RDFa: The Semantic Web's Missing Link
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RDFa enables users to publish RDF data simply through HTML and HTTP, filling a gap in the semantic web. It extends HTML metadata features to accommodate RDF concepts, allowing for a more semantic approach to web content. Advances include support for CURIEs, context setting with @about, and the ability to mark-up OWL documents in HTML.
![Mark Birbeck Managing Director, Backplane Ltd. http://webBackplane.com/mark-birbeck http://twitter.com/markbirbeck [email_address]](https://image.slidesharecdn.com/rdfathesemanticwebsmissinglink-090617004715-phpapp02/85/RDFa-The-Semantic-Web-s-Missing-Link-36-320.jpg)
RDFa: The Semantic Web's Missing Link
- 1. RDFa: The semantic web's missing link Mark Birbeck SemTech 2009
- 7. Solution part 1 RDFa allows anyone who can publish HTML, to publish data.
- 8. Solution part 2 RDFa covers all of RDF. (Well...nearly.)
- 9. Solution So RDFa allows us to publish data, through the simple means of HTML and HTTP.
- 14. Why is RDFa the semantic web's missing link? Can now publish RDF as easily as HTML
- 15. What does RDFa look like? There are some metadata features in HTML already... ...so we give them an RDF interpretation... ...then we generalise them... ...and then we add a few more.
- 16. HTML's metadata features (1) <html> <head> <title>RDFa: Now everyone can have an API</title> <meta name="author" content="Mark Birbeck" /> <meta name="created" content="2009-05-09" /> <link rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/" /> </head> . . . </html>
- 17. HTML's metadata features (2) <a href="http://creativecommons.org/licenses/by-sa/3.0/" >CC Attribution-ShareAlike</a> <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/" >CC Attribution-ShareAlike</a>
- 18. RDFa extends @rel/@href to images <img src="image01.png" rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/" /> <img src="image02.png" rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/" />
- 19. RDFa extends meta/@content to body <html> <head> <title>RDFa: Now everyone can have an API</title> <meta name="author" content="Mark Birbeck" /> <meta name="created" content="2009-05-09" /> </head> <body> <h1>RDFa: Now everyone can have an API</h1> Author: <em >Mark Birbeck</em> Created: <em >May 9th, 2009</em> </body> </html>
- 20. RDFa extends meta/@content to body <html> <head> <title>RDFa: Now everyone can have an API</title> </head> <body> <h1>RDFa: Now everyone can have an API</h1> Author: <em property="author" content="Mark Birbeck" >Mark Birbeck</em> Created: <em property="created" content="2009-05-09" >May 9th, 2009</em> </body> </html>
- 21. RDFa extends meta/@content to body <html> <head> <title>RDFa: Now everyone can have an API</title> </head> <body> <h1>RDFa: Now everyone can have an API</h1> Author: <em property="author" > Mark Birbeck </em> Created: <em property="created" content="2009-05-09" >May 9th, 2009</em> </body> </html>
- 22. Vocabularies use CURIEs <html xmlns:dc="http://purl.org/dc/terms/" > <head> <title>RDFa: Now everyone can have an API</title> </head> <body> <h1>RDFa: Now everyone can have an API</h1> Author: <em property=" dc:creator " >Mark Birbeck</em> Created: <em property=" dc:created " content="2009-05-09" >May 9th, 2009</em> </body> </html>
- 23. CURIEs, or Compact URIs Named after Marie Curie, who was the first person to receive two Nobel prizes, one for physics and one for chemistry. CURIEs allow a full URI to be expressed in a simple prefix:suffix form. The 'suffix' part is looser than in XML namespaces, supporting formulations such as abc:123 .
- 24. Properties can also apply to images <img src="image01.png” rel="license" href=" http://creativecommons.org/licenses/by-sa/3.0/ " /> <img src="image02.png” rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/" />
- 25. Properties can also apply to images <img src="image01.png" rel="license" href=" http://creativecommons.org/licenses/by-sa/3.0/ " property="dc:creator" content="Mark Birbeck" /> <img src="image02.png" rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/" property="dc:creator" content="Mark Birbeck" />
- 26. Relationships and properties on anything <a href="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" >The 5 minute guide to RDFa...in only 6 minutes and 40 seconds</a>
- 27. Relationships and properties on anything <a rel="license" href="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" >The 5 minute guide to RDFa...in only 6 minutes and 40 seconds</a> Doesn't say what we want.
- 28. Relationships and properties on anything <a href="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" >The 5 minute guide to RDFa...in only 6 minutes and 40 seconds</a> is licensed under <a href="http://creativecommons.org/licenses/by-sa/2.5/" >CC BY SA</a>.
- 29. Relationships and properties on anything <a href="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" >The 5 minute guide to RDFa...in only 6 minutes and 40 seconds</a> is licensed under <a about="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" rel="license" href="http://creativecommons.org/licenses/by-sa/2.5/" >CC BY SA</a>.
- 30. Relationships and properties on anything <a href="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" >The 5 minute guide to RDFa...in only 6 minutes and 40 seconds</a> is licensed under <a about="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" rel="license" href="http://creativecommons.org/licenses/by-sa/2.5/" property="dc:creator" content="Mark Birbeck" >CC BY SA</a>.
- 31. @about sets context <div about="http://www.slideshare.net/mark.birbeck/the-5-minute-guide-to-rdfain-only-6-minutes-40-seconds" > <h1>The 5 minute guide to RDFa...</h1> Author: <em property="dc:creator" >Mark Birbeck</em> Created: <em property="dc:created" content="2009-05-09" >May 9th, 2009</em> </div>
- 32. @about sets context <html xmlns:dc="http://purl.org/dc/terms/"> <head> <title>RDFa: Now everyone can have an API</title> </head> <body> <h1>RDFa: Now everyone can have an API</h1> Author: <em property="dc:creator" >Mark Birbeck</em> Created: <em property="dc:created" content="2009-05-09" >May 9th, 2009</em> </body> </html>
- 33. Basics of RDFa generalise HTML's existing semantic features; add support for CURIEs for property and relationship names; add @about.
- 34. Advanced RDFa use of @datatype to set the data type of @content; use of @typeof to set rdf:type ; support for bnodes; support for XML literals; ability to chain statements together. Note that since RDFa supports all of the features you'll find in RDF, then it means that you can even mark-up OWL documents in HTML.
- 35. Tools server-side parsers; client-side parsers and post-processors. See http://rdfa.info/rdfa-implementations Also note my RDFa parser Ubiquity RDFa and Jeni Tennison's jQuery-based rdfQuery , as two further client-side processors that aren't mentioned there.
- 36. Mark Birbeck Managing Director, Backplane Ltd. http://webBackplane.com/mark-birbeck http://twitter.com/markbirbeck [email_address]