Hacking with Semantic Web

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

Hacking with Semantic Web

by tompraison on Aug 17, 2012

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