Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Preserving Semantics in the Web Ralph R. Swick MIT LCS & W3C [email protected] Semantic Web Goal • Encourage humans and machines to put more specificity of meaning into the Web to enable … • people to find definitions, constraints, translations • machines to automate [portions of] processing • preservation of intention across time & space Annotea - Shared Annotations • Human-level Annotation object described by RDF properties e.g. • • • • • author date created, date modified context (specific location within annotated doc) body (the “text” of the annotation) type (e.g. Comment, Example, Explanation, …) Model of an Annotation Instance 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 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 ... … 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 Schema Additions for WAI task rdf:subclass Annotation EARLeval rdf:type a:annotates 4GVF1D818 dc:creator Marja XDoc.html a:context problem explanation a:created dc:date OHFR427 2000-01-10T17:20Z checkpoint 2000-01-10T17:20Z “non spacer IMG with equivalent ALT -- MANUAL –” WCAG CP 1.2 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.” Equivalence (Synonyms) samePropertyAs subClassOf equivalentTo Formulae • http://www.w3.org/2000/10/swap/log# • semantics “This connects a document and the formula it parses to.” • forAll • forSome • implies • ... cwm - Logic Processor • Forward chaining inference engine • Implements some first-order logic properties for expressing rules in RDF i.e. those in http://www.w3.org/2000/10/swap/log# 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” Further Information • Annotea http://www.w3.org/2001/Annotea • cwm http://www.w3.org/2000/10/swap/ • Semantic Web http://www.w3.org/2001/sw/ • RDF & Web Ontology Language http://www.w3.org/2001/sw/WebOnt/