INLS 520 – Fall 2007 Erik Mitchell INLS 520 Information Organization

INLS 520 – Fall 2007 Erik Mitchell Today Ontology Presentations The Semantic web & information organization –Linked data –Democratization of data –Ideas & discussion, Examples, Play time Yahoo Pipes

INLS 520 – Fall 2007 Erik Mitchell Overview - Semantic Web Semantic Web –“The Semantic Web is an extension of the current Web that will allow you to find, share, and combine information more easily. It relies on machine-readable information and metadata expressed in RDF.” DefinitionsDefinitions –Tim Berners-Lee InterviewTim Berners-Lee Interview

Semantic Web elements Actions / Uses –Discovery –Knowledge Organization –Automation –Data use/re-use –Integration –Structured meaning Concepts –Linked Data –Socio-Semantic Web –Ontologies Technology –OWL –RDF –SPARQL INLS 520 – Fall 2007 Erik Mitchell

Technology RDF – Resource description framework –Statements about resources OWL – Web Ontology Language –Defined language to express relationships SPARQL – Query Language for RDF –Standard method of querying RDF data INLS 520 – Fall 2007 Erik Mitchell

XML/RDF INLS 520 – Fall 2007 Erik Mitchell <rdf:RDF xmlns:rdf=" xmlns:contact=" Eric Miller Dr.

FOAF Friend of a friend –Metadata standardMetadata standard –RDF syntax –Open Content foundation FOAF creator FOAF your facebook profile –ExampleExample Uses? INLS 520 – Fall 2007 Erik Mitchell

RDFa –Half-way between HTML & RDF –Uses defined attributes to add context to HTML elements rel property typeOf –ExampleExample INLS 520 – Fall 2007 Erik Mitchell

Linked Data? Guiding principles –Content/Data is indentified with URIs –URIs on the web are easily retrieved –URIs can have useful/structured information –URI located content can contain other URIs Linked Data Browser Tabulator –Example Linked data siteExample Linked data site –Library of CongressLibrary of Congress INLS 520 – Fall 2007 Erik Mitchell

INLS 520 – Fall 2007 Erik Mitchell Semantic Web examples Form into 4 groups Investigate assigned site / organization Answer the questions Report back

Discussion Questions INLS 520 – Fall 2007 Erik Mitchell What is the site about? What about this site is ‘semantic web’ related? Is this a good or bad example of the semantic web? Can you think of something more relevant/interesting?

INLS 520 – Fall 2007 Erik Mitchell Miscellaneous Description Weinberger’s points –Idea of ‘democratized’ description –The Long tail – getting past primary topicality –Lumping & splitting, lists, categories, the ‘third order” Two sides of community description / software –Provide a place to create/share –Provide a means to harvest / remix

Open Standards “Specifications that are public-that is, not owned by any company or individual”(1)1 Source “A program in which the source code is available to the general public for use and/or modification from its original design free of charge” (2)2 Content “The term "Open Content" is used for creative works which are published without or at least under alleviated copyright restrictions” (3)3 Access A publication model where in neither readers nor a reader's institution are charged for access to articles or other resources (4)4 INLS 520 – Fall 2007 Erik Mitchell

INLS 520 – Fall 2007 Erik Mitchell Remix Culture –A society which allows and encourages derivative works. Such a culture would be, by default, permissive of efforts to improve upon, change, integrate, or otherwise remix the work of copyright holders (Wikipedia) - Lawrence Lessig Mashups –Consists of the combination (usually by digital means) of the music from one song with the a cappella from another. Typically, the music and vocals belong to completely different genres. At their best, bastard pop songs strive for musical epiphanies that add up to considerably more than the sum of their parts An example

INLS 520 – Fall 2007 Erik Mitchell Remixing data Common features –APIs enable access to data/functionality outside of traditional interface –Open licensing agreements enable re-use of data –Organization and encoding standards enable interoperability

INLS 520 – Fall 2007 Erik Mitchell Yahoo Pipes exercise Go to

INLS 520 – Fall 2007 Erik Mitchell Adding functionality Facebook applications –Facebook developers kitFacebook developers kit Yahoo Widgets –Some brief infoSome brief info Microsoft Silverlight The programmable web

INLS 520 – Fall 2007 Erik Mitchell What’s interesting about this? Google support –IDE, Hosting, Data storage, Marketing Facebook –Application platform, exposure Amazon –Data, storage systems, commerce applications, APIs

INLS 520 – Fall 2007 Erik Mitchell Next Week Final week –Poster presentations –Group work evaluation –Wrap-up

INLS 520 – Erik Mitchell RDF Subject, property, object triples Transmitted in xml RDFS extends RDF with an ontology language –Properties, specialization OWL –More powerful extension of RDFS –Uses same syntax of RDF

INLS 520 – Erik Mitchell RDF Model Webpage: “Saki Knafo” Author (Value) Object (Property type) Predicate (Resource) Subject “The author of the stuff webpage is Saki Knafo” - A literal, a triple, a statement

INLS 520 – Erik Mitchell How is RDF different? RDF is a descriptive model that –Allows variable contextualized description –Deconstructs the descriptive process –Allows more granular automated processing of data –Uses exact markup to indicate the context of values (namespaces, schemas) –Bags, Sequences, Alternative values, parseType

INLS 520 – Erik Mitchell Encoding RDF in XML <rdf:RDF xmlns:rdf=" xmlns:dcterms=" xmlns:dc=" xmlns:rdfs=" The Hang: The Island of Black Jeans SAKI KNAFO Sun, 16 Sep :04:40 GMT descriptive content

INLS 520 – Erik Mitchell Iterative RDF description <rdf:RDF xmlns:rdf=" xmlns:vcard=" card.xsd" xmlns:dc=" xmlns:rdfs=" The Hang: The Island of Black Jeans Sun, 16 Sep :04:40 GMT descriptive content rdf:about=" Saki Knafo

INLS 520 – Erik Mitchell RDFS RDF Schema –Defines additional rdf elements that help type relationships Special Classes –Based on RDF Classes / Properties / Attributes with additional Allows the creation of vocabularies / ontologies

INLS 520 – Erik Mitchell OWL (Web Ontology Language) An ontolgy that is geared towards representing information on the web –Classes, properties, and relationships that describe URIs and their facets. Based on the Triple concept –Subject, Predicate, Object –3 versions: OWL-Lite, OWL-DL, OWL-Full Formatted in RDF/XML –Uses RDF and RDFS as a foundation –Adds new elements in the owl namespace

INLS 520 – Erik Mitchell OWL Versions OWL-Lite –Simple hierarchies, constraints OWL-DL –Uses description logics Logic-based semantic markup based on first-order predicate logic –Still guarantees finite relationship processing –Adds ‘reasoning’ capacity to infer information/relaitonships OWL-Full –Most complex –Open ended, possible to get into infinite processing

INLS 520 – Erik Mitchell OWL Example <rdf:RDF xmlns:rdf= xmlns:rdfs=" xmlns:owl= xmlns= xml:base=" 1.0 An ontology containing the basic part relations: partOf, hasPart, partOf_directly, and hasPart_directly. These are described in the accompanying note. Author: Chris Welty (Chris Welty)

OWL – Lite features Class A collection of things related to each other by properties rdfs:subClassOf A way of showing hierarchical class relationships rdf:Property A stated relationship between an thing and a value (hasChild, hasRelative, hasSibling, hasAge) Bi-directional, Transitive (hasAncestor), Rdf:subPropertyOf Similar to subClassOf, a way of showing property hierarchies Individual Instances of classes (objects) INLS 520 – Erik Mitchell

OWL relationships INLS 520 – Erik Mitchell Practical guide to OWL ontologies