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					                  ISO/IEC JTC1/SC32/WG2 N1485




MFI-7: Metamodel for
Service Registration

      Zaiwen Feng, Keqing He, Chong Wang, Jian Wang,
                        Peng Liang
            SKLSE, Wuhan University, P.R. China
                        2010.11.09

                                                   1
                      Outline
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         2
                      Outline
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary
            Motivation of this Work
   Heterogeneity in service
   Different Description languages
    WSMO, OWL-S, WADL, WSDL, SAWSDL, SA-rest…




     Solution: Providing a metamodel as the common
registration mechanism for different kinds of services.


                                                          4
                      Outline
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         5
                     Definitions of Service
   Service (systems architecture): the provision of a discrete
    function within a systems environment
       In the context of Enterprise architecture, Service-orientation, and Service-
        oriented architecture, the term service refers to a set of related software
        functionality, together with the policies that should control their usage.
         From: wikipedia (http://en.wikipedia.org/wiki/Service_(systems_architecture))



   Web service: a software system to support interaction over
    a network
       OASIS : a mechanism to enable access to one or more capabilities, where
        the access is provided using a prescribed interface and is exercised
        consistent with constraints and policies as specified by the service
        description.
       Web services are frequently just Internet Application Programming
        Interfaces (API) that can be accessed over a network, such as the Internet,
        and executed on a remote system hosting the requested services
            From: Wikipedia – Web Service
                                                                                         6
         Service Definition in MFI-7
   Service is defined as a modular functionality
    entity with provision of value that can be invoked
    by accessing its interface.
   Currently, we focus on
       SOAP Web service
       Restful Web service
       Web API




                                                         7
                      Outline
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         8
                                  Scope of MFI-7(1/2)

                                                       Common Facilities in MFI
WSDL: Web Services Description Language (W3C)
OWL-S: Web Ontology Language for Services(W3C)
WSMO: Web Service Modeling Ontology(W3C)
WADL: Web Application Description Language(W3C)
SA-Rest: Semantic Annotation-representational state
transfer(Wright State University, US)
                                                              Service Registry
SAWSDL: Semantic Annotation Web Services Description          based on MFI-7
Language(W3C)
SWSO: Semantic Web Service Ontology (W3C)

              Registration                                                        Interoperation

              Specification

                                                                                             …
                         WADL             SAWSDL OWL-S             SA-REST SWSO     WSMO

                                                                                                   9
               Scope of MFI-7(2/2)
   It is intended to
       specify a metamodel for registering services that can
        enable users to discover appropriate services.
       define the common functional and nonfunctional
        description of services.
       promote semantic interoperation between various
        services.
   It does not specify
       the elements expressed in specific languages
       details of service composition


                                                                10
                      Outline
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         11
    Overview of Service Semantics in
                 MFI-7
                         Objective
                         Semantic




Functional Semantic   Service Semantic   Interaction
                                          Semantic




                      Non Functional
                        Semantic




                                                       12
     Objective Semantics of Service
   Objective Semantics
       Objective that a client may have when consulting a
        Web Service

       For example:
            WSMO: It describe Objective semantic by post-condition and
             effect in service goal




                                                                          13
     Function Semantics of Services
   Function Semantics describes service
    functionality, i.e. what a service can offer to its
    clients when it is invoked. It includes that:
       Capability: the functionality defined using conditions
        which must hold before and after service invocation




                                                                 14
    Function Semantics of Services
   For example:
       Function Semantics
            WSMO: It describes function semantics by preconditon,
             postcondition(constrained input/output), and assumption,
             effect (conditions for service usage)
            SWSO: It describes function of service by input, output,
             precondition and effect
            SAWSDL(WSDL): It describes function of service by
             interface_name, operation_name, input and output
            OWL-S Profile: It describes feature of service by specifying
             the category of a given service, for example, the category of
             service within the UNSPSC classification system. Further, it
             shows function semantics through input, output, pre-
             condition and post-condition

                                                                             15
     Interaction Semantic of Service
   Interaction semantic: It is the formal description
    which defines a service’s public behavior.
       MFI-7 focuses on External behavior, which describes a
        protocol that can be used by the client to consume the
        service functionality
       We call the public behavior of service is choreography
        in MFI-7




                                                                 16
     Interaction Semantic of Service
   Interaction semantic
       OWL-S: From orchestration perspective, it describes a
        process model inside service
       WSMO: From choreography view, it specifies the
        behavior interface for service consumption; and from
        orchestration view, it specifies how the functionality of
        a web service is achieved by aggregating other web
        services
       SWSO: From orchestration view, it defines how to
        construct a process model inside a service



                                                                    17
    Non-Function Semantic of Service
   Non-Function Semantic: It describes attributes
    specifying quality of service
        We describe quality of service based on WS-Policy
         framework in MFI-7
        WS-Policy contains an attachment specification, WS-
         PolicyAttachment, which defines mechanisms for
         associating policies with policy subjects




                                                               18
    Non Function Semantic of Service
   Non Functional Semantic of Service
        For example:
              WSDL-S 1.0: It investigates how to represent QoS assertions
              using ontologies and rules by extending the WS-Policy
              framework (future work)
             OWL-S Profile: It provides information about quality rating of
              service
             SWSO: It consists of various attributes in the part of Service
              Descriptors, e.g. Service Trust, Service Reliability and Service
              Cost in order to describe QoS
             WSMO: It describes Web Service specific non-Functional
              properties in the part of Capability, e.g. Accuracy, Availability,
              Financial…


                                                                                   19
           How MFI-7 is constructed
   Harmonization of Service models for registration
       WSDL (Web Services Description Language, W3C, 2007)
       OWL-S (Web Ontology Language for Services, W3C,
        2007)
       WSMO (Web Service Modeling Ontology, W3C, 2005)
       SAWSDL(Semantic Annotation for WSDL, W3C, 2007)
       SWSO(Semantic Web Service Ontology, W3C, 2005)
       WADL (Web Application Description Language, W3C,
        2009)
       SA-Rest: Semantic Annotation-representational state
        transfer (W3C, 2010)
       …
                                                              20
   How to select elements and relationships from
    current service-related specifications?
       Function Semantics
       Non-Function Semantics
       Objective Semantics
       Interaction Semantics




                                                    21
Service concepts in OWL-S

  Condition
                       hasCondition

                                               hasParameter
    Result                                                      Parameter
                       hasResult


 ServiceCategory                              Profile
                         hasServiceCategory
                                                                  Input
                          presents
                                          ServiceProfile
                                                                  Output
                                        hasQualityRating
                           supports
             Service                     ServiceGrounding
                                                              Quality Rating

                          describedBy
                                           ServiceModel




           From: W3C, OWL-S: Semantic Markup for Web Services,
  http://www.daml.org/services/owl-s/1.2/overview/, accessed on 2010-05-12
                                                                               22
Service concepts in WSMO
                                   hasInterface
               Web Service                             interface

                          hasCapability      requestsInterface
                                 requestsCapability
               Capability                                 goal

         hasAssumption
                  hasEffect                               hasOrchestration
hasPrecondition           hasPostcondition
                  Axiom                              orchestration


hasSharedVariables                                          hasChoreography

            sharedVariables                           choreography




  From: W3C, Web Service Modeling Ontology, http://www.wsmo.org/TR/d2/v2.0/,
                          accessed on 2010-05-10

                                                                               23
Service concepts in SAWSDL
                                            hasSemantics
                                                                    Type


                                                     hasSemantics


                                 Fault                          Message
                          1..*            1..*            1..*
                                                     hasInput         1..*
           hasSemantics     hasInFault        hasOutFault
                                                                hasOutput
                                     1..1    1..1     1..1 1..1

       SemanticConcept                           Operation

                                     hasOperations      1..*
                  hasSemantics                          1..1

                                                 Interface




From: W3C, Semantic Annotations for WSDL and XML Schema, http://www.w3.org/TR/sawsdl/,
                                accessed on 2010-05-10

                                                                                         24
   Service concepts in SWSO
                                                      Service_name
                                       name
                                                      Service_Trust
                                      trust
          Service Descriptors
                                                      Service_Cost
                                              cost
                                       reliability
                                                      Service_Reliabiltiy
      hasDescriptor

                                describedBy
                SWSO Element                     Process Model

      support                     hasConstraints          hasFlowCore

     Grounding         Control Constraints            FLOWS-Core            composedOf



                                      message          AtomicProcess         channel



                   Input            Output           Precondition       Postcondition



From: W3C, Semantic Web Services Ontology, http://www.w3.org/Submission/SWSF-SWSO/
                                    access on: 2010-11-09


                                                                                         25
  Service concepts in SA-REST

                          Service



                                  hasOperation

                                                hasMethod
                         operation                               HTTTMethod



         hasInput                  hasOutput



             Input                  Output




From: W3C, SA-REST: Semantic Annotation of Web Resources, http://www.w3.org/Submission/SA-REST/
                                      access on: 2010-11-09


                                                                                                  26
     Service Concept in WADL
                    1

                           hasMethod       method
            Resource                  -name
                          1..1 1..*
    *                                 -id
                                    1..1            1..1
                           hasRequest                  hasRequest

                            0..1                               1..2
                            request                      response
                            1                           1..1
                                                               hasReresentation
                            *                           1..1
                                param                 representation
                         -name                       -mediaType
                         -style                      -element




From: W3C, Web Application Description Language, http://www.w3.org/Submission/wadl/
                                      access on: 2010-11-09


                                                                                      27
          MFI-7: Metamodel for Service Registration

                          presentedBy                                                                                                                   Assertion
                                           1..1
                                                      1..*                                                                   -valueType : ConceptfromDomainOntology
                1..1
                                 StateSignature                                                                              -comparisonOperator : ConceptfromDomainOntology
                  presentedBy                                        hasStateSingature            1..1                       -assertionName : ConceptfromDomainOntology
                                 TransitionRules
                                                             hasTransitionRules
                           -Condition[1..*] : string                                  Choreography
                           -Action[1..*] : string    1..*                  1..1            1..1
                                                                                                                                                    Alternative
                                                                          hasInteraction
                                                                                        1..1                              hasPolicy
                                                                                                                   1..1          0..*                    Policy
                                                                                        Service
                                                                                                                                        -Quality_Property_Type[1..*] : string
                                                                     -URI[1..1] : string
                                                                                                                      1..1

                                                                           1..1                      1..1     1..1 hasPostcondition
                                hasInput
                                                                                                     hasPrecondition
         1..*
                            0..*                                                                     0..*
                       Input                                                                              Precondition
       -Message_Type[1..1] : Parameter_Type                                            -Parameter[1..*] : ConceptfromDomainOntology
       -annotation[0..*] : Concept_URI             1..*       constrainedBy       0..* -Predicate[1..1] : ConceptfromDomainOntology


                       Output                                                                               Postcondition
1..*   -Message_Type[1..1] : Parameter_Type        1..*                                -Parameter[1..*] : ConceptfromDomainOntology
                                                              constrainedBy       0..*
       -annotation[0..*] : Concept_URI                                                 -Predicate[1..1] : ConceptfromDomainOntology              0..*
                             0..*

                                   hasOutput
  Comparison between MFI-7 and
      Other Specifications
  MFI-7           WSMO             OWL-S               SWSO             SAWSDL
  Service       Web services        Service             Service         Web service
    Input       precondition         Input               input             input
   Output       postcondition       Output              output            output
   Policy         Quality       ServiceParameter       Service              —
                  Aspects                          Trust/Reliability/
                                                         Cost
Precondition     assumption        Condition         precondtion            —

Postcondition      effect            Result              effect             —

 Interaction    choreography          —                   —                 —




                                                                                      29
     Function-related Metaclasses(1)
   Precondition
        specifies the state that should be satisfied before a service is
         invoked
   Postcondition
      specifies the state that should be satisfied after a service is
       invoked successfully
    Their properties are Parameter and Predicate

                         1..1     1..1 hasPostcondition

                          hasPrecondition
                                       0..*

                                Precondition




                                Postcondition
                                                          0..*
                                                                            30
    Function-related Metaclasses(2)
   Input, output
     the link between service and outer space
     Their type can be depicted as Message_Type

   Message_Type
       specifies the type of message that is used, as input variable, out
        variable.
       It can be the domain concepts in Ontology




                                                                             31
Non-Function Related Metaclass(1)
   Policy: It provides a grammar for representing
    the non-functional attributes of entities in a Web
    service based XML environment
   Quality_Property_Type: Current WS-Policy
    specification makes assertion in different
    domains, e.g. security, transaction, cost…




                                                         32
Non-Function Related Metaclass(2)
   A policy is defined as a finite set of alternatives.
    It can also be expressed as a disjunction of all its
    alternatives
   An alternative is defined as a finite set of
    assertions. It can also be expressed as a
    conjunction of all its assertions




                                                           33
Non-Function Related Metaclass(3)
   Assertion: A policy assertion represents an
    individual requirement, capability, or other
    property of a behavior.
       valueType: It is used to specify whether an assertion
        is a numeric or a non-numeric assertion
       comparisonOperator: It is used to represent the
        relationship between the assertion name and value
       assertionName: It describes name of assertion
                              <semsecurity:TokenType
                              assertionType="sempolicy:Requirement"
                              valueType="owl:object"
                              comparisonOperator="sempolicy:EQ">
                                   semsecurity:Kerberosv5TGT
                              </semsecurity:TokenType >

                                                                      34
        Interaction Related Metaclass
   Choreography
       The Choreography interface describes the behaviour of the
        service from the client's point of view (W3C Glossary, 2004)
       Users may be other Web Services, applications or human beings
       Transitionrule
       It deals with basic operations on instance data, such as adding,
        removing and updating instances to the states.
       State
       It defines the state ontology used by the service together with
        the definition of the types of modes the concepts and relations
        may have




                                                                           35
Choreography example
                     Choreography_Item 1



              phonenumber before monthnumber

                    Choreography_Item 2



                password before monthnumber

                     Choreography_Item 3



           monthnumber after authentication result


                   Choreography
                                                     36
Relationships with Other Parts in MFI




                                                       Metaclass from MFI-5
                                                       Metaclass from MFI-8
 annotation attributes are annotated by Ontology_Atomic_Construct from MFI-3
                                                                               37
                      Outline
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         38
           Registration example(1/4)
                   in WSMO
   Case study: Book Ticket

   Description
       The service can achieve the goal which specifies the
        intent of buying a ticket for a trip from one place to
        another


   Service Language
       WSMO



                                                                 39
              Registration example(2/4)
                      in WSMO
                  WS1                                WS2
                 Booking                            Paying
                                                                Reservation
                                  Book Ticket WS
Reservation
 Request

                         P1                 P2
                        Booking            Paying


creditCard

                                                             ticket




               I want to book a ticket!
                                                                         40
Maybe, In the above example, we should register three Web Services:
Web Service1: Booking (for invoking by business process)
Web Service2: Paying (for invoking by business process)
Web Service3: Book Ticket WS (the whole service)




                                                                      41
              Registration example(2/4)
                      in WSMO
                                                     reservationRequest

                                                    temporaryReservation
Reservation
 Request                    Reservation             temporaryReservation
              Book Ticket
                 WS                        Book           creditCard
                            ticket         Ticket        reservation
                                            WS
creditCard                                                  ticket

                                                    temporaryReservation
                       What is
                      my Goal?                           creditCard

                                                         negative
                I want to book a ticket!
                                                                           42
     What can we find proper service
                  by?
                                 Objective
                                 Semantic

                      MFI-8


Functional Semantic           Service Semantic              Interaction
                                                             Semantic


                                                                MFI-7

                              Non Functional
                                Semantic
       MFI-7                       Response time <= 5 seconds
                                   Security is high
                                   … … MFI-7
                                                                          43
Registration example (3/4)
        in WSMO




                             44
Registration example (3/4)
        in WSMO




                             45
Registration example (4/4)
        in WSMO




                             46
Registration example (4/4)
        in WSMO




                             47
Registration example (4/4)
        in WSMO




                             48
          Registration example(1/4)
                  in WADL
   Case study: Amazon item search service

   Description
       The service provided by Amazon is to search items in
        Amazon Internet Shop. Browser will return item
        information after user inputs keywords or index of
        item


   Service Language
       WADL


                                                               49
Registration example(2/4)
        in WADL

      SubscriptionId
                                   name
       SearchIndex     Amazon
                         Item
                                 description
         KeyWord        Search

                                    price
     ResponseGroup




     I want to search item in Amazon?
Registration example(3/4)
          WADL




                            51
Registration example(4/4)
          WADL




                            52
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         53
                      MFI-7 v.s. UDDI
   UDDI
       lacks description of service semantics
       mainly considers SOAP Web services
   MFI-7
       Provides a mechanism to register service semantics
        based on MFI-3&-5&-8
       Considers other kinds of services
            different protocols, such as SOAP, HTTP,…
            Restful Web Service, Mashup, …


                                                             54
   Motivation of this Work
   Definition of Service
   Scope of MFI-7
   Metamodel for Service Registration
   Service Registration Example
   MFI-7 v.s. UDDI
   Summary




                                         55
         Summary and Future Work
   Summary
       MFI-7 provides a means to register interaction
        information and capability of services
   Future work
       Submit CD version in 2010
       Coordinate with other specifications
       Support interoperation between services in cloud
        computing
       Refer more Web Services non-functional specifications
        to MFI-7 (E.g. SLA…)

                                                                56
Thank you!

  Q&A


             57

				
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