1. An Introduction to RDFa QingXia Liu 2016-11-201

2. Contents What is RDFa? Why RDFa? Versions of RDFa An Example 2016-11-202

3. What is RDFa? Resource Description Framework in attributes – First proposed by Mark Birbeck in 2004Mark Birbeck – A W3C Recommendation 2016-11-203

4. What is RDFa? The gap between what programs and humans understand: 2016-11-204 What browsers seewhat humans see

5. What is RDFa? Aim: to allow a single RDF graph to be carried in various types of document markup. 2016-11-205

6. What is RDFa? Essence: attributes machine- readable it provides a set of markup attributes to augment the visual information on the Web with machine- readable hints. These attributes are: about, src, rel, rev, href, resource, property, content, datatype, typeof… 2016-11-206

7. What is RDFa? HTML : HTML :... The trouble with Bob Date: 2011-09-10 Alice...... Jo's Barbecue Date: 2011-09-14 Eve...... HTML + RDFa 1.1:... The trouble with Bob Date: 2011-09- 10 Alice...... Jo's Barbecue Date: 2011-09- 14 Eve...... 2016-11-207 mark up human-readable data with machine-readable indicators

8. What is RDFa? Example: The trouble with Bob Date: 2011-09-10 Alice Jo's Barbecue Date: 2011-09-14 Eve 2016-11-208

9. Why RDFa? Embedding RDF subject-predicate-object expressions in existing markup languages such as XHTML.RDFsubject-predicate-object expressions Enables the extraction of RDF model triples by compliant user agents Apps: – To provide richer search results by extracting fine-grained structured details from the Web pages they crawl. 2016-11-209

10. Versions RDFa 1.0 – was specified only for XHTML RDFa 1.1 – is the newer version specified for both XHTML and HTML5. – also works for any XML-based languages like SVG 2016-11-2010

11. Changes Differences between RDFa 1.1 and RDFa1.0: – The removal of the specific rules for XHTML - these are now defined in XHTML + RDFa – Dayatype Expansion : RDFa attributes can contain Terms, CURIES, or Absolute IRIs. – Host languages are permitted to define collections of default terms, default prefix mappings, and a default vocabulary – The ability to define a default vocabulary to use for Terms that are undefined (via @vocab)..@vocab – Terms are required to be compared in a case-insensitive manner. – A richer behavior of the @property attribute, that can replace, in many cases the @rel attribute. – A slightly different handling of @typeof, making it better adapted to practical usage. 2016-11-2011

12. Current Status Standards: 2012-06-07 – RDFa Core 1.1 – XHTML+RDFa 1.1 – RDFa Lite 1.1 Group Notes: before 2012-07-05 RDFa API, RDF Interfaces, RDFa 1.1 Primer, HTML Data Guide, XML in HTML Meeting Report Drafts: 2012-03-29 HTML+RDFa1.1 2016-11-2012

13. Example The trouble with Bob... Alice Birpemswick, Email: alice@example.com, Phone: +1 617.555.7332...... 2016-11-2013

14. Example The trouble with Bob... Alice Birpemswick, Email: alice@example.com, Phone: +1 617.555.7332...... 2016-11-2014

15. Example 2016-11-2015

16. Example The trouble with Bob Alice...... The trouble with Bob Alice...... 2016-11-2016 Alice Birpemswick, Email: alice@example.com, Phone: +1 617.555.7332... Alice Birpemswick, Email: alice@example.com, Phone: +1 617.555.7332...

17. Example 2016-11-2017

18. References The W3C RDFa 1.1 Primer The W3C RDFa 1.1 Core The Wikipedia entry on RDFa 2016-11-2018

19. Thank you ! 2016-11-2019