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Armin Haller & Florian RosenbergA Semantic Data Model for WebApplicationsCSIRO ICT Centre Conference

Semantic WebAdds machine readable data to Webresources

Semantic Web“First step is putting data on the Webin a form that machines can naturallyunderstand, or converting it to thatform. This creates what I call aSemantic Web - a web of data thatcan be processed directly or indirectlyby machines.” – Tim Berners-Lee

Web ResourceA page about a book<html><head><title>Tractatus Logico-Philosophicus</title></head><body><img src="tractatus.png" /> Written by: Ludwig Wittgenstein With an Introduction by: Bertrand RussellNew York Harcourt, Brace & Company, Inc. London: Kegan Paul, Trench, Trubner & Co.,Ltd. 1922</body></html>

Web ResourceA Book – Metadata elementsTitleAuthorPublisherDateContributor

Four principles to add machine readable data1. Identify resources2. Reuse ontologies3. Express meaning4. Link to other Web resources

Semantic Web1. Identify resources– Uniquely assign a Uniform ResourceIdentifier (URI) to every Web resource

TitleAuthorPublisherDateContributorWeb Resource1. Identify resourceshttp://example.org/book/Tractatus_Logico-Philosophicus

Semantic Web2. Reuse Ontologies– Specification of a conceptualization,ie. a description of the concepts andrelationships in a domain– Link to information in ontologies bytheir URI to reuse the samedefinition of common concepts, suchas the "book" or the "title“

TitleAuthorPublisherDateContributorWeb Resource2. Reuse ontologies – e.g. Dublin Corehttp://purl.org/dc/elements/1.1/creatorhttp://purl.org/dc/elements/1.1/datehttp://purl.org/dc/elements/1.1/publisherhttp://purl.org/dc/elements/1.1/contributorhttp://purl.org/dc/elements/1.1/title

Semantic Web3. Express meaning– Add structured information and setof rules to Web resources– Use knowledge representationlanguage – typically RDF• statements about Web resources in theform of Subject-Predicate-Object(S P O) triples

Web Resource3. Express meaninghttp://example.org/book/Tractatus_Logico-Philosophicusdc:titlehas awhich is

Web Resource3. Express meaninghttp://example.org/book/Tractatus_Logico-Philosophicusdc:creatorhas awhose name is

Web Resource3. Express meaninghttp://example.org/book/Tractatus_Logico-Philosophicusdc:contributorhasawhose name is

Web Resource3. Express meaninghttp://example.org/book/Tractatus_Logico-Philosophicusdc:publisherwhich ishas a

Web Resource3. Express meaninghttp://example.org/book/Tractatus_Logico-Philosophicusdc:datehas awhich is

@prefix dc: <http://purl.org/dc/terms/> .@prefix : <http://example.org/book#> .:Tractatus_Logico-Philosophicus dc:title "Tractatus Logico-Philospohicus" .:Tractatus_Logico-Philosophicus dc:creator "Ludwig Wittgenstein" .:Tractatus_Logico-Philosophicus dc:contributor "Bertrand Russell" .:Tractatus_Logico-Philosophicus dc:publisher "Harcourt, Brace & Company, Inc." .:Tractatus_Logico-Philosophicus dc:date "1922" .Resulting triples3. Express meaning

<?xml version="1.0" encoding="UTF-8"?><rdf:RDFxmlns:dc="http://purl.org/dc/terms/"xmlns="http://example.org/book#"xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><rdf:Description rdf:about="http://example.org/book#Tractatus_LogicoPhilosophicus"><dc:title>Tractatus Logicao-Philospohicus</dc:title><dc:creator>Ludwig Wittgenstein</dc:creator><dc:contributor>Bertrand Russell</dc:contributor><dc:publisher>Harcourt, Brace & Company, Inc.</dc:publisher><dc:date>1922</dc:date></rdf:Description></rdf:RDF>Resulting triples in RDF/XML3. Express meaning

Semantic Web4. Link to other Web resources– Progressively link to existing Webresources that someone else hasdefined already

Web Resource4. Link to other Web resourceshttp://example.org/book/Tractatus_Logico-Philosophicusdc:creatorhas awhose name is

Web Resource4. Link to other Web resourceshttp://example.org/book/Tractatus_Logico-Philosophicusdc:creatorhas ahttp://dbpedia.org/page/Ludwig_Wittgensteinwhosenameis

RDF → for agentsRDF annotations often expressmetadata (as in our book example)– usually stored in a separate .rdf file– useful for agents, limited use for humans

RDFa → for agents and humansRDFa = RDF in attributes– a way to mark up data in a web page– RDFa encodes RDF triples in HTML– useful for agents and (relatively) easyto use for humans

HTML<html><head><title>Tractatus Logico-Philosophicus</title></head><body><img src="tractatus.png" /> Written by: Ludwig Wittgenstein With an Introduction by: Bertrand Russell New York Harcourt, Brace & Company, Inc. London: Kegan Paul, Trench, Trubner & Co., Ltd. 1922</body></html>

RDFa example<html prefix="dc: http://purl.org/dc/terms/“base="http://example.org/book/Tractatus_Logico-Philosophicus"><head><title about="" property="dc:title">Tractatus LogicoPhilosophicus</title></head><body><img src="tractatus.png" /> Written by: LudwigWittgenstein With an Introduction by: Bertrand Russell New York Harcourt, Brace & Company, Inc. London: Kegan Paul, Trench, Trubner & Co., Ltd. 1922</body></html>

RDFa – metadata vs. dataRDFa mostly used for metadata, e.g.the book metadata as beforeBut: the principle of the SemanticWeb and Linked Data is to addmeaning to metadata and data– Data could be metadata,– but it could be data, e.g. a bookpurchase at Amazon

Forms, metadata vs. datae.g. Book purchase on AmazonFirst Name:Last Name:JaneDoeEmail: jane.doe@example.comPassword: ********Gender:Birthday: 03 04 1976Male Female

1976Forms, metadata vs. datae.g. Book purchase on AmazonFirst Name:Last Name:JaneDoeEmail: jane.doe@example.comPassword: ********Gender:Birthday: 03 04Male FemaleTitle:Author:Tractatus Logico PhiLudwig WittgensteinPrice: 25 GBPAmount: 1DeliveryAddress:10 Downing StreetLondonSW1A 2AAUnited Kingdom

1976Forms, metadata vs. datae.g. Book purchase on AmazonFirst Name: JaneDoeEmail: jane.doe@example.comPassword: ********Gender:Birthday: 03 04Male FemaleTitle:Author:Tractatus Logico PhiLudwig WittgensteinPrice: 25 GBPAmount:1DeliveryAddress:10 Downing StreetLondonSW1A 2AAUnited Kingdom1976041Cardholder:CC Number:Expiry Date:CVV: 999Price:Type: MastercardJane Doe5999 9999 9999 999904 1325 GBPLast Name:

Forms, metadata vs. datae.g. Book purchase on Amazon197604FemaleTitle:Author:Tractatus Logico PhiLudwig WittgensteinPrice: 25 GBPAmount: 1DeliveryAddress:10 Downing StreetLondonSW1A 2AAUnited Kingdom→ metadata→ metadata→ metadata / data→ data→ data→ data→ data→ data

Issue – Adding RDFa for data to formsForm input elements can beannotated with RDFaBut: RDFa annotations for input datais not possible → no binding

Issue – Adding RDFa for data to formse.g. “Jane” can not be defined asfoaf:firstNameFirst Name:Last Name:JaneDoeEmail: jane.doe@example.comPassword: ********Gender:Birthday: 03 04 1976Male Female<input type="text" name=“First Name" value="" />span>No binding!

Making input data available onthe Semantic Web!

Model and System for semantic Web applications– RDF-based model for forms (RaUL)http://purl.org/NET/raul#– RESTful Web service (ActiveRaUL)http://raul.deri.ie/raul– JavaScript RDFa API

RaUL form modelDefines meta model for form elements

RaUL form model– Triples defining the structure of a form– Triples defining the dataFirst Name:Last Name:JaneDoeEmail: jane.doe@example.comPassword: ********Gender:Birthday: 03 04 1976Male Female→ foaf:firstName→ foaf:surname→ foaf:mbox→ foaf:sha1→ foaf:gender→ time:day, time:month, time:year

ActiveRaUL Web serviceModel-View-Controller– Model: RaUL– View: Rendering serviceto generate RaUL-basedWeb forms inXHTML+RDFa– Controller: Web servicethat maps HTTP terms toCRUD operations on RaULWeb forms

JavaScript RDFa API– Parses RDFa– Manages data binding of form inputto data model

Lifecycle1. Form Modeling:form model in RDFbased on the RaULontology– Actor: ontology engineer

Lifecycle2. Form Deployment:form submitted bycalling ActiveRaUL– Generic form models in apublic namespace →standard form models– Actor: ontology engineer

Lifecycle3. Form Usage: accessand manipulate a formmodel by callingActiveRaUL– submit instance data for aform → bound to a datamodel– Actor: Web user or agent

Lifecycle4. Data Reuse: Add linkto existing, local data ordata in the Linked datacloud– RDFa API retrieves datafrom that URI and prefillsform controls– Actor: Form Provider

ConclusionRDFa annotated Web forms which follow theprinciples of Linked Open Data.Advantages:1. Non-ambiguous model: typed through an ontologicalmodel.2. RDF data submission: submitted data encoded in RDF.3. Explicit form structure: form elements are explicitlymodelled as RDF statements.4. External schema augmentation: reuse existingschemas for form data5. Reuse of Linked Open Data: retrieve data from theLinked Open Data cloud

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