4. To lead the World Wide
Web to its full potential
by developing protocols
and guidelines that
ensure long-term
growth for the Web.
—W3C, Mission
The World Wide Web
Consortium (W3C) is the main
international standards organization for
the World Wide Web (W3).
W3C has sixteen World Offices covering Australia, the
Benelux countries (the Netherlands, Luxemburg, and Belgium),
Mainland China, Finland, Germany and Austria, Greece, Hong
Kong, Hungary, India, Ireland, Israel, Italy, Japan, South Korea,
Korea, Morocco, Spain, Sweden, the United Kingdom and the
United States.
7. • XML provides a surface syntax for structured
documents, but imposes no semantic constraints
on the meaning of these documents.
• XML Schema is a language for restricting the
structure and content elements of XML
documents.
• RDF is a simple data model for referring to
objects ("resources") and how they are related.
An RDF-based model can be represented in XML
syntax.
• OWL adds more vocabulary for describing
properties and classes: among others, relations
between classes
8. A Uniform Resource Identifier (URI), is a
compact string of characters used to identify or
name a resource.
For example, the URL http://www.wikipedia.org/ is
a URI that identifies a resource (Wikipedia's
home page) and implies that a representation of
that resource (such as the home page's current
HTML code, as encoded characters) is obtainable
via HTTP from a network host named
www.wikipedia.org.
Uniform Resource Identifier (URI)
9. Syntax
"http", "ftp", "mailto", "urn", "mms", "rtsp", etc., followed by a
colon character, and then a scheme-specific part.
Examples of absolute URIs
http://somehost/absolute/URI/with/absolute/path/to/resource.txt
ftp://somehost/resource.txt
urn:issn:1535-
Examples of URI references
http://example/resource.txt#frag01
10. Resource Description Framework
(RDF)
The RDF metadata model is based upon the idea of
making statements about resources in the form of subject-
predicate-object expressions, called triples in RDF
terminology.
Basic RDF Model
Example:
Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila.l
15. Applications
1. FOAF (Friend of a Friend) - designed to describe people,
their interests and interconnections.
2. Many other RDF schemas are available by searching
Schema Web
16. What is XML?
• XML stands for EXtensible Markup Language
• XML is a markup language much like HTML
• XML was designed to describe data
• XML tags are not predefined. You must define your own tags
• XML uses a Document Type Definition (DTD) or an XML
Schema to describe the data
• XML with a DTD or XML Schema is designed to be
self-descriptive
• XML is a W3C Recommendation
• XML is an extension from SGML.
• XML is extended to XHTML, RSS, Atom, ...
17. Features of XML
1. XML can Separate Data from HTML
With XML, your data is stored outside your HTML.
2. XML is Used to Exchange Data
With XML, data can be exchanged between incompatible
systems.
3. XML and B2B
With XML, financial information can be exchanged over the
Internet.
4. XML Can be Used to Share Data
With XML, plain text files can be used to share data.
5. XML Can be Used to Store Data
With XML, plain text files can be used to store data.
6. XML Can Make your Data More Useful
With XML, your data is available to more users.
7. XML Can be Used to Create New Languages
XML is the mother of WAP and WML.
18. Strengths of XML
Some features of XML that make it well-suited for data transfer are:
• It is simultaneously human and machine-readable format;
• It supports Unicode, allowing almost any information in any written human
language to be communicated;
• The strict syntax and parsing requirements make the necessary parsing
algorithms extremely simple, efficient, and consistent.
XML is also heavily used as a format for document storage and processing, both
online and offline, and offers several benefits:
• Its robust, logically-verifiable format is based on international standards;
• It is platform-independent, thus relatively immune to changes in technology;
Weaknesses of XML
1. Generic XML parsers must be able to recurse arbitrarily nested data structures and
may perform additional checks to detect improperly formatted or differently ordered
syntax or data
Eg: Embedded Applications.
19. The XML Example Document
Look at the following XML document ("cd_catalog.xml"),
that represents a CD catalog:
<?xml version="1.0" encoding="ISO-8859-1"?>
<CATALOG>
<CD>
<TITLE>Empire Burlesque</TITLE>
<ARTIST>Bob Dylan</ARTIST>
<COUNTRY>USA</COUNTRY>
<COMPANY>Columbia</COMPANY>
<PRICE>10.90</PRICE>
<YEAR>1985</YEAR> </CD>
.
.
.
more ....
20. The Main Difference Between XML and HTML
XML was designed to carry data.
1. XML is not a replacement for HTML.
XML and HTML were designed with different goals:
2. XML was designed to describe data and to focus on what data is.
HTML was designed to display data and to focus on how data looks.
3. HTML is about displaying information, while XML is about describing
information.
XML Does not DO Anything
XML was not designed to DO anything.
XML is Free and Extensible
XML tags are not predefined. You must "invent" your own tags.
XML is a Complement to HTML
XML is not a replacement for HTML.
XML is going to be everywhere.
21. Ontology Web Language (OWL)
OWL is based on earlier languages OIL and DAML+OIL, and is now
a W3C recommendation (i.e., a standard).
OWL is written in XML.
OWL was developed mainly because it has more facilities for
expressing meaning and semantics than XML, RDF.
History:
W3c recommended OWL group in NOV 1,2001 by James Hendler.
22. Sublanguages :
OWL Lite supports those users primarily needing
a classification hierarchy and simple constraints.
OWL DL supports those users who want the
maximum expressiveness while retaining
computational completeness and decidability.
OWL Full is meant for users who want maximum
expressiveness and the syntactic freedom of RDF
with no computational guarantees.
