Quick Introduction to the Semantic Web, RDFa & Microformats


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Google's recent announcement that it will support the use of microformats in their search opens up new possibilities for librarians and library technologists to support the goals of the semantic web; namely to provide better access, reuse and recombinations of library resources and services on the open web. This lightning talk introduces the semantic web and semantic markup technologies.

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  • Current web has problem with data integration across the web. http & browsers – separated data transport from web apps Data stovepiped: integration, aggregation & reuse difficult
  • Tim Berners Lee – In 2001 wrote about vision of the evolution of the existing Web to a Semantic Web. Recently TBL: "This simple idea, however, remains largely unrealized." – The Semantic Web Revisited, Intelligent Systems IEEE, Lee, Shabolt, & Hall < http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1637364 >
  • * rdf encodes the semantic web, vocabularies are written in it * Sparql – RDF query language and RDF dbs (triple stores) * OWL is the WEB ontology language used for defining precise relationships b/t model elements (e.g. owl:sameAs)
  • The core technology is RDF. Resource Description Framework Expresses data in a Subject-Predicate-Object form So, Tim love ice cream, Tim hates pickles In a relational db world the relationship b/c tables might be semantic – This is one of that – but its not encoded into the actual data. RDF does that – the relationship b/t the objects is spelled out within the code and subsequently machines can read and act on this. SemWeb often called Giant Global Graph
  • Another essential principle of semweb is that it use URIs for names of things (uniform resource identifier) This disambiguates similar people/places/things based on the uniqueness of the uri. A uri for john smith on a berkeley domain would be different from john smith on a stanford domain.
  • Example RDF – Friend of a Friend file
  • Organizations are not only publishing their data in RDF, but are exposing the data as “linked data” which interconnect the RDF with other RDF stores – So Dbedia uses the wordnet links for defining words etc. Linking Open Data
  • Recent example of exposing linked data as RDF is the Library of congress Subject headings. On this site you can download the RDF for the LCSH It has a RESTful web service that you can program to. And it has a human interface where you can search and exlpore.
  • An example of a graph of the terms on LCSH. Provides a nice visualization of the concepts. This is a major step b/c it mean that the LCSH now has URIs associated with the concepts – which can be used to link up previously unconnected data on the web.
  • Quick Introduction to the Semantic Web, RDFa & Microformats

    1. 1. Semantic Web, RDFa & Microformats Tim Dennis Research Technologist Data Lab Emerging Tech Lightning Talks UC Berkeley Library
    2. 5. “The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries” (World Wide Web Consortium, 2008a)
    3. 6. RDF 1. Resource Description Framework 2. Presents relationships in a simple data structure 3. We can draw graphs of those relationships 4. We can represent those relationships in multiple formats for computers --Tim Berners-Lee, Linked Data - Design Issues. http://www.w3.org/DesignIssues/LinkedData.html
    4. 7. Design Principles 1. Use URIs for names of things 2. Use HTTP URIs so people can look up those names 3. Provide useful information in standard formats at those URIs 4. Include links to other URIs so people can discover more things --Tim Berners-Lee, Linked Data - Design Issues. http://www.w3.org/DesignIssues/LinkedData.html
    5. 8. FOAF RDF Example: http://www.w3schools.com/rdf/rdf_example.asp
    6. 9. Linked Data: http://linkeddata.org/
    7. 10. http://id.loc.gov/authorities/
    8. 11. http://id.loc.gov/authorities/
    9. 12. RDFa & Micoformats <ul><li>Embeds semantics into existing XHTML
    10. 13. Annotates XHTML web pages with RDF (RDFa)
    11. 14. Mix of human readable & machine readable
    12. 15. RFDa uses CURIE – a way to prefix an inline namespace (amazonisbn: 0596153813)
    13. 16. More large services are publishing Microformats (been around longer) – linkedin, digg </li></ul>
    14. 17. Microformats <ul><li>Events information - hCalendar.
    15. 18. People or organisations - hCard.
    16. 19. Geocode - Geo.
    17. 20. Copyright license - rel=license.
    18. 21. Social networking data - XFN
    19. 22. Tagging - rel=tag or xFolk.
    20. 23. Lists - XOXO.
    21. 24. Reviews - hReview. </li></ul>http://microformats.org/
    22. 25. RFDa Vocabularies <ul><li>Geo
    23. 26. FOAF
    24. 27. Dublin core
    25. 28. RDF Calendar
    26. 29. Beer & Wine Ontology
    27. 30. Resume
    28. 31. Many many more at schemaweb.info </li></ul>RDFa Primer: http://www.w3.org/TR/xhtml-rdfa-primer/
    29. 32. Google Rich Snippets Microformats & RFDa <ul><li>Reviews
    30. 33. People
    31. 34. Products
    32. 35. Businesses and organizations </li></ul>
    33. 36. Yahoo! SearchMonkey Accepted RDFa Vocabulary (you can also define own) <ul><li>Dublin Core Document metadata
    34. 37. Friend-Of-A-Friend Personal profiles and social networks
    35. 38. VCard Personal and business addresses
    36. 39. VCalendar Events and other calendar items
    37. 40. hReview Reviews
    38. 41. SIOC Blogs, discussion forums, Q&A sites
    39. 42. GoodRelations Product price specification, delivery and payment etc.
    40. 43. DBPedia Generic vocabulary
    41. 44. Freebase Generic vocabulary </li></ul>
    42. 45. Yahoo! Search results Google search results RDFa & Microformat Enhanced Search Results RDFa Review Markup Microformat hReview Markup
    43. 46. MIT's Simile Exhibit – Structured data web publishing tool. Can consume RDF. Example below is of the timeline widget. < http://www.simile-widgets.org/exhibit/ > Music Composer Database: http://www.musicedmagic.com/Exhibit/composers.html
    44. 47. Simile Exhibit – Faceted view of structured data. < http://simile-widgets.org/exhibit/examples/nobelists/nobelists.html>