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Hacking with Semantic Web
 

Hacking with Semantic Web

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    Hacking with Semantic Web Hacking with Semantic Web Presentation Transcript

    • Hacking with Semantic Web Tom Praison Developer @ Yahoo! http://twitter.com/tompraison
    • What’s in here?• Evolution of the web• Poorly Solved Information Needs• Semantic Web Technologies• Linked Data• Demo of confhopper.in, a site built using open datasets• Some techniques for getting Structured Information from Web.• Demo of Yahoo! Contextual Analysis Platform and Open Dapper
    • I just had to take the hypertext idea and connect it to the Transmission Control Protocol and domain name system ideas and—ta-da!—the World Wide Web.Tim Berners Lee – Inventor of the WWW
    • WEB 1.0Few Content Creators! Majority Consumers! http://www.flickr.com/photos/leandrociuffo/3665883373/
    • WEB 2.0 Web as a platform http://www.flickr.com/photos/lambertwm/4737580179/
    • WEB 1.0 vs WEB 2.0 Ofoto Flickr Personal Website Blogging Britannica Online WikipediaDirectories(taxonomy) Tagging(“folksonomy”)Content Management Wikis Systems
    • WEB 3.0 Which direction will it take? http://www.flickr.com/photos/markhillary/337685031
    • Semantic WebVirtual Web WEB 3.0 Pervasive Web Could be anything! Artificial Personalization Intelligence
    • Today’s WebA Web of Documents rather than Data!
    • Poorly Solved Information Needs• Multiple interpretations – Apple• Long tail queries – Roja (I meant a south indian actress)• Imprecise or overly precise searches – jim hendler – pictures of strong adventures people• Searches for descriptions – countries in africa – 25 year old computer engineer living in Bangalore – Reliable smart phone under 15,000 rupees
    • THE SOLUTION Semantic Web
    • Publish data on the Web• Linked Data: linking data similar to how we link documents on the Web• Query databases over the Web
    • Architectural Challenges• A common format for sharing data• Sharing the meaning of data• Infrastructure
    • Semantic Web standards from W3C• Data and schema languages (RDF, OWL, RIF)• Document formats (RDF/XML, RDFa)• Protocols (SPARQL, HTTP)
    • Current Researches & Other Efforts• Semantic Web research into knowledge representation and reasoning, data integration, data quality and many other topics• Community effort (Linked Data movement)
    • 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)
    • Graphical and textual notation foaf:Person type my:Joe name “Joe A.”A number of ways to serialize an RDF model into an RDF document RDF/XML, Turtle, N3, N-Triples
    • RDF is designed for the Web• URIs provide web-wide global identification across datasets – A resource may be described by multiple documents – URIs are intended to be reused – Unique, but not single identifiers: two URIs may denote the same thing
    • RDF is designed for the Web• URIs can be retrieved from the Web – 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: http://xmlns.com/foaf/0.1/Person redirects to the specification
    • URIs implicitly link data together (#joe, #loves, #mary)(#joe, #name, “Joe A.”)(#joe, #email, mailto:joe@joe.com) A social networking site (#mary, name, “Mary B.”) Joe’s homepage (#mary, gender, “female”) Mary’s homepage (#name, #type, #Property) (#name, #domain, #Person) Schema doc
    • Put together, triples form a single ‘global’ graph #name “Joe A.”#joe #email “joe@joe.com” #loves #name “Mary B.” #mary #gender “female”
    • RDF Example
    • Linked Data cloud: interlinked RDF datasets on the Webhttp://linkeddata.org/
    • DBPedia• Dbpedia is dataset that contains much of the structured data in Wikipedia – Data from the info-boxes – Links between Wikipedia pages – Categories – Disambiguation and redirect pages• Links to other datasets
    • Fetching individual resources• Use your web browser • http://dbpedia.org/resource/Yahoo redirects to http://dbpedia.org/page/Yahoo • You can plug in this URI into other Linked Data browsers• HTTP GET to fetch data – Using curl: add Accept: application/rdf+xml for RDF and enable redirect • curl -L -H Accept:application/rdf+xml http://dbpedia.org/resource/Berlin’• Data dumps – http://wiki.dbpedia.org/Datasets
    • Querying using SPARQL• Interactive query builders • SPARQL Explorer: http://dbpedia.org/snorql/ • Examples at: http://wiki.dbpedia.org/OnlineAccess• Using HTTP GET – GET /sparql/?query=EncodedQuery HTTP/1.1 – Example: • SELECT ?film ?x WHERE { ?film <http://dbpedia.org/ontology/language> <http://dbpedia.org/resource/French_language> . ?film <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Film>} • curl http://dbpedia.org/sparql?query=encodedQuery’
    • ConfHopper.in• Award winning app in WWW2012 Metadata Challenge.• Confhopper.in is a desktop / mobile HTML5 based application designed for conference attendees.• Built with the help of open datasets from http://data.semanticweb.org/ and various other sources.
    • Some Techniques for getting Structured Information from Web• Semantic Markup• NER• Extraction Tools (Dapper)
    • Semantic Markup• Microdata (Schema.org)• RDFa• Open Graph Protocol (ogp.me)• Example: http://getschema.org/microdataextractor?url =http://www.tompraison.com&out=json
    • NER – Named Entity Recognition• Yahoo! Content Analysis API• http://developer.yahoo.com/contentanalysis/
    • Dapperhttp://open.dapper.netDapper is a tool that enables users to create update feeds fortheir favorite sites and website owners to optimize anddistribute their content in new ways.
    • References• http://www.slideshare.net/tompraison• http://inkdroid.org/journal/2010/06/04/the- 5-stars-of-open-linked-data/• http://www.freebase.com/• http://dbpedia.org/About