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Preserving Semantics in the Web

Preserving Semantics in the Web. Ralph R. Swick MIT LCS & W3C swick@lcs.mit.edu. Semantic Web Goal. Encourage humans and machines to put more specificity of meaning into the Web to enable … people to find definitions, constraints, translations

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Preserving Semantics in the Web

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  1. Preserving Semantics in the Web Ralph R. SwickMIT LCS & W3Cswick@lcs.mit.edu

  2. Semantic Web Goal • Encourage humans and machines to put more specificity of meaning into the Webto enable … • people to find definitions, constraints, translations • machines to automate [portions of] processing • preservation of intention across time & space

  3. Annotea - Shared Annotations • Human-level Annotation object described by RDF propertiese.g. • author • date created, date modified • context (specific location within annotated doc) • body (the “text” of the annotation) • type (e.g. Comment, Example, Explanation, …)

  4. Model of an Annotation Instance

  5. Annotations and Meaning • Present: annotators define personal/group/ task/community annotation types using an RDF Schema • each type means whatever its definer wishes it to mean, but that meaning is advertised in the Web • Future: annotators define personal/…/ community properties using RDF Schema or Web Ontology Language

  6. An Annotea Use Case: WAI • WAI (Web Accessibility Initiative) Evaluation and Repair Tool • ERT property definitions are created that are specialized to this task • Annotations include task-specific properties identifying the WAI guidelines that a document fails to meet...

  7. … use case: WAI • ERT annotations can be created by a human expert or by an automated evaluation tool • ERT annotations can be evaluated by a human (a document author) and by automated repair tools • Document author can augment the annotation to communicate state to reviewers and to other tools

  8. XDoc.html Schema Additions for WAI task rdf:subclass Annotation EARLeval rdf:type a:annotates a:context 4GVF1D818 “non spacer IMG with equivalent ALT -- MANUAL –” dc:creator problem Marja explanation a:created OHFR427 dc:date WCAGCP 1.2 2000-01-10T17:20Z checkpoint 2000-01-10T17:20Z

  9. Adding Logic and Rules • Common case:http://www.w3.org/2001/10/daml+oil#samePropertyAs “for samePropertyAs(P, R), read P is an equivalent property to R.”

  10. Equivalence (Synonyms) samePropertyAs subClassOf equivalentTo

  11. Formulae • http://www.w3.org/2000/10/swap/log# • semantics“This connects a document and the formula it parses to.” • forAll • forSome • implies • . . .

  12. cwm - Logic Processor • Forward chaining inference engine • Implements some first-order logic properties for expressing rules in RDFi.e. those in http://www.w3.org/2000/10/swap/log#

  13. WAI proto- rule • “X annotates document_D, X has type EARL:Evaluation, X has EARL:Assertor P, P has WAIcredentials WAIexpert, P asserts R, R has predicate EARL:Fails R has object TestCase_C”implies “X fails TestCase_C”

  14. Further Information • Annoteahttp://www.w3.org/2001/Annotea • cwmhttp://www.w3.org/2000/10/swap/ • Semantic Webhttp://www.w3.org/2001/sw/ • RDF & Web Ontology Languagehttp://www.w3.org/2001/sw/WebOnt/

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