disseminating web (3.0) knowlege xml standards : rdf, owl
TRANSCRIPT
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Disseminating Web (2.0) informationXML standards : RDF, OWL
Henry BocconGibod (EDF R&D)Tuesday, November 20, morning : 8:00 – 12:00
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Disseminating (Web 3.0 ? ) knowledgeXML standards : RDF, RDFS, OWL
Henry BocconGibod (EDF R&D)Tuesday, November 20, morning : 8:00 – 12:00
ATHENS 2007 ENSAM Paris Henry BocconGibod
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Something anybody may observe
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Something anybody may observe
• Human people speak together using two main kinds of expressions :– Messages, Orders, Documents,
• Structured, sequentially organized, in a way already known by both – speaker and auditor– writer and reader
– Descriptions• set of assertions with relationships• not significantly ordered, but organized
– A grammar is a description– Schematics are descriptions
• Are the way knowledge is exchanged
• Obviously that is not obvious :– Messages, orders, documents may encapsulate descriptions– Descriptions may refer message, orders and documents
• Messages, Orders, Documents need initial Descriptions……Of the way they are structured, sequentially organized
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Trees and Graphs
• Typically– Messages, orders, documents are organized as trees
• Standards for documents such as GML, SGML and then XML provide basic structures to express tree organizations
– Descriptions are organized as graphs• Linguists, terminologists, knowledge engineers
– are claiming for graph expressions – cannot be fully satisfied by XML structures designed
for documents .• Obviously
– Document Type Definitions, XML schemas may express descriptions
• Unbounded Choices, ID, IDrefs mechanisms allows graphs expressions
• XML Schema, XSL specifications are kind of graph descriptions…
• But are not suitable to actually support efficient knowledge expression
• Hopefully – Any graph may be supported by a tree…
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From Syntaxic Web To Semantic Web
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Djoser Pyramid, designed by Imhotep
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XML Schémas
HTML
DTDs
Web Pyramid, designed by Sir Tim Berners Lee
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URI UnicodeHTML
• … the earth of computers was an hostile wasteland, and darkness covered the abyss of operating systems, while a mighty wind swept over the proprietary networks”
• “ then Tim Berners Lee said, "Let there be the Web," and Robert Cailleau did it, and there was the Web… ”
• “… and the Web (1.0) was just a way to share HTML published identified documents stored on heterogeneously designed computers linked together by network of networks using the Internet protocol, and to display them through navigator software “
“In the beginning…
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URI Unicode
NamespacesXMLDTDs XML Schémas
HTML
Then came new recommendations…
• Of structuring principles adapted for all kinds of documents– Defined using structures of embedded segments, delimited by tags,– XML, adaptation of SGML,
• which HTML is one model (DTD)
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LANGUEART
TI SEC1
TSEC1
TSEC2
SEC2
AL
SEC2
STI M NOTEIDNT
ANOTE RIDNT
SEC1
TSEC1 SEC2
TSEC2 AL TSEC2 AL
NOTE D'ETUDE 2EME STADE
E M E LM 99 0102
Pièce N° 1 Note de synthèse
1.1.1 Historique
1.1 origine de la modification
1.1.2 Énoncé du problème - But recherché
La note d'étude EXX/FC 2.17 ind. A attire l'attention sur le fait que le temps de blahblah important dû à la complexité du système de verrouillage est paradoxal pour un système de secours. Faisant suite à cette conclusion le SEPTEN (note d'étude EXX/FC 2.18) ind. A que blahblah…
1.2 Description de la modification
1.2.1 Solution retenue
Le XXX des YYY se traduit par la mise en place de ZZZ dans les armoires d'aiguillage permettant de ligner le ABC vers la totalité des tableaux RRR du site
1 CCE 3.14159 du 31/12/03
La logique de verrouillage associée au système ABC a pour but de garantir la sécurité du personnel, lors des manœuvres d’exploitation.blahblah
Depuis sa création, les objectifs en matière de sûreté et de disponibilité du système ABC ont évolué. A ce titre la CCE 3.141591 a confié au SEPTEN une étude précisant pour les différents états des tranches les conditions d'utilisation des BZZ. A la suite de l'étude SEPTEN le CTE du 30/02/1995 donne son accord pour la réalisation du xxx de yyy sur zzz
A document is a « Tree of typed objects »
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XTM
URI Unicode
Namespaces
RDF
XMLDTDs XML Schémas
HTML
“Be fertile and multiply; fill the earth and subdue it”. So did websites, they multiply and invade the globe…
• Searching and finding published information, build indexes of access to documents became a challenge
– To which web search engines provided solutions• But with plenty of noise and silence
• A structured meaningful index, building a concept network cannot be expressed as a simple tree
– Topic Maps (ISO Standard) et RDF(W3Cstandard) provide two ways of representation of networks of concepts using the XML language
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The fence problem ?
• pickets or intervals, that is the question !fences in a country may be seen as
• networks of pickets linked together, or as • barriers intervals connected through pickets
• RDF and Topic Maps differs by their approach– linguists used to prefer a “picket” approach– Artificial Intelligence used to prefer the “interval” approach
XTMTopic Maps
RDFResource Description
Framework
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About Topic Maps
• From Wikipedia :– Topic Maps is an ISO standard for the representation and interchange of
knowledge, with an emphasis on the ability to find information. The standard is formally known as ISO/IEC 13250:2003.
– A topic map can represent information using topics (representing any concept, from people, countries, and organizations to software modules, individual files, and events), associations (which represent the relationships between them), and occurrences (which represent relationships between topics and information resources relevant to them).
– Topic Maps are thus similar to semantic networks and both concept and mind maps in many respects. In loose usage all those concepts are often used synonymously, though only topic maps are standardized.
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Example of Index using Topic Maps : a document content navigation system
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XTM
Two kinds of complementary model descriptions
URI Unicode
Namespaces
RDF
RDF Schema
Ontology
XMLDTDs XML Schémas
HTML
• XML Schema and DTDs for the description of document structure• RDFSchema et OWL for semantic description of knowledge networks
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Ontologies… …formally expressed
• Ontology is a study of conceptions of reality and the nature of being. • In philosophy, ontology (from the Greek , genitive : ὤν ὄντος of being (part. of : εἶναι
to be) and λογία: science, study, theory) is the study of being or existence and forms the basic subject matter of metaphysics.
– It seeks to describe or posit the basic categories and relationships of being or existence to define entities and types of entities within its framework.
• In both computer science and information science, an ontology is a data model that represents a set of concepts within a domain and the relationships between those concepts. It is used to reason about the objects within that domain. (…that is an other way to express the same thing)
– an ontology is a structure set of concepts. – Concepts are organized as a graph in which relations can be :
• semantic relations ; • composition relations and inheritance relations (au sens objet)
– Knowledge that refer one or several ontologies use their vocabularies without ambiguity
Ontology
… From Parmenides to Tim Berners Lee
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UML
XMI
Where may be situated UML …
URI Unicode
Namespaces
RDF
RDF Schema
Ontology
XMLDTDs XML Schémas
HTML
• Any UML diagram can be expressed as a populated ontology• But XMI has been defined as a low level XML idiom…
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Expressing Rules
Rules
LogicFramework
• SWRL (Semantic Web Rule Language) is a proposal for a Semantic Web ruleslanguage, combining sublanguages of the OWL Web Ontology Language (OWL DL and Lite) with those of the Rule Markup Language (Unary/Binary Datalog).The specification was submitted in May 2004 to the W3C.
• The Rule Interchange Format (RIF) is a W3C recommendationtrack effort to develop a format for interchange of rules in rulebased systems on the semantic web. The goal is to create an interchange format for different rule languages and inference engines. The RIF initiative is closely related to Ontologies. Whereas ontologies describe distributed information objects in a computer executable manner, rules in this sense combine such information and derive new information on top of ontologies.
(source Wikipedia)
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Populated ontology gets benefits from the logic of their description
URI Unicode
Namespaces
RDF
RDF Schema
Ontology
Rules
LogicFramework
Enc
rypt
ion
Sig
natu
re
XMLDTDs XML Schémas
HTML
• Linked to inference engines, ontologies gets benefits from artificial intelligence reasoning on knowledge
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XTM
UML
XMI
Sir Tim Berners Lee’s full vision,
URI Unicode
Namespaces
RDF
RDF Schema
Ontology
Rules
LogicFramework
Proof
Trust
Enc
rypt
ion
Sig
natu
re
XMLDTDs XML Schémas
HTML
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RDF
Resource Description Framework
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Issues of the access to Web resources
• «World Wide Web was initially designed for human understanding, and while all that is published on the web is readable by a computer, these data are not understood by computers. »
• « It is hard to build automatic processing of data on the web, but due to the amount of published data, it is impossible to manage it manually ».
• « The proposed solution is to use metadata in order to describe data published on the Web ».
• « Metadata are data about data ( for instance a library catalogue is a compilation of metadata as it is a description of the books its contain) ; in the web case metadata are data about web resources. »
• « Difference between data and metadata is not obvious. It depends on specific needs and on applications that fulfill these needs. A same resource may be tackled simultaneously in different ways »
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• Le Dublin Core est un ensemble de 15 éléments de métadonnées ayant trait:– au Contenu: Title, Description, Subject, Source, Coverage, Type, Relation – à la Propriété intellectuelle: Creator, Contributor, Publisher, Rights – à la Version: Date, Format, Identifier, Language
• Les balises du Dublin core forment un vocabulaire non ambigu par leur association à l’espace de nom du Dublin Core– http://purl.org/dc/elements/1.1/
Information about rights held in and over the resource Rightsdroits
The extent or scope of the content of the resource including spatial location temporal period or jurisdictionCoveragecouverture
A reference to a related resource. Recommended best practice is to reference the resource by means of a string or number conforming to a formal identification system. Relationrelation
A language of the intellectual content of the resource Languagelangue
A Reference to a resource from which the present resource is derived Sourcesource
An unambiguous reference to the resource within a given context Identifieridentifiant
The physical or digital manifestation of the resource. Formatformat
The nature or genre of the content of the resource (Collection Dataset Event Image InteractiveResource MovingImage PhysicalObject Service Software Sound StillImage Tex)t
Typetype
A date linked to an event in the lifecycle of the resourceDatedate
Any entity, person or organization that contributes to the content of the resourceContributorcontributeur
Organization responsible of the publication of the resource , may be fo instance an university department, or a company.Publisheréditeur
description of the resource contentDescriptiondescription
Subject of the resource contentSubjectsujet et motsclefs
Organization or person responsible of the resource creationCreatorcréateur
Resource nameTitletitre
DefinitionIdentifierFrench name
The « Dublin Core » initiative
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RDF : an introduction
• RDF (Resource Description Framework) is a mean of register, exchange and reuse structured metadata in order ti describe data. It is an XML idiom developed by W3C and of which the first recommendation was published in 1999.
• RDF do not give a set of fixed semantic of the resources described by different users communities. Euach of them may introduce its own vocabulary using a specific namespace and a schema giving a descrption of each term used.
• Based on XML, RDF is also an extensible language i.e. a meta language il is a framework of resource description tat may be applicable to any application domain.
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RDF triples
• RDF expressions are triples – Subject predicate object
ou– Resource property value
• Exemple :– The document XML Schéma was written by Eric Van der Vlist
subjet predicate object
• These triples are formalized as oriented graphs
XML SchemaAuthor
predicatesubject (resource)
object (value)
Eric Van der Vlist
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Resource Identification
• Resources are identified through URI (Unified Resource Identifier). URI are set of names used to address any thing or concept (URL Unified Resource Locator are kind of URI).
• In our example the document XML Schema may be identified by its URI:http://www.oreilly.fr/XML_Schema.pdf
• predicates (properties) are also identified using URI – The URI of the predicate “author" may so be the Creator element of the Dublin Core schema:
http://purl.org/dc/elements/1.1/creator
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« Bootstrap » of the RDF Syntax
• RDF is designed to be a description language of facts and of relationships between these facts. Even if that is the expression of a graph, it is a fact that any graph may be supported by a tree structure. That allows the expression of RDF using the XML syntax principles, using the root element :<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns" />
• As the aim of RDF is facts description, the first element of RDF expressions is « Description » <rdf:Description/>
• A description is like a sequenced story attached to facts introduced using an identifier, and then referred <rdf:Description rdf:ID="unURI"/><rdf:Description rdf:about="#unURI"/>
• A description links fact with properties, of which the meaning may by known only by their association to a defined vocabulary. Such as the Dublin Core vocabulary :
xmlns:dc="http://purl.org/dc/elements/1.1/"a fact is expressed through the association of a value to a property of anything we want to describe:<rdf:Description rdf:ID="unURIdeLivre">
<dc:Title>un titre<dc:Title></rdf:Description>
A property may have a literal content or refer an other fact, which need also… … to be described <rdf:Description rdf:ID="unURIdeLivre">
<dc:author> <rdf:Description rdf:ID="unURIdAuteur"> <dc:author></rdf:Description>
So is the XML Syntax principle for an RDF triple Subject / Predicate /Object
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Groups, categories, classes, and all that sort of things
So is a common characteristic of human languages,perhaps due to the architecture of their brain,in order to remember facts and speak of them the need to categorize them !
<rdf:Description rdf:ID="unURIdeLivre">
<rdf:type rdf:resource="#livre"/></rdf:Description>
So are people uses,in order to simplify their expressionsthey designates facts using category names And give name of characteristics as name of these categories!
<blind rdf:ID="Ray_Charles">
<rdf:type rdf:resource="#singer"/></blind>
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EBNF Formalization (Extended BackusNaur form) of RDF grammar
[1] RDF ::= ['<rdf:RDF>'] description* ['</rdf:RDF>'] [2] description ::= '<rdf:Description' idAboutAttr? '>' propertyElt* '</rdf:Description>' [3] idAboutAttr ::= idAttr | aboutAttr [4] aboutAttr ::= 'about="' URIreference '"' [5] idAttr ::= 'ID="' IDsymbol '"' [6] propertyElt ::= '<' propName '>' value '</' propName '>' | '<' propName resourceAttr '/>' [7] propName ::= Qname [8] value ::= description | string [9] resourceAttr ::= 'resource="' URIreference '"‘[10] Qname ::= [ NSprefix ':' ] name [11] URIreference ::= string, interpreted per [URI] [12] IDsymbol ::= (any legal XML name symbol) [13] name ::= (any legal XML name symbol) [14] NSprefix ::= (any legal XML namespace prefix)[15] string ::= (any XML text, with "<", ">", and "&" escaped) [2a] description ::= '<rdf:Description' idAboutAttr? propAttr* '/>' | '<rdf:Description' idAboutAttr? propAttr* '>' propertyElt*
'</rdf:Description>' | typedNode [6a] propertyElt ::= '<' propName '>' value '</' propName '>' | '<' propName resourceAttr? propAttr* '/>' [16] propAttr ::= propName '="' string '"' (with embedded quotes escaped) [17] typedNode ::= '<' typeName idAboutAttr?
propAttr* '/>' | '<' typeName idAboutAttr? propAttr* '>' property* '</' typeName '>'
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XML Syntax of RDF (cont’d)
• a subject (resource) may own several predicates (properties) That is expressed in the RDF syntax :
<?xml version="1.0" encoding="UTF-8"?><rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"xmlns:dc="http://purl.org/dc/elements/1.1/"><rdf:Description
rdf:about="http://www.oreilly.fr/XML_Schema.pdf"><dc:creator>Eric Van der Vlist</dc:creator>
</rdf:Description></rdf:RDF>
URL of Dublin Core predicates
Subject
Predicate object
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RDF : graphs expression
• Les resources may be linked and embedded:<?xml version="1.0" encoding="UTF-8"?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:dc="http://purl.org/dc/elements/1.1/">xmlns:s="http://description.org/schema/">
<rdf:Description about="http://www.oreilly.fr/XML_Schema.pdf"> <dc:Creator> <rdf:Description about="http:XMLfr.org">
<rdf:type resource="http://description.org/schema/Person"/> <v:Nom>Eric Van der Vlist</v:Nom> <v:Email>[email protected]</v:Email>
</rdf:Description></dc:Creator>
</rdf:Description>
</rdf:RDF>
XML Schema XMLfr.orgcreator
name
mail [email protected]
Eric Van der Vlist
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Basic terms of the RDF Vocabulary
• RDF vocabulary namespace http://www.w3.org/1999/02/22rdfsyntaxns
– Resource : • Any “thing” refered by an RDF expression, identified by an URI
– Property : • Any aspect, characteristic of a Resource, its relation with another Resource ; • Is itself a kind of Resource
– Statement : • expression of the value of a named property attached to a given Resource.• Is a triple “subject / predicate / value” reification
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Schemas and Namespaces
• What is required for the human understanding of statements is also required for computer applications using RDF in order to get proper results.
• It is required that writer and reader of a statement get the same understanding of the used terms meaning, such as Creator, ApprovedBy, Copyright. Any confusion, or mismatch of concepts understanding should be avoided
• In RDF the meaning is expressed through reference to a schema• A schema is a kind of dictionary. It defines terms to be used in RDF statements and
give them unique meanings• Different forms of schema may be used in RDF, including a specific one defined in a
separate document [RDFSchema] which has a set of specific characteristics defined in order to help task automation using RDF
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Culminate : two different concepts for two different aims
• One should make difference between:
– Schema XML that express structure constraints and syntax for XML “documents”
– Schema RDF that express semantic constraints building model of RDF “descriptions”
• Concept of RDF schema– RDF schema describe a vocabulary and a semantic for the property types utilized by
a community of users.– RDF schema define the valid properties foe a specific RDF description, as well as
the characteristics and constraints of the description vocabulary.
– As an example on may look at the Dublin Core RDF Schema version 1.1
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RDF Schema
• A schema is the place where properties definitions and usage restrictions are documented.
• In order to avoid confusion between independents definitions – with possible conflicts – of a same term, RDF implements the XML namespaces features.
• Namespaces are just a way to link any specific use of a term in a specific context to the dictionary (schema) where its definition is supposed to be defined.
• Each RDF predicate used in a statement must be identified with exactly one namespace or a schema.
• A Description element may contain statements with predicates from several different de schemas.
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Abbreviated syntax
• Full Description :<rdf:Description rdf:ID=’Henry’ >
<rdf:type resource=’#Researcher’ /><vehicle> <rdf:Description>
<rdf:type resource=’#Car’ /><brand>Renault</brand>
</rdf:Description></vehicle>
</rdf:Description>
• abbreviated syntax, about types :<Researcher rdf:ID=’Henry’>
<vehicle> <car brand=’Renault’/></vehicle>
</Researcher>
• Other kind of abbreviated syntax about attributes :<rdf:Description rdf:ID=’Henry’ rdf:type=’#Researcher’ />
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Containers
• It is often necessary to refer a collection of resources . For instance a group of people, a list of actions to do, or to choose. RDF containers are designed to express such lists of resources or literals.
• RDF define three kinds of containing objects : –Bag
• a list of resources or literals without order. Bag is used to set that a property owns several values and that there is no meaning attached to the way they are listed. Identical values are allowed .
–Sequence • an ordered sequence of resources or literals. The order of values of a
property is heare meaningful. Identical values are allowed .
–Alternative • A list of resources or literals that represent alternative choices for the unique
value of a property.
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Examples
<rdf:Description rdf:about="http://www.recshop.fake/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 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:cd="http://www.recshop.fake/cd#"> <rdf:Descriptionrdf:about="http://www.recshop.fake/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>
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Closed Collections
• The attribute rdf:parseType="Collection"Define a non ordered closed list of elements<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:cd="http://recshop.fake/cd# "xmlns:bt="http://recshop.fake/cd/Beatles#" xmlns="http://recshop.fake/cd/Beatles#" >
<rdf:Description rdf:about="http://recshop.fake/cd/Beatles"> <cd:artist rdf:parseType="Collection">
<rdf:Description rdf:about="#George"/> <rdf:Description rdf:about="#John"/> <rdf:Description rdf:about="#Paul"/> <rdf:Description rdf:about="#Ringo"/>
</cd:artist> </rdf:Description> </rdf:RDF>
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N3 : An other kind of RDF expression
• N3 notation is simple :subject verb object punctuation<#pat> <#knows> <#jo> .
(All is URL ; the character # indicate that the resource is attached to the URI of the current document courant, which namespace is a default )
• Only object can be literal :<#pat> <#aged> 24.
• More readable :<#pat> is <#aged> 24.
• punctuation ";" et"," allows to factorize the subject respectively for verb and object<#pat> is <#child>of <#jo> ; is <#parent> of <#fred>.
• [ ] identify resource from properties <#pat> has<#child> [ <#aged> 21], [ <#aged> 24],
• Other kind of expression :[ <#name> "Pat"; <#age> 24; <#eyecolor> "blue" ].
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N3 : An other kind of RDF expression (cont’d)
• The current document is sayed as followed<> <#title> "A simple example of N3".
• However attachment to a namespace is preferable :<> <http://purl.org/dc/elements/1.1/title> " titre de ce document ".
• prefix mechanism used to refer a namespace :@prefix dc: <http://purl.org/dc/elements/1.1/> . <> dc:title " titre de ce document ".
(where the fact that the name is colonized allow to avoid de <>) • To declare the use of a default prefix :
@prefix : <#> . • Then one may write :
:pat :aged 24. au lieu de <#pat> <#aged> 24 .
• vocabulary equivalence is expressed using the sign =:woman = foo:human_female .:Title a rdf:Property; = dc:title .
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Exercise
• Description in RDF of the relationships in the town of Verona between Montaigu and Capulets, Roméo and Juliette…
Vérone
Montaigu Capulet
Roméo Juliettelove
hate
is is
Live in Live in
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<?xml version='1.0' encoding='UTF-8'?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:a="http://www.MonVocabulaire#" xmlns:kb="http://www.MonVocabulaire#" xmlns:rdfs="&rdfs;"><kb:Personne rdf:about="http://www.MonVocabulaire#KB_155146_Instance_4" kb:Label="Romeo" rdfs:label="Romeo"/><kb:Personne rdf:about="http://www.MonVocabulaire#KB_155146_Instance_6" kb:Label="Juliette" rdfs:label="Juliette"/><kb:Famille rdf:about="http://www.MonVocabulaire#KB_155146_Instance_7" kb:Label="Montaigu" rdfs:label="Montaigu"/><kb:Famille rdf:about="http://www.MonVocabulaire#KB_155146_Instance_8" kb:Label="Capulet" rdfs:label="Capulet"/><kb:Ville rdf:about="http://www.MonVocabulaire#KB_155146_Instance_9" kb:Label="Verone" rdfs:label="Verone"/><kb:aime rdf:about="http://www.MonVocabulaire#Shakespeare_Instance_0" rdfs:label="Shakespeare_Instance_0"> <a:_to rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_4"/> <a:_from rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_6"/></kb:aime>
<kb:aime rdf:about="http://www.MonVocabulaire#Shakespeare_Instance_1" rdfs:label="Shakespeare_Instance_1"> <a:_from rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_4"/> <a:_to rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_6"/></kb:aime><kb:hait rdf:about="http://www.MonVocabulaire#Shakespeare_Instance_2" rdfs:label="Shakespeare_Instance_2"> <a:_to rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_7"/> <a:_from rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_8"/></kb:hait><kb:hait rdf:about="http://www.MonVocabulaire#Shakespeare_Instance_3" rdfs:label="Shakespeare_Instance_3"> <a:_from rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_7"/> <a:_to rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_8"/></kb:hait><kb:habite rdf:about="http://www.MonVocabulaire#Shakespeare_Instance_4" rdfs:label="Shakespeare_Instance_4"> <a:_from rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_8"/> <a:_to rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_9"/></kb:habite><kb:habite rdf:about="http://www.MonVocabulaire#Shakespeare_Instance_5" rdfs:label="Shakespeare_Instance_5"> <a:_from rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_7"/> <a:_to rdf:resource="http://www.MonVocabulaire#KB_155146_Instance_9"/></kb:habite></rdf:RDF>
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RDFS
• First Initiative of description of RDF resources organisation • Extension of RDF, as RDF define a basic set of classes and properties.• In the beginning was…
…the « resource » from which all come… – rdfs:Resource : class of which all class is a subtype– rdfs:Class, instance of itself, subtype of rdfs:Resource – rdfs:Literal instance of rdfs:Class, subtype of rdfs:Resource– rdfs:Datatype is the class of attributes. its instances correspond to a data model
described in the specification of RDF concepts. rdfs:Datatype is as well an instance and a subclass of rdfs:Class. Each instance of rdfs:Datatype is a subtype of rdfs:Literal.
– rdfs:Property it the class of RDF properties, instance of rdf:Class– rdfs:range and rdfs:domain are instances of rdfs:Property attached recursively
to rdfs:Property, : the domain rdfs:domain de rdfs:range and of rdfs:domain is rdfs:Property…
– rdf:type is an instance of rdfs:Property used to define a resource as an instance of a class.
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RDFS (suite)
– rdfs:subClassOf is an instance of rdfs:Property which defines that instances of a classe are instances of an other classe from which its inherits
– rdfs:subPropertyOf is an instance of rdfs:Property which defines that all resources addressed by a property are also resources of an other property from which its inherits.
– rdfs:label is an instance of rdfs:Property used to give a human readable version of a resource.
– rdfs:comment is an instance of rdfs:Property used to document a resource by a comment
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The class of RDF Lists.rdf:List
The class of container membership properties, rdf:_1, rdf:_2, ..., all of which are subproperties of 'member'.rdfs:ContainerMembershipProperty
The class of RDF containers.rdfs:Container
The class of containers of alternatives.rdf:Alt
The class of ordered containers.rdf:Seq
The class of unordered containers.rdf:Bag
The class of RDF statements.rdf:Statement
The class of RDF datatypes.rdfs:Datatype
The class of RDF properties.rdf:Property
The class of classes.rdfs:Class
The class of XML literals values.rdf:XMLLiteral
The class of literal values, e.g. textual strings and integers.rdfs:Literal
The class resource, everything.rdfs:Resource
commentClass name
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rdfs:Resourcerdf:StatementThe object of the subject RDF statement.rdf:object
rdfs:Resourcerdf:StatementThe predicate of the subject RDF statement.rdf:predicate
rdfs:Resourcerdf:StatementThe subject of the subject RDF statement.rdf:subject
rdfs:Resourcerdfs:ResourceIdiomatic property used for structured values (see the RDF Primer for an example of its usage).rdf:value
rdfs:Resourcerdfs:ResourceThe definition of the subject resource.rdfs:isDefinedBy
rdfs:Resourcerdfs:ResourceFurther information about the subject resource.rdfs:seeAlso
rdf:Listrdf:ListThe rest of the subject RDF list after the first item.rdf:rest
rdfs:Resourcerdf:ListThe first item in the subject RDF list.rdf:first
rdfs:Resourcerdfs:ResourceA member of the subject resource.rdfs:member
rdfs:Literalrdfs:ResourceA description of the subject resource.rdfs:comment
rdfs:Literalrdfs:ResourceA humanreadable name for the subject.rdfs:label
rdfs:Classrdf:PropertyA range of the subject property.rdfs:range
rdfs:Classrdf:PropertyA domain of the subject property.rdfs:domain
rdf:Propertyrdf:PropertyThe subject is a subproperty of a property.rdfs:subPropertyOf
rdfs:Classrdfs:ClassThe subject is a subclass of a class.rdfs:subClassOf
rdfs:Classrdfs:ResourceThe subject is an instance of a class.rdf:type
rangedomaincommentProperty name
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Tragedy Sample<?xml version='1.0' encoding='UTF-8'?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:a="http://www.MonVocabulaire#" xmlns:kb="http://www.MonVocabulaire#" xmlns:rdfs="&rdfs;">
<rdfs:Class rdf:about="http://www.MonVocabulaire#Famille" rdfs:label="Famille"><rdfs:subClassOf
rdf:resource="http://www.MonVocabulaire#Objet_tragique"/></rdfs:Class><rdf:Property rdf:about="http://www.MonVocabulaire#Label"
a:maxCardinality="1" rdfs:label="Label"><rdfs:domain rdf:resource="http://www.MonVocabulaire#Famille"/><rdfs:domain rdf:resource="http://www.MonVocabulaire#Personne"/><rdfs:domain rdf:resource="http://www.MonVocabulaire#Ville"/><rdfs:range rdf:resource="&rdfs;Literal"/>
</rdf:Property><rdfs:Class rdf:about="http://www.MonVocabulaire#Objet_tragique"
rdfs:label="Objet_tragique"><rdfs:subClassOf rdf:resource="&rdfs;Resource"/>
</rdfs:Class><rdfs:Class rdf:about="http://www.MonVocabulaire#Personne"
rdfs:label="Personne"><rdfs:subClassOf
rdf:resource="http://www.MonVocabulaire#Objet_tragique"/></rdfs:Class><rdfs:Class rdf:about="http://www.MonVocabulaire#Ville"
rdfs:label="Ville"><rdfs:subClassOf
rdf:resource="http://www.MonVocabulaire#Objet_tragique"/></rdfs:Class><rdfs:Class rdf:about="http://www.MonVocabulaire#aime"
rdfs:label="aime"><rdfs:subClassOf
rdf:resource="http://www.MonVocabulaire#_directed_binary_relation"/></rdfs:Class><rdfs:Class rdf:about="http://www.MonVocabulaire#habite"
rdfs:label="habite"><rdfs:subClassOf
rdf:resource="http://www.MonVocabulaire#_directed_binary_relation"/></rdfs:Class><rdfs:Class rdf:about="http://www.MonVocabulaire#hait"
rdfs:label="hait"><rdfs:subClassOf
rdf:resource="http://www.MonVocabulaire#_directed_binary_relation"/></rdfs:Class></rdf:RDF>
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OWL
• OWL : acronym of Web Ontology Language(en plus chouette!)
– Wikipedia : The Web Ontology Language (OWL) is a language for defining and instantiating Web ontologies. An OWL ontology may include descriptions of classes, along with their related properties and instances. OWL is designed for use by applications that need to process the content of information instead of just presenting information to humans. It facilitates greater machine interpretability of Web content than that supported by XML, RDF, and RDF Schema (RDFS) by providing additional vocabulary along with a formal semantics. OWL is based on earlier languages OIL and DAML+OIL, and is now a W3C recommendation. .
– To the concepts of class, resource, literal and properties of subclasses, de sub properties, of value fields, of application domains already existing in RDFS, OWL add concepts of equivalent classes, of equivalent properties , equivalent resources, different resources, opposite , de symmetric resources. It adds also the concept of cardinality...
• The OWL documents became a formal W3C recommendation on February 10, 2004 and the working group was disbanded on May 31, 2004.[4]
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The three levels of OWL
• Wikipedia : OWL currently has three sublanguages (sometimes also referred to as 'species'): OWL Lite, OWL DL, and OWL Full. These three increasingly expressive sublanguages are designed for use by specific communities of implementers and users. :
– OWLLite, • supports those users primarily needing a classification hierarchy and simple constraints. For example, while it
supports cardinality constraints, it only permits cardinality values of 0 or 1. It should be simpler to provide tool support for OWL Lite than its more expressive relatives, and OWL Lite provides a quick migration path for thesauri and other taxonomies. OWL Lite also has a lower formal complexity than OWL DL; see the section on OWL Lite in the OWL Reference for further details.
– OWLDL,• supports those users who want the maximum expressiveness while retaining computational completeness (all
conclusions are guaranteed to be computed) and decidability (all computations will finish in finite time). OWL DL includes all OWL language constructs, but they can be used only under certain restrictions (for example, while a class may be a subclass of many classes, a class cannot be an instance of another class). OWL DL is so named due to its correspondence with description logic, a field of research that has studied the logics that form the formal foundation of OWL
– OWLFull., • is meant for users who want maximum expressiveness and the syntactic freedom of RDF with no computational
guarantees. For example, in OWL Full a class can be treated simultaneously as a collection of individuals and as an individual in its own right. OWL Full allows an ontology to augment the meaning of the predefined (RDF or OWL) vocabulary. It is unlikely that any reasoning software will be able to support complete reasoning for every feature of OWL Full.
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OWL Class
• Owl:Thing is the mother class of all classes• Owl:noThing is the child class of all classes
• An OWL class may be defined– by a reference (URI)
<owl:Class rdf:ID="Toto" rdf:resource= "http://toto.org">
– through a list of instances:<owl:Class rdf:ID="continents"><owl:oneOf rdf:parseType="Collection">
<owl:Thing rdf:about="#Eurasie"/><owl:Thing rdf:about="#Afrique"/><owl:Thing rdf:about="#Amerique_du_Nord"/><owl:Thing rdf:about="#Amerique_du_Sud "/><owl:Thing rdf:about="#Australie"/><owl:Thing rdf:about="#Antarctique"/>
</owl:oneOf></owl:Class>
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OWL Class
• An OWL class may be defined– by its properties (intension definition)
• Properties Types : owl:allValuesFrom,owl:someValuesFrom
• Properties Values : owl:hasValue
• Properties Cardinality : owl:maxCardinality, owl:minCardinality, owl:Cardinality
Example : class of resources which have one or more property #author of type #novelist
<owl:Restriction><owl:onProperty rdf:resource="#author" /><owl:allValuesFrom rdf:resource="#novelist" />
</owl:Restriction>
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OWL Class
• An OWL class may be defined– as union, intersection, complement of other classes
<owl:Class><owl:intersectionOf rdf:parseType="Collection">
<owl:Class rdf:about="continents"><owl:Class>
<owl:oneOf rdf:parseType="Collection"><owl:Thing rdf:about="#Europe" /><owl:Thing rdf:about="#Asie" /><owl:Thing rdf:about="#Afrique" />
</owl:oneOf></owl:Class>
</owl:intersectionOf></owl:Class>
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• rdfs:subClassOf : the extension of a class is included in the extension of the other
• owl:equivalentClass : both classes have same extension, but are not of the same concept.
<footballTeam owl:equivalentClass us:soccerTeam />• owl:disjointWith : disjoint classes
OWL Class
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Properties
• RDF Schema provide the concepts of: – rdfs:subPropertyOf, rdfs:domain and rdfs:range
• OWL enlarge relationship between properties :– owl:equivalentProperty : both have same extension, but are not
identicals :– owl:inverseOf : one is the inverse of the other.
<owl:ObjectProperty rdf:ID="enfant"><owl:inverseOf rdf:resource="#parent"/>
</owl:ObjectProperty>
– cardinality constraints de : owl:FunctionalProperty (monovaluées), et owl:InverseFunctionalProperty
– logical constraints :owl:SymmetricProperty (exemple époux)owl:TransitiveProperty (exemple ascendant)
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Shakespeare example (ontology)
<owl:ObjectProperty rdf:ID="habite"> <rdfs:domain rdf:resource="#famille"/> <rdfs:range rdf:resource="#ville"/> </owl:ObjectProperty> <owl:ObjectProperty rdf:about="#a_pour_amant"> <owl:inverseOf rdf:resource="#a_pour_amante"/> <rdfs:range rdf:resource="#garçon"/> <rdfs:domain rdf:resource="#fille"/> </owl:ObjectProperty> <owl:DatatypeProperty rdf:ID="nom"> <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#FunctionalProperty"/> <rdfs:domain> <owl:Class> <owl:unionOf rdf:parseType="Collection"> <owl:Class rdf:about="#personne"/> <owl:Class rdf:about="#famille"/> <owl:Class rdf:about="#ville"/> </owl:unionOf> </owl:Class> </rdfs:domain> </owl:DatatypeProperty>
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Shakespeare example (ontology)
<owl:ObjectProperty rdf:ID="a_pour_amante"> <rdfs:range rdf:resource="#fille"/> <owl:inverseOf> <owl:ObjectProperty rdf:ID="a_pour_amant"/> </owl:inverseOf> <rdfs:domain rdf:resource="#garçon"/> </owl:ObjectProperty> <owl:ObjectProperty rdf:ID="hait_de_génération_en_génération"> <rdfs:range rdf:resource="#famille"/> <rdfs:domain rdf:resource="#famille"/> </owl:ObjectProperty> <owl:ObjectProperty rdf:ID="appartient_à_la_famille"> <rdfs:domain rdf:resource="#personne"/> <rdfs:range rdf:resource="#famille"/> <owl:inverseOf> <owl:ObjectProperty rdf:ID="inverse_of_appartient_à_la_famille"/> </owl:inverseOf> </owl:ObjectProperty> <owl:ObjectProperty rdf:about="#inverse_of_appartient_à_la_famille"> <owl:inverseOf rdf:resource="#appartient_à_la_famille"/> <rdfs:range rdf:resource="#personne"/> <rdfs:domain rdf:resource="#famille"/> </owl:ObjectProperty>
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Shakespeare example (ontology)
<owl:ObjectProperty rdf:ID="habite"> <rdfs:domain rdf:resource="#famille"/> <rdfs:range rdf:resource="#ville"/> </owl:ObjectProperty> <owl:ObjectProperty rdf:about="#a_pour_amant"> <owl:inverseOf rdf:resource="#a_pour_amante"/> <rdfs:range rdf:resource="#garçon"/> <rdfs:domain rdf:resource="#fille"/> </owl:ObjectProperty> <owl:DatatypeProperty rdf:ID="nom"> <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#FunctionalProperty"/> <rdfs:domain> <owl:Class> <owl:unionOf rdf:parseType="Collection"> <owl:Class rdf:about="#personne"/> <owl:Class rdf:about="#famille"/> <owl:Class rdf:about="#ville"/> </owl:unionOf> </owl:Class> </rdfs:domain> </owl:DatatypeProperty>
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Shakespeare example (populated ontology)
<personne rdf:ID="personne_9"> <a_pour_amant> <garçon rdf:ID="personne_7"> <nom rdf:datatype="http://www.w3.org/2001/XMLSchema#string" >Roméo</nom> <a_pour_amante rdf:resource="#personne_9"/> <rdf:type rdf:resource="#personne"/> <appartient_à_la_famille> <famille rdf:ID="Montaigu"> <habite> <ville rdf:ID="ville_13"> <nom rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Vérone</nom> </ville> </habite> <inverse_of_appartient_à_la_famille rdf:resource="#personne_7"/> </famille> </appartient_à_la_famille> </garçon> </a_pour_amant> <nom rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Juliette</nom> <rdf:type rdf:resource="#fille"/> <appartient_à_la_famille> <famille rdf:ID="famille_11"> <inverse_of_appartient_à_la_famille rdf:resource="#personne_9"/> <habite rdf:resource="#ville_13"/> <hait_de_génération_en_génération rdf:resource="#Montaigu"/> <nom rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Capulet</nom> </famille> </appartient_à_la_famille> </personne>
</rdf:RDF>
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Semantic Web Rule Language (swrl)
•SWRL (Semantic Web Rule Language) is a rule language for the semantic web, that combine des sublanguages OWL (OWL DL and OWL Lite) with those of Rule Markup Language (Unary/Binary Datalog).
•Exemple of family rule: hasParent(?x1,?x2) hasBrother(?x2,?x3) hasUncle(?x1,?x3) ∧ ⇒
<ruleml:imp> <ruleml:_rlab ruleml:href="#example1"/> <ruleml:_body>
<swrlx:individualPropertyAtom swrlx:property="hasParent"> <ruleml:var>x1</ruleml:var>
<ruleml:var>x2</ruleml:var> </swrlx:individualPropertyAtom>
<swrlx:individualPropertyAtom swrlx:property="hasBrother"> <ruleml:var>x2</ruleml:var>
<ruleml:var>x3</ruleml:var></swrlx:individualPropertyAtom>
</ruleml:_body> <ruleml:_head>
<swrlx:individualPropertyAtom swrlx:property="hasUncle"> <ruleml:var>x1</ruleml:var> <ruleml:var>x3</ruleml:var>
</swrlx:individualPropertyAtom> </ruleml:_head>
</ruleml:imp>
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Huge set of syntax… … but efficient tools exist
that allow to build and populate ontologies, for instance :– Protégé
• From Stanford University, is the most known, popular and used ontology tool. It is an Opensource software, initially based on a frame model, adapted to RDF, RDFS OWL standards. It is a platform on which plugins may be connected for reasoning, graphical display etc.
• http://protege.stanford.edu/
– Swoop• Is an ontology development tool created by the Maryland University
for the MINDSWAP project. It has been natively based on RDF and OWL standards, with their different syntaxes (not only XML). It is a lighter application than Protégé but it accepts the connection of inference engines.
• http://www.mindswap.org/2004/SWOOP/
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Culminate 2 : Yet an other standard ! For what is it useful ?
• As for XML, plenty of RDF/RDFS/OWL applications do not initially depend on the Web.
– Ontologies are formal standard expressions of kind of data managed by popular mind mapping tools
• Mind manager• The Brain,• Visual Mind • SmartDraw • FreeMind
• OWL Ontologies do not have the rigidity of SQL database models
– One can expand and improve easily models of populated ontology, without loss of data
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Development of ontologies contents
• Plenty ontologies are already used to store huge knowledge– Generic knowledge
• OpenCyc ; Cyc is an artificial intelligence project that attempts to assemble a comprehensive ontology and database of everyday common sense knowledge, with the goal of enabling AI applications to perform humanlike reasoning. ,
• Sumo, Suggested Upper Merged Ontology, is an upper ontology intended as a foundation ontology for a variety of computer information processing systems. It was originally developed by the Teknowledge Corporation and now is maintained by Articulate Software. It is one candidate for the "standard upper ontology" that IEEE working group 1600.1 is working on. It can be downloaded and used freely.
– A Generic Ontology Search engine• http://swoogle.umbc.edu/
– Knowledge In biological sciences• Gene ontology
– http://geneontology.org/index.shtml– http://archive.geneontology.org/latesttermdb/go_dailytermdb.owl.gz
• Open Biomedical Ontologies– OBO, Another ontological expression : http://genomebiology.com/2005/6/5/R46 – http://www.berkeleybop.org/ontologies/#ontologies
– …
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Lexter®
Exter®
Worldtrek®
XTM Topic Maps publication
Web
Worldtrek®
Human
Expertise
corpusTML
Term
candidates
network
TML
Structured
Validated
Terminology
Human knowledge
texts resources TMF concepts & terms
corpus
OWL Ontology
Classes
Individuals
Terminology
A pragmatic ontology building method: using a linguistic terminology to ontology chain
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A pragmatic ontology building method: using a linguistic terminology to ontology chain
OWL-DL rules
SWRL rules
knowledge
Application
Web portal
corpusTMFOWL
OWL editor Protégé®Swoop®…
TML20WL
(XSL)
OWL2TML
Jena
CleanOWL®
(Java)
accessed classes
description
prescription
operation
inference
other services
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Example of ontology construction using the WorldTrek terminology edition tool
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Result of terminology edition in : Protégé®
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Pragmatic ontologies application :for Services Oriented Architecture (SOA)
• Ontologies are pragmatic ways for web service discovery– A semantic network index is a better solution than a flat directory – OWLS initiative provides mechanism to manage Web services
metadata
Service
ServiceGrounding
ServiceProfile
ServiceModel
Has description
present support
What servicesare proposed ?
How serviceswork ?
How to accessto services ?
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Pragmatic ontologies application : Enterprise Information System architecture
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Perspective, in order to conclude
” People keep asking what Web 3.0 is. I think maybe when you've got an overlay of scalable vector graphics everything rippling and folding and looking misty on Web 2.0 and access to a semantic Web integrated across a huge space of data, you'll have access to an unbelievable data resource. ”
Tim BernersLee,