Download presentation
Presentation is loading. Please wait.
1
CSIRO ICT Centre Conference
Armin Haller & Florian Rosenberg A Semantic Data Model for Web Applications CSIRO ICT Centre Conference
2
Adds machine readable data to Web resources
Semantic Web Adds machine readable data to Web resources
3
Semantic Web “First step is putting data on the Web in a form that machines can naturally understand, or converting it to that form. This creates what I call a Semantic Web - a web of data that can be processed directly or indirectly by machines.” – Tim Berners-Lee
4
A page about a book Web Resource <html> <head>
<title>Tractatus Logico-Philosophicus</title> </head> <body> <p> <img src="tractatus.png" /><br/> Written by: Ludwig Wittgenstein <br /> With an Introduction by: Bertrand Russell </p> New York <br /> Harcourt, Brace & Company, Inc. <br /> London: Kegan Paul, Trench, Trubner & Co., Ltd. <br /> <p>1922</p> </body> </html>
5
A Book – Metadata elements
Web Resource A Book – Metadata elements Title Author Contributor Publisher Date
6
Link to other Web resources
Four principles to add machine readable data Identify resources Reuse ontologies Express meaning Link to other Web resources
7
Semantic Web Identify resources Uniquely assign a Uniform Resource Identifier (URI) to every Web resource
8
Identify resources Web Resource Title Author Contributor Publisher
Title Author Contributor Publisher Date
9
Semantic Web Reuse Ontologies Specification of a conceptualization, ie. a description of the concepts and relationships in a domain Link to information in ontologies by their URI to reuse the same definition of common concepts, such as the "book" or the "title“
10
Reuse ontologies – e.g. Dublin Core
Web Resource Reuse ontologies – e.g. Dublin Core Title Author Contributor Publisher Date
11
Semantic Web Express meaning Add structured information and set of rules to Web resources Use knowledge representation language – typically RDF statements about Web resources in the form of Subject-Predicate-Object (S P O) triples
12
Express meaning Web Resource
has a which is dc:title
13
Express meaning Web Resource
has a dc:creator whose name is
14
Express meaning Web Resource
has a dc:contributor whose name is
15
Express meaning Web Resource
has a which is dc:publisher
16
Express meaning Web Resource
has a which is dc:date
17
Express meaning Resulting triples
@prefix dc: < . @prefix : < . :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 triples Express meaning
18
Express meaning Resulting triples in RDF/XML
<?xml version="1.0" encoding="UTF-8"?> <rdf:RDF xmlns:dc=" xmlns=" xmlns:rdf=" <rdf:Description rdf:about=" Philosophicus"> <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/XML Express meaning
19
Link to other Web resources
Semantic Web Link to other Web resources Progressively link to existing Web resources that someone else has defined already
20
Link to other Web resources
has a dc:creator whose name is
21
Link to other Web resources
has a whose name is dc:creator
22
Where is the semantic Web?
23
RDF annotations often express metadata (as in our book example)
RDF ® for agents RDF annotations often express metadata (as in our book example) usually stored in a separate .rdf file useful for agents, limited use for humans
24
RDFa = RDF in attributes
RDFa ® for agents and humans RDFa = RDF in attributes a way to mark up data in a web page RDFa encodes RDF triples in HTML useful for agents and (relatively) easy to use for humans
25
HTML <html> <head>
<title>Tractatus Logico-Philosophicus</title> </head> <body> <p> <img src="tractatus.png" /><br /> Written by: Ludwig Wittgenstein <br /> With an Introduction by: Bertrand Russell <br /><br /> New York <br /> Harcourt, Brace & Company, Inc. <br /> London: Kegan Paul, Trench, Trubner & Co., Ltd. <br /> <p>1922</p> </body> </html>
26
RDFa example <html prefix="dc: base=" <head> <title about="" property="dc:title">Tractatus Logico Philosophicus</title> </head> <body> <p about=""> <img src="tractatus.png" /><br /> Written by: <span property="dc:creator">Ludwig Wittgenstein</span> <br /> With an Introduction by: <span property="dc:contributor"> Bertrand Russell</span><br /><br /> New York <br /> <span property="dc:publisher">Harcourt, Brace & Company, Inc. </span><br /> London: Kegan Paul, Trench, Trubner & Co., Ltd. <br /> <p about=""><span property="dc:date">1922</span></p> </body> </html>
27
RDFa mostly used for metadata, e.g. the book metadata as before
RDFa – metadata vs. data RDFa mostly used for metadata, e.g. the book metadata as before But: the principle of the Semantic Web and Linked Data is to add meaning to metadata and data Data could be metadata, but it could be data, e.g. a book purchase at Amazon
28
e.g. Book purchase on Amazon
Forms, metadata vs. data e.g. Book purchase on Amazon First Name: Jane Last Name: Doe Password: ******** Gender: Male Female Birthday: 03 04 1976
29
e.g. Book purchase on Amazon
Forms, metadata vs. data e.g. Book purchase on Amazon First Name: Jane Last Name: Doe Password: ******** Title: Gender: Tractatus Logico Phi Male Female Author: Birthday: Ludwig Wittgenstein 03 04 1976 Price: 25 GBP Amount: 1 Delivery Address: 10 Downing Street London SW1A 2AA United Kingdom
30
e.g. Book purchase on Amazon
Forms, metadata vs. data e.g. Book purchase on Amazon First Name: Jane Last Name: Doe Password: ******** Title: Gender: Tractatus Logico Phi Male Female Author: Birthday: Ludwig Wittgenstein 03 04 1976 Price: 25 GBP Amount: 1 Price: Delivery Address: 25 GBP 10 Downing Street Type: Mastercard London Cardholder: SW1A 2AA 04 1 1976 Jane Doe CC Number: United Kingdom Expiry Date: 04 13 CVV: 999
31
e.g. Book purchase on Amazon
Forms, metadata vs. data e.g. Book purchase on Amazon ® metadata ® metadata metadata / data data ® data Title: Tractatus Logico Phi Female Author: Ludwig Wittgenstein 04 1976 Price: 25 GBP Amount: 1 Delivery Address: 10 Downing Street London SW1A 2AA United Kingdom
32
Form input elements can be annotated with RDFa
Issue – Adding RDFa for data to forms Form input elements can be annotated with RDFa But: RDFa annotations for input data is not possible ® no binding
33
e.g. “Jane” can not be defined as foaf:firstName
Issue – Adding RDFa for data to forms e.g. “Jane” can not be defined as foaf:firstName First Name: Jane Last Name: Doe Password: ******** Gender: Male Female Birthday: 03 04 1976 <span about="" property="foaf:firstName" content=""> <input type="text" name=“First Name" value="" /> </span>span> No binding!
34
Making input data available on the Semantic Web!
35
RDF-based model for forms (RaUL) http://purl.org/NET/raul#
Model and System for semantic Web applications RDF-based model for forms (RaUL) RESTful Web service (ActiveRaUL) JavaScript RDFa API
36
Defines meta model for form elements
RaUL form model Defines meta model for form elements
37
RaUL form model Triples defining the structure of a form
Triples defining the data foaf:firstName foaf:surname foaf:mbox foaf:sha1 foaf:gender time:day, time:month, time:year First Name: Jane Last Name: Doe Password: ******** Gender: Male Female Birthday: 03 04 1976
38
ActiveRaUL Web service Model-View-Controller
Model: RaUL View: Rendering service to generate RaUL-based Web forms in XHTML+RDFa Controller: Web service that maps HTTP terms to CRUD operations on RaUL Web forms
39
Manages data binding of form input to data model
JavaScript RDFa API Parses RDFa Manages data binding of form input to data model
40
Form Modeling: form model in RDF based on the RaUL ontology
Lifecycle Form Modeling: form model in RDF based on the RaUL ontology Actor: ontology engineer
41
Form Deployment: form submitted by calling ActiveRaUL
Lifecycle Form Deployment: form submitted by calling ActiveRaUL Generic form models in a public namespace ® standard form models Actor: ontology engineer
42
Form Usage: access and manipulate a form model by calling ActiveRaUL
Lifecycle Form Usage: access and manipulate a form model by calling ActiveRaUL submit instance data for a form ® bound to a data model Actor: Web user or agent
43
Lifecycle Data Reuse: Add link to existing, local data or data in the Linked data cloud RDFa API retrieves data from that URI and prefills form controls Actor: Form Provider
44
Conclusion RDFa annotated Web forms which follow the principles of Linked Open Data. Advantages: Non-ambiguous model: typed through an ontological model. RDF data submission: submitted data encoded in RDF. Explicit form structure: form elements are explicitly modelled as RDF statements. External schema augmentation: reuse existing schemas for form data Reuse of Linked Open Data: retrieve data from the Linked Open Data cloud
Similar presentations
![The Semantic Web – WEEK 5: RDF Schema + Ontologies The “Layer Cake” Model – [From Rector & Horrocks Semantic Web cuurse]](/16/5007861/big_thumb.jpg "The Semantic Web – WEEK 5: RDF Schema + Ontologies The “Layer Cake” Model – [From Rector & Horrocks Semantic Web cuurse]>")