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 Universityrurban@fsu.edu@musebrarian #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
  5. 5. http://en.wikipedia.org/wiki/Semantic_Web_Stack#lod4h
  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: http://goo.gl/4wQss 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
  13. 13. MODELING LINKED DATAWITH RDFS#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 Editorhttp://protege.stanford.edu/#lod4h
  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" .}http://mith.umd.edu/dhwiwiki/index.php/SPARQL_Examples#lod4h
  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:http://www.w3.org/TR/rdf-sparql-query/#tests#lod4h
  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 endpointhttp://dbpedia.org/snorql/ Faceted Searchhttp://dbpedia.org/fct/ View SPARQL#lod4h
  33. 33. LINKED DATA FOR PROJECTS#lod4h
  34. 34. Next up: 5:30-7:00 pmDHWI Public DH: API WorkshopRegistered Attendees Only#lod4h