Your SlideShare is downloading. ×
Hack U Barcelona 2011
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.

Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Hack U Barcelona 2011


Published on

Very brief intro to Semantic Web and BOSS for a Yahoo! Hack U event at UPC in Barcelona, Spain.

Very brief intro to Semantic Web and BOSS for a Yahoo! Hack U event at UPC in Barcelona, Spain.

Published in: Technology, Education

  • Be the first to comment

  • Be the first to like this

No Downloads
Total Views
On Slideshare
From Embeds
Number of Embeds
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

No notes for slide


  • 1. Fun with the Semantic Web
    Peter Mika
    Yahoo! Research Barcelona
  • 2. Vague, but exciting… Berners-Lee and the dawn of the Web
  • 3. Semantic Web
    Publish data on the Web
    Linked Data: a web of data instead of web ofdocuments
    Query databases over the Web
    Two main architectural challenges
    A common format for sharing data
    Sharing the meaning of data
    Semantic Web standards from W3C
    Data and schema languages (RDF, OWL, RIF)
    Document formats (RDF/XML, RDFa)
    Protocols (SPARQL, HTTP)
    Semantic Web research into knowledge representation and reasoning, data integration, data quality and many other topics
    Community efforts to publish data and develop schemas (Linked Data)
  • 4. RDF (Resource Description Framework)
    The basic data model of the Semantic Web
    A universal model to capture all sorts of data: networks, relational, object-oriented…
    Basic unit of information is a triple
    A tuple of (subject, predicate, object)
    Example: (Joe, loves, Mary)
    Each triple gives the value of a property for a given resource or relates two objects to one another
    Object is either a resource or a literal
    An RDF model is a set of triples
    Ordering of statements in an RDF document is irrelevant (unlike XML)
  • 5. Resources vs. literals
    Resources are identified by a URI or otherwise the are called a blank node
    URIs are a generalization of URLs
    Notation: <> or ex:Person
    Literals have an optional language and datatype (string, integer etc.)
    Literals can not be subjects of statements
    Datatypes are identified by URIs, e.g. XML Schema datatypes
    Two literals are the same if their components are the same
    Notation: “Joe B.” or Joe@en^^http://…#string
  • 6. Graphical and textual notation
    “Joe A.”
    A number of ways to serialize an RDF model into an RDF document
    RDF/XML, Turtle, N3, N-Triples
  • 7. RDF is designed for the Web
    URIs provide web-wide global identification across datasets
    A resource may be described by multiple documents
    We know it’s the same resource because the same URI is used or through reasoning (advanced topic…)
    URIs are intented to be reused
    Unique, but not single identifiers: two URIs may denote the same thing
    URIs are dereferencable (can be retrieved)
    A well-behaved URI returns a description of the resource
    Provides authority: the definition of foaf:Person lives at that URI
    Ontologies can be looked up as well
    Typically at the root of the URIs, also known as the namespace
    Example: redirects to the specification
  • 8. URIs implicitly link data together
    (#joe, #loves, #mary)
    (#joe, #name, “Joe A.”)
    (#joe, #email,
    A dating site
    (#mary, name, “Mary B.”)
    (#mary, gender, “female”)
    Joe’s homepage
    Mary’s homepage
    (#name, #type, #Property)
    (#name, #domain, #Person)
    Schema doc
  • 9. Put together, triples form a single ‘global’ graph
    “Joe A.”
    “Mary B.”
  • 10. Linked Data
    Open your data
    Publish it in RDF, the lingua franca of the data web
    Data first, schema second
    Worry about linking, data integration later… someone else can do it for you!
    Optionally, provide query access using the SPARQL query language and protocol
    Powerful, SQL-like query language
    HTTP or SOAP protocol to communicate with SPARQL servers
  • 11. Linked Data cloud: interlinked RDF datasets on the Web
  • 12. Dbpedia
    Dbpedia is dataset that contains much of the structured data in Wikipedia
    Data from the info-boxes
    Links between Wikipedia pages
    Disambiguation and redirect pages
    Links to other datasets
  • 13. Fetching individual resources
    Use your web browser redirects to
    You can plug in this URI into other Linked Data browsers
    HTTP GET to fetch data
    Using curl: add Accept: application/rdf+xmlfor RDF and enable redirect
    curl -L -H 'Accept:application/rdf+xml' '’
    Data dumps
  • 14. Querying using SPARQL
    Interactive query builders
    SPARQL Explorer:
    Examples at:
    Using HTTP GET
    GET /sparql/?query=EncodedQuery HTTP/1.1
    curl '’
    Result type is an XML document
  • 15. More data
    New York Times
    Example URI:
    Also supports JSON
    Append .json or set Accept:text/javascript
    Example URI
    Data dump
  • 16. And more data…
    Geonames: open geo data
    Open Government data efforts
  • 17. Spanish open gov’t data and linked data efforts
    Spanish open data efforts
    La AsociaciónEspañola de Linked Data (AELID)
    Regional/local efforts (RDF, SPARQL) (RDF, SPARQL) (RDF) (RDF)
    Competition AbreDatos 2010
  • 18. More info
    Segaran et al.: Programming the Semantic Web, O’Reilly, 2010.
    W3C Semantic Web Activity
    Presentations, guides etc.
    RDF Primer
    SPARQL query language and protocol specs
    Search SlideShare etc. for more intro material
  • 19. Build your Own Search Service (BOSS)
    Peter Mika
    Yahoo! Research Barcelona
  • 20. Innovate with Search!
    It’s really simple…
    pay $0.0008 for a query, earn $0.01 per query
    100,000 users a day, each making 1 query a day
    Earn $920 dollars a day!
  • 21. Yahoo BOSS: Yahoo’s Search API
    Ability to re-order results and blend-in addition content
    No restrictions on presentation
    No branding or attribution
    Access to multiple verticals (web search, image, news)
    Spelling suggestions
    40+ supported language and region pairs
    Pricing (BOSS)
    10,000 free queries a day
    Pay for more queries
    Serve any ads you want
    For more info,
    New in BOSS v2
    Powered by Bing
    Retrieve ads from Yahoo! and earn money ;)
  • 22. Using BOSS
    Simple HTTP GET calls, no authentication
    Get an Application ID at
  • 23. Queries you can play with
    Yahoo!’s WebScope program
    Data sharing with universities and research institutions
    Some of the most exciting data that we have!
    Request access online
    Requires approval by Department Chair
    For HackU, you can sign up here for access to a dataset containing real world user queries
    Yahoo! Search Tiny Sample v1.0: a set of 4,500 queries
    Ideal for testing and demonstrating your search-based apps
    Can you really show something interesting for all these users?