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Steffen Staab 1WeST Web Science & Technologies University of Koblenz ▪ Landau, Germany Structured Data on the Web Introduction to.

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Presentation on theme: "Steffen Staab 1WeST Web Science & Technologies University of Koblenz ▪ Landau, Germany Structured Data on the Web Introduction to."— Presentation transcript:

1 Steffen Staab 1WeST Web Science & Technologies University of Koblenz ▪ Landau, Germany Structured Data on the Web Introduction to Web Science Steffen Staab

2 Steffen Staab 2WeST Agenda  HTML Meta  Microdata  Microformats  RDF  RDF-a  Applications  Schema.org  Wikidata  Open data (especially Open government data)

3 Steffen Staab 3WeST The Semantic Tower of Babel Microformats Microdata XML XHTML, HTML5 GRDDL RDFa JSON

4 Steffen Staab 4WeST MICROFORMATS

5 Steffen Staab 5WeST Microformat A microformat (sometimes abbreviated μF) is a web-based approach to semantic markup  re-use existing HTML/XHTML tags to convey metadata  other attributes  in web pages and  In other contexts that support (X)HTML, such as RSS.  Predefined classes  hcard, hcal,...  Example

6 Steffen Staab 6WeST

7 Steffen Staab 7WeST Trade-offs + maximal re-use of HTML tags -lack of global identifiers for types -lack of global identifiers for properties -lack of global identifiers for objects

8 Steffen Staab 8WeST HTML MICRODATA

9 Steffen Staab 9WeST HTML Microdata Working draft:  machine-readable data to be embedded in HTML documents  in an easy-to-write manner  an unambiguous parsing model.  compatible with other data formats including RDF and JSON.

10 Steffen Staab 10WeST Hello, my name is John Doe, I am a graduate research assistant at the University of Dreams. My friends call me Johnny. You can visit my homepage at I live at 1234 Peach Drive Warner Robins, Georgia.

11 Steffen Staab 11WeST

12 Steffen Staab 12WeST Google rich snippet testing tool

13 Steffen Staab 13WeST Trade-offs + URIs for Types + Microdata DOM API + standardized conversion to JSON -no URIs for objects -no URIs for properties

14 Steffen Staab 14WeST JSON Java-script Object Notation

15 Steffen Staab 15WeST

16 Steffen Staab 16WeST RDF

17 Steffen Staab 17WeST RDF  RDF is a graph data format  Different syntaxes to write down graphs  Turtle  XML/RDF  RDFa

18 Steffen Staab 18WeST RDF Model  Resources (Subject, Object) connected by Predicates (relationships) SubjectObject predicate

19 Steffen Staab 19WeST RDF model  Resources  A resource is a referenced entity (Class, Individual, Relationship, …)  Resources must have URIs – Uniform Resource Identifiers or IRIs - Internationalized Resource Identifiers

20 Steffen Staab 20WeST RDF Model  Resource  Resource is a referenced entity (Class, Object, Entity, Relationship, …)  Resource must have: URIs – Uniform Resource Identifiers or IRIs - Internationalized Resource Identifiers  Property (relationship)  Similar to association in UML or relationship in database  Relationships between Resources and other Resources, or Resources to Literals  Property is also a Resource (have URI)  Literal  Simple (atomic) data type (e.g String, int …)  Statements  “Resource has Property with Value”  Format: Subject –[Property]  Object  Resources and/or literals are included in statement

21 Steffen Staab 21WeST Statement example  Statement  “Resource has name Institute WeST”http://west.uni-koblenz.de/#west  Structure  Resource(subject)  Property(predicate)  Value(object) “Institute WeST” here: literal  Related Graph #west Institute WeST

22 Steffen Staab 22WeST RDF represented as graphs  Nodes:  Resources represented by URIs  Unnamed Resources (Blank Nodes)  Literals represented by Strings  Directed Edges:  Represented by URIs Institute WeST #west hasEmployee

23 Steffen Staab 23WeST Example: Turtle notation Turtle Turtle with s s:hasEmployee s:hasName Institute WeST s:hasEmployee #WeST

24 Steffen Staab 24WeST Example: Turtle notation s s:hasEmployee. s:hasName “Institute WeST” Shorter u s:hasEmployee u:~staab/#me; s:hasEmployee u:~sizov/#me; s:hasEmployee u:~groener/#me; s:hasName “Institute WeST”. Even u s:hasEmployee u:~staab/#me, u:~sizov/#me, u:janik/#me; s:hasName “Institute WeST”.

25 Steffen Staab 25WeST RDFA

26 Steffen Staab 26WeST  RDFa 1.1 Primer  Rich Structured Data Markup for Web Documents  W3C Working Group Note 07 June 2012  RDFa Core 1.1  Syntax and processing rules for embedding RDF through attributes  W3C Recommendation 07 June 2012

27 Steffen Staab 27WeST RDFa example

28 Steffen Staab 28WeST Defining and mixing vocabularies

29 Steffen Staab 29WeST Graph: Multiple Items per Page

30 Steffen Staab 30WeST More complex graph example

31 Steffen Staab 31WeST Tools für RDFa 

32 Steffen Staab 32WeST GRDDL

33 Steffen Staab 33WeST GRDDL  Gleaning Resource Descriptions from Dialects of Languages (GRDDL)  W3C Recommendation 11 September 2007  Input: XML  Output: RDF  Examples: + microformat to RDF

34 Steffen Staab 34WeST COMPARISON OF STRUCTURED DATA APPROACHES

35 Steffen Staab 35WeST The Semantic Tower of Babel Microformats Microdata XML XHTML, HTML5 GRDDL RDFa JSON

36 Steffen Staab 36WeST Comparison (in flux) ber-comparison-rdfa-md-uf/

37 Steffen Staab 37WeST Conclusion  Big common core (triples)  Too many things to do almost the same  Methods to do it the Web style  using URIs all over the place  mixing vocabularies should be preferred


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