Introduction to semantic web. Includes its goal, features, why we need, semantic web related framework, RDF's, Advantages, Uniform resource locator, web ontology language, micro-formats.
2. Web We Know
Target consumers: humans
web 2.0 mashups provide some improvement
Rules about the structure and visualization of information,
but not about its intended meaning
Intelligent agents can’t easily use the information
Granularity: document
One giant distributed file system of documents
One document can link to other documents
Integration & reuse: very limited
Cannot be easily automated
Web 2.0 mashups provide some improvement
3. Limitations of Current Web
Finding information
Data granularity
Resource identification
Aggregation & reuse
Data integration
Inference of new information
4. The Need For Smarter Web
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.
The Semantic Web is a mesh of data that are
associated in such a way that they can easily be
processed by machines instead of human operators. It
can be conceived as an extended version of the existing
World Wide Web, and it represents an effective means
of data representation in the form of a globally linked
database.
5. Building Semantic Web
The Semantic Web is driven by the World Wide Web
Consortium (W3C). It builds on W3C's Resource
Description Framework (RDF), and is usually designed
with syntaxes that use Uniform Resource Identifiers
(URIs) to represent data. These syntaxes are known as
RDF syntaxes. The inclusion of data to RDF files
enables computer programs or Web spiders to search,
discover, collect, assess and process the data on the
Web.
6. Goals Of Semantic Web
The key goal of the Semantic Web is to trigger the
evolution of the existing Web to enable users to
search, discover, share and join information with less
effort.
The Semantic Web can be considered a vision for the
future in which data could be quickly interpreted by
machines, allowing them to carry out numerous
tedious tasks related to discovering, blending, and
taking action on the information available on the Web.
7. The Semantic Web
Target consumers: intelligent agents
Explicit specification of the intended meaning
information
Intelligent agents can make use the information
Granularity: resource/fact
One giant distributed database of facts about resources
One resource can be linked (related) to other resources
Integration & reuse: easier
Resources have unique identifiers
With explicit semantics transformation & integration can
be automated
8. Vision of Semantic Web
Data should be accessed using the general Web
architecture (e.g., URI-s, protocols, …)
Data should be related to one another just as
documents are already
Data to be shared and reused across
Data to be processed automatically
New relationships between pieces of data to be
inferred
10. Resource Description Framework
A simple data model for
Formally describing the semantics of information in a
machine accessible way
representing meta-data (data about data)
A set of representation syntaxes
XML (standard)
Building blocks
Resources (with unique identifiers)
Named relations between pairs of resources (or a
resource and a literal)
11. RDF’s Advantages
Simple but expressive data model
Global identifiers of all resources (URIs)
Reduces ambiguity
Easier incremental data integration
Can handle incomplete information.
Graph structure
Suitable for a large class of tasks
Data merging is easier
12. RDF Schema
RDFS provides means for:
Defining Classes and Properties
Defining hierarchies (of classes and properties)
RDFS differs from XML Schema (XSD)
Open World Assumption vs. Closed World
Assumption
RDFS is about describing resources, not about
validation
13. URI
Uniform Resource Identifier
A simple and extensible means for identifying a
resource
A URL is a type of URI
14. Web Ontology Language (OWL)
More expressive than RDFS
Identity equivalence/difference
same As, different From, equivalent Class/Property
More expressive class definitions
Class intersection, union, complement, disjointness
Cardinality restrictions
More expressive property definitions
Object/Data type properties
Transitive, functional, symmetric, inverse properties
Value restrictions
15. RDFa
RDFa provides a set of XHTML attributes that express
RDF data.
New standard for resource description and access
designed for the digital world
16. Microformats
Microformats are simple conventions for embedding
semantics in HTML.
These are designed first for humans and then for
machines.
No name spaces, no new tags
Built Upon existing standards like vCard, iCalender
etc.
17. HTML vCard represents people, companies, places,
organizations.
HTML iCalendar represents calendar events.
18. Summary
“I have a dream for a web in which computer become
capable of analyzing all the data on the web.”
Tim Berners Lee – 1999
Inventor of the Web
The Semantic Web is not a separate web but it is an
extension of the current web.
19. At present, the Semantic Web is increasingly used by small
and large business. Oracle, IBM, Adobe, Software AG,
or Yahoo! are only some of the large corporations that have
picked up this technology already and are selling tools as
well as complete business solutions.
The Semantic Web will provide an infrastructure that
enables not just web pages, but databases, services,
programs, sensors, personal devices, and even household
appliances to both consume and produce data on the web.
Software agents can use this information to search, filter
and prepare information in new and exciting ways to assist
the web user.