Services and Semantics

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Services and Semantics
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Motivating Problem

• The Web currently contains 30 billion Web pages
• Nearly 100M active sites
• 10 million new pages added each day
• Children can create web pages
• BUT the Web contains only 28000 true Web
  services (Seekda.com)

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Overall Goals

• SOA4All will transform the Web into a domain
  where billions of parties are exposing and
  consuming services in a seamless transparent
  fashion
• SOA4All will integrate the service world of
  large enterprises, SMEs, and end-users enabling
  them to engage as peers (i.e., service consumers
  as well as service providers) within a network of
  equals

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Overall Architecture
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Overall Architecture
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Overall Architecture
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Overall Architecture
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Overall Architecture
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Overall Architecture
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Overall Architecture
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Approach
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Web Principles

• Openness
• Decentralized management, evolution
• Google is an abstraction rather than central
  control
• Enabling nm relationship
• Anonymous distribution through publication
• Serendipity
• Statelessness
• Common basis URI, HTTP methods

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Web 2.0 Principles

• Blurring the distinction between content
  consumers and content providers
• Moving from media for individuals towards media
  for communities
• Blurring the distinction between service
  consumers and service providers

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Semantics
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Machine Readable Web Pages
John Domingue B.Sc. (Hons)
(Computer Science), University of Warwick. Ph.D.
The Open University. Since the late 1990s my
research interests have been centred on
ontologies, the Semantic Web and Semantic Web
Services. An ontology is a shared formal
conceptualisation of a viewpoint over a domain of
discourse. In 1997 I developed WebOnto, an
easy-to-use ontology editor, which was the first
to support.
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Machine Readable Web Pages
John Domingue B.Sc. (Hons)
(Computer Science), University of Warwick. Ph.D.
The Open University. Since the late 1990s my
research interests have been centred on
ontologies, the Semantic Web and Semantic Web
Services. An ontology is a shared formal
conceptualisation of a viewpoint over a domain of
discourse. In 1997 I developed WebOnto, an
easy-to-use ontology editor, which was the first
to support.
name
education
CV
research
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Machine Readable Web Pages
John Domingue B.Sc. (Hons)
(Computer Science), University of Warwick. Ph.D.
The Open University. Since the late 1990s my
research interests have been centred on
ontologies, the Semantic Web and Semantic Web
Services. An ontology is a shared formal
conceptualisation of a viewpoint over a domain of
discourse. In 1997 I developed WebOnto, an
easy-to-use ontology editor, which was the first
to support.
name
education
CV
research
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WSMO Background
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WSMO Top Level
Provide the formally specified terminology of the
information used by all other components

• Semantic description of Web Services
• Capability (functional)
• Interfaces (usage)
• Non Functional Properties

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WSMO Top Level
Provide the formally specified terminology of the
information used by all other components

• Semantic description of Web Services
• Capability (functional)
• Interfaces (usage)
• Non Functional Properties

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WSMO Top Level
Provide the formally specified terminology of the
information used by all other components

• Semantic description of Web Services
• Capability (functional)
• Interfaces (usage)
• Non Functional Properties

22
WSMO Top Level
Provide the formally specified terminology of the
information used by all other components

• Semantic description of Web Services
• Capability (functional)
• Interfaces (usage)

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WSMO Lite
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WSDL
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WSDL Simplified
Web service
input
Operation 1
output
input
Operation 2
output
.
.
.
input
Operation N
output
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Upper Service Ontology

• Service rdftype rdfsClass
• hasOperation rdftype rdfProperty
• Operation rdftype rdfsClass
• hasInputMessage rdftype rdfProperty
• hasOutputMessage rdftype rdfProperty
• hasInputFault rdftype rdfProperty
• hasOutputFault rdftype rdfProperty
• Message rdftype rdfsClass

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SAWSDL
But no predefined semantics!
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SAWSDL Properties

• modelReference rdftype rdfProperty
• liftingSchemaMapping rdftype rdfProperty
• loweringSchemaMapping rdftype rdfProperty
• Attached to elements of the service model

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WSMO-Lite Terms

• Ontology rdftype rdfsClass
• rdfssubClassOf
  owlOntology
• ClassificationRoot rdfssubClassOf rdfsClass
• NonFunctionalParameter rdftype rdfsClass
• Condition rdftype rdfsClass
• Effect rdftype rdfsClass

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Classification Example

• exService
• rdftype wlClassificationRoot
• exeCommerceService
• rdfssubClassOf exService
• exTravelReservationService
• rdfssubClassOf exeCommerceService
• exAccommodationReservationService
• rdfssubClassOf exeCommerceService

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Condition Example

• exRomaHotelReservationPrecondition
• rdftype wlCondition
• rdfvalue
• ?request
• numberOfGuests hasValue ?guests
• and city hasValue ?city
• memberOf ReservationData
• and ?guests lt 10
• and ?city 'Roma wsmlAxiomLiteral

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WSMO-Lite Example

• ltwsdldescriptiongt
• ltwsdltypesgt ltxsschemagt
• ltxselement name"ReservationRequest"
• sawsdlmodelReference"exReserva
  tion"
• sawsdlloweringSchemaMapping"ex
  ResMapping.xsparql" /gt
• lt/xsschemagt lt/wsdltypesgt
• ltwsdlinterface name"HotelReservations"
• sawsdlmodelReference
• "exAccommodationReservationS
  ervice"gt
• ltwsdloperation name"searchForRooms"
• sawsdlmodelReference"wsdlxSafe
  Interaction"gt
• lt/wsdloperationgt
• lt/wsdlinterfacegt
• ltwsdlservice name"RomaHotels"
  interface"HotelReservations"
• sawsdlmodelReference"exRomaHot
  elReservationPrecondition
• 
  exReservationFee" /gt
• lt/wsdldescriptiongt

I
I
F
B
F
N
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MicroWSMO
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hRESTS

• Microformat
• Collaboration with Amit Sheth
• Introduces the service model structure
• Service
• Operations
• Address, method
• Inputs, Outputs (only their existence)
• MicroWSMO, SA-REST

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Example hRESTS

• ltdiv class"service" id"svc"gt
• ltpgtDescription of the
• ltspan class"label"gtACME Hotelslt/spangt
  servicelt/pgt
• ltdiv class"operation" id"op1"gtltpgt
• The operation ltcode class"label"gtgetHotelDet
  ailslt/codegt is
• invoked using the method ltspan
  class"method"gtGETlt/spangt
• at ltcode class"address"gthttp//example.com/h
  /idlt/codegt,
• with ltspan class"input"gtthe ID of the
  particular hotel replacing
• the parameter ltcodegtidlt/codegtlt/spangt.
• It returns ltspan class"output"gtthe hotel
  details in an
• ltcodegtexhotelInformationlt/codegt
  document.lt/spangt
• lt/pgtlt/divgt
• lt/divgt

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MicroWSMO

• Extends hRESTS
• mref for model references
• lifting, lowering
• Applies WSMO-Lite semantics

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MicroWSMO Example

• ltdiv class"service" id"svc"gt
• ltpgtltspan class"label"gtACME Hotelslt/spangt is a
• ltabbr class"mref" title".../ecommerce/hotel
  Reservation"gt
• hotel reservationlt/abbrgt service.lt/pgt ...
• ltdiv class"operation" id"op1"gtltpgt ...
• ltspan class"input"gtA particular hotel ID
  replaces the param
• ltcode class"mref" title".../onto.owlHot
  el"gtidlt/codegt
• (lta rel"lowering" href".../hotelID.xslt"
  gtloweringlt/agt).
• lt/spangt. ...
• lt/pgtlt/divgt
• lt/divgt

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WSMO-Lite MicroWSMO
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Context
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Contextual Service Adaptation Framework
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Ontology Stack
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Obtaining Service Data
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Annotation Structure
Provider
Service Doc
Domain
Service
Pricing Doc
WSDL Doc
Service Doc
WSDL Doc
Service Doc
WSDL Doc
Service Doc

• WSDL ? Endpoint ? Domain ? Provider
• Endpoint ? Host ? Country
• Input/Output HTTP Status ? authentication
• Pricing Documentation ? commercial / on sale
• Service Documentation ? public

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SOA4All Summary
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SOA4All aims to transform the Web from a Web of
data to a dynamic Service Web comprised of
billions of services
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Underlying Principles

• SOA to move from software to serviceware
• Web principles and technology as the underlying
  infrastructure for the integration of services at
  a world wide scale
• Web 2.0 to facilitate ease-of-use and to blur
  distinction between provider and consumer
• Semantic Web technology as a means to abstract
  from syntax to semantics as required for
  meaningful service discovery and mediation
• Context management to ensure that provision
  functionalities fully meet the needs of users

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Thanks