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Network density and the p-median solution
Dalarna University, School of Technology and Business Studies, Statistics.ORCID iD: 0000-0002-7512-5321
Dalarna University, School of Technology and Business Studies, Statistics.ORCID iD: 0000-0003-2317-9157
Dalarna University, School of Technology and Business Studies, Information Systems. Dalarna University, School of Technology and Business Studies, Human Geography.ORCID iD: 0000-0003-4871-833X
2013 (English)Report (Other academic)
Abstract [en]

The p-medianmodel is commonly used to find optimal locations of facilities for geographically distributed demands. So far, there are few studies that have considered the importance of the road network in the model. However, Han, Håkansson, and Rebreyend (2013) examined the solutions of the p-median model with densities of the road network varying from 500 to 70,000 nodes. They found as the density went beyond some 10,000 nodes, solutions have no further improvements but gradually worsen. The aim of this study is to check their findings by using an alternative heuristic being vertex substitution, as a complement to their using simulated annealing. We reject the findings in Han et al (2013). The solutions do not further improve as the nodes exceed 10,000, but neither do the solutions deteriorate.

Place, publisher, year, edition, pages
Borlänge: Högskolan Dalarna , 2013. , 11 p.
Series
Working papers in transport, tourism, information technology and microdata analysis, ISSN 1650-5581 ; 2013:25
Keyword [en]
P-median Model, Vertex Substitution, Simulated Annealing, Dense Network
National Category
Discrete Mathematics
Research subject
Complex Systems – Microdata Analysis, General Microdata Analysis - methods; Complex Systems – Microdata Analysis, General Microdata Analysis - transports
Identifiers
URN: urn:nbn:se:du-12980OAI: oai:DiVA.org:du-12980DiVA: diva2:648633
Available from: 2013-09-16 Created: 2013-09-16 Last updated: 2015-12-01Bibliographically approved
In thesis
1. Road network and GPS tracking with data processing and quality assessment
Open this publication in new window or tab >>Road network and GPS tracking with data processing and quality assessment
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

GPS technology has been embedded into portable, low-cost electronic devices nowadays to track the movements of mobile objects. This implication has greatly impacted the transportation field by creating a novel and rich source of traffic data on the road network. Although the promise offered by GPS devices to overcome problems like underreporting, respondent fatigue, inaccuracies and other human errors in data collection is significant; the technology is still relatively new that it raises many issues for potential users. These issues tend to revolve around the following areas: reliability, data processing and the related application.

This thesis aims to study the GPS tracking form the methodological, technical and practical aspects. It first evaluates the reliability of GPS based traffic data based on data from an experiment containing three different traffic modes (car, bike and bus) traveling along the road network. It then outline the general procedure for processing GPS tracking data and discuss related issues that are uncovered by using real-world GPS tracking data of 316 cars. Thirdly, it investigates the influence of road network density in finding optimal location for enhancing travel efficiency and decreasing travel cost.

The results show that the geographical positioning is reliable. Velocity is slightly underestimated, whereas altitude measurements are unreliable.Post processing techniques with auxiliary information is found necessary and important when solving the inaccuracy of GPS data. The densities of the road network influence the finding of optimal locations. The influence will stabilize at a certain level and do not deteriorate when the node density is higher.

Place, publisher, year, edition, pages
Borlänge: Högskolan Dalarna, 2015. 85 p.
Series
Dalarna Licentiate Theses, 3
Keyword
GPS tracking, Reliability, Road network, visualized map, road network, Map-matching, P-median Model, Network density
National Category
Social and Economic Geography
Research subject
Complex Systems – Microdata Analysis
Identifiers
urn:nbn:se:du-17354 (URN)978-91-89020-92-4 (ISBN)
Presentation
2015-01-21, B247, Högskolan Dalarna, 79188 Falun, Borlänge, 10:00 (English)
Opponent
Supervisors
Available from: 2015-05-07 Created: 2015-05-06 Last updated: 2017-04-05Bibliographically approved

Open Access in DiVA

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CiteExportLink to record
Permanent link

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Cite
Citation style
  • apa
  • harvard1
  • ieee
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More styles
Language
  • de-DE
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  • nn-NB
  • sv-SE
  • Other locale
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Output format
  • html
  • text
  • asciidoc
  • rtf