What Is Linked Historical Data?
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The document discusses the concept of linked historical data, emphasizing the ontological framework and the characteristics that differentiate primary and secondary sources. It explores issues of persistence, immutability, and the identity problem regarding historical sources in RDF, while proposing metaproperties to ensure their reliability. Future work involves collaboration with historians to refine these concepts and explore new historical ontologies.
What Is Linked Historical Data?
- 1. What Is Linked Historical Data? Albert Meroño-Peñuela Rinke Hoekstra @albertmeronyo EKAW 2014, Linköping, Sweden 26/11/2014
- 4. Historical Sources… • Independence • Reliability • Immutability
- 5. …as RDF Graphs? 1. An IRI, once minted, should never change its intended referent. 2. Literals, by design, are constants and never change their value. 3. A relationship that holds between two resources at one time may not hold at another time. 4. RDF sources may change their state over time. That is, they may provide different RDF graphs at different times. 5. Some RDF sources may, however, be immutable snapshots of another RDF source, archiving its state at some point in time. From http://www.w3.org/TR/rdf11-concepts/#change-over-time on RDF and change over time
- 6. …as RDF Graphs? 1. An IRI, once minted, should never change its intended referent. 2. Literals, by design, are constants and never change their value. 3. A relationship that holds between two resources at one time may not hold at another time. 4. RDF sources may change their state over time. That is, they may provide different RDF graphs at different times. 5. Some RDF sources may, however, be immutable snapshots of another RDF source, archiving its state at some point in time. From http://www.w3.org/TR/rdf11-concepts/#change-over-time on RDF and change over time
- 7. Linked Historical Data: A Matter of Life and Death Dichotomy: • Alive Web • Dead Web
- 8. An Ontological Framework of Historical Sources • Problem: fundamental requirements from historians on historical sources seem flawed by design in Linked Data • (part-of) Solution: gain understanding on the essential characteristics of historical sources • Gain understanding = explicitly state their semantics – Persistence theories (e.g. inst. in DOLCE) – OntoClean methodology
- 9. Persistence • The continued or prolonged existence of something • Perdurantism: ordinary things have temporal parts (i.e. persist by perduring) • Endurantism: ordinary things are wholly present whenever they exist (i.e. persist by enduring) – Can “genuinely” change over time
- 10. Persistence of Historical Sources • Secondary sources are endurants • Primary sources – Same enduring properties – Requirement: perdurance immutability (can change but should not) – Strong endurants (i.e. can’t change over time)
- 11. The Identity Problem: OntoClean If sources can change over time, how can we guarantee that they are the same entity? Study of the essential characteristics of primary and secondary sources – OntoClean metaproperties
- 12. Metaproperties of Historical Sources • Rigidity (+R): a rigid property is a property that is essential to all its instances, i.e. ∀x φ(x) → ☐φ(x) • Non-rigid (-R), anti-rigid (~R) • E.g. person(x), student(x) • Primary sources = +R • Secondary sources = ~R
- 13. Metaproperties of Historical Sources • Sortals (+I): classes all of whose instances are identified in the same way • Identity criteria of historical sources as RDF graphs? • Primary sources = +I • Secondary sources carry no identity criteria
- 14. Metaproperties of Historical Sources • Unity (+U): classes all of whose individuals are wholes under the same relation (a whole does not create instances of its class when subdivided). • E.g. person(x), clay(x) • Primary sources = ~U • Secondary sources = +U
- 15. Metaproperties of Historical Sources • Dependence (+D): a property is dependent if each instance of it implies the existence of another entity. • E.g. student(x) → teacher(y) • Primary sources = -D • Secondary sources = +D
- 16. Violating Historical Source Metaproperties • Historical graphs published in arbitrary sources on the Web • The AAA rule: Anyone can say Anything about Any topic – Historical graph ?g with { ?s ?p ?o } changed by • Unauthoritative statement on a primary source: { ?s’ ?p’ ?o’ } with ?s’ = ?s • Inbound links { ?s’ ?p’ ?o’ } with ?o’ = ?s • Reliability? Independence?
- 17. Trusted primary sources from digital archives ASK Reliability True / false answer on the existence of authoritative primary source statements
- 18. Trusted in-archive IRI dereferencing services easy:anne-frank-diary ? Independence Qualified copy Primary source RDF graph • IRIs of the primary source remain intact • Copy has prov:wasDerivedFrom relations • Resolution and dereferenceability mechanisms
- 19. Future Work • Further theoretical study w/ historians • Experimental evaluation w/ historians – Metaproperties • Existing historical ontologies (scarce) • New ones – Primary source resolution http://easy.dans.knaw.nl/ • Use cases, historical concepts – Dutch historical censuses http://cedar-project.nl/ – Dutch book trade http://stcn.data2semantics.org/
- 20. Thank you Primary Source Secondary Source Dead (archived) graphs Living LOD Strong endurant Endurant Rigid (+R) Anti-rigid (~R) Sortal (+I) Non-sortal (-I) Anti-unity (~U) Unity (+U) Independent (-D) Dependent (+D) Dereferenceable only by archives Dereferenceable by anyone Comments, suggestions most welcome @albertmeronyo https://www.cedar-project.nl/