PowerPoint Presentation

Introduction to Semantic Web

1OutlineWhat is semantic web?Semantic Web Concepts SPARQL examplesData Modeling using Ontologies

#2What is Semantic Web?

Web 3.0, Linked Data, Web of Data..More of meaning, less structure

#Representing Knowledge

#What type of knowledgeNovels and short stories are booksA book is a documentEvery book has an authorA document has a title A title is a String#What challenges can be solved?How to extract meaningful information from large amounts of dataHow to connect pieces of information to other piecesHow to visualize complex information structures#6How to represent this using:Conceptual GraphsDatabase ModelRDF(S)

#Conceptual Graphs - Databases

BoyIdGirlId12BoyIdName1JohnGirlIdName2Eva#RDFFlexible and extensible way to represent information about WWW resources#RDF

#RDFThe "http://en.wikipedia.org/wiki/Tony_Benn",published by Wikipedia, has for title 'Tony Benn "Wikipedia . "Tony Benn" .

#RDFThe "http://en.wikipedia.org/wiki/Tony_Benn", published by Wikipedia, has for title 'Tony Benn. Tony Benn Wikipedia

#SPARQLQuery language for getting information from RDF graphs. It provides facilities to:extract information in the form of URIs, blank nodes, plain and typed literals. extract RDF subgraphs. construct new RDF graphs based on information in the queried graphs

#SPARQLPREFIX foaf: SELECT ?name ?email WHERE { ?person rdf:type foaf:Person. ?person foaf:name ?name. ?person foaf:mbox ?email. }

#SPARQL Example 1Data: "SPARQL Tutorial" .

Query:SELECT ?title WHERE { ?title . }

#SPARQL Example 2Data:@prefix foaf: .

_:a foaf:name "Johnny Lee Outlaw" . _:a foaf:mbox ._:b foaf:name "Peter Goodguy" . _:b foaf:mbox . _:c foaf:mbox .

#SPARQL Example 2Query:PREFIX foaf: SELECT ?name ?mbox WHERE { ?x foaf:name ?name . ?x foaf:mbox ?mbox } name mbox "Johnny Lee Outlaw "Peter Goodguy"

#OntologyAn ontology is an explicit specification of a conceptualization An ontology is a logical theory accounting for the indented meaning of a formal vocabulary . . in a bit simpler way .An ontology is a formal definition of a body of knowledge#OntologyA given field of domain of interestWithin the boundaries of which things are assumed to existIn a formalized, explicit, and semantically consistent way#OWLOntology web languageAn OWL ontology is a set of axiomsClass Axioms: C D, C DRole Axioms: R S, Func(R), Trans(S)Individual Axioms: a:C, :R

#An OWL ontology is a set of axioms which include classes axioms C is a subclass of D, or C is equivalent to D, role axioms R is a subrole of S, R is a functional role, S is a transitive role, and individual axioms, a is an individual of C, a participates in a R role with b.

20Ontology EngineeringdeterminescopeconsiderreuseenumeratetermsdefineclassesdefinepropertiesLet us build a simple pizza Ontology.Its like the hello world program of Ontology#Ontology - ScopeWhich Pizza characteristics should I consider when choosing a Pizza?Is Veg or Non Veg?Does Pizza go well with Ice Cream?Which is the best choice among Veg pizza .What kind of Pizza bases available?Pizzas from which countries are available?Which Pizza is the least spicy?

#Ontology - ReuseWhy reuse other ontologies?to save the effortto interact with the tools that use other ontologiesto use ontologies that have been validated through use in applications

#Ontology Enumerate Terms What are the properties of these terms?What do we want to say about the terms?Pizza, Cheese , Toppings , Mexican , Sauce , Pizza Base,Crispy

#Ontology - ClassesA class is a concept in the domaina class of Pizzaa class of PizzaBasea class of CountryClasses can have hierarchyPizza is a subclass of FoodVegetarianPizza is a subclass of Pizza#Ontology - PropertiesSlots in a class definition describe attributes of instances of the class and relations to other instancesEach pizza will have hasBase, hasTopping, hasCountryOfOrigin

#ToolsProtgApache Jena

#Questions?#