Post on 28-Dec-2015
Semantic Web and Semantic Web and Knowledge ManagementKnowledge Management
Ching-Long Yeh 葉慶隆Department of Computer Science and Engineering
Tatung UniversityTaipei, Taiwan
Email: chingyeh@cse.ttu.edu.twhttp://www.cse.ttu.edu.tw/chingyeh
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ContentContent
• Web technology evolution• Semantic Web • Ontology and Languages• Semantic Web Service• Semantic Web Applications• Summary
Web Technology EvolutionWeb Technology Evolution
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Web TechnologyWeb Technology
• HTML, HTTP• XML• Electronic Business• Semantic Web
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InformationPool
WWWWWW
HTTP (Hyper Text Transport Protocol)HTML (Hyper Text Markup Language)URL (Uniform Resource Locator)
Web server
ApplicationClient
HTTP
URL
HTML Document
• Human-to-machine interaction• Information explosion
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InformationPool
Interaction Using XML
XML (eXtensible Markup Language)SOAP (Simple Object Access Protocol)
SOAP server
Application
HTTP
XML Document
• Machine-to-machine interaction • Service automation
SOAP server
Application
InformationPool
XML Document
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Web Service Architecture
Serviceregistry
Servicerequester
Serviceprovider
FindWSDL, UDDI
PublishWSDL, UDDI
Bind
Servicedescriptions
Servicedescriptions
Services
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Electronic Business
Transport, routing, packaging
Business processes,business documents
Company ACompany B
Transport, routing, packaging
Business processes,business documents
ERPERP
• Application-to-Application• Business Process Automation• RosettaNet• ebXML
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Semantic WebSemantic Web
• The Semantic Web is a vision:
• See “W3C Semantic Web Activity,” by Marja-Riitta Koivunen, for more descriptions.
the idea of having data on the web defined and linked in a way that it can be used by machines not just for display purposes, but for automation, integration and reuse of data across various applications
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Semantic WebSemantic Web
• The Semantic Web is the new generation of the World Wide Web, based on the semantic network knowledge representation formalism, which enables packaging information in the form of object-attribute-value statements, so called triplets.
• By assuming that terms used in these statements are based on the formally specified meaning (for the community of interest), i.e. ontologies, these triplets can be semantically processed by machine agents.
From: http://www2002.org/CDROM/poster/130.pdf
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The Semantic Web Layered ArchitectureThe Semantic Web Layered Architecture
(http://www.w3.org/2001/Talks/0228-tbl/slide5-0.html)
Tim Berners-Lee:“Axioms, Architecture and Aspirations”W3C all-working group plenary Meeting28 February 2001
URI Unicode
XML Namespaces
XML Schema
Sig
RDF M&S
RDF Schema
Ontology
Rules
Logic
Proof
Trust
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The Big Picture of SW
(http://semanticweb.org/about.html#bigpicture)
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查詢 瀏覽語意入口網站服務
後設資料層
全球網資源
The metadata layer of the Semantic Web
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What Is in an Ontology?What Is in an Ontology?
• One widely cited definition of an ontology is Gruber’s [Gruber 1993] “A specification of a conceptualization”.
• An ontology is a formal explicit description of – concepts in a domain of discourse (classes (sometimes called
concepts)),
– properties of each concept describing various features and attributes of the concept (slots (sometimes called roles or properties)), and
– restrictions on slots (facets (sometimes called role restrictions)).
• An ontology together with a set of individual instances of classes constitutes a knowledge base.
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Ontology SpectrumOntology Spectrum
What is an Ontology?What is an Ontology?
Catalog/ID
GeneralLogical
constraints
Terms/glossary
Thesauri“narrower
term”relation
Formalis-a
Frames(properties)
Informalis-a
Formalinstance
Value Restrs.
Disjointness, Inverse, part-
of…
(From: http://www.ksl.stanford.edu/people/dlm/papers/ontologies-come-of-age-mit-press-(with-citation).htm)
Semantic Web LanguagesSemantic Web Languages
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What is XML?What is XML?
• Extensible Markup Language• A Syntax for Documents • A Meta-Markup Language• A Structural and Semantic Language, not a Formatting
Language• Not just for Web pages
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XML StandardsXML Standards
• DTD• Namespace• Schema• DOM• CSS, XSL-T, XSL-FO• XLink• XPointer
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XML Protocol: SOAPXML Protocol: SOAP
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RDF M&SRDF M&S• RDF (Resource Description Framework)
– Beyond Machine readable to Machine understandable
• RDF consists of two parts– RDF Model (a set of triples)– RDF Syntax (different XML serialization syntaxes)
• RDF Schema for definition of Vocabularies (simple Ontologies) for RDF (and in RDF)
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RDF Data ModelRDF Data Model• Resources
– A resource is a thing you talk about (can reference)– Resources have URI’s– RDF definitions are themselves Resources (linkage, see
requirement 1)
• Properties – slots, define relationships to other resources or atomic values
• Statements– “Resource has Property with Value”– (Values can be resources or atomic XML data)
• Similar to Frame Systems
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A Simple ExampleA Simple Example• Statement
– “Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila”
• Structure– Resource (subject) http://www.w3.org/Home/Lassila– Property (predicate) http://www.schema.org/#Creator– Value (object) "Ora Lassila”
• Directed graph
http://www.w3.org/Home/Lassilas:Creator
Ora Lassila
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OWLOWLW3C Web Ontology LanguageW3C Web Ontology Language
• OWL provides three increasingly expressive sublanguages: OWL Lite, OWL DL, and OWL Full.
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OWLOWLW3C Web Ontology LanguageW3C Web Ontology Language
OWL Lite language constructs
RDF Schema Features: Class rdf:Property rdfs:subClassOf rdfs:subPropertyOf rdfs:domain rdfs:range Individual
(In)Equality: equivalentClass equivalentProperty sameAs differentFrom allDifferent
Property Characteristics: inverseOf TransitiveProperty SymmetricProperty FunctionalProperty InverseFunctionalProperty
Property Type Restrictions: allValuesFrom someValuesFrom
Restricted Cardinality: minCardinality (only 0 or 1) maxCardinality (only 0 or 1) cardinality (only 0 or 1)
Header Information: ontology imports
Semantic Web ServicesSemantic Web Services
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Some Motivating TasksSome Motivating Tasks
• The kinds of task we expect OWL-S to enable:– Automatic Web service discovery – Automatic Web service invocation – Automatic Web service composition and interoperation – Automatic Web service execution monitoring
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High-level View of the Service OntologyHigh-level View of the Service Ontology
ServiceProfile
ServiceModel
ServiceGrounding
ServiceResourceprovides
presents
describedBy
supports
What the service does
How it works
How toAccess it
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Top Level of the Process OntologyTop Level of the Process Ontology
Process Profile
AtomicProcess Composite
ProcessSimpleProcess
ControlConstruct
SequenceRepeatUntil
ProcessComponent=Process U ControConstruct
ProcessComponent=Process U ControConstruct
ProcessComponent=Process U ControConstruct
hasProcesshasProfile
computedInputcomputedOutputcomputedEffect
computedPreconditioninvocab
compsedBy
expandcollapserealizes
realizedBy
hasGrounding
InputPrecondition
Outputeffect
Condition
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Grounding a Service to a Concrete Realization Grounding a Service to a Concrete Realization
Process Model
Atomic Process
Operation
DL-Based Types
Inputs/Outputs
Message
Binding to SOAP, HTTP, etc.
WSDL
OWL-S
Semantic Web Services ArchitectureSemantic Web Services Architecture
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IntroductionIntroduction
• Develop architectural and protocol abstractions forming a reference architecture to support Semantic Web Service technologies
• The support functions the architecture will cover– Dynamic Service Discovery– Service Process Enactment and Management– Negotiation and Contracting– Semantic Web Community Support Services– Semantic Web Service Lifecycle and Resource
Management Services– Cross-cutting Issues
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IntroductionIntroduction
• Semantic Web Services are viewed as a way to extend the capabilities of web services in the direction of dynamic interoperability.– Commercial web services, in both B2B and B2C applications– Grid computing– Ubiquitous computing– Information Services
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Functional AreasFunctional Areas
Dynamic Service Discovery B2B B2C Ubiq Grid Info
Advertising of Service Descriptions
Candidate Service Query Formulation
Candidate Service Matchmaking
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Functional AreasFunctional Areas
Service Process Enactment and Management B2B B2C Ubiq Grid Info
Candidate Service Selection
Service request formation and response interpretation
Request and Response Translation
Choreography interpretation and execution
Process mediation and delegation
Dynamic Service Composition
Process status monitoring and event notification
Service failure handling and compensation
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Functional AreasFunctional Areas
Negotiation and Contracting B2B B2C Ubiq Grid Info
Service contract negotiation
Dispute Resolution and Compliance
Non-Repudiation/Audit Tracking/Explanation
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Functional AreasFunctional Areas
Semantic Web Community Support Services B2B B2C Ubiq Grid Info
Ontology Management and Mapping Services
Service catalog and Information brokering Services
Membership and Authority Services
Security (identification/authentication, authorization, delegation)
Privacy Services
Reputation Services
Policy and Protocol Management Services
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Functional AreasFunctional Areas
Service Lifecycle Support B2B B2C Ubiq Grid Info
Executable process management services
Resource Allocation and Provisioning services
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SummarySummary
• Abstractions of services on emerging technological architectures
• The Semantic Web Service Architecture is probably an integration of the abstractions of services for various functional areas.
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An Architecture of An Architecture of Semantic Community Web Portals
(From: http://www9.org/w9cdrom/134/134.html)
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Development of Web PortalsDevelopment of Web Portals
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A KM Framework over SWA KM Framework over SW
(From: http://www2002.org/CDROM/poster/130.pdf)
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What is Sesame ?What is Sesame ?
Sesame is RDF Schema-based repository
and querying facility that offers:
• A persistent store of RDF data
• Export of repository contents in RDF format
• Data administration functionality
• Query engine (RQL , SeRQL)
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Sesame’s ArchitectureSesame’s Architecture
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Web server
Web server
Web server
Web server
Content providers
User User User User
Ontology Knowledgewarehouse
Portal
Annotator Wrapper
Discovery Use Tailoring Social
Inference engine
An Ontology-Based Portal for Digital Library Services
Syntax Transformation of RDFSyntax Transformation of RDF
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What is RDFWhat is RDF• RDF (Resource Description Framework)
– The common language used for the semantic interoperability of the Semantic Web.
– Consisting of • a data model in directed labeled graph and • the corresponding XML serializations
<rdf:RDF> <rdf:Description about="http://www.w3.org/Home/Lassila"> <s:Creator> <rdf:Description about="http://www.w3.org/staffId/85740"> <v:Name>Ora Lassila</v:Name> <v:Email>lassila@w3.org</v:Email> </rdf:Description> </s:Creator> </rdf:Description> </rdf:RDF>
http://www.w3.org/Home/Lassila
Ora Lassila lassila@w3.org
Creator
Name Email <rdf:RDF> <rdf:Description about="http://www.w3.org/Home/Lassila"> <s:Creator rdf:resource="http://www.w3.org/staffId/85740"/> </rdf:Description> <rdf:Description about="http://www.w3.org/staffId/85740"> <v:Name>Ora Lassila</v:Name> <v:Email>lassila@w3.org</v:Email> </rdf:Description></rdf:RDF>
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(RDF in XML)n
(RDF in XML)i
(RDF in XML)2
(RDF in XML)1DOM +
Procedure1
A single RDF data model
MultipleRDF in XML
DOM +Procedure2
DOM +Procedurei
DOM +Proceduren
Transformation ofRDF Using DOM
Transformation of RDF Using DOM
Resulti
Transformation results
ProblemProblem
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MultipleRDF in XML
Transformation ofRDF Using DOM
Resulti
Transformation results
Syntax-directed Transformation of RDF
(RDF in XML)n
(RDF in XML)i
(RDF in XML)2
(RDF in XML)1
Syntax-directedTransformation
GoalGoal
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Two System ArchitecturesTwo System Architectures
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RDF Grammar to Yacc RulesRDF Grammar to Yacc RulesAn RDF Grammar RuleRDF ::= ['<rdf:RDF>'] obj* ['</rdf:RDF>']RevisionRDF ::= xmlDeclaration stgRDF obj* etgRDFxmlDeclaration::= ‘<?xml’ ‘version’ ‘=‘ ‘1.0’ encoding ‘>’encoding::= ‘encoding’ ‘=‘ coding | emptystgRDF::= '<‘ ‘rdf:’ ‘RDF’ namespaceDef xmlBase ‘>‘ | emptyetgRDF::= '<‘ ‘/’ ‘rdf:’ ‘RDF’ ‘>‘ | empty
def p_stgRDF(t): 'stgRDF : LP rdf RDF namespaceRule xmlbaseRule RP'def p_etgRDF(t): 'etgRDF : LP DIV rdf RDF RP'def p_namespaceRule(t): '''namespaceRule : namespace | empty'''def p_xmlbaseRule(t): '''xmlbaseRule : xmlbase1 | empty'''def p_empty(t): 'empty : ' pass
Yacc Rulesdef p_RDF(t): 'RDF_file : xmlDeclaration RDFRule‘ global triplec; triplec=len(triple) storeNamaspace(); storeResource(); storeProperty(); storeObject(); storeTriple(); displayTripleTable()
def p_xmlDeclaration(t): '''xmlDeclaration : declaration | empty'''def p_RDFRule(t): '''RDFRule : stgRDF obj etgRDF | obj'''
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RDF Grammar to DCG RulesRDF Grammar to DCG RulesAn RDF ruledescription::='<rdf:Description' idAboutAttr? bagIdAttr? propAttr* '/>' | '<rdf:Description' idAboutAttr? bagIdAttr? propAttr* '>‘ propertyElt* '</rdf:Description>' | typedNode
The DCG rule:description(_) --> halfSTG('Description',NS),(idAboutAttr(IdAboutAttr);[]), (bagIdAttr(BagIdAttr);[]),propAttrStar(IdAboutAttr), (['/>'];['>'], propertyEltStar(_,IdAboutAttr),fullETG('Description',NS)), {reificationOfStatements(IdAboutAttr,BagIdAttr),!} ;typedNode.
DCG rules for converting RDF to Triples and frames % RDF to Tripleobj(Obj) --> container(Obj);description(_),{getAllTriples(Obj)}.%RDF to KSLobj(Obj) --> container(Obj);description(_),{getKSLDocument(Obj)}.
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ConclusionConclusion
• The Web is evolving toward automation of resource consumption and services– Electronic Business – Semantic Web and Services
• The Semantic Web Service Architecture is probably an integration of the abstractions of services for various functional areas.– Commercial applications, including B2B, and B2C– Grid computing– Ubiquitous computing– Information services