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The Semantic Web. Jonathan Jackson GCUU Master’s Seminar Spring 2005. Agenda. Background Information Story Problem Statement What is the Semantic Web What can the Semantic Web do What’s out there now Conclusion. Background.
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The Semantic Web Jonathan Jackson GCUU Master’s Seminar Spring 2005
Agenda • Background Information • Story • Problem Statement • What is the Semantic Web • What can the Semantic Web do • What’s out there now • Conclusion
Background • The World Wide Web is one of the leading sources of information • Not all information on the WWW is accurate or important to a given search • Searching the WWW for information can be long and frustrating • It would be nice to have a way of automating this
The Current Internet • Web Pages contain information know as metadata • This information provides a description of the content of the page • Metadata is normally used by search engines
The Current Internet • Not all pages contain metadata • Data that describes pages has no set format • Descriptions of content have no meaning other than what people and understand intuitively
Story • Would like to make an appointment with a dentist • Would like a program that can find a dentist within 10 miles of office • Make an appointment as soon as possible within one of the available time periods
Story • Programs would have a hard time searching the WWW for information and providing these types of services • This is due to the disorganization of information
Problem Statement • Is there a way to formalize information on the WWW • Would a developer be able to provide meaning to descriptions on web pages • Could this be done in a way that would make automation easy
What is the Semantic Web • A framework for organizing information in a formal matter • This framework provides structure to information along with the ability to make inferences based on the data • Using a formal framework allows programs to extract and analyze information more efficiently
The Semantic Web • RDF - provides syntax • Ontologies - analysis of information • Agents - programs created for Semantic Web use
Resource Descriptive Framework (RDF) • Provides syntax for the Semantic Web • Object-oriented system • Made up of sets of triples • Each triple consists of a subject, object, predicate
RDF Examples Animal rdf:type rdf:Class Human rdfs:subClassOf Animal Dog rdfs:subClassOf Animal Duck rdfs:subClassOf Animal
Example Steve rdf:type Human Daffy rdf:type Duck Pluto rdf:type Dog
Example • We can also add relationships between objects on a page owns rdf:type rdf:Property Steve owns Pluto
RDF • Use the RDF to describe the information that is read by people • The structure provided by RDF is similar to the structure that the reader creates in his head • i.e., On Steve’s page, we know that Steve is a person and he owns a dog named Pluto
Ontologies • Give meaning and express relationships between words • Ex. Want to find a dentist with the “zip code” 11575
Ontologies • Can create inferences about the data • Ex. Want to find the names of secondary relatives of a student • Problem: Agents can still become confused
Ontologies:Problems • People can use different ontologies for the same purposes • Can still have ambiguity of meaning • How does one give meaning to words • Easy for restricted domains but very difficult of larger domains
What’s Out There Now? • Retsina • Calendar/Organizer agent • Uses Semantic Web and M$ Outlook • Allows users to view schedules, book meetings, and email
What’s Out There Now • MusicBrainz • Database-driven website that stores information about music artists and their work • Semantic Web version of CDDB (Gracenote)
Conclusion • The Semantic Web is a promising idea • The Semantic Web framework does not solve problems of misinformation • The problems involves with ontologies are similar to those in AI and do not look to be solved any time soon • Agents will work well in small domains but will suffer as generality increases