a foundational calculus which can model both compile-time and run-time evaluated HGMP, allowing us to model, for the first time, languages such as Template Haskell. The calculus is designed such that it can be gradually enhanced with the features needed to model many of the advanced features of real languages. We demonstrate this by showing how a simple, staged type system as found in Template Haskell can be added to the calculus.
Cite as

Martin Berger, Laurence Tratt, and Christian Urban. Modelling Homogeneous Generative Meta-Programming. In 31st European Conference on Object-Oriented Programming (ECOOP 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 74, pp. 5:1-5:23, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)

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@InProceedings{berger_et_al:LIPIcs.ECOOP.2017.5,
  author =	{Berger, Martin and Tratt, Laurence and Urban, Christian},
  title =	{{Modelling Homogeneous Generative Meta-Programming}},
  booktitle =	{31st European Conference on Object-Oriented Programming (ECOOP 2017)},
  pages =	{5:1--5:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-035-4},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{74},
  editor =	{M\"{u}ller, Peter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2017.5},
  URN =		{urn:nbn:de:0030-drops-72775},
  doi =		{10.4230/LIPIcs.ECOOP.2017.5},
  annote =	{Keywords: Formal Methods, Meta-Programming, Operational Semantics, Types, Quasi-Quotes, Abstract Syntax Trees}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2007.1181
02. Applied Railway Optimization in Production Planning at DSB S-tog - tasks, tools and challenges

Authors: Jens Clausen

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

Abstract
Efficient public transportation is becoming increasingly vital for modern capitals. DSB S-tog a/s is the major supplier of rail traffic on the infrastructure of the city-rail network in Copenhagen. S-tog has experienced a demand for increasing volume and quality of the transportation offered to the customers, and has concurrently been met with demands for higher efficiency in the daily operation. The plans of timetable, rolling stock and crew must hence allow for a high level of customer service, be efficient, and be robust against disturbances of operations. It is a highly non-trivial task to meet these conflicting goals. S-tog has therefore on the strategic level decided to use software with optimization capabilities in the planning processes. We describe the current status for each activity using optimization or simulation as a tool: Timetable evaluation, rolling stock planning, and crew scheduling. In addition we describe on-going efforts in using mathematical models in activities such as timetable design and work-force planning. We also identify some organizatorial key factors, which have paved the way for extended use of optimization methods in railway production planning.
Cite as

Jens Clausen. 02. Applied Railway Optimization in Production Planning at DSB S-tog - tasks, tools and challenges. In 7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07). Open Access Series in Informatics (OASIcs), Volume 7, pp. 15-29, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2007)

Copy BibTex To Clipboard

@InProceedings{clausen:OASIcs.ATMOS.2007.1181,
  author =	{Clausen, Jens},
  title =	{{02. Applied Railway Optimization in Production Planning at DSB S-tog - tasks, tools and challenges}},
  booktitle =	{7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07)},
  pages =	{15--29},
  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.2007.1181},
  URN =		{urn:nbn:de:0030-drops-11819},
  doi =		{10.4230/OASIcs.ATMOS.2007.1181},
  annote =	{Keywords: Operations research, urban railways, timetabling, crew, disruption management}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2007.1167
08. Branching Strategies to Improve Regularity of Crew Schedules in Ex-Urban Public Transit

Authors: Ingmar Steinzen, Leena Suhl, and Natalia Kliewer

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

Abstract
We discuss timetables in ex-urban bus traffic that consist of many trips serviced every day together with some exceptions that do not repeat daily. Traditional optimization methods for vehicle and crew scheduling in such cases usually produce schedules that contain irregularities which are not desirable especially from the point of view of the bus drivers. We propose a solution method which improves regularity while partially integrating the vehicle and crew scheduling problems. The approach includes two phases: first we solve the LP relaxation of a set partitioning formulation, using column generation together with Lagrangean relaxation techniques. In a second phase we generate integer solutions using a new combination of local branching and various versions of follow-on branching. Numerical tests with artificial and real instances show that regularity can be improved significantly with no or just a minor increase of costs.
Cite as

Ingmar Steinzen, Leena Suhl, and Natalia Kliewer. 08. Branching Strategies to Improve Regularity of Crew Schedules in Ex-Urban Public Transit. In 7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07). Open Access Series in Informatics (OASIcs), Volume 7, pp. 107-123, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2007)

Copy BibTex To Clipboard

@InProceedings{steinzen_et_al:OASIcs.ATMOS.2007.1167,
  author =	{Steinzen, Ingmar and Suhl, Leena and Kliewer, Natalia},
  title =	{{08. Branching Strategies to Improve Regularity of Crew Schedules in Ex-Urban Public Transit}},
  booktitle =	{7th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'07)},
  pages =	{107--123},
  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.2007.1167},
  URN =		{urn:nbn:de:0030-drops-11674},
  doi =		{10.4230/OASIcs.ATMOS.2007.1167},
  annote =	{Keywords: }
}
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