CircThread seeks to make appliances like boilers, batteries, dishwashers washing machines, and solar panels sustainable, both from environmental and social perspectives. To achieve this, the aim is to swiftly extend the lifespan, repairability and reuse of appliances to ensure that products are properly recycled when they are no longer repairable.
CircThread project aims to solve this challenge, by implementing a software platform for all actors to share critical information about appliances. In this platform, information will be shared between product designers, manufacturers, retailers, customers, repairers, and recyclers, as shown in Figure 1. Thereby, this improves the ability to make better lifespan improvement, reuse, and recycling decisions. It will enable a digital exchange of data across the extended product life cycle to form a Digital Circular Thread of products. The data will be linked to the software services to provide decision recommendations for all actors across the product life cycle, further supporting consumers and other stakeholders with circularity decision-making at all stages of a product’s life cycle. Thus, together ensuring that products and materials stay in the economic loop for as long as possible, benefiting the sustainability of the economy and the environment and reducing carbon emissions.
As part of the EU Green Deal, the EU, in the process of legislating the Ecodesign for Sustainable Products Regulation (ESPR), launches the framework of the multi-sectoral Digital Product Passport (DPP) into the EU regulations to support the circular economy and product traceability. The DPP is a data set that summarises the components, materials, and chemical substances or also information on repairability, spare parts, or proper disposal information for a product. The requirements for a functioning economical landscape with DPPs will require all companies for a particular product category to make available, and exchange product data, within a given data structure. The exchange of product data with a given data structure brings the need for a product metadata vocabulary that helps to share information in a standardised product description for the involved stakeholders. For a clear understanding of product metadata and its relevance to the digital product passport, it is helpful to look at a classic international passport for persons.
Figure 2 illustrates a comparison between person-related and product-related passports. Passports are known to be used internationally to identify people. The terms must be understood transnationally. Therefore, it is crucial to use a standardised vocabulary. A vocabulary includes common terms to describe a thing/item. Vocabulary items for a classic person-based passport are e.g., surname, name, date of birth, nationality, and ID number. These standardised words can be used to describe and identify every single person worldwide, as these attributes are common characteristics of all people. Similarly, the DPP describes and identifies products with their components, materials, and other utility information.
In this context, the use of open and global standards as the basis of the DPP helps to ensure the interoperability of data for all and to make the global supply chain uninterrupted. In the digital product passport, the products are again represented in a key-value relationship, whereby the key again consists of the metadata elements, e.g., product ID, and the values represent concrete products, e.g., AA1234567.
The German Research Centre for Artificial Intelligence (DFKI), with its excellence in research and technology transfer to economic and social applications, aims to contribute towards a sustainable and environmental-friendly economy. In CircThread, by participating in several work packages and leading the work-package 4 (WP4), DFKI aims to not only build a service that enables information linkage and storage for DPPs but also provide a product metadata catalogue vocabulary that standardises information exchange.
As mentioned above, CircThread aims to enable information linkage and exchange across several lifecycle phases of a product and actors/stakeholders. This linkage of information and its exchange is proposed to be realised as a semantic system as shown in Figure 3.
As shown in Figure 3, the DPPs carrying information (based on the Product Metadata Catalogue Vocabulary) on the products are instantiated as individuals or entities of a graph database. Users of the CircThread Platform like Manufacturers, Recycler, Customers, etc., could access a Product’s DPP across its lifecycle through an interface provided by the CircThread Platform by scanning a QR-Code that represents a unique identifier of the product in consideration. After being authenticated, information about the product could either be retrieved or new information added using a query language. Information Addition or Retrieval involves working with a Graph Database, which connects products and their underlying information schema (The Product Metadata Catalogue Vocabulary), thus, achieving a semantic system in the process. A semantic system is especially of benefit in applications like CircThread because it facilitates implicit inference of information also in cases where an explicit availability of the same is not guaranteed.
The purpose of the works carried out, as part of Task 4.1 (D4.1), is to deliver the structure, meta-data items, and the underlying semantic models for the information exchanges, which combined provide for the vocabulary of the meta-data product catalogue and the CircThread Data Space. To this end, the following points are described in the deliverable in detail:
- The relevance of a common generic vocabulary from the CircThread project to describe all life cycle phases of a product as the foundation of the digital product passport.
- Explain the creation and use of ontologies.
- Present the implementation of the vocabulary with a modular ontology based on the PPR model.
- Embed this approach into the description of a semantic system.
- Validate the completeness of the vocabulary.
- Give an outlook on the use of the vocabulary within the CircThread project and the scientific community in general.
- Illustrate further extensions and a workflow to update the vocabulary in the future.
The target audience of this report is all participants of the product life cycle as well as the scientific community and related projects, especially those that include works on developing common vocabularies and ontologies. Within CircThread this report targets all pilot partners and CircThread service providers, especially those who want to exchange information in a unified, structured way.
Authors: Jonas Brozeit, Leonhard Kunz, Nastaran Moarefvand, Tapanta Bhanja, Dr. Christiane Plociennik (DFKI)
 European Commission. (2019). A European Green Deal | European Commission – 640 final.
 Götz, T., Berg, H., Jansen, M., Adisorn , T., Cembrero, D., Markkanen, S., & Chowdhury, T. (2022, 07). Digital Product Passport: the ticket to achieving a climate neutral and circular European economy? CLG Europe. Retrieved 11 15, 2022