Semantic Web: A web that is not the Web


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An introduction to semantics, RDF, and RDFa, with links to examples.

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  • Semantic Web: A web that is not the Web

    1. 1. The Semantic Web A web that is not the Web for North NJ UX Meetup Bruce Esrig, 11 June 2009
    2. 2. Aspects of the Semantic Web • What is the semantic web? • What happens behind the scenes? • Where can we see semantics in action? • How does semantic technology help? • How can I design some knowledge? • How can I use semantics in Web sites?
    3. 3. Disclaimer • There is lots of material about the semantic web. • You’ll hear the terminology and see some examples. • Each subject requires more investigation to make sense in an actionable way. • If you’re new to this, don’t expect to understand it all the first time through.
    4. 4. What is semantics? • The art of constructing formal answers to the question: “How does this work, really?” • A geek-fest
    5. 5. Semantics in the history of science • Galileo: Who cares what we think it does? Let’s look and see what it really does. • Frege, Peirce, Russell, Whitehead, Hilbert, Goedel: Math is formal, let’s formalize that. Oh, wait a second, math is too hard. • Church, Kleene, Turing, ..., Milner: Maybe we can formalize some sensible sub-domains.
    6. 6. Semantics as a way to model the world An ideal, intermediate layer “Dog” Map to semantic layer Map to reality a real dog
    7. 7. Semantics as a way to model the world The concept of a dog “Dog” Dog friends-with a real dog
    8. 8. Semantics as a way to model the world Dogs as individuals “Maggie” “Molly” friends-with Maggie Molly friends-with one real dog another real dog
    9. 9. What is semantics? Semantics 1. (Profession) A discipline that constructs artificial languages that mediate between the real world and the languages ordinarily used for communication. 2. (Knowledge representation) Any intermediate language constructed for the purpose of explaining the concepts and relationships from the real world that appear in utterances in a particular language used for communication.
    10. 10. What is the Semantic Web? Semantic web 1. (Knowledge representation) The description of concepts and relationships in particular knowledge domains, and the URI-based links among those concepts and relationships 2. (Web 3.0) The use of knowledge to enable semantics-aware behavior on the web
    11. 11. What is semantics? (Introducing FOAF) Here is a statement written in ordinary text: Jimmy Wales knows Angela Beesly Let’s agree to think about it this way: Jimmy Wales and Angela Beesly are each the name of a Person. The first Person knows the second Person.
    12. 12. What is semantics? foaf:knows foaf:Person foaf:Person foaf:name foaf:name Jimmy Wales Angela Beesly
    13. 13. What happens behind the scenes? RDF triples: <foaf:Person rdf:about=quot;#JWquot;> <foaf:knows> <foaf:Person rdf:ID=quot;AngelaBeeslyquot;> . <foaf:Person rdf:about=”#JW”> <foaf:name> “Jimmy Wales” . <foaf:Person rdf:ID=”AngelaBeesly”> <foaf:name> “Angela Beesly” .
    14. 14. What happens behind the scenes? <rdf:RDF xmlns:foaf=quot;; xmlns:rdf=quot;; <foaf:Person rdf:about=quot;#JWquot;> <foaf:name>Jimmy Wales</foaf:name> <foaf:knows> <foaf:Person> <foaf:name>Angela Beesley</foaf:name> <!-- Wikimedia Board of Trustees --> </foaf:Person> </foaf:knows> </foaf:Person> </rdf:RDF> Example is from:
    15. 15. Where can we see semantic modeling in action? Site Semantic Feature Catalog site Taxonomy of departments and offerings Faceted search for items (by body type, size, fit, fabric ...) CSS classes for globalnav, leftnavigation, banners and headings, product, swatches, product name, price
    16. 16. Where can we see the semantic web in action? Site Semantic Feature SearchMonkey accepts uploads of page Search site specification data behind the scenes. For Wikipedia pages, TOC and first image show up in search results. Semi-automatic indexing of Wikipedia Reference site articles (with help from DBpedia). Shows topic and related topics for various properties.
    17. 17. How does semantic technology help? • Enables sites to expose data indicating what their content is about • Enables sites to organize themselves around what their content is about • Enables users to access information according to what it is about • Enables users to establish profiles stating what they care about • Enables sites to offer content their users care about
    18. 18. How can I design some knowledge? As tags: User contributed • Let users tag topics (and fragments) • Look at their tags and promote the useful ones Curated • Figure out what aspects of your topics are significant • Make up tags for each significant aspect, ignoring how the tags might relate to each other or group together • Tag the topics
    19. 19. How can I design some knowledge? As structured data: • Figure out who your individuals are. Be prepared to support a topic or fragment for each individual. • Figure out what the individuals have in common and define groups that individuals can join. • Link the individuals according to what groups they have in common. • If necessary, group the groups. Offer navigation by group. • Figure out what relationships the individuals (or groups) have • Link from one topic to another using the relationships.
    20. 20. How can I use semantics in web sites? Site Semantic Feature RDFa standard example Integrate semantic assertions into a web page. primer/alice-example.html Promotional video (Drupal) Automatic indexing. Better search results based on clues in the content. v=r4WgTRIRoa0 Course reading lists (Plymouth) Indicate relationships among texts. lists/abf203.html Code snippets (Creative Commons) Declare significance of parts of the page. Highlight creative commons licenses. RDFa See “RDFa in the wild” for more examples (in the future).
    21. 21. M eet Semantic Alice Alice Birpemswick Email: Phone: +1 617.555.7332 My buddies: * Bob * Eve * Manu
    22. 22. M eet Semantic Alice <div class=quot;socialnetquot; typeof=quot;foaf:Personquot; about=quot;#mequot;> <p property=quot;foaf:namequot;>Alice Birpemswick</p> <p>My buddies:</p> <ul rel=quot;foaf:knowsquot;> <li typeof=quot;foaf:Personquot;> <a href=quot;; rel=quot;foaf:homepagequot; property=quot;foaf:namequot;>Bob</a></li> <li typeof=quot;foaf:Personquot;> <a href=quot;; rel=quot;foaf:homepagequot; property=quot;foaf:namequot;>Eve</a></li> <li typeof=quot;foaf:Personquot;> <a href=quot;; rel=quot;foaf:homepagequot; property=quot;foaf:namequot;>Manu</a></li> </ul></div>
    23. 23. Extra slides
    24. 24. What happens behind the scenes? <rdf:RDF xmlns:foaf=quot;; xmlns:rdf=quot;; xmlns:rdfs=quot;;> <foaf:Person rdf:about=quot;#JWquot;> <foaf:name>Jimmy Wales</foaf:name> <foaf:mbox rdf:resource=quot;mailto:jwales@bomis.comquot; /> <foaf:homepage rdf:resource=quot;; /> <foaf:nick>Jimbo</foaf:nick> <foaf:depiction rdf:resource=quot;; /> <foaf:interest rdf:resource=quot;http://www.wikimedia.orgquot; rdfs:label=quot;Wikipediaquot; /> <foaf:knows> <foaf:Person> <foaf:name>Angela Beesley</foaf:name> <!-- Wikimedia Board of Trustees --> </foaf:Person> </foaf:knows> </foaf:Person> </rdf:RDF>