This document discusses the development and implications of the Semantic Web. It begins with an overview of the evolution from Web 1.0 to the current Web 2.0 to the envisioned Web 3.0 or Semantic Web. Key aspects of the Semantic Web include linked data through ontologies, metadata, URIs and RDF which will enable more precise, relevant search results and access to data across applications. Challenges include preparing existing web content and data for the Semantic Web. The document provides examples of early Semantic Web applications and initiatives.
Semantic Web (IS 535 presentation) by ITRL students Deborah Ratliff and Marilyn Pontius
1. Semantic Web
Marilyn Pontius and Debi Ratliff
IS 535 Advanced Information Retrieval
Final Project Fall 2011
2. Development of the
Semantic Web
Web 3.0
Web 2.0 • WWW database
• Linked data
• Social networks • Web page
Web 1.0 • Blogs and wikis content from
• Tagging many places
• HTTP • Web pages • Intelligent
• Static HTML web dynamic and personal agents
pages interactive
Desktop
• Databases
Computing • File servers
• Modems
• Networking
Packet Equipment
Switching
• TCP/IP
• Email
• FTP
3. Metadata
Karen Coyle,
“Understanding the
Semantic Web:
Bibliographic Data and
Metadata”. ALA
TechSource.2010.
4. Metadata
Karen Coyle, “Understanding the Semantic
Web: Bibliographic Data and Metadata”.
ALA TechSource.2010.
5. Implications for
Information Retrieval
• The web we know: documents
are linked based on syntactic
structure using HTML; hypertext
is coded with location for linked
document
• Semantic Web: data is linked
based on meaning using XML,
RDF, URIs, and ontologies
6. • The web we know: human
searches, human decides
what’s relevant, retrieved results
often irrelevant
• Semantic Web: machine
readable data searchable by
“agents”, retrieves precise,
relevant results due to ontology,
URI, and RDF
7. Web publishing now: propensity
for production; overload of
information is disorganized and
inaccessible
Semantic Web: linked data will
result in more efficient,
automated searching; more
reuse of information
8. • The web we know: data across
systems is not inter-changeable;
metadata schema in differing
databases preclude retrieval
from outside systems
• Semantic Web: data retrieved
based on meaning, not structure
or syntax; data accessible
across applications
9. • The web we know: Web 2.0
mashups use fixed sets of data
• Semantic Web: will use
unbound, global data
10. Ontology
• Unlike a taxonomy, has “open”
vocabulary in which the creator
of the subject description
language is allowed to define
the language at will(Garshol, 2004, p 384).
• Flexibility allows expression
and description of relationships
between objects
11. RDF
• In order to share and reuse information
between disparate systems, data must be
in the same or similar format or language
• RDF breaks each piece of data down into a
simple three-part statement called a triple.
Each triple has a subject, predicate and
object which is assigned a Unique
Resource Identifier (URI)
• This simple structure allows different
computer applications to read and relate
each triple with other data
• Example: Melville wrote Moby Dick
(subject) (predicate) (object)
12. XML
• The base on which semantic technologies
operate
• Like HTML, XML has strict syntax rules so
that a computer can read and process it
easily and reliably
• RDF & XML allows interoperability
13. Web Ontology
Language (OWL)
• OWL links together triples from
disparate sources and meshes
them with each other
• Results in linked data that can
provide new meaning
• Reuse of data is possible
14. Semantic Web
Readiness
Libraries
Text based MARC
World Wide Web / Semantic Web
Unicode, XML
15. Libraries and the
Semantic Web
• FRBR
Work, Expression, Manifestation, Item
• RDA
Cataloging rules aligned with FRBR
• LOC Subject Authorities
16. Semantic Web
What‘s possible for
Libraries
Providing service where the customers are:
Lincoln
Customer is reading an essay about Lincoln.
Clicks on Lincoln, and a list of books about Lincoln
in their local library is displayed.
Shows what is on the shelf and available, and a
hold is placed (Coyle).
Global Warming
Student enters phrase to search.
Multimedia report returned gathered from validated
sites across the web, including library information
(Ohler).
17. Examples on the Web
• Friend of a Friend (FOAF) http://www.foaf-project.org/
Data on different social network sites are linked together.
• Dbpedia http://wiki.dbpedia.org/OnlineAccess
W3C project to extract structured data from Wikipedia
articles (data in graphs, side tables, etc), make it available
on the web, and link it to other datasets.
• Hakia http://www.hakia.com/ semantic search
engine, includes New Pub Med with a comparison of
Hakia semantic search of Pub Med to keyword indexed
search of same content. MoodTRADE (financial).
Aerohakia (aerospace industry)
• SIMILI http://simile.mit.edu/ MIT libraries and MIT
Computer Science Artificial Intelligence Lab.