1. RDF For Semantic Web Dhaval Patel 2nd Year Student School of IT
IIT Kharagpur
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2. Presentation Outline Introduction Syntactic Web Semantic Web
Basic RDF Terminology
RDFS
Reference
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3. Introduction
TBL’s Original vision of the Web
……a goal of the Web was that, if the interaction between person and hypertext could be so intuitive that the machine-readable information space gave an accurate representation of the state of people's thoughts, interactions, and work patterns, then machine analysis could become a very powerful management tool, seeing patterns in our work and facilitating our working together through the typical problems which beset the management of large organizations….. (from w3c)
Realising this vision, which has become known as the “Semantic Web”
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4. Syntactic Web Current Web Contents are represented using
Natural Language (English…)
Graphics, Multimedia
Human can
Process this information easily
Combine information easily from various source (Even information is represented using different Technologies / Format)
For Machine
Difficult to make a sense from image
Drawing Analogy automatically is Difficult and many more…
Example: False Hit on Google Search Engine
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5. Semantic Web
…An article in May 2001 issue of Science and Technology at Scientific American…
Article Title
The Semantic Web
A new form of Web content that is meaningful to computers will unleash a revolution of new possibilities
Author
Tim Berners-Lee, James Hendler and Ora Lassila
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6. Definition
Semantic Web is
Extension of the current Web
Information is given well-defined meaning
Enabling computers and people to work in cooperation
Aim of Semantic Web
Medium of data and information that can be processed automatically
Imp. For Semantic Web
Knowledge Representation
Examples
Automatic Assistance, Data Integration, Digital Library, Semantic of Web Services
(“find me the most elegant credit card verification service?”)
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7. 21/09/2018

8. Giant Working for Semantic Web
Tim Berners-Lee
Dan Brickley
Dan Connolly
Sandro Hawke
Jose Kahan
Marja Koivunen,
Eric Miller
Eric Prud'hommeaux
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9. What is Needed? Each resource describe itself
Means Provide information
It is also Called as Meta Data
Meta Data is in machine process able format
Vocabulary about the meta data should be defined
Agent is able to reason about the meta data
How to make Metadata Machine Process able Format
Define Unambiguous Name (URI)
Data Model (RDF – To Express Metadata)
Common Vocabulary (Ontology)
The “Semantic Web” is a metadata based infrastructure for reasoning on the Web
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10. Semantic Web is Not AI on Web Use element of Logic
SW is mainly about the representing and characterizing metadata
AI is using the Metadata of SW
SW Principles
Any abstract thing can have a URI#xxx
Vocabularies can merge and be replaced with time
Anyone can say anything about anything
No one system knows everything
Design must be minimalist
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11. RDF – Resource Description Framework
RDF is graphical formalism
For representing metadata
It is the “Official” W3C format
For describing the semantics of information in a machine accessible
way
It represent metadata as a set of statements
Statements
Statements are <subject, properties, object> triples
Subject = Object = Resource (An element, URI, Literal)
(a document, a picture, a paragraph on the Web)
Statements describe properties of Resource
Properties is directed relations between two resources
Properties themselves are also resources (URIs)
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12. RDF Graph
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13. XML Representation of RDF Graph
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14. Encoding Style of RDF Graph
«Element for #FullSlide»
«Element for graphics Type»
Chart
«/Element for graphics Type»
«/Element for #FullSlide»
«Element for #FullSlide»
«Element for labelledBy»
«Element for #BottomLegend»
«/Element for labelledBy»
«/Element for #FullSlide»
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15. Example
<rdf:RDF xmlns:rdf="
<rdf:Description rdf:about="#FullSlide">
<axsvg:labelledBy>
<rdf:Description rdf:about="#BottomLegend"/> </axsvg:labelledBy>
</rdf:Description>
<rdf:RDF>
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16. Chaining of Resource <rdf:Description rdf:about="#FullSlide">
<axsvg:labelledBy>
<rdf:Description rdf:about="#BottomLegend"/> </axsvg:labelledBy>
</rdf:Description>
<rdf:Description rdf:about="#BottomLegend"> <axsvg:isAnchor>True</axsvg:isAnchor>
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17. Simplification <property>
<rdf:Description rdf:about="URI"/>
</property>
Simplified As
<property rdf:resource="URI"/>
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18. Programming Practice Python + RDFLib PHP Java 21/09/2018

19. RDF Schema (RDFS)
Also known as RDF Vocabulary Description Language (RDFS)
In RDF,
Some words may be incorrect or unknown
Interpretation is an arbitrary binary relation
Not given any special meaning to vocabulary such as sub-Class-Of or type
RDF Schema defines “schema vocabulary” that supports definition of ontologies
Gives “extra meaning” to particular RDF properties and resources (such as subClassOf)
This “extra meaning”, or semantics, specifies how a term should be interpreted
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20. RDF Schema Terms (Construct)
Class
Property
type
Sub Class Of
range
domain
<Person, type, Class>
<hasColleague, type, Property>
<Professor, subClassOf, Person>
<Carole, type, Professor>
<hasColleague, range, Person>
<hasColleague, domain, Person>
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21. Vocabulary
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22. Point to be Taken care <Species, type, Class>
No Distinction Between Class and Resource
<Species, type, Class>
<Lion, type, Species>
<Leo, type, Lion>
Properties has themselves properties
No Difference Between Construct and user defined Construct
<Property , type, Class>
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23. Continue …… Problem with RDFS
No transitive, inverse or symmetrical ( IsPartof, hasPart)
Ontology
Web Ontology Language
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24. Reference [1] http://www.sciam.com/article.cfm
[1]
[2]
[3]
[4]
[5]
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