Semantic Web and Knowledge Management Ching-Long Yeh 葉慶隆 Department of Computer Science and Engineering Tatung University Taipei, Taiwan

SW, EB2 Content Web technology evolution Semantic Web Ontology and Languages Semantic Web Service Semantic Web Applications Summary

Web Technology Evolution

SW, EB4 Web Technology HTML, HTTP XML Electronic Business Semantic Web

SW, EB5 Information Pool WWW HTTP (Hyper Text Transport Protocol) HTML (Hyper Text Markup Language) URL (Uniform Resource Locator) Web server Application Client HTTP URL HTML Document Human-to-machine interaction Information explosion

SW, EB6 Information Pool 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 Information Pool XML Document

SW, EB7 Web Service Architecture

SW, EB8 Electronic Business Transport, routing, packaging Business processes, business documents Company A Company B Transport, routing, packaging Business processes, business documents ERP Application-to-Application Business Process Automation RosettaNet ebXML

SW, EB9 Semantic Web The Semantic Web is a vision: See “W3C Semantic Web Activity,” by Marja-Riitta Koivunen, for more descriptions.W3C Semantic Web Activity 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

SW, EB10 Semantic 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:

SW, EB11 The Semantic Web Layered Architecture ( alks/0228-tbl/slide5-0.html) Tim Berners-Lee: “Axioms, Architecture and Aspirations” W3C all-working group plenary Meeting 28 February 2001 URIUnicode XMLNamespaces XML Schema Sig RDF M&S RDF Schema Ontology Rules Logic Proof Trust

SW, EB12 The Big Picture of SW (

SW, EB13 The metadata layer of the Semantic Web

SW, EB14 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.

SW, EB15 Ontology Spectrum (From:

Semantic Web Languages

SW, EB17 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

SW, EB18 XML Standards DTD Namespace Schema DOM CSS, XSL-T, XSL-FO XLink XPointer

SW, EB19 XML Protocol: SOAP

SW, EB20 RDF 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)

SW, EB21 RDF 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

SW, EB22 A Simple Example Statement –“Ora Lassila is the creator of the resource ” Structure –Resource(subject) –Property(predicate) –Value(object) "Ora Lassila” Directed graph s:Creator Ora Lassila

SW, EB23 OWL W3C Web Ontology Language OWL provides three increasingly expressive sublanguages: OWL Lite, OWL DL, and OWL Full.

SW, EB24 OWL W3C 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 Services

SW, EB26 Some 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

SW, EB27 High-level View of the Service Ontology ServiceProfile ServiceModel ServiceGrounding Service Resource provides presents describedBy supports What the service does How it works How to Access it

SW, EB28 Top Level of the Process Ontology ProcessProfile Atomic Process Composite Process Simple Process Control Construct Sequence Repeat Until ProcessComponent= Process U ControConstruct ProcessComponent= Process U ControConstruct ProcessComponent= Process U ControConstruct hasProcess hasProfile computedInput computedOutput computedEffect computedPrecondition invocab compsedBy expand collapse realizes realizedBy has Grounding Input Precondition Output effect Condition

SW, EB29 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 Architecture

SW, EB31 Introduction 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

SW, EB32 Introduction 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

SW, EB33 Functional Areas Dynamic Service DiscoveryB2BB2CUbiqGridInfo Advertising of Service Descriptions Candidate Service Query Formulation Candidate Service Matchmaking

SW, EB34 Functional Areas Service Process Enactment and ManagementB2BB2CUbiqGridInfo 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

SW, EB35 Functional Areas Negotiation and ContractingB2BB2CUbiqGridInfo Service contract negotiation Dispute Resolution and Compliance Non-Repudiation/Audit Tracking/Explanation

SW, EB36 Functional Areas Semantic Web Community Support ServicesB2BB2CUbiqGridInfo 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

SW, EB37 Functional Areas Service Lifecycle SupportB2BB2CUbiqGridInfo Executable process management services Resource Allocation and Provisioning services

SW, EB38 Summary 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.

SW, EB39 An Architecture of An Architecture of Semantic Community Web Portals (From:

SW, EB40 Development of Web Portals

SW, EB41 A KM Framework over SW (From:

SW, EB42 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)

SW, EB43 Sesame’s Architecture

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SW, EB46 An Ontology-Based Portal for Digital Library Services

Syntax Transformation of RDF

SW, EB48 What 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 Ora Lassila Ora Creator Name Ora Lassila

SW, EB49 (RDF in XML) n (RDF in XML) i (RDF in XML) 2 (RDF in XML) 1 DOM + Procedure 1 A single RDF data model Multiple RDF in XML DOM + Procedure 2 DOM + Procedure i DOM + Procedure n Transformation of RDF Using DOM Transformation of RDF Using DOM Result i Transformation results Problem

SW, EB50 A single RDF data model Multiple RDF in XML Transformation of RDF Using DOM Result i Transformation results Syntax-directed Transformation of RDF (RDF in XML) n (RDF in XML) i (RDF in XML) 2 (RDF in XML) 1 Syntax-directed Transformation Goal

SW, EB51 Two System Architectures

SW, EB52 RDF Grammar to Yacc Rules An RDF Grammar Rule RDF ::= [' '] obj* [' '] Revision RDF ::= xmlDeclaration stgRDF obj* etgRDF xmlDeclaration::= ‘ ’ encoding::= ‘encoding’ ‘=‘ coding | empty stgRDF::= ' ‘ | empty etgRDF::= ' ‘ | 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 Rules def 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'''

SW, EB53 RDF Grammar to DCG Rules An RDF rule description::=' ' | ' ‘ propertyElt* ' ' | 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 Triple obj(Obj) --> container(Obj);description(_),{getAllTriples(Obj)}. %RDF to KSL obj(Obj) --> container(Obj);description(_),{getKSLDocument(Obj)}.

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SW, EB60 Conclusion 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