Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Edge-based graph centrality measures with spatial analytics to support vulnerability assessment and maintenance planning in sewer networks
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.ORCID iD: 0000-0001-8603-6941
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.ORCID iD: 0000-0003-1725-6478
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.ORCID iD: 0000-0001-9541-3542
2024 (English)In: Journal of Hydroinformatics, ISSN 1464-7141, E-ISSN 1465-1734, Vol. 26, no 9, p. 2146-2161, article id 2146Article in journal (Refereed) Published
Abstract [en]

In this study, the spatial relationship between critical pipes identified using edge-based centrality measures and pipes with higher failure probability-based vulnerability indicators were analysed in sanitary sewer networks. By analysing two sub-networks, one residential and the other a central network, significant spatial associations between pipes with high centrality values and those exhibiting adverse conditions (poor CCTV grades, previous blockages, and low self-cleaning capabilities) were identified. Path-based centrality measures, particularly edge betweenness and K-path edge centrality were less influenced by weights when identifying critical pipes. In contrast, non-path-based measures like nearest neighbour edge centrality could identify localised spatial patterns between critical pipes and pipes in adverse conditions within the sewer networks investigated. The results showed that the spatial patterns between critical pipes and pipes in adverse conditions were not random and could support proactive maintenance planning and the development of more resilient networks. Additionally, the impact of network structure, connectivity, and differences in the composition of pipe attributes could contribute to variations in the strength of observable spatial associations.

Place, publisher, year, edition, pages
IWA Publishing, 2024. Vol. 26, no 9, p. 2146-2161, article id 2146
Keywords [en]
asset management, complex network theory, network resilience, proactive maintenance planning, topological analysis
National Category
Infrastructure Engineering
Research subject
Urban Water Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-101738DOI: 10.2166/hydro.2024.300ISI: 001281233300001Scopus ID: 2-s2.0-85205948291OAI: oai:DiVA.org:ltu-101738DiVA, id: diva2:1806242
Note

Validerad;2024;Nivå 2;2024-11-04 (signyg);

Full text license: CC BY;

This article has previously appeared as a manuscript in a thesis.

Available from: 2023-10-20 Created: 2023-10-20 Last updated: 2024-11-04Bibliographically approved
In thesis
1. Analytics-driven approaches supporting asset management of sanitary sewer networks
Open this publication in new window or tab >>Analytics-driven approaches supporting asset management of sanitary sewer networks
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Analysdrivna metoder som stöder tillgångsförvaltning av spillvattennät
Abstract [en]

Sewer blockages can cause overflows and flooding, with consequences such as damage to property and environmental pollution, risks to public health and economic loss. Despite the causes being understood, blockages in sewer networks may occur unpredictably. The responsible staff for sewer networks at water utilities need to efficiently determine the most effective action (what), the specific network location needing attention (where), the optimal timing for intervention (when), and the appropriate remedial task (how), especially given the unpredictability of blockages. Today a reactive approach to asset management and maintenance is often adopted. Additionally, data availability, quality and interoperability between systems are not always at levels that can support decided objectives, proactive maintenance planning and asset management of pipe networks. Thus, the aim of this thesis is to propose and evaluate approaches that can support analytics-driven maintenance planning and asset management for sewer networks. These approaches aim to contribute to mitigating the impact of siloed data structures and enhance the understanding of blockage root causes from a spatial perspective.

In this thesis, the challenges of data management in the asset management of pipe networks were investigated through focus group workshops and questionnaire surveys. A conceptual framework was developed based on findings from focus group workshops and surveys. The framework combines data quality assessments, interoperability evaluations between asset management tools, data collection, and informational benefits analysis. This framework aimed to identify the presence of data silos and plausible pathways towards more data-driven data management strategies. A performance assessment combining performance indicators associated with blockages and partial least squares regression (PLS) was conducted to draw inferences that could be useful at a strategic level. Furthermore, a spatial heterogeneity assessment of blockages and factors affecting blockages was carried out. This approach combined network kernel density estimation (NKDE), network k-function, and geographically weighted Poisson regression (GWPR). Lastly, a vulnerability assessment was carried out that combined topological analysis using edge-based centrality measures and network cross-k-function. These approaches were applied to three sewer networks.

The focus group workshops and questionnaire surveys identified several challenges affecting data management in the context of pipe network asset management. Many of the challenges could be ascribed to issues related to data quality and interoperability. Results from the preliminary application of the conceptual framework showed how it could be applied for identifying data silos and pathways to data-driven decision-making towards proactive management blockages in sewers. The observed spatial trends and patterns from network k-function analysis and network kernel density estimation showed spatial variability in the occurrence of blockages (single occurring and recurring). Geographically-weighted Poisson regression analysis showed spatial heterogeneity in factors influencing blockage propensity. The network cross-k-function analysis demonstrated that pipes with historical blockage incidents tend to be clustered around critical pipes with higher centrality values. These results could support vulnerability assessments in sewer networks and the development of targeted maintenance strategies. These approaches together could aid data-informed maintenance planning and asset management at the strategic, tactical and operational levels.

Abstract [sv]

Avloppsstopp kan orsaka översvämningar vilket kan medföra konsekvenser som skador på egendom och spridning av föroreningar och leda till ekonomiska förluster samt risker för folkhälsan. Trots att orsakerna till avloppsstopp är kända, inträffar ibland oförutsedda avloppsstopp i ledningsnäten. De som ansvarar för avloppsledningarna behöver kunna fastställa effektiva åtgärder (hur), den specifika punkt i nätverket som behöver åtgärdas (var) och den optimala tidpunkten för åtgärd (när). Idag sker ofta åtgärder på ledningsnät reaktivt. Vidare är inte alltid data för analys tillgänglig eller av god kvalitet. Det finns även problem med interoperabilitet mellan system som kan stödja uppsatta mål för proaktiv underhållsplanering och tillgångsförvalting av ledningsnät. Därför är syftet med denna avhandling att föreslå och utvärdera metoder som kan stödja analytiskt driven underhållsplanering och tillgångsförvalting av avloppsledningsnät. Dessa metoder syftar till att minska negativa effekter av så kallade datasilos och förbättra förståelsen av grundorsaker till avloppsstopp utifrån ett spatialt perspektiv.

I denna avhandling undersöktes utmaningar med datahantering inom tillgångsförvalting i ledningsnät genom fokusgruppsworkshopar och enkätundersökningar. Ett konceptuellt ramverk utvecklades, baserad på resultat från workshoparna och en av enkäterna. Ramverket innefattade användning av datakvalitetsbedömningar och utvärdering av interoperabilitet mellan verktyg för tillgångsförvalting och datainsamling. Vidare analyserades fördelar med att identifiera förekomsten av datasilor och tänkbara tillvägagångssätt för att nå mer datadrivna strategier för datahantering. En prestandautvärdering som kombinerade prestandaindikatorer relaterade till avloppsstopp som kombinerades med regressionsanalys med minsta-kvadrat-metoden genomfördes för att dra slutsatser som kan vara av nytta på strategisk nivå. Vidare gjordes en spatial bedömning av avloppsstoppens förekomst och deras variationer över ledningsnätet samt faktorer som påverkar avloppsstopp. Denna analys kombinerade en täthetsanalys (kernel density estimation) med en network k-function samt en geografiskt viktad Poisson-regression analys. Slutligen genomfördes en sårbarhetsbedömning som kombinerade en topologisk analys baserad på grafteori och network cross-k-function. Metoderna tillämpades på tre avloppsnät.

Fokusgruppsworkshoparna och enkätundersökningar identifierade en mängd utmaningar som påverkar datahantering i tillgångsförvalting av ledningsnät. Flera av utmaningarna kunde tillskrivas problem relaterade till datakvalitet och interoperabilitet. Resultaten från den preliminära tillämpningen av det konceptuella ramverket visade hur det kunde användas för att identifiera datasilor. De observerade spatiala trenderna genom analysen med network k-function och täthetsanalysen visade spatial variabilitet i förekomsten av avloppsstopp. Den geografiskt viktade Poisson-regressionsanalysen visade spatial heterogenitet i faktorer som påverkar förekomsten av avloppsstopp. Analysen med Network cross k-function visade att ledningar med historiska incidenter med avloppsstopp tenderade att grupperas kring rör med högre centralitetsvärden som med det bedömdes som mer kritiska för ledningsnätens funktion. Dessa metoder skulle tillsammans kunna bidra till en mer datainformerad underhållsplanering och tillgångsförvaltning på strategisk, taktisk och operativ nivå.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2024
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
Data-driven, Decision Support, Network Robustness
National Category
Water Engineering
Research subject
Urban Water Engineering
Identifiers
urn:nbn:se:ltu:diva-103607 (URN)978-91-8048-464-0 (ISBN)978-91-8048-465-7 (ISBN)
Public defence
2024-03-11, C305, Luleå University of Technology, Luleå, 09:00 (English)
Opponent
Supervisors
Available from: 2024-01-11 Created: 2024-01-11 Last updated: 2024-02-19Bibliographically approved

Open Access in DiVA

fulltext(939 kB)20 downloads
File information
File name FULLTEXT02.pdfFile size 939 kBChecksum SHA-512
1e378fc456740f75b1b672a7a10140159805f1f6bf4519a1d45bd000e41846c28cdb45c217c11e14c4a442b8a08e0da20ca9d25078fb21bdea9f0bda67946d68
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopus

Authority records

Okwori, Emmanuel JenkeriViklander, MariaHedström, Annelie

Search in DiVA

By author/editor
Okwori, Emmanuel JenkeriViklander, MariaHedström, Annelie
By organisation
Architecture and Water
In the same journal
Journal of Hydroinformatics
Infrastructure Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 32 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 162 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf