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Documents authored by Werner, Christian


Document
Short Paper
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
Short Paper
Abstract Data Types for Spatio-Temporal Remote Sensing Analysis (Short Paper)

Authors: Martin Sudmanns, Stefan Lang, Dirk Tiede, Christian Werner, Hannah Augustin, and Andrea Baraldi

Published in: LIPIcs, Volume 114, 10th International Conference on Geographic Information Science (GIScience 2018)


Abstract
Abstract data types are a helpful framework to formalise analyses and make them more transparent, reproducible and comprehensible. We are revisiting an approach based on the space, time and theme dimensions of remotely sensed data, and extending it with a more differentiated understanding of space-time representations. In contrast to existing approaches and implementations that consider only fixed spatial units (e.g. pixels), our approach allows investigations of the spatial units' spatio-temporal characteristics, such as the size and shape of their geometry, and their relationships. Five different abstract data types are identified to describe geographical phenomenon, either directly or in combination: coverage, time series, trajectory, composition and evolution.

Cite as

Martin Sudmanns, Stefan Lang, Dirk Tiede, Christian Werner, Hannah Augustin, and Andrea Baraldi. Abstract Data Types for Spatio-Temporal Remote Sensing Analysis (Short Paper). In 10th International Conference on Geographic Information Science (GIScience 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 114, pp. 60:1-60:7, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{sudmanns_et_al:LIPIcs.GISCIENCE.2018.60,
  author =	{Sudmanns, Martin and Lang, Stefan and Tiede, Dirk and Werner, Christian and Augustin, Hannah and Baraldi, Andrea},
  title =	{{Abstract Data Types for Spatio-Temporal Remote Sensing Analysis}},
  booktitle =	{10th International Conference on Geographic Information Science (GIScience 2018)},
  pages =	{60:1--60:7},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-083-5},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{114},
  editor =	{Winter, Stephan and Griffin, Amy and Sester, Monika},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GISCIENCE.2018.60},
  URN =		{urn:nbn:de:0030-drops-93881},
  doi =		{10.4230/LIPIcs.GISCIENCE.2018.60},
  annote =	{Keywords: Big Earth Data, Semantic Analysis, Data Cube}
}
Document
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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