Roxana ontology: a standard-based knowledge model for the formalisation of adaptive human-based processes in the manufacturing industry

Figures & data

Figure 1. Knowledge ladder according to North.

Seven stages in the following ascending order: ‘Character’, ‘Data’, ‘Information’, ‘Knowledge’, ‘Act’, ‘Expertise’ and ‘Competitiveness’. An arrow indicates the differentiation between explicit and implicit knowledge for the levels under ‘Act’ and ‘Knowledge’ respectively. Figure Long Description: Seven levels are divided by colour into three areas, in ascending order: area one consists of ‘Character’, ‘Data’, and ‘Information’, area two consists of ‘Knowledge’ and ‘Act’, and area three consists of ‘Expertise’ and ‘Competitiveness’. An arrow indicates the differentiation between explicit and implicit knowledge for the levels under ‘Act’ and ‘Knowledge’ respectively.

Figure 2. Notation for classes and instances used in the scope of this paper.

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Rectangles symbolise classes and instances, and arrows symbolise relationships, such as subclasses or object relations. Specifications of entities from other ontologies are marked in colour by blocks that build on each other. Figure Long Description: Rectangles symbolise classes and instances, and arrows symbolise relationships, such as subclasses or object relations. The illustration is general in the upper part and uses the example of a car in the lower part. Accordingly, a car represents a subclass of vehicle. The object relation ‘has Component’ shows that tyres are components of a car. Specifications of entities from other ontologies are marked in colour by blocks that build on each other. From the general to the specific, the BFO is characterised by the IOF Core and the latter, in turn, by the ROXANA ontology.

Figure 3. Annual number of Scopus-listed studies on ontologies in production with a focus on engineering and computer science, survey date mid-2023.

A diagram showing the years 1994 to 2022 on the X-axis and the number of studies limited to 70 on the Y-axis reveals that the number of publications increased from 2004 onwards, while there were almost no publications in the years before.

Figure 4. 12 ontologies from the production domain and the comparison of the model contents according to the BFO elements.

Dots indicate which concepts are contained in the 12 ontologies as counterparts to the elements in the BFO. In total, 12 entities of the BFO are represented.

Figure 5. Abstract relationship between knowledge model and data instantiation for integration and use in a software application.

A pyramid is made up of the BFO as the top-level ontology, the CCOs and IOF Core as the mid-level ontology in the middle, and ROXANA as the domain application ontology at the lowest level. A software application uses the RDF-serialised data based on ROXANA, which is displayed at the same level of the ontology.

Figure 6. Overview of the central concept elements of the ROXANA ontology; version one using the BFO standard and the CCO references.

Exemplary entities show the relationships in ROXANA. Partially overlapping borders indicate different modelling aspects, such as ‘Relation to Machine Variables’ or ‘Machine Components and States’.

Figure 7. Categorisation of human activities in commissioning as subclasses of ‘ActOfCommissiong’; version one, based on the BFO and CCO taxonomy.

An excerpt from the ontology editor Protegé shows the class taxonomy under ‘occurent’ with the categorisation of human activities as subclasses under ‘Act of Artifact Assembly’.

Figure 8. Specification of the IOF Core class taxonomy around material machine components; on the right the subclasses under ‘PieceOfEquipment’ in ROXANA and on the left the original IOF Core differentiation.

Two excerpts from the ontology editor Protegé show the class taxonomy, on the right-hand side under ‘Piece of Equipment’ in ROXANA and on the left-hand side the subclasses in the IOF Core under ‘material entity’.

Figure 9. Abstract concept representation of the ROXANA ontology with labelling of used concepts of the IOF Core reference and the BFO standard in a block representation.

Exemplary entities show the relations in ROXANA in version two based on the IOF Core and the BFO. Colour blocks illustrate the use of BFO and IOF Core for the depicted entities in ROXANA.

Figure 10. Overview of the mapping of object relations in the taxonomy; version one based on BFO and CCO; version two based on the IOF Core building on the BFO structure.

The defined relations of ROXANA in version one based on the BFO and the CCOs on the left-hand side are contrasted with those in version two based on the BFO and the IOF Core on the right-hand side.

Figure 11. The class taxonomy under ‘occurrent’ with ROXANA specifications of manual commissioning steps in bold; version two, based on the IOF Core taxonomy.

An excerpt from the ontology editor Protegé shows the class taxonomy under ‘occurent’ with the categorisation of human activities in version two of ROXANA as subclasses under ‘Assembly Process’ from the IOF Core.

Figure 12. Excerpt from GraphDB with SPARQL query and the associated results for determining the temporal precedence relationship of machine errors; with ROXANA version one.

The excerpt shows the query in the upper area and the results in table form in the lower area. The table consists of two columns and shows between which process steps there is a precedence relationship.

Figure 13. Extract from GraphDB with SPARQL query and the associated results for determining the sub-steps associated with a plan, including states of material artifacts as incoming or outgoing parts; with ROXANA version two.

The section shows the query in the upper area and the results in table form in the lower area. The table consists of 4 columns labelled: step, state part, state output and project number.

Figure 14. Extract from GraphDB with SPARQL query and the associated results for determining which steps (previous step) create the prerequisite of the state components for a subsequent process step; with ROXANA version two.

The section shows the query in the upper area and the results in table form in the lower area. The table consists of three columns and illustrates in columns two and three in which process step a status form in column one is caused or required.

Data availability statement

The ROXANA ontologies, as well as instructions and notes, are available on the public GitHub repository. The ontology also contains annotations as definitions, comments, and practical examples. The company-specific documents on the commissioning process itself cannot be made public due to confidentiality obligations and to protect the competitiveness of the companies.