How OWL is different with RDF?

We can say that their is no much more difference b/w OWL and RDF.but main difference b/w both OWL and RDF is that OWl is an stronger language which has great interoperability with machine than RDF.

 Also OWL has a large collection than RDF.
 Syntax of OWL is much stronger than RDF.

What is OWL?

OWL is stands for Web Ontology Language. It is an language which we used to process web application.

I have explain you OWL with using some points.
1. We placed OWL on top of RDF.
2. OWL is for processing information on the web.
3. We designed OWL to read only by computer not  
   by peoples.
4. OWL is written in XML language.
5. Also OWL has three sublanguages.
6. OWL is an W3C standard given by W3C.

How to define term Ontology in Web Ontology Language(OWL)?

Ontology means to exact description of things and how to relate them. 
In case of Web we can define Ontology as to exact description of web information and to define relationships b/w them(web information).

Why we use OWL?

Future aspect of OWL is that,

1. We use OWL for exact description of Web information.
2.Using OWl Web information can be processed through computers.
3.OWl also helps computers to integrate information from the web.

Tell me about terms in RDF?

To describe the elements of container we have to talk about list of values attach with container.

In RDF we said all list of values members.To consider that,

We used container to store the things. Things(not the list of values)that are contained by container are told as members.  
 

How you define collection in RDF?

We use collection to describe the groups that store only specified members.We describe the collection using attribute rdf:parseType=\"Collection\".

Example:
<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://r4r.in/cd#\"> 
<rdf:Description
rdf:about=\"http://r4r.in/cd/Beatles\">
<cd:artist rdf:parseType=\"Collection\">
<rdf:Description rdf:about=\"http://r4r.in/cd/Beatles/George\"/>
<rdf:Description rdf:about=\"http://r4r.in/cd/Beatles/John\"/>
<rdf:Description rdf:about=\"http://r4r.in/cd/Beatles/Paul\"/>
<rdf:Description rdf:about=\"http://r4r.in/cd/Beatles/Ringo\"/>
</cd:artist>
</rdf:Description>
</rdf:RDF>

What is the RDF Schema?

 We can also write RDF Schema in short RDFS.Basically, We don\'t use RDF Schema allow for actual application-specific classes and properties.

We can say that RDF classes are same as classes that we defined in Object Oriented Programming Language. This enable resources to define the subclasses of class and instance of classes.

Example:
<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf= \"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:rdfs=\"http://www.w3.org/2000/01/rdf-schema#\"
xml:base=\"http://www.abc.com/animals#\">
<rdf:Description rdf:ID=\"animal\">
  <rdf:type 
   rdf:resource=\"http://www.w3.org/2000/01/rdf-schema#Class\"/>
</rdf:Description>
<rdf:Description rdf:ID=\"lion\">
  <rdf:type
   rdf:resource=\"http://www.w3.org/2000/01/rdf-schema#Class\"/>
  <rdfs:subClassOf rdf:resource=\"#animal\"/>
</rdf:Description>
</rdf:RDF>
 In the above example we use the resource \"lion\"
as a subclass of \"animal\" class.  

What is RDF?

 RDF is stands for Resource Description Framework.It is an W3C standard. Using RDF we can describe web resources.Like: title,author,content,copyright which gives information of a Web page.

Some other important about RDF are given below:

1.RDF is written in XML.
2.RDf become a W3C Recommendation 10Feb2004.
3.RDF is a part of W3C\'s Semantic Web Activity.
4.RDF is designed to read and understood by computer and not for being displayed to people.
5.Rdf gives us model for data and a syntax. Because of it independent parties can use and exchange data.

Where we use RDF?

 I have some places where we use RDF

1.RDF is used to describe properties(like: price, availability,quality etc.)
2.This is also used to describe the time schedules of web elements.
3.This is also used to describe some information about web pages like content,author,created and modified date.
4.Using this we can describe electronic libraries.
5.Using this we can describe the content for search engines.
6.Using this we can also describe content and rating for web pictures.

Whar are the RDF rules?

To identify web identifiers(URIs) uses RDF.Also using RDF we can describe resources with properties and their respected values.
Resource: resouces is anything that have a URI.Like: \"http://www.r4r.co.in/RDF\"
Property: It is a resource than can have name like: \"author\" or \"homepage\".
Property value: It is used to define the value of property. Like: \"Vivek Kr. Agarwal\" or \"http://www.r4r.co.in\"


Example: I define you RDF by using an example.

<?xml version=\"1.0\"?>
<RDF>
  <Description about=\"http://www.r4r.co.in/RDF\">
    <author>Vivek Kr. Agarwal</author>
    <homepage>http://www.r4r.co.in</homepage>
  </Description>
</RDF>

How you define Statements in RDF?

 Statement is an combined form of a Resource, a property and a property value these are also called as subject, predicate and object of a statement.

Example:
Statement1: \"The author of http://www.r4r.co.in/RDF is Vivek Kr.Agarwal\".
Where as,In the above statement
Subject is: http://www.r4r.co.in/RDF
Predicate is: author
Object is: Vivek Kr. Agarwal
 
Statement2: \"The homepage of http://www.r4r.co.in/RDF is http://www.r4r.co.in\".
Where as,In the above statement
Subject is: http://www.r4r.co.in/RDF
Predicate is: homepage
Object is: http://www.r4r.co.in

Explain RDF with an Example?

 I have given you example of cd list.
Title        Artist        country   Price
The Reader   Kate Winslet    USA     11.80
Just My Luck Lindsay Lohan   USA     12.99

The create this cd list by using RDF like that,

<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
  rdf:about=\"http://www.r4r.in/cd/The Reader\">
  <cd:artist>Kate Winslet</cd:artist>
  <cd:country>USA</cd:country>
  <cd:price>11.80</cd:price>
</rdf:Description>
<rdf:Description
  rdf:about=\"http://www.r4r.in/cd/Just My Luck\">
  <cd:artist>Lindsay Lohan</cd:artist>
  <cd:country>USA</cd:country>
  <cd:price>12.99</cd:price>
</rdf:Description>
</rdf:RDF>

In the above example In first step RDF document is the XML declaration by using <rdf:RDF>.
 We use xmlns:rdf namespace to define the elements with the rdf prefix are from the namespace,
\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\".
 We use xmlns:cd namespace to define the elements with the cd prefix are from the namespace,
\"http://www.r4r.in/cd#\".
 We use <rdf:Description> element which has whole discription of the source identified by rdf:about aattribute.

And the elements: <cd:artist>, <cd:country>, <cd:price> are properties of the resource.

What is RDF Online Validator?

Using online RDF validator you can parse your RDF document,can also check your syntax and also to generate tabular and graphical view of our RDF document.

I have given you a example of RDF Validator.

<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:si=\"http://www.r4r.in/siteinfo#\">
  <rdf:Description rdf:about=\"http://www.r4r.co.in/RDF\">
   <si:author>Vivek Kr. Agarwal</si:author>
   <si:homepage>http://www.r4r.co.in</si:homepage>
  </rdf:Description>
</rdf:RDF>

How you define elements in RDF?

 Their are two main elements in RDF that are <RDF> and <Description> element. These element are use to identify the source.

<rdf:RDF> Element is an root element of RDF document which is use to identify XML document to be an RDF document.This element is also use to contain a reference of RDF namespace.
Syntax:
<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">
.
Write here description
.
</rdf:RDF>

<rdf:Description> Element is used to identify a resource with attribute.
<rdf:Description> element has elements using this we can describe the resource.

Example:
<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
 rdf:about=\"http://www.r4r.in/cd/The Reader\">
  <cd:artist>Kate Winslet</cd:artist>
  <cd:country>USA</cd:country>
  <cd:price>11.80</cd:price>
</rdf:Description>
</rdf:RDF>

 In the above example elements, artist, country, and price are defined in http://www.r4r.in/cd# namespace. This namespace is not the part of RDF means outside the RDF.RDF used only to define the framework. The elements artist, country and price should be defined by someone else like: company, organization, person etc.).

How use properties to define attribute?

We can also use property to define attribute like that,
<?xml version=\"1.0\"?>

<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
 rdf:about=\"http://www.r4r.in/cd/The Reader\"
  cd:artist=\"Kate Winslet\"  cd:country=\"USA\"
  cd:price=\"11.80\"/>
</rdf:RDF>

How to use properties to define Resources?

 We can also use properties as resource like that,
Example:<?xml version=\"1.0\"?>

<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
 rdf:about=\"http://www.r4r.in/cd/The Reader\">
  <cd:artist rdf:resource=\"http://www.r4r.in/cd/winslet\" />
  .
  .
  .
</rdf:Description>
</rdf:RDF>

How to use Container element in RDF?

 Using RDF container we can desribe the groups of things.Like: use to list artist of a movie, to create the list of author.
 I have given you some RDF element(<Bag>,<Seq> and <Alt>)that are used to describe groups.

<rdf:Bag> Element: It is used to describe a list of values that is intended to be unordered.
 <rdf:Bag> element can contain duplicate values.
Example:
<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
 rdf:about=\"http://www.r4r.in/cd/Beatles\">
 <cd:artist>
   <rdf:Bag>
     <rdf:li>John</rdf:li>
     <rdf:li>Paul</rdf:li>
     <rdf:li>George</rdf:li>
     <rdf:li>Ringo</rdf:li>
   </rdf:Bag>
  </cd:artist>
</rdf:Description>
</rdf:RDF>
<rdf:Seq> Element: It is used to describe a list of values that is intended to be ordered. (Example: can define values in alphabetical order).
 <rdf:Seq> element can contain duplicate values.
Example:

<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
 rdf:about=\"http://www.r4r.in/cd/Beatles\">
 <cd:artist>    
   <rdf:Seq>
     <rdf:li>George</rdf:li>
     <rdf:li>John</rdf:li>
     <rdf:li>Paul</rdf:li>
     <rdf:li>Ringo</rdf:li>
   </rdf:Seq>
  </cd:artist>
</rdf:Description>
</rdf:RDF>

<rdf:Alt> Element: It is used to describe a list of alternative values(Using this user can select only one of the values).
Example:

<?xml version=\"1.0\"?>
<rdf:RDF
xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" 
xmlns:cd=\"http://www.r4r.in/cd#\"> 
<rdf:Description
 rdf:about=\"http://www.r4r.in/cd/Beatles\">
 <cd:format>    
   <rdf:Alt>
     <rdf:li>CD</rdf:li>
     <rdf:li>Record</rdf:li>
     <rdf:li>Tape</rdf:li>
   </rdf:Alt>
  </cd:format>
</rdf:Description>
</rdf:RDF>

How can say OWL is Web Standard?

W3C(World Wide Web Consortium) has has recommended OWL as Web Standard in Feb 2004.

 W3C recommendations are easily understand and accepted by industry.And web community also accepted as web standard.