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Application of knowledge graphs for
creating a library of reusable knowledge
in the smart city domain
Dmitry Kudryavtsev, PhD, Head of methodology and R&D
Natalia Chichkova, Knowledge engineer
Digital City Planner Oy

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Agenda
1. Introduction and motivation
2. Application of knowledge graphs for creating a library of
reusable knowledge in the digital city planning domain
3. Overview of the pilot project and ORKG (Open Research
Knowledge Graph)
4. Overview of the digital city planning observatory content
5. Application scenarios (current and future)
6. Conclusions

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1. Introduction and motivation
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Smart city domain
A smart city is a municipality that uses information and communication
technologies (ICT) to increase operational efficiency, share information
with the public and improve both the quality of government services and
citizen welfare.
Sharon Shea & Ed Burns, TechTarget
https://internetofthingsagenda.techtarget.com/definition/smart-city
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Key Issues for Smart City transformation
Transforming a city is a complex task that requires new
approaches and management technologies:
• Number of tasks, stakeholders, problem-solving ways, and
approaches is huge
• Life speed is high and increasing: people need the newest
innovative technologies and applications
• New services for businesses, citizens and the government
need to appear
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City digital transformation actors and activities
Actors:
• City development managers
• Digital transformation teams
• Solution providers
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Activities:
• Data integration and modeling
• Design and development of city
digital solutions and systems
• (Re-)Design of public services
and processes
• Smart city management and
development

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Knowledge reuse can improve many activities
(areas) within a city’s digital transformation
1. Data integration and modeling activities can be improved via the reuse
of data models and ontologies,
2. Design and development of city digital solutions and systems can be
improved via reference architectures and reuse of existing
solutions/systems/methods,
3. (Re-)Design of public services and processes can be improved via the
reuse of patterns and reference process models,
4. Smart city management and development can be improved by reusing
proven key performance indicators from existing reference models and
standards or by reusing existing cutting-edge solutions for city
analysis, monitoring, and control (including city digital twins).
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From problems and opportunities
to a knowledge-based solution
Problems:
1. Limited access to the world’s best
practices and experience in the smart
city area
2. The need to hire top/external
consultants
3. Lack of a holistic and evidence-based
smart city development system
Opportunities:
There is a lot of reference and reusable content
in the smart city domain, such as:
• reference models,
• ontologies,
• data models,
• classifications/taxonomies (e.g. of processes
or services),
• patterns,
• good practice cases,
• reusable methods and systems.
Collect, prepare and pack knowledge
for reuse and worldwide replication

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Existing solutions and their limitations
1. Broad scope platforms with smart city solutions:
• Bee smart city platform (https://www.beesmart.city/)
• Bable (https://www.bable-smartcities.eu/)
2. Domain-specific platforms:
• Eltis – The Urban Mobility Observatory (https://www.eltis.org/) etc.
3. Platforms for the specific type of content:
• Smartcity.linkeddata.es etc.
Although these platforms include well-structured libraries of materials,
they use the "traditional" approach for knowledge representation:
text documents with metadata.
Such an approach has limitations in terms of knowledge access,
reuse, and applicability for creating intelligent services.

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2. Application of knowledge graphs for
creating a library of reusable knowledge in
the digital city planning domain
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Application of knowledge graphs in the
smart city domain
• Smart city best practices and cases can be accumulated via
knowledge graphs in order to make them more findable and
reusable.
• The city knowledge graph initiatives exist in the world, for
example, Zaragoza’s Knowledge Graph.
• But the existing city knowledge graph initiatives are mostly
related to the collection and integration of smart city data,
while we are interested in smart city knowledge reuse.

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The suggested solution
Collect, prepare and
pack knowledge
for reuse and worldwide
replication
Knowledge graph
technology
Knowledge
reuse
City’s digital
transformation

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3. Overview of the pilot project and ORKG
(Open Research Knowledge Graph)
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A pilot project for creating a library of
reusable knowledge for smart city domain
“The Open Research Knowledge Graph utilizes the recent progress in
information technologies to build the next generation digital libraries
for semantic scientific knowledge. We aim to describe scientific
knowledge in a structured, machine-interpretable way. This will help
researchers find relevant contributions to their field and create state-
of-the-art comparisons and reviews”
https://www.orkg.org/orkg/about/1/Overview
Collect, prepare and pack knowledge
for reuse and worldwide replication
Publicly available research papers
Open Research Knowledge Graph (ORKG)
platform
provided by the TIB Leibniz Information Centre
for Science and Technology
Library of reusable knowledge for city
digital transformation
Curation of the Smart City Planning observatory within the ORKG

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Representation of smart city reusable
knowledge in the ORKG, key components
Research papers
Contributions
Comparisons
Structured description
using knowledge graph
Reviews

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Representation of smart city reusable
knowledge in the ORKG, some details

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4. Overview of the digital city planning
observatory content
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Structured Descriptions of Research
papers via Contributions (1/2)
https://orkg.org/paper/R138642/R138645
A) provides a structured description of a paper, which suggests smart city ontology [14]

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Structured Descriptions of Research
papers via Contributions (2/2)
https://orkg.org/paper/R138187/R138189
B) provides a structured description of a paper, which suggests a recommender system for smart cities [15]

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Comparisons as an integration of contributions
“Ontologies for smart city:
levels and key classes”
comparison,
which compares the content of
6 smart city ontologies
described in the corresponding
research papers.
It shows and compares classes
of the ontologies along 18
levels (e.g. physical level,
service level, safety, and risk
management level)
https://doi.org/10.48366/R215443

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Review as integration of contributions and
comparisons
Smart city's ontologies review
Ontologies for
smart city: levels
and key classes
Domain coverage
in smart city
ontologies
Ontology reuse in
smart city
ontologies
Review
Comparison 1 Comparison 2 Comparison 3
Approx. 40
Contributions
18 papers

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Сity digital transformation information/
knowledge requirements (fragment)
City digital transformation
activities
Questions
Data integration and
modeling
What concepts (objects), domains, layers, dimensions, and relationships can be used for describing a city?
Design and development of
city digital solutions and
systems
What are the examples of digital solutions/systems for improving a specific domain or solving a particular
problem? Are there any reusable ones?
What are the results and outcomes of a solution/system application in smart cities?
What methods and approaches are used within the particular solution?
(Re-)Design of public
services and processes
What digital services can be offered to a specific category of citizens or businesses within a particular
context (event)?
How can services be delivered and implemented?
How specific processes can be organized and/or transformed using available technologies?
Smart city management and
development
What indicators can we use for measuring domain X?
What city ranking systems exist, and what are the differences between them?
What indicators can we use for measuring outcomes, outputs, processes, and inputs in domain X?
How to integrate and present city-related data for decision-making?
How city digital twins can be used for city management and development?

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Overview of the digital city planning
observatory content (fragment)
Totally the Digital City Planning (DCP) observatory within the Open Research Knowledge Graph
(ORKG) includes 296 papers, 32 comparisons, 3 reviews (for 28.01.2022).
City digital transformation
activities
Questions The DCP observatory content at the ORKG
Data integration and
modeling
What concepts (objects), domains, layers, dimensions,
and relationships can be used for describing a city?
Review: Smart city's ontologies review [17]
Comparisons: Ontologies for smart city: levels and key classes [14]
Domain coverage in smart city ontologies [18]
Design and development
of city digital solutions
and systems
What are the examples of digital solutions/systems for
improving a specific domain or solving a particular
problem?
Comparison: Recommender systems for smart cities, Smart
governance dimension [19]
Smart city management
and development
What indicators can we use for measuring domain X?
What indicators can we use for measuring outcomes,
outputs, process and inputs in domain X?
How to integrate and present city-related data for
decision making?
How city digital twins can be used for city management
and development?
Review: Smart and sustainable city's indicators [20]
Comparisons: Standardized indicators for Smart sustainable cities, by
type of indicators [21]
Analysis of natural environment indicators in Smart Cities' standards
[22]
Review: Towards a city digital twin [23]
Comparisons: Thematic Identification of the City Digital Twin Potentials
[24]
Application areas of Digital Twin solutions in the smart city domain [25]

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5. Application scenarios
(current and future)
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Current application scenarios: Faceted search
Faceted search for
relevant
contributions (and
corresponding
papers) within the
ORKG

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Current application scenarios: Visual analytics
Visualization of
the comparison
content
This example
diagram may help
to find the most
relevant standard
with the required
types of
indicators.

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Source data for
visualization –
the comparison
Current application scenarios: Visual analytics

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Current application scenarios
The specific indicators of a certain type can be taken for reuse from this comparison

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Future application scenarios (next steps)
A platform for creating and reusing city digital transformation knowledge
From cities to organizations in general (cities + commercial organizations)
Knowledge producers Knowledge consumers

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Conclusions
• City (and business) digital transformation can be enhanced via
knowledge reuse.
• Although there are several platforms for smart city knowledge sharing
and reuse, they apply a traditional document-oriented approach to
knowledge representation.
• Knowledge graphs technology can provide a better way of collecting
and curating digital city planning reusable content.
• A pilot project of applying knowledge graphs was demonstrated: the
curation of the digital city planning observatory within the ORKG.
• Such an approach can be scaled into a platform for creating and
curating reusable knowledge for digital transformation of cities and
commercial organizations

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Contacts
Dmitry Kudryavtsev
dmitry.kudryavtsev@digicityplanner.com
Mobile phone/Whatsapp: +358 45 3444329
https://digicityplanner.com/
Lapinlahdenkatu 16, 00180 Helsinki (Maria 01)
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