Semantic Web Presented by: Edward Cheng Wayne Choi Tony Deng Peter Kuc-Pittet Anita Yong

Agenda  Introduction  Semantic Web components  Example  Pros/Cons

The Current World Wide Web  Network of hypertext documents containing text, images, audio, and video  Is readable and understandable by humans, but only readable (via parsing) by machines  What is missing is this understanding of the semantics  For example vs.

Semantics  The definition of semantics is meaning  The idea is to give a keyword (or a subject) a definition  These definitions are then related to objects  Humans do this easily but often make mistakes, so to have computers perform these operations would eliminate mistakes  Does not mean that there are no mistakes in the algorithms used, but idea is that using the logic of Semantic Web these errors could be caught

What is Semantic Web?  Tim Berners-Lee’s vision of a network of data fully understandable by machines without requiring human intervention  Standardized way of defining relations between things that have meaning  A globally and semantically linked network of information underlying the current Web

Wedding Cake

Components  Unicode:  A standard and universal way of encoding text  URI (Uniform Resource Identifier) :  A unique string identifying a name or resource  XML (Extensible Markup Language) :  Used to describe and communicate data

Components  Namespaces:  A way of encapsulating a vocabulary  XML Query:  Used to extract data from an XML document  XML Schema:  A description of an XML document, imposing constraints on its content and structure

Components  RDF Model (Resource Description Framework) :  Makes a statement about a resource using a (subject, predicate, object) URI triple  (  Santa is interested in Wikipedia’s dieting entry

Ontology  An ontology is a data model that describes individuals, classes, attributes, and relations  RDF schema is the base RDF ontology, putting constraints on an RDF subject’s relationship to an object for a given predicate  foaf:person foaf:knows foaf:person  foaf:image foaf:knows foaf:person  OWL (Web Ontology Language):  A more complicated and expressive ontology than RDF Schema  Three forms: OWL Lite, OWL DL, OWL Full

Querying  A Semantic Web query connects to multiple RDF dataset agents to gather information, and returns the set of best matched results. Cheapest Support Labour? North American Firm A North American Firm B Overseas Firm A Agent

Bob: Book doctors appointment Target: Person Type: Patient Type: Bob Type: Doctor Type: Rick Target: Hospital Employee Target: Schedule Time Type: Sched Time

Pros  Searching with semantic meaning and relations  Agents (programs) acting as intermediaries to meet user needs  Better knowledge management as data is connected in meaningful ways

Cons  Need to maintain two different versions of web content – a machine readable version and a human interaction version  Only useful if Semantic Web is adopted by the masses

Questions?