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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Doctoral Consortium, November</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">1613-0073</issn>
    </journal-meta>
    <article-meta>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Mikael Lindecrantz</string-name>
          <email>mikael@digistate.io</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="editor">
          <string-name>Circular Economy, Semantic Web, Ontology, Value Networks, Digital twins</string-name>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Linköping University, Department of Computer and Information Science</institution>
          ,
          <addr-line>58183 Linköping</addr-line>
          ,
          <country country="SE">Sweden</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Ragn-Sells AB</institution>
          ,
          <addr-line>Väderholmens gård, 191 36 Sollentuna</addr-line>
          ,
          <country country="SE">Sweden</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2023</year>
      </pub-date>
      <volume>0</volume>
      <fpage>6</fpage>
      <lpage>10</lpage>
      <abstract>
        <p>Semantic interoperability of data is one of the biggest barriers towards data sharing in the Circular Economy (CE). Semantic Web technologies can provide the technical foundations for information flows that will transform European Industry towards a CE, by means of digitalization and data sharing. By leveraging open standards for semantic data interoperability and establishing a shared network of ontologies for data documentation. Ontologies have been applied in many domains, and are widely understood as a key technology to address semantic interoperability. A solution to these challenges needs to leverage open standards for semantic data interoperability in establishing a shared vocabulary (ontology network) for data documentation, as well as create a decentralized digital platform that enables collaboration in a secure and confidentiality-preserving manner. This vocabulary can then be used to construct digital twins of circular value networks to further enable open collaboration. Once defined, the blueprints of these digital twins will be reusable as templates and can be reused with a diferent set of actors, or used within a diferent industry domain. This vision includes a number of open research problems, including the development of ontologies that need to model a wide range of diferent materials and products, not only providing vertical interoperability but also horizontal interoperability, for crossindustry value networks. As well as transdisciplinary research on methods to find, analyze and assess new circular value chain configurations, and form their decentralized digital twins.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>CEUR
ceur-ws.org</p>
    </sec>
    <sec id="sec-2">
      <title>1. Introduction</title>
      <p>Semantic interoperability of data is one of the biggest barriers towards data sharing in the
Circular Economy (CE)1. Semantic Web technologies can provide the technical foundations for
information flows that will transform European Industry towards a CE, by means of
digitalization and data sharing. By leveraging open standards for semantic data interoperability and
establishing a shared network of ontologies for data documentation, as well as implementing
a decentralized digital platform that enables collaboration in a secure and
confidentialitypreserving manner this will allow for automation of discovery, planning, management, and
execution of cross-industry circular value networks.
https://digistate.io/ (M. Lindecrantz)</p>
      <p>© 2023 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
CEUR
Workshop
Proceedings
htp:/ceur-ws.org
IS N1613-073</p>
      <p>CEUR Workshop Proceedings (CEUR-WS.org)
1https://ellenmacarthurfoundation.org/topics/circular-economy-introduction/overview</p>
      <p>
        Combined with automated access control policies for data privacy and confidentiality,
this enables automation while protecting company-internal data, and allows data sharing at
the right level of granularity. For putting this in place a EU-funded project, Onto-DESIDE2,
was started in 2022. Onto-DESIDE will develop a technology for allowing data sharing
about materials and products at a global scale. Since access to verifiable information is
central, well-established open standards for secure and confidentiality-preserving information
sharing are core components. Ownership and storage of data should remain with the
data producer; hence a decentralized approach is necessary. Metadata and structures for
transforming data into information (semantic descriptions, i.e. ontologies) will be open,
and comply with FAIR principles3, to enable the highest possible degree of semantic
interoperability and automation in data sharing. For sensitive data, methods allowing for
proof of existence of the data can be used, where proofs can be shared while actual data
is kept private. Equality, democracy, and ethics are key aspects in collaboration and data
sharing, and aspects that will be central in developing the details of the data sharing architecture.
Another aspect is to address the use of these technologies in a business context, and
study the circular economy as a complex system to develop integrated tools and methods for
further enhancing CE. Although the importance of various ‘flows’ - namely: resource flows,
information flows, value flows, and energy flows - has been widely acknowledged within the
transformation to CE, so far they have not been integrated or linked into a single framework
or approach [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Without such integration or linking it is currently not possible to make
robust designs of circular value networks, and to conduct value network coordination towards
implementation and operation within industry. Moreover, this should result in robust value
networks that are profitable, equitable, and invite long-term collaborations and partnerships.
Therefore, apart from the solutions needing to be technically feasible, there is also a need to
explore how such value networks can be designed and developed, using the ontologies for data
documentation and data sharing, but considering the interplay of resource, information, value
and energy flows, i.e. considering how the value network will behave as a system.
      </p>
    </sec>
    <sec id="sec-3">
      <title>2. Core components of the Onto-DESIDE vison</title>
      <p>
        Within the Onto-DESIDE project, four core components that need to be explored are envisioned:
• A network of ontologies[
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] for data documentation, that allows for semantic
interoperability and supports flexible, automated, decentralized data sharing between industry
actors.
• An open circularity platform, i.e. a secure and confidentiality-preserving decentralized
data sharing platform allowing the creation of digital twins of circular value flows, by
enabling FAIR sharing of data between industry actors, facilitating the initiation of new
collaborations in the circular economy.
• Methods to find, analyze, and assess new circular value chain configurations opened
up by considering resource, information, value, and energy flows as an integral part of
2https://ontodeside.eu/
3https://www.go-fair.org/fair-principles/
transitioning to a circular metabolism within industrial systems through co-design and
co-creation.
• Validation - demonstrating and quantifying the potential for increased retainment of
value when applying the above outcomes in cross-border and cross-industry sector circular
value networks in Europe.
      </p>
      <p>The focus of my research work is on the technological aspects, and in particular those related
to Semantic Digital Twins, namely:</p>
      <sec id="sec-3-1">
        <title>1 - An ontology network for data documentation</title>
        <p>Based on established technologies and standards (i.e. using the W3C standard OWL4 for
ontology representation), develop and evaluate an ontology network for data documentation
targeting the cross-industry domain of circular economy. A number of additional challenges not
present in any existing eforts will have to be addressed, including the need to cover a wide range
of diferent materials and products, as well as the need not only for vertical interoperability of
ontologies but also a minimal level of horizontal interoperability, for cross-industry value networks.</p>
      </sec>
      <sec id="sec-3-2">
        <title>2- The digital twin of circular value networks</title>
        <p>
          While semantic interoperability, and ontology-based data documentation, are essential enablers
for large scale CE, it is not enough in itself. Semantically described data also need to be put
into use, in automated processes. Today, there is limited data collaboration within industry
domains and even less across domains, consequently new circular value networks are only
created between known actors that have a certain degree of comfort working together [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ]
limiting the possibilities of more high value circulation scenarios. Open collaboration could
remedy this, but data and ontologies cannot solve the problem alone.
        </p>
        <p>
          To facilitate open collaboration in a data driven circular economy a new entity is needed;
the digital twin of circularity. The concept of digital twins has been put to use for many
use cases and in many industries [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ] and the fundamental theory behind the concept is
not a new thing. For instance, one study [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ] explored the usage of digital twins in the
context of a circular value network for remanufacturing in the construction industry. But,
the idea of constructing digital twins of circular value networks, with the value network
itself, and related ‘flows’, as the objects in focus, is a novel idea and has not been explored before.
If digital twins are built upon shared ontologies, i.e. the ontology network, once
deifned, their blueprints are also reusable as templates for a certain type of circular value
network, and could at minimal efort be shared with a diferent set of actors or used within a
diferent industry domain to instantiate new value networks. Previous work that implements
such ideas are for example the sectoral circular economy business model patterns within
manufacturing companies [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ]. Another example, this time from the construction industry,
is the concept of making use of Building Information Models (BIM), and BIM objects, to
explore the notion of generic capabilities [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ]. The vision is for Onto-DESIDE to develop
these ideas further, by viewing the digital twin as a form of design pattern [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ], essentially
blueprints of executable circular value flows applicable in various domains, which is a
novel idea. In addition, the use of ontologies to describe such blueprints for digital twins
of circular value flows is also both challenging, but promising and novel. Technically, the
digital twin idea will be implemented as an open circularity platform using existing, and
emerging, Web technologies, such as RML for semantically annotating and transforming
heterogeneous data sources [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ], Solid for building decentralized applications based on Linked
Data principles [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ], and incorporating validation and verification methods that provide
proofs of data authenticity [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ]. Figure 1 aims at visualizing how the envisioned core
components of Onto-DESIDE interact to enable the concept of digital twins of circular value networks.
Focusing on the above, further work in the validation part of the project will make up
the main setting for evaluating the research questions for my work. The setup of the project
are such as that we have set up three industry use-cases where access to real industry data
will be used to validate the ontology network and open circularity platform. This will ensure
that future results are based on real data and collaboration between real organization, thus
contributing to the validity of the results.
        </p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>3. Related work</title>
      <p>
        Ontologies have been applied in many domains, and are widely understood as a key technology
to address semantic interoperability. Standard ontology networks exist in several domains,
such as the Semantic Sensor Networks (SOSA/SSN) ontology network [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], which is a W3C and
OGC standard, or SAREF5 as an alternative for smart applications, and the OBO Foundry [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]
in biomedicine. No similar efort, or standard, as the ones mentioned above exist neither in the
overall CE domain, nor in the more specific subdomains facilitating semantic interoperability
of typical CE data categories, such as information about materials, products, capabilities etc.
There are general ontologies for products, such as GoodRelations [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] which is
targeted at the online retail market, as well as domain-specific product ontologies, e.g. specifically
for construction, or manufacturing industry. However, none of these are built with CE
requirements in focus, and do not target product reuse, refurbishing, recycling etc. Similarly,
many ontologies have been proposed to model organizations, from the generic W3C
standard ORG-ontology [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ], to ontologies focusing on specific business use cases. Still, these
do not cover the requirements of the CE, for forming and executing new circular value networks.
A central part of the foreseen ontology network are related to materials models, which can
be used to describe both virgin materials, product parts during a product life cycle, and
recycled materials. Examples of such eforts includes the Materials Genome Initiative 6, and
the API-based efort of Open Databases Integration for Materials Design (OPTIMADE) 7[
        <xref ref-type="bibr" rid="ref15">15</xref>
        ].
A recent approach is the Novel Materials Discovery (NOMAD) [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. However, none of these
eforts use ontologies to provide semantic interoperability.
      </p>
    </sec>
    <sec id="sec-5">
      <title>4. Hypothesis and research questions</title>
      <p>The main overarching theme for my research work focus on the enablers for data sharing
that semantic web technologies provides in the context of the Circular Economy. The main
hypothesis I aim to answer are as follows:
Could Semantic web technologies enable data sharing in the Circular Economy and
enable the construction of digital twins of circular value networks?
Based on the above hypothesis, three sub-questions are formulated to investigate
certain aspects in order to provide evidence towards falsifying or acknowledging this hypothesis:
1. How should ontologies be designed and developed considering the CE context?
2. How can ontology design patterns and ontology modularity support such CE ontologies?
3. How can patterns of circular value networks be captured and reused?
The intention are not to provide a fully comprehensible proof that the hypothesis are valid or
not, rather, by providing answers to these questions in the setting of Onto-DESIDE, provide
validated results and to point to relevant areas for further research.</p>
    </sec>
    <sec id="sec-6">
      <title>5. Current results</title>
      <p>The Onto-DESIDE project started in 2022, by September 2023 we are one year into the project.
So far, the results have been in the form of project deliverables that are published on the project
website at: https://ontodeside.eu/results/8. Additionally, a number of research papers have
been produced that cover surveys of the current state of ontologies in the domain of CE9 as
well as the recently held Knowledge Graphs for Sustainability workshop10 that was held in
conjunction with The Web Conference in Austin Texas 202311. Other than building up the
needed infrastructure, no results towards answering the three research questions have been
produced yet.</p>
    </sec>
    <sec id="sec-7">
      <title>6. Evaluation</title>
      <p>The main validation of the results in my research will be performed in the context of
OntoDESIDE. In this, we will make use of semantic web technologies to describe and map distributed
data in a industry setting, relying on the validation and demonstration of the three industry
use-cases in the project. Further on, towards the end of the Onto-DESIDE project and after,
additional validations would be setup to provide additional results that could be used to answer
the research questions. As of today, I am not able to say in what context these validations could
take place.</p>
    </sec>
    <sec id="sec-8">
      <title>7. Reflection and future work</title>
      <p>Performing this research in the context of the Onto-DESIDE project provide ample opportunity
for validating the results in real-world scenarios. As we are early into the project, we are not
yet in the position that we are able to validate the research questions, rather focus have been
on setting up the needed infrastructure and processes needed in the project. Going forward,
end of 2023 and early 2024, we would be able to perform validations using the semantic web
technologies outlined in the project and in this paper.</p>
    </sec>
    <sec id="sec-9">
      <title>Acknowledgments</title>
      <p>Thanks to all the partners in the Onto-DESIDE consortium and the EU for providing funding
for the research performed under European Union’s Horizon Europe research and innovation
program under grant agreement no. 101058682 (Onto-DESIDE)12. I also want to thank my
employer Rang-Sells AB13 for realizing the strategic importance of data in the circular economy
and thus providing the needed support in researching this topic.</p>
      <p>Also, I would like to thank my two supervisors. Firstly, I would like to thank my
excellent supervisor Eva Blomqvist14 at Linköping University for dedicating the time and efort it
takes to discuss the topics, questions and concerns related to this research. Second, I would like
to thank Vinit Parida15 at Luleå Technical University for providing valuable business ecosystem
context to the technologies used in this research.
10https://kg4s.org/
11https://www2023.thewebconf.org/
12https://cordis.europa.eu/project/id/101058682
13https://www.ragnsells.com/
14https://liu.se/medarbetare/evabl45
15https://www.ltu.se/staf/v/vinpar-1.12657</p>
    </sec>
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