Semantic Web Presented by: Edward Cheng Wayne Choi Tony Deng Peter Kuc-Pittet Anita Yong.
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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
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 (http://santa.com, http://xmlns.com/foaf/0.1/#term_interest, http://en.wikipedia.org/wiki/Dieting http://santa.com http://en.wikipedia.org/wiki/Dietinghttp://santa.com http://en.wikipedia.org/wiki/Dieting 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