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Semantic Web

Faculty of Computer Science, IBA


Agenda


Overview of course and grading policy.



What is Semantic Web? Why we need it?

Quratulain

2

Course Description


The

World

Wide

Web

(WWW)

has

changed

the

way

in

which

people

conduct

business

and

shared

knowledge
.

The

explosive

growth

of

the

Web

has

led

the

problem

of

information

overload
.

The

Semantic

Web

can

be

seen

as

the

solution

to

the

problems

of

WWW
.



In

this

course,

we

examine

existing

Semantic

Web

technologies
:

XML,

RDF

(Resource

Description

Framework),

OWL

(Web

Ontology

Language),

understand

the

role

of

ontology,

ontology

modeling,

reasoning,

and

querying

mechanisms
.



Latest

papers

published

in

recent

Semantic

Web

conference

proceedings

and

journals

are

also

discussed
.



This

course

also

offers

a

practical

experience

using

Protégé

ontology

editor,

Jena

ontology

API

with

JAVA

programming

language
.

Students

are

required

to

complete

the

semantic

web

project

at

the

end

of

the

semester
.


Quratulain

3

Text Books


The Semantic Web
primer

by
Grigoris

Antoniou and Frank van
Harmelen
, MIT press.


Semantic Web Programming

by
John
Hebeler
, Matthew Fisher, Ryan
Blace

and Andrew Perez
-
Lopez.


Quratulain

4

Tentative Course Outline


The Semantic Web Vision


Semantic Web Architecture


Structured Web Document in XML


Ontology languages:


RDF (Resource Description Framework)


RDFS (RDF Schema)


OWL (Web Ontology Language)


Ontology Development using Protégé editor


Ontology Querying


Ontology Reasoning and Description Logic (DL)


Semantic Web Application Areas


Ontology programming with Jena API


Ontology Engineering


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5

Tools and Programming Language


Protégé ontology editor


Jena ontology API


JAVA programming
language


Eclipse IDE for JAVA programming


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6

Grading Policy


Midterm Exams: 30%


Final Exam: 30%


Assignments: 20%


Project: 20%


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7

Course Wiki


Check the website frequently for relevant links
on tutorials, updated syllabus, lectures and
assignments


http://cse661semanticwebfall2011.wikispaces.com/


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8

Contact Information


Email:
quratrajput@yahoo.com


Cell: 03452324452


Counseling hours: Tuesday and Thursday
(3:00PM to 6:00PM)


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9

Course Feedback


First time course is being offered.


I encourage positive/negative feedback about
how the class is going.



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10



Any question regarding course description.


?

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11

Today’s Web


HTML provides only
presentation layout to the
web content. Such as font
size, color, hyperlinks.


Understandable by
human.

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12

<
tr
> <td width="43%" align="left"
valign
="top" class="td"><div
align="justify"><
br

/> IBA has 80
full time and 85 part time and
visiting faculty members teaching
courses in Management,
Marketing, HR, Strategy, Finance,
Economics, Quantitative Methods,
Organizational Behavior, Computer
Sciences, Ethics, Social Sciences,
Chinese, Arabic. <
br
>
&
nbsp
;</div></td> <td
width="57%"
valign
="top"
class="td"><div align="right"><
br

/> <
img

border="0"
src
="
images/grp_fullfac_011010_s
mall.jpg
" width="400"
height="147"></div></td> </
tr
>
<
tr
>

Today’s Web


Automatically generated data from databases
also presented on web pages without
following database structure.


For example, online library.


Once the query is performed on library database,
the search result display on the web page as a
text.

Quratulain

13

Today’s Web


Querying


Find PhD scholarship in the field of Computer
Science in Europe?


Lot of hard work require by users:


Search different scholarship web sites.


Read the detail of each scholarship ads.


Finally you can get information.


Not possible to review each scholarship ads due to
large size of web content.


Quratulain

14

Today’s Web

Quratulain

15

Limitation of Today’s Web


Search results are highly depends on keywords.


High recall but low precision


Human involvement necessary to combine results.


Information is not processable by machines.


Lack of semantics.


Due to large size of web content, user cannot utilize
most of the available information.


The structure of Web contents is heterogeneous.
Therefore information cannot share or integrate
automatically among web pages.

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16

Limitation of Today’s Web


No Querying system is available.


If the location of information is fixed then wrappers
can be written to get information automatically. But
specific to a website and become obsolete if the
change location has been changed.


Other techniques based on Artificial Intelligence and
computational linguistic can be applied for text
processing but not capable enough.


Due to heterogeneous structure of web content not
possible to apply one technique consistently over a
large scale of web content.

Quratulain

17

Today’s Web: impossible queries


Find the information about people that start
using glasses before the age of 30?


Find information in data repository


Find average price of Honda civic model of the year
2000?


Find airline ticket with cheapest price from
K
arachi to
Bangkok.


Delegating complex tasks to web “
agents



Book me a holiday next weekend somewhere warm, not
too far away, and where they speak French or English


Quratulain

18

Semantic Web Vision


Provide semantics to the web content.


Information on the web can be process by machine.


Automatic integration of information from different
web pages.


Not only assigned metadata but also conceptualization
of a domain knowledge.

Quratulain

19

I have an excellent condition HP Pavilion dv2500 Special
Edition laptop with a core duo 1.5ghz processor 250gb
hd

and 2gb ram. It comes with Windows Vista Home Premium
32
-
bit. The case has a few scratches and the battery life is
currently low lasting only 10
-
20min. However, if replaced
probably for $30
-
40 it should last close to 6 hours. I am
looking for $450 or best offer.


Hard disk

RAM

Processor Speed

Brand

Price

Use Ontologies to provide semantic

User definable

and
domain specific

markup

<
H1>
IBA FCS program
</
H1>


<
UL>



<
LI>
Instructor: Quratulain


<LI>
Course: Semantic Web


</
UL>


HTML:

<FCS
-
Courses>


<
title>
IBA FCS program
</
title>


<instructor>
Quratulain
</instructor>


<Course>
Semantic Web
</Course>

</FCS
-
Courses>

XML
:

20

Quratulain

Semantic Web


According to
W3C


“an evolving
extension of the World Wide Web

in
which web content can be …
read and used by
software agents
, thus permitting them to
find,
share and integrate information

more easily”


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21

From Today’s Web to Semantic Web


Examples


Knowledge management


B2C E
-
Commerce


B2B E
-
Commerce


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22

Knowledge Management


Knowledge management concerns itself with acquiring,
accessing, and maintaining knowledge within an organization


K
ey activity of large businesses
:

internal knowledge as an
intellectual asset
from which they can increase their
competitiveness.


Most
information is currently available in a weakly structured
form (e.g. text, audio, video)


23

Quratulain

Knowledge management:

Limitation of current technology


Searching information: Depends on keyword
based search.


Extracting information: Human time and effort
are required.


Maintaining information: Consistent information
and remove outdated once.


Uncovering information: Difficult to apply data
mining techniques on weakly structure document


Viewing information: Hard to realize a restricted
view of information over Web.


Quratulain

24

25

Semantic Web Enabled Knowledge
Management


Knowledge will be organized in conceptual spaces
according to its meaning.


Automated tools for maintenance and knowledge
discovery


Semantic query answering


Query answering over several documents


Defining who may view certain parts of information (even
parts of documents) will be possible.

25

Quratulain

26

The Semantic Web Impact: E
-
Commerce


A

typical scenario: user visits one or several online shops,
browses their offers, selects and orders products.



Ideally humans would visit all, or all major online stores;
but too time consuming


Shopbots

are a useful tool but have limitations


Rely on wrappers


Reprogrammed

is costly if there
is a
change in online
stores.


Relies on textual analysis


26

Quratulain

Chapter 1

A Semantic Web Primer

27

Semantic Web Enabled E
-
Commerce


Software agents that can interpret the product
information and the terms of service.


Pricing and product information, delivery and privacy
policies will be interpreted and compared to the user
requirements.



I
nformation about the reputation of shops


S
ophisticated shopping agents will be able to conduct
automated negotiations


27

Quratulain

Semantic Web Impact


Wikis


Social networks


Tags


User Profiles

28

Quratulain

Ontology


Knowledge Representation using Ontologies


Definition:


Wikipedia: is a formal representation of knowledge as a set
of concepts within a domain, and the relationships
between those concepts. It is used to reason about the
entities within that domain, and may be used to describe
the domain.


Webopedia: computer
-
based resources that represent
agreed domain semantics...relatively generic knowledge
that can be reused by different kinds of applications or
tasks.


Gruber: A formal, explicit specification of a shared
conceptualization

29

Quratulain

Ontologies and Relational Databases


Similarities


Both use a model to identify common classes and properties


ER model can be seen as a simple hierarchical ontology


Differences


Ontologies are broader in scope (rules, incomplete
knowledge)


Ontologies provide a way for automated reasoning to occur in
order to discover new relationships between entities

Ramez Elmasri, Shamkant B. Navathe: Fundamentals of Database Systems, 3rd Edition. Benjamin/Cummings 2000

30

Quratulain

Reading Assignment


Berners
-
Lee, Hendler, Lassila, The Semantic
Web, Scientific American, May 2001



http://kill.devc.at/system/files/scientific
-
american_0.pdf

31

Quratulain