Introduction to the Semantic WebPresentation Transcript
The Semantic Web - a useful, usable technology? Liddy Nevile La Trobe University
The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries. It is a collaborative effort led by W3C with participation from a large number of researchers and industrial partners. It is based on the Resource Description Framework ( RDF ), which integrates a variety of applications using XML for syntax and URIs for naming. - W3C
WWW2004 Semantic Web Track and Devday Presentations Online 2004-05-26 ,The W3C Track on the Semantic Web and the Semantic Web Developers Day presentations are now online. These presentations provide a status update on the Semantic Web Activity at the W3C and highlight examples of industry adoption and novel applications using Semantic Web technologies.
See http://www.w3.org/2001/ sw /
"The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation. ” -- Tim Berners-Lee, James Hendler, Ora Lassila, The Semantic Web , Scientific American, May 2001
A use case
DCMI has elements, terms, schemata, as well as growing sets of documents. All these need to be managed. What happens when new terms are created, when new documents are generated?
Can the semantic web technology being developed make this nightmare of human management an automated task?
A better question …
Can metadata become operational so it does some of the things that we have had to do to it in the past?
Instead of having to develop applications to sort and shift information about, can we get the information to do that work for us?
General Public (on the Web) Users (with middle wear/ AT / Browsers) Website Your Current Website Semantic Annotations, Automatic Fixes, Database views Engine Layer of Meaning Presentational Layer Alternative versions Untouched original
Before…. As see on the Web Navigation Bar made with images-only. Completely inaccessible to assistive technology. Relationship between text and form elements inaccessible to assistive technology.
After…(1) Meaning behind images is known Relationship between text and form elements is known Enhanced Navigation for screen readers, PDA’s and orientation As see on the Web
Middleware Architecture (taken from SWAP) Original HTML SWAP ML Translation rules Semantic annotations Data Base XHTML Scenario-specific transformations XHTML XHTML XHTML Original presentation Extract presentation Scenario-specific CSS Rules and transformations
Additional layers of information
Provide meanings of terms
Provide relationship information
Links to relevant information
Links to relevant people
Allow software agents to manipulate this information
Ontology defines terms
Resource Description Framework (RDF)
Language for semantic web
Not just machine readable information
Also machine understandable information
<? xml version="1.0" ?> <rdf:RDF xmlns:rdf=" http://www.w3.org/1999/02/22-rdf-syntax-ns# " xmlns:s=" http://description.org/schema/ "> <rdf:Description about=" http://www.w3.org/Home/Lassila " bagID=" D_001 "> <s:Creator> Ora Lassila </s:Creator> <s:Title> Ora's Home Page </s:Title> </rdf:Description> </rdf:RDF>
System of concepts and relations between them:
Table [is piece of] furniture
Arm [is part of] body
Japan [is located in] East Asia
A method for storing and representing knowledge
EGs of types of annotations
Meaning behind text gaps – text equivalents
Relationship to applications – no frames / functional equivalents
Relationship between text nodes and form elements - accessible forms and labels
Structural identification of page elements - orientation
Role information – this is a data, types of content
Concepts – implied content
Resolving ambiguities and relative importance – simplifications
Plus interpretation = communication of knowledge
Relationships and meanings
This picture has meaning of welcome
This picture is a link to the home page
This color code implies feminine relevance
This list of links is similar to a main menu
This format is similar to a title
This paragraph is less important for this user group
The word ‘it’ refers to the table
an ontology for accessibility
a authoring tool for creating RDF using this ontology for specific pages
a user agent that renders accessible pages based on our ontology
a flexible testing tool
Roles and rel’ships (predicates)
IsBlock - point to a block of links (is included in V1 of SWAP) and associates a content type
BelongsToBlock - associates link or section of content with a block (IsBlock) (is included in V1 of SWAP)
ContentType - associates a section of content or link with a content type
Header - points to link block header, Can also associate a block of links (sub-menu) with a parent menu, etc
SubmenuOf - associates a sub-menu with main menu
Association – Implied meaning behind the content and presentation
Warning (less safe)
Annotation Based Accessibility
Provide conditional alternate content
Address traditionally problematic areas in accessibility
Interfaces for cognitive / age related disabilities
Summaries, clarifications and illustrations for these disabilities can be hidden..
Address emerging accessibility issues
Schemas can be annotated
Elements can be marked as “similar”..
What else can it do?
Allow anyone to annotate any document with alternatives
Attach a user profile to alterative content
Concept mapping / sign and symbols
Remove ambiguity in language
Knowledge systems integration
Support for internationalization / localization and translation ….
Quinkan Example 1
Translation .. service
Tommy George inspecting red rock ochre. "A lot of paintings are made in red."