3 Search Results for "Werner, Nils"

Document

DOI: 10.4230/LIPIcs.SEA.2024.26

Scalable Hard Instances for Independent Set Reconfiguration

Authors: Takehide Soh, Takumu Watanabe, Jun Kawahara, Akira Suzuki, and Takehiro Ito

Published in: LIPIcs, Volume 301, 22nd International Symposium on Experimental Algorithms (SEA 2024)

Abstract

The Token Jumping problem, also known as the independent set reconfiguration problem under the token jumping model, is defined as follows: Given a graph and two same-sized independent sets, determine whether one can be transformed into the other via a sequence of independent sets. Token Jumping has been extensively studied, mainly from the viewpoint of algorithmic theory, but its practical study has just begun. To develop a practically good solver, it is important to construct benchmark datasets that are scalable and hard. Here, "scalable" means the ability to change the scale of the instance while maintaining its characteristics by adjusting the given parameters; and "hard" means that the instance can become so difficult that it cannot be solved within a practical time frame by a solver. In this paper, we propose four types of instance series for Token Jumping. Our instance series is scalable in the sense that instance scales are controlled by the number of vertices. To establish their hardness, we focus on the numbers of transformation steps; our instance series requires exponential numbers of steps with respect to the number of vertices. Interestingly, three types of instance series are constructed by importing theories developed by algorithmic research. We experimentally evaluate the scalability and hardness of the proposed instance series, using the SAT solver and award-winning solvers of the international competition for Token Jumping.

Cite as

Takehide Soh, Takumu Watanabe, Jun Kawahara, Akira Suzuki, and Takehiro Ito. Scalable Hard Instances for Independent Set Reconfiguration. In 22nd International Symposium on Experimental Algorithms (SEA 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 301, pp. 26:1-26:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{soh_et_al:LIPIcs.SEA.2024.26,
  author =	{Soh, Takehide and Watanabe, Takumu and Kawahara, Jun and Suzuki, Akira and Ito, Takehiro},
  title =	{{Scalable Hard Instances for Independent Set Reconfiguration}},
  booktitle =	{22nd International Symposium on Experimental Algorithms (SEA 2024)},
  pages =	{26:1--26:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-325-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{301},
  editor =	{Liberti, Leo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SEA.2024.26},
  URN =		{urn:nbn:de:0030-drops-203913},
  doi =		{10.4230/LIPIcs.SEA.2024.26},
  annote =	{Keywords: Combinatorial reconfiguration, Benckmark dataset, Graph Algorithm, PSPACE-complete}
}

Document

DOI: 10.4230/LIPIcs.ESA.2022.89

Combining Predicted and Live Traffic with Time-Dependent A* Potentials

Authors: Nils Werner and Tim Zeitz

Published in: LIPIcs, Volume 244, 30th Annual European Symposium on Algorithms (ESA 2022)

Abstract

We study efficient and exact shortest path algorithms for routing on road networks with realistic traffic data. For navigation applications, both current (i.e., live) traffic events and predictions of future traffic flows play an important role in routing. While preprocessing-based speedup techniques have been employed successfully to both settings individually, a combined model poses significant challenges. Supporting predicted traffic typically requires expensive preprocessing while live traffic requires fast updates for regular adjustments. We propose an A*-based solution to this problem. By generalizing A* potentials to time dependency, i.e. the estimate of the distance from a vertex to the target also depends on the time of day when the vertex is visited, we achieve significantly faster query times than previously possible. Our evaluation shows that our approach enables interactive query times on continental-sized road networks while allowing live traffic updates within a fraction of a minute. We achieve a speedup of at least two orders of magnitude over Dijkstra’s algorithm and up to one order of magnitude over state-of-the-art time-independent A* potentials.

Cite as

Nils Werner and Tim Zeitz. Combining Predicted and Live Traffic with Time-Dependent A* Potentials. In 30th Annual European Symposium on Algorithms (ESA 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 244, pp. 89:1-89:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{werner_et_al:LIPIcs.ESA.2022.89,
  author =	{Werner, Nils and Zeitz, Tim},
  title =	{{Combining Predicted and Live Traffic with Time-Dependent A* Potentials}},
  booktitle =	{30th Annual European Symposium on Algorithms (ESA 2022)},
  pages =	{89:1--89:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-247-1},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{244},
  editor =	{Chechik, Shiri and Navarro, Gonzalo and Rotenberg, Eva and Herman, Grzegorz},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2022.89},
  URN =		{urn:nbn:de:0030-drops-170271},
  doi =		{10.4230/LIPIcs.ESA.2022.89},
  annote =	{Keywords: realistic road networks, shortest paths, live traffic, time-dependent routing}
}

Document

DOI: 10.4230/OASIcs.KiVS.2011.26

A Service-Oriented Operating System and an Application Development Infrastructure for Distributed Embedded Systems

Authors: Martin Lipphardt, Nils Glombitza, Jana Neumann, Christian Werner, and Stefan Fischer

Published in: OASIcs, Volume 17, 17th GI/ITG Conference on Communication in Distributed Systems (KiVS 2011)

Abstract

The paradigm of service-orientation promises a significant ease of use in creating and managing distributed software systems. A very important aspect here is that also application domain experts and stakeholders, who are not necessarily skilled in computer programming, get a chance to create, analyze, and adapt distributed applications. However, up to now, service-oriented architectures have been mainly discussed in the context of complex business applications. In this paper we will investigate how to transfer the benefits of a service-oriented architecture into the field of embedded systems, so that this technology gets accessible to a much wider range of users. As an example, we will demonstrate this scheme for sensor network applications. In order to address the problem of limited device resources we will introduce a minimal operating system for such devices. It organizes all pieces of code running on a sensor node in a service-oriented fashion and also features the relocation of code to a different node at runtime. We will demonstrate that it is possible to design a sensor network application from a set of already existing services in a highly modular way by employing already existing technologies and standards.

Cite as

Martin Lipphardt, Nils Glombitza, Jana Neumann, Christian Werner, and Stefan Fischer. A Service-Oriented Operating System and an Application Development Infrastructure for Distributed Embedded Systems. In 17th GI/ITG Conference on Communication in Distributed Systems (KiVS 2011). Open Access Series in Informatics (OASIcs), Volume 17, pp. 26-37, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{lipphardt_et_al:OASIcs.KiVS.2011.26,
  author =	{Lipphardt, Martin and Glombitza, Nils and Neumann, Jana and Werner, Christian and Fischer, Stefan},
  title =	{{A Service-Oriented Operating System and an Application Development Infrastructure for Distributed Embedded Systems}},
  booktitle =	{17th GI/ITG Conference on Communication in Distributed Systems (KiVS 2011)},
  pages =	{26--37},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-27-9},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{17},
  editor =	{Luttenberger, Norbert and Peters, Hagen},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.KiVS.2011.26},
  URN =		{urn:nbn:de:0030-drops-29550},
  doi =		{10.4230/OASIcs.KiVS.2011.26},
  annote =	{Keywords: service-oriented OS, sensor network, distributed embedded systems}
}

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1 Fischer, Stefan
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1 Applied computing → Transportation
1 Computing methodologies → Discrete space search
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1 Theory of computation → Shortest paths

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1 Benckmark dataset
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