1. Steffen Staab staab@uni-koblenz.de 1WeST Web Science & Technologies University of Koblenz ▪ Landau, Germany Structured Data on the Web Introduction to Web Science Steffen Staab

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

3. Steffen Staab staab@uni-koblenz.de 3WeST The Semantic Tower of Babel Microformats Microdata XML XHTML, HTML5 GRDDL RDFa JSON

4. Steffen Staab staab@uni-koblenz.de 4WeST MICROFORMATS

5. Steffen Staab staab@uni-koblenz.de 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 staab@uni-koblenz.de 6WeST

7. Steffen Staab staab@uni-koblenz.de 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 staab@uni-koblenz.de 8WeST HTML MICRODATA

9. Steffen Staab staab@uni-koblenz.de 9WeST HTML Microdata Working draft: http://dev.w3.org/html5/md/http://dev.w3.org/html5/md/  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 staab@uni-koblenz.de 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 www.JohnnyD.com. I live at 1234 Peach Drive Warner Robins, Georgia.

11. Steffen Staab staab@uni-koblenz.de 11WeST

12. Steffen Staab staab@uni-koblenz.de 12WeST Google rich snippet testing tool

13. Steffen Staab staab@uni-koblenz.de 13WeST Trade-offs + URIs for Types + Microdata DOM API + standardized conversion to JSON -no URIs for objects -no URIs for properties

14. Steffen Staab staab@uni-koblenz.de 14WeST JSON Java-script Object Notation

15. Steffen Staab staab@uni-koblenz.de 15WeST

16. Steffen Staab staab@uni-koblenz.de 16WeST RDF

17. Steffen Staab staab@uni-koblenz.de 17WeST RDF  RDF is a graph data format  Different syntaxes to write down graphs  Turtle  XML/RDF  RDFa

18. Steffen Staab staab@uni-koblenz.de 18WeST RDF Model  Resources (Subject, Object) connected by Predicates (relationships) SubjectObject predicate

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

22. Steffen Staab staab@uni-koblenz.de 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 http://www.uni-koblenz.de/~staab/#me http://west.uni-koblenz.de/ #west http://west.uni-koblenz.de/preds/hasName http://west.uni-koblenz.de/preds/ hasEmployee

23. Steffen Staab staab@uni-koblenz.de 23WeST Example: Turtle notation Turtle Turtle with Namespaces @prefix s s:hasEmployee s:hasName Institute WeST http://www.uni-koblenz.de/~staab/#me s:hasEmployee http://west.uni-koblenz.de/ #WeST

24. Steffen Staab staab@uni-koblenz.de 24WeST Example: Turtle notation (cont’d) @prefix s s:hasEmployee. s:hasName “Institute WeST” Shorter version @prefix s @prefix u s:hasEmployee u:~staab/#me; s:hasEmployee u:~sizov/#me; s:hasEmployee u:~groener/#me; s:hasName “Institute WeST”. Even shorter @prefix s @prefix u s:hasEmployee u:~staab/#me, u:~sizov/#me, u:janik/#me; s:hasName “Institute WeST”.

25. Steffen Staab staab@uni-koblenz.de 25WeST RDFA

26. Steffen Staab staab@uni-koblenz.de 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 staab@uni-koblenz.de 27WeST RDFa example

28. Steffen Staab staab@uni-koblenz.de 28WeST Defining and mixing vocabularies

29. Steffen Staab staab@uni-koblenz.de 29WeST Graph: Multiple Items per Page

30. Steffen Staab staab@uni-koblenz.de 30WeST More complex graph example

31. Steffen Staab staab@uni-koblenz.de 31WeST Tools für RDFa  http://www.w3.org/2001/sw/wiki/RDFa

32. Steffen Staab staab@uni-koblenz.de 32WeST GRDDL

33. Steffen Staab staab@uni-koblenz.de 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 staab@uni-koblenz.de 34WeST COMPARISON OF STRUCTURED DATA APPROACHES

35. Steffen Staab staab@uni-koblenz.de 35WeST The Semantic Tower of Babel Microformats Microdata XML XHTML, HTML5 GRDDL RDFa JSON

36. Steffen Staab staab@uni-koblenz.de 36WeST Comparison (in flux) http://manu.sporny.org/2011/u ber-comparison-rdfa-md-uf/

37. Steffen Staab staab@uni-koblenz.de 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