TW Website Ontology Working Group - tw:Concept change to skos:Concept

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The purpose of this document is to propose changing the TW Ontology class tw:Concept to a skos:Concept based system.

Reasoning for the Change
Currently there is a class, tw:Concept, that has many individuals currently ( This is a simple, flat, dictionary of terms that we use to tag documents, projects, events, people’s interests and more. However, these concepts have grown in number and we can start seeing hierarchical representations of many of the concepts as well as certain concepts being part of separate schemes. There’s concepts related to the sciences, such as Earth Science, Web Science, Data Science and Computer Science. There’s concepts related to Research ideas.

What brought on this desire for change is that we are starting to keep track of use cases and functional requirements documents. Each of these is related to a particular project and within that project a particular system or set of tasks. But there is currently no way to tag these entities without just adding more concepts to that flat list. And because of this we can not list use cases and functional requirements documents for particular working groups without manually adding them.


The proposal is to add that all tw:Concept are also skos:Concept and use all of the properties and relationships designed by skos.

The current individuals will still be a tw:Concept, we will simply add the relationship that they are a skos:Concept.

With this new relationship we can begin to define a hierarchical structure to the concepts. We can also begin to define different schemes within the TW system. As mentioned above, we could have schemes related to the Sciences - Earth Science, Ocean Science, Solar Terrestrial Science, Data Science, Computer Science, Web Science. We could have schemes related to biomedical concepts, semantic concepts, and ... project concepts.

The remainder of this document will focus on the new scheme that I will be proposing towards the end of this document.

One change will definitely be made to the current ontology. We are mis-using foaf:name, should be dc:title or rdfs:label.

Relationships that we'll be initially using

skos:Concept -> skos:prefLabel -> “something”@en
skos:Concept -> skos:definition -> “something”@en
skos:Concept -> skos:broader -> skos:Concept
skos:Concept -> skos:narrower -> skos:Concept
skos:Concept -> skos:inScheme -> skos:ConceptScheme
skos:ConceptScheme -> skos:hasTopConcept -> skos:Concept
skos:Concept -> skos:topConceptOf -> skos:ConceptScheme

broader is the inverse of narrower

Again, focusing on the new use of concepts within the system, project related concepts.

The Top Level

twi:ProjectScheme a skos:ConceptScheme
twi:ProjectConcept a skos:Concept
twi:ProjectConcept skos:inScheme twi:ProjectConceptScheme
twi:ProjectConcept skos:topConceptOf twi:ProjectScheme
twi:ProjectScheme skos:hasTopConcept twi:ProjectConcept

Example set of concepts

DCOProjectConcept broader ProjectConcept
    DCOBoundaryActivity broader DCOProjectConcept
        DCODataRescue broader DCOBoundaryActivity

Project Management

Expected Effort

  • First Pass
    • For the first pass we simply add the relationships that all tw:Concept are also skos:Concept, copy foaf:name to skos:prefLabel, and dc:description to skos:definition.
    • We add the DCO Project Concepts to the system using the new scheme and not retrofit it to the old scheme.
  • Second Pass
    • We change the current queries and xslt to use the new scheme
    • We begin to take the current tw:Concept individuals and creating a hierarchy of concepts.

Expected Implications
No implications are expected

Suggested Future Work

  • A hackathon where we take the current tw:Concept individuals and make the changes mentioned above including the hierarchical classification of the concepts.

Agree in Principle

Meaning, you agree that this needs to happen and the general ideaas presented, but implementation still open for discussion

+ Patrick


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