Terms to concepts
The journey starts with the migration from term-based taxonomies to concept-based taxonomies enabled by SKOS.
This simple step-change separated the identifier for each concept from its lexical labels. With RDF, these identifiers are represented with HTTP-URIs.
The community gained many advantages from this breakthrough. For example, the method for managing multilingual taxonomies became massively simpler (once concept could now hold multiple language labels), resulting in huge cost savings compared with the previous data model.
Taxonomy to ontology
Next came the migration from taxonomy to ontology.
The widespread adoption of RDF as a semantic data model transformed simple taxonomies into extensible and expressive ontologies. Once the semantics of the knowledge organization system was no longer confined to hierarchical and associative relationships, people could define any named relationship between things, and define classes of things with distinct sets of properties. Not only are these ontologies capable of representing any domain of knowledge, but the structure of the data model is also transparent and intelligible to both humans and machines.
Ontologies in RDF also support machine inferencing, allowing new knowledge to be derived from existing data.
Labels as things
Another step-change came when labels became things that can have their own properties. The data model evolved to support SKOS-XL.
A concrete example helps to explain the breakthrough. The person with the birth name ‘Stephen King’ wrote a novel called The Shining. The same person also wrote a novel called The Running Man, but he did so under the penname ‘Richard Bachman’. With SKOS-XL, Stephen King and Richard Bachman are bound together as one concept, but each label also has a unique URI making it a thing rather than a string, which enables each name to have independent properties, such as ‘Stephen King’ authorOf The Shining, and ‘Richard Bachman’ authorOf The Running Man.
Relationships as things
It’s perhaps not surprising what came next. With RDF-Star, relationships became things. Using RDF-Star, the relationship joining two concepts (in graph speak, the edge between two nodes) can carry its own set of properties.
Again, a concrete example will help explain why this was a powerful breakthrough. Standard RDF lets us express the following statement ‘Stephen King’ authorOf The Shining. With RDF-Star we can add a date to the relationship between the person and the book, and state that ‘Stephen King’ published The Shining in 1977.
The final step in model complexity covered in my talk is the advent of enterprise knowledge graphs, and, more specifically, what Synaptica calls content-aware knowledge graphs.
What do we mean by content aware knowledge graphs? When our auto-categorization engine, Graphite Knowledge Studio, tags content with metadata derived from taxonomies, we also capture and store this content metadata inside the knowledge graph, thereby linking concepts to the content they describe. As more content gets tagged, the knowledge graph expands, providing a powerful resource for business insights and analytics as well as powerful business functions like similarity indexing and recommendations.
With great solutions, come new challenges . . .
As the ontological schema have successfully evolved to manage increasingly complex knowledge models, the user experience challenge increased. How can tooling and interfaces make what is inherently complex appear simple and comprehensible?
Synaptica’s Graphite application provides a collaboration space for knowledge engineers and content managers to create and manage enterprise taxonomies and ontologies. Graphite’s intuitive drag-and-drop user interface provides a simplification layer on top of complex semantic data models, enabling non-experts to rapidly design and build standards-compliant knowledge organization systems.
As I will explore below, we have brought this same investment in usability to our newest product, Graphite Knowledge Studio, to embrace the same diverse user community we have long served through Graphite.