Publishing and Using Linked Open Data - Day 2

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  1. 1. Publishing and UsingLinked Open DataRichard J. Urban, Ph.D.School of Library and Information StudiesFlorida State #lod4h
  2. 2. January 8, 2013Tuesdays Schedule 9:00 am- 10:30 am Class Session: Information Modeling Fundamentals 10:30-10:45 am break 10:45- NoonClass Session: Linked Data Models Noon- 1:00 pmLunch (on your own) 1:00- 2:45 pmClass Session: Searching Linked Data 2:45- 3:00 pmbreak 3:00-5:00 pm Class Session: Identifying Linked Data for ParticipantProjects 5:30-7:00 pmDHWI Public DH: API WorkshopRegistered Attendees Only#lod4h
  3. 3. Humanities Data Models What are the models that we currentlyuse? Document-based models Database Models Probabilistic/Statistical Models (NLP)#lod4h
  4. 4. How RDF is Different Based in knowledge representationlanguages (artificial intelligence) Grounded in formal predicatelogic/description logics 20th Century developments in the philosophy oflanguage (Leibnitz, Russell, Wittgenstein, Peirce,Frege, Kripke, Tarski, etc.) Intended to enable intelligent reasoning#lod4h
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  6. 6. Model-Theoretic Semantics1. use formal structures and rules to ensure that every legitimate language expression has a well-defined meaning;2. define what is means for a statement in a language to be true under a particular interpretation;3. allow us to formalize the intuitive notion of logical consequence, that is, of one statement following logically from others; and4. provide a basis for implementing automated reasoning via an appropriate proof theory. #lod4h
  7. 7. Interpretations The basic intuition of model-theoreticsemantics is that asserting a sentence makesa claim about the world: it is another way ofsaying that the world is, in fact, so arrangedas to be an interpretation which makes thesentence true. In other words, an assertionamounts to stating a constraint on thepossible ways the world might be. Anyone can say anything about anything. Butyou need to tell me what your interpretationis so I can evaluate it. #lod4h
  8. 8. Entailment A entails B A is true Therefore B istrue #lod4h
  9. 9. EntailmentA. Jane is the mother of John.B. All mothers are females.C.No females are males.D. Jane is not a male. Entailment enables us to generate validinferences from RDF data. #lod4h
  10. 10. Identity & Constants Logical languages, like first-order logic,rely on binding constants to referents. RDF does this by using URIs as aconstant. #lod4h
  11. 11. Literal/Non-Literal Literal: Text strings that are directly usedas objects of a statement. Typed Literals: strings that conform to adatatype XML Datatypes: XMLLiteral Non-Literal: URIs that name a resource. #lod4h
  12. 12. Examplesfoaf:name Leonardo da VinciPlain literaldcterms:title La Joconde@fr Plain literal w/dcterms:title Mona Lisa@en language:birthday1452-04-15^^ . Type literal #lod4h
  14. 14. Classes/subclasses Class: types of resources which we wishto assign properties and relationships. Subclasses inherit all the properties of aclass. RDFs allows a subclass to have multipleparents.#lod4h
  15. 15. @prefix rdf: @prefix rdfs: @prefix xsd: @prefix ex: ex:vessel rdf:type rdfs:class ;rdfs:label Vessel ;ex:ship rdf:type rdfs:class; rdfs:subClassOf ex:vessel ; rdfs:label Ship .#lod4h
  16. 16. Properties/subproperties Properties: attributes of defined classes.Establish relationships between resourcesand values (literals, non-literals). #lod4h
  17. 17. ex:length rdf:type rdfs:property ;rdfs:label Lengthex:loa rdf:type rdfs:property; rdfs:subPropertyOf ex:length ; rdfs:label Length over all ;ex:lwl rdf:type rdfs:property; rdfs:subPropertyOf ex:length ; rdfs:label Length at waterline . #lod4h
  18. 18. Domain/Range Domain: which class may have a property(what can be the subject of a triple thatuses this property) Range: what class of objects can be usedwith this property. A class of resources Literals/datatypes, etc. #lod4h
  19. 19. ex:loa rdfs:range xsd:floatex:vessel_type rdf:type rdfs:property; rdfs:domain ex:vessel ; rdfs:range skos:concept .#lod4h
  20. 20. Limitations of RDFs Cardinality Transitivity Equivalence (of classes/instances) Constraining range based on domain Domain:basketball teamMembers 5 Domain:soccer teamMembers 11 #lod4h
  21. 21. An easier way! Protg Ontology Editor
  22. 22. Cultural Heritage CIDOC Conceptual Reference Model Lightweight Information Describing Objects(LIDO) (XML Schema) Europeana Data Model (EDM) Bibliontology Open Annotation Collaboration #lod4h
  23. 23. LUNCH#lod4h
  24. 24. SPARQL #lod4h
  25. 25. Basic SPARQLPrefix Declare what schemas you are using.Prefix SELECT ?displayVariables Query resultsFROM/FROM NAMEDSpecify a datasetWHERE{subject object predicate . Query pattern} Query modifiersORDER BY/LIMIT/OFFSET#lod4h
  26. 26. SELECT ?personWHERE{ ?person :givenName "Richard" .}
  27. 27. SELECT ?propertyName ?propertyValueWHERE{?propertyName ?propertyValue .}#lod4h
  28. 28. SELECT *WHERE{?s ?p ?o .} #lod4h
  29. 29. SELECT *WHERE{?s ?p ?o .} #lod4h
  30. 30. SELECT *WHERE{?s ?p ?o .FILTER (regex (?o, "edu", "i"))}Additional functions:
  31. 31. CONSTRUCT: returns results as RDFtriples (not a web page to browse) ASK: returns boolean (true/false) DESCRIBE: provide a specified set ofproperties for a resource #lod4h
  32. 32. dbPedia SPARQL endpoint Faceted Search View SPARQL#lod4h
  34. 34. Next up: 5:30-7:00 pmDHWI Public DH: API WorkshopRegistered Attendees Only#lod4h