- Source fragmentAn inspectable passageA selector locates evidence in a fixed source snapshot.is used by an evidence relation
- Evidence relationHow the source bears on itSupporting, opposing or another governed role.is evaluated by that relation
- AssertionAn attributable claimSubject, predicate, value, status and generating activity.
Key idea & worked example
A graph stores named things and explicit relationships. RDF expresses a statement as a subject, a relationship and an object; many such statements can share the same subject.
A graph makes relationships addressable and traversable; it does not make the linked assertions automatically true.See the worked example →On this page
Make the graph explain its own claims
Four short decisions connect plain-language diagrams to the released ontology terms. Answer in any order and follow the links when you want the complete example.
Keep what is represented separate from its representation
A physical instrument and a digital representation need separate identifiers. MODAVIS uses representationOf to connect them. Cuntz’s GLB depicts aspects of the organ; changing a mesh does not change the identity of the physical instrument.
- Instrument IRIex:instrumentMusicalInstrument: the research subject.
- Representation IRIex:modelDigitalRepresentation: a separate digital resource.
Read all lessons and answers
This complete reading version also works without JavaScript and is included when printing.
Keep what is represented separate from its representation
A physical instrument and a digital representation need separate identifiers. MODAVIS uses representationOf to connect them. Cuntz’s GLB depicts aspects of the organ; changing a mesh does not change the identity of the physical instrument.
- Instrument IRIex:instrumentMusicalInstrument: the research subject.
- Representation IRIex:modelDigitalRepresentation: a separate digital resource.
Which connection is appropriate for a model and the instrument it depicts?
- model representationOf instrument — Correct. The relation connects two distinct identities without claiming completeness or equivalence.
- model owl:sameAs instrument — sameAs collapses their identities. A representation relation is not an identity claim.
- Use the instrument’s identifier for the model file too — One identifier should name one thing at one identity layer. Keep the digital resource separate.
A role assignment is a record of its own
The released violin fixture distinguishes a string component, its membership in the instrument, and a FunctionalRoleAssignment of sound generator. Use qualified memberships and assignments when structural kind or scope matters. The component itself is not just its function.
- InstrumentA violinThe generic released example works beyond organs.has a component record
- ComponentIts stringA component identity is distinct from membership.has a role assignment
- Assigned roleSound generatorA FunctionalRoleAssignment carries the role.
You need to record a component’s functional role in a scoped configuration. What do you preserve?
- Component identity plus a qualified role-assignment record — Exactly. Keep the assignment and its scope separate from the component identity.
- Only rename the component “sound generator” — A label does not preserve the assignment relationship or its scope.
- Treat its current role as a permanent identity — A function can be contextual. Missing scope does not establish a permanent universal role.
Keep production history and applicability on separate paths
The real Cuntz observation gives 1281 mm and a source-cell flag. Its resultTime is qualified as a workbook modification timestamp, while another flag identifies a source series of 2019. Retaining both lets another researcher understand the record without inventing its measurement-session date.
- File history16 September 2020Workbook modification timestamp, 10:33:05Z.
- Source flagSeries 2019A source-series flag, not a recovered session date.
The workbook was modified in 2020. What should your reused claim say about the measurement session?
- The session date remains unresolved; retain the timestamp qualification — Yes. The file-history timestamp and source-series flag support different statements.
- The pipe was measured at that precise 2020 instant — That interpretation is not established by the released evidence.
- It was certainly measured on a known day in 2019 — The series flag does not identify a specific session day. Preserve what is known and what remains unknown.
Use a structural check, then review the claim
The generic learning graph conforms when the model represents the separate instrument. The intentionally invalid variant fails because it creates a self-representation cycle. SHACL can expose that structural problem. It cannot decide whether a historically plausible reconstruction is correct.
- OWLIdentity & relationshipsExpress the ontology’s semantic distinctions.
- SHACLRequired record structureCheck a graph against a declared profile.
Your graph passes the released exchange shapes. What can you conclude?
- It meets the checks run against that graph and profile — Correct. Record the inputs, version and scope; scientific interpretation still needs evidence and review.
- All its statements are scientifically true — Shape conformance is not a truth test for historical or acoustic claims.
- It meets every possible publication or application profile — Different profiles can add requirements. The report must name which checks were actually run.
A small graph you can reuse today
Choose one question from your own collection and write down the subject, the statement, the source and the scope. Give the statement and source their own identities when you need to preserve review or disagreement. Translate only those relationships whose published definitions fit the question. Then validate, inspect the report and ask another reader to follow the source trail.
What does a knowledge graph add to a catalogue entry?
A graph stores named things and explicit relationships. RDF expresses a statement as a subject, a relationship and an object; many such statements can share the same subject.
- InstrumentCuntzThe physical research subject.follow the component
- Component recordPipe key-036The released record identifies a particular pipe.inspect its observation
- Observation1281 mmA result about the identified feature and property.
Work through the example 3 STEPS
Consider the Cuntz pipe represented as rank:ged:pipe:key-036. A measurement, a source workbook and an activity can all refer to it without being squeezed into one text field.
Start with a plain sentence
“This observation concerns that pipe.” Here the observation is the subject, the feature-of-interest relationship connects it to the pipe, and the pipe is the object.
Connect the evidence
The observation points to the measurement activity and raw-result workbook realization. The activity names Philipp Hosbach as its agent. These links answer different questions: what was observed, where it came from and who is credited.
Ask a connected question
A reader can follow the pipe to an observation, then to the workbook cell, unit and processing history. That chain is more useful than merely finding the same word in several descriptions.
- Cuntz Positiv · VAO 0.5.0-rc.2 ↗
Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.
- MODAVIS Ontology Network 0.1.0 ↗
Identity, state, configuration, evidence, assertions, context and provenance. Teaching examples explain its distinctions without inventing new normative properties.
These sentences explain graph structure. They are not a copy-and-paste RDF serialization or a claim that English relationship labels are normative ontology terms.
The useful distinction. A graph makes relationships addressable and traversable; it does not make the linked assertions automatically true.