Autonomous Semantic Web Services by vev19514

VIEWS: 49 PAGES: 61

									Autonomous Semantic Web
Services


       Katia Sycara
       Intelligent Software Agents and Web
       Technologies Lab
       Carnegie Mellon University
       katia@cs.cmu.edu
       http://www.cs.cmu.edu/~softagents/
                                ISRI-Seminar-05



    Talk Overview
       The Vision
       Requirements and Challenges
       Web Services
       Semantic Web
       Multi Agent Systems (MAS)
       Semantic Web Services
              OWL-S
       Future Directions




2      Copyright Katia Sycara
                                        ISRI-Seminar-05



    From the Internet to the Semantic Web




                    Old World :                                    New World:
              “The eye-ball Web”                               “The Semantic Web”



       The architecture of the Web is                     The content of the Web
       geared towards delivering                          becomes computer intelligible
       information visually (Internet                     (Internet filled with machine
       filled with human readable                         understandable information)
       information)




      Source: IBM

3         Copyright Katia Sycara
                                        ISRI-Seminar-05



    From the Internet to Web Services




                    Old World :                                     New World:
              “The eye-ball Web”                             “The transactional Web”



       The architecture of the Web is                     The architecture of the Web
       geared towards delivering                          geared towards exchanging
       information visually (Internet                     information between
       filled with human readable                         applications (Internet filled
       information)                                       with executables)




      Source: IBM

4         Copyright Katia Sycara
                                        ISRI-Seminar-05



    From the Internet to Semantic Web Services




                    Old World :                                     New World:
              “The eye-ball Web”                             “The Coordination Web”



       The architecture of the Web is                     The architecture of the Web
       geared towards delivering                          geared towards applications
       information visually (Internet                     that intelligibly coordinate
       filled with human readable                         information exchanges
       information)                                       (Internet filled with machine
                                                          understandable executables)




      Source: IBM

5         Copyright Katia Sycara
                                        ISRI-Seminar-05



    From the Internet to Autonomous Semantic Web Services




                    Old World :                                     New World:
              “The eye-ball Web”                                 “The Agent Web”



       The architecture of the Web is                     The architecture of the Web
       geared towards delivering                          geared towards goal directed
       information visually (Internet                     applications that intelligibly
       filled with human readable                         and adaptively coordinate
       information)                                       information and action
                                                          (Internet filled with context-
                                                          aware and self organizing
                                                          agents)



      Source: IBM

6         Copyright Katia Sycara
                                 ISRI-Seminar-05



    The Integration Challenge
      Integrate multiple independent and heterogeneous
         Data repositories
         Processes
         Applications
      Ensure
         Semantic equivalence of equivalent concepts
         Performance
         Communication of “semantic” agreements
         Dynamism: real time access works accurately
         Flexibility: systems enter and leave integration


7       Copyright Katia Sycara
                                 ISRI-Seminar-05



    The Integration Past and Future?
      Numerous solutions to date (since the ’70s):
        Tool driven
        Data driven
        Process driven
        Model driven
        Web services




8       Copyright Katia Sycara
                                     ISRI-Seminar-05



    Web Services - A New Paradigm?

    Web Services heralded as:
     “… self-contained, self-describing, modular applications that can be published,
       located, and invoked across the Web…”
    Which will allow…
       …on the fly composition of new functionality through the use of loosely
       coupled reusable software components
       …decomposition and distribution of large-scale processing tasks into
       component tasks executed simultaneously across many devices


     “Web services are expected to revolutionize our life in much the same way as the
       Internet has during the past decade or so.” (Gartner)




9        Copyright Katia Sycara
                                       ISRI-Seminar-05



     So what is new about Web Services?


               Component-Based Model                     Web Services Model
       Tightly coupled software applications   Loosely coupled software applications
       (high dependencies between              (low dependencies between
       systems)                                applications)


       Mainly designed for processes within    Mainly designed for processes across
       the enterprise                          enterprises

       Uses different protocols and            Uses standard protocols and
       technologies (e.g., Microsoft DCOM,     technologies (e.g., XML, SOAP, WSDL,
       CORBA)                                  HTTP)



       Web Services do for programs what the Web did for Documents


10         Copyright Katia Sycara
                                   ISRI-Seminar-05



     Requirements and Challenges
        Information and action integration across the Web (currently the
        user is the “glue”)
        System integration/interoperability Web-wide (within and across
        organizations)
        Semantic Interoperability
        Consistency of behavior of long running transactions (both for e-
        commerce and e-science) in the face of partial, distributed failures
        Dynamic and goal-directed discovery, interaction and composition
        of applications across the Web



         Tension between the “anarchy” of the Web and the requirements for
           reliable, consistent, trusted transactions of e-commerce and e-science



11       Copyright Katia Sycara
                                   ISRI-Seminar-05



     Current State: Web Services Standards
         SOAP: XML based web services communication protocol
       Limitations
          Unbounded message format
          Has no communicative speech acts (cannot determine intention of
          actors or type of the message)
         WSDL: Structured mechanism to describe a WS
         interface
              Abstract operations that a Web Service can perform
              Format of messages it can process
              Protocols it can support
              Physical bindings to URIs and protocols
       Limitations
               No semantics for message sequencing and correlation
                No semantics for message content
12        Copyright Katia Sycara
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     Current State: Web Services Standards (cnt.)
     BPEL: Description of how Web Services are composed
       Flow Model describes the structure of the business
       process in terms of activities of process steps and data
       and control links
        Global Model
                • Describes interaction between provider and requester
                • Mappings between internal operations and WSDL port types
     Limitations
             No IOPEs
             Allows execution of a manually constructed composition
       UDDI: Directory Service for Web Services
     Limitations: keyword searches, limited capability search
13      Copyright Katia Sycara
                                         ISRI-Seminar-05


     Tackling Semantic Interoperability…

        Lack of Semantic Interoperability is a major hurdle for
            Discovery
               • Different terms used for advertisements and requests
            Invocation
               • Different specs for messages and WS interface
            Understanding
               • Interpreting the results returned by the Web service
            Composing Services
               • Reconciling private goals with goals of the WS
            Negotiating contracts & communications
               • Different terminology and protocols used




14        Copyright Katia Sycara
                                     ISRI-Seminar-05



     Is this a real problem?

       World Wide Annual Integration plus Data Quality Costs:
        $1 Trillion / year

       “The problem is not in the plumbing. It’s in the semantics”
       (quotation from Michael Brodie’s invited talk at ISWC 2003)




       Note: some standards committees, e.g. WSDL and UDDI start realizing this
          truth and planning to incorporate RDF and OWL in these standards


15         Copyright Katia Sycara
                                  ISRI-Seminar-05



     Three Significant Technological Visions
         Semantic Web
         Multi Agent Systems (MAS)
         Semantic Web Services




16       Copyright Katia Sycara
                                                                     ISRI-Seminar-05



 Autonomous Semantic Web Services Stack Diagram
                                            Autonomous Semantic Web Services
                               Eg Contracts; Info Integration; Business Process Automation; Tasking
                     Choreography eg BPEL
Web Services Stack




                                                                                                                                                                      RDF Model & Syntax
                                                                                                          Logic Framework
                                                                                                                            Rules eg RuleML
                                                                                                                                              DAML+OIL
                                                                                                                                                         RDF Schema
                     Process Specifications




                                                                                          Trust
                                                                                                  Proof
                      Directories, e.g. UDDI
                           Messaging
                                WSDL
                                  SOAP                                                    Semantic Web Stack
                                                     XML                                                                    Namespaces
                              URI                                     Unicode                         Encryption, Signature
                                                   Copyright Semantic Web Services Initiative
   17                     Copyright Katia Sycara
                                           ISRI-Seminar-05

     Semantic Web
     Definition
          Goal of Web Semantics: Development of common representation format, shared
          ontologies, reasoning mechanisms, and query engines to support improved
          utilization of Web knowledge
          Semantic Web technologies and tools
                Rdf
                OWL


       “The Semantic Web is an extension of the current Web in which information is given a
          well-defined meaning, better enabling computers and people to work in
          cooperation. It is the idea of having data on the Web defined and linked in a way
          that it can be used for more effective discovery, automation, integration and reuse
          across various applications. The Web can reach its full potential if it becomes a
          place where data can be processed by automated tools as well as people”

                                                From the W3C Semantic Web Activity statement


                            Semantic Web: semantic metadata and ontologies for web
                            content to enable information access, integration,
                            interoperation and consistency.

18         Copyright Katia Sycara
                                             ISRI-Seminar-05

     Semantic Web
     OWL
           OWL is a W3C standard
           OWL is a Description Logic-based Language: provides the basic
           constructs to describe ontologies
                 Definition of concepts
                 Relations between concepts
                 Special relation: subclass for generalization
                 Effectively computable
                    • Good optimization algorithms support inference

           OWL specifications
                W3C page on OWL
                  • http://www.w3c.org/2001/sw/WebOnt/
                OWL Guide and language reference
                  • http://www.w3.org/TR/owl-guide/
                  • http://www.w3.org/TR/owl-ref/
           Tutorials
                Costello and Jacobs’ OWL tutorial: http://www.xfront.com/owl



19          Copyright Katia Sycara
                                  ISRI-Seminar-05



     RCal Calendar Agent
     Retsina Semantic Web Calendar Agent supports:
       Browsing of agendas and schedules marked up in OWL & RDF
       Invocation of related tasks, such as scheduling meetings and email
       Integration of selected meetings and events into MS Outlook
     Can parse markup using several ontologies, including
       Hybrid ICal Calendar Ontology
       Dublin Core Ontology
       Friend-of-a-Friend Ontology
     Schedule markup using other ontologies can be
     accessed via translation agents
       DMA2ICal Agent converts OWL Meeting Agenda markup into ICal
       Markup.
                    http://www.daml.ri.cmu.edu/Cal
20       Copyright Katia Sycara
                                   ISRI-Seminar-05



     Importing Schedules into MS Outlook




21        Copyright Katia Sycara
                                     ISRI-Seminar-05


     Multi Agent Systems
     Agent Characteristics
      A software agent is a computational entity with the following key
         characteristics:

              Situatedness: agent receives sensory inputs from its environment
              and outputs actions (physical environments, Internet)

              Autonomy: agent is goal-directed and has control over its internal
              state (can reason and act without direct intervention of others)

              Interactivity/Sociability: agents interact in peer to peer fashion with
              humans and/or other agents in pursuit of their goals (individual or
              collective)

              Adaptivity: agents respond reactively or proactively to changes in
              their environment


22          Copyright Katia Sycara
                                      ISRI-Seminar-05



     Relation Agents/Web Services
       Decision Making
          Goal Directed
   Situation Awareness
                                     Agent
  Coordination/Teaming
                                          Semantic    Data structures to concepts
                                          Web Service Interaction Management
                                                      Service Composition
 Network Interface Mgm
   Binding of end points          Web Service
      Data Serialization
 Remote Procedure Call
                                     Network




23       Copyright Katia Sycara
                                    ISRI-Seminar-05
     Multi Agent Systems
     Autonomous behavior is needed for Open
     Environments & Complex Interactions

        Open Environments
           No predefined structure
           Agents leave and join the society dynamically
           Communication is not ensured all the time
           Information sources may appear and disappear


        Complex Interactions
           Dynamic task decomposition & allocation
           Provider selection
           Planning for composition of MAS reasoning



24         Copyright Katia Sycara
                                    ISRI-Seminar-05


     Multi Agent Systems
     Generic Tasks in Open Environments

           Agents must be able to:
              discover each other. We distinguish the notion
             of agent identity from the notion of agent
                 functionality.
                    Identity is found through Agent Name
                    Services (ANS)
                    Functionality/capability is found through
                    Middle Agents
                 interact/transact with each other
                 compose results of their reasoning
                 monitor progress of delegated tasks
25         Copyright Katia Sycara
                                                    ISRI-Seminar-05


           Multi Agent Systems
           RETSINA Multi-Agent Organization

                                                      User 1                User 2             User u
 Distributed                         Goal and Task
 adaptive                            Specifications                                                        Results

 collections of                                  Interface Agent 1      Interface Agent 2   Interface Agent i

 agents                                  Tasks                                                             Solutions
 (autonomous                                        Agent/Service        Agent/Service2     Agent/Service t

 services) that
 coordinate to do                       Info & Service         Information and Task Execution
                                                                                                                Replies
 tasks on the user’s                       Requests                  Conflict Resolution

 behalf                                                                  MiddleAgent 2
                                                                                             Agent/Service n
                                                                    Advertisements
     RETSINA download at                         Agent/Service1                                         Answers
     www.cs.cmu.edu/~softagents
                                                                                                  Info
                                                              Info                              Source m
                                          Queries                              Info
                                                            Source 1
                                                                             Source 2
26          Copyright Katia Sycara
                                             ISRI-Seminar-05

     Multi Agent Systems
     Agent Discovery and Mediation

           Agents that provide services advertise their expertise/capabilities
           to middle agents
           Requester agents ask middle agents for agents with particular
           capabilities
           Middle agents match requests to advertisements and return results
           Communication protocols include formal semantics and ontologies
           for interoperation
           The discovery scheme enables system robustness through
           functional substitutability of agents
           Our research at CMU has identified 28 types of middle agents with
           different functionalities, protocols and performance tradeoffs



       Hao-Chi Wong and Katia Sycara “A taxonomy of middle agents for the Internet”, In Proceedings of
          the Fourth International Conference on Multi-Agent Systems (ICMAS'2000)


27          Copyright Katia Sycara
                                                ISRI-Seminar-05

     Multi Agent Systems
     Matchmaker


                                      Request for service
           Requester                                              Matchmaker
                                      Contact information of
                                     providers that match the
                                             request                           Advertisement
                                                                               of capabilities
                                      Delegation of service
           Results of
         service request                                          Provider 1   Provider n



             This is blueprint for the “SOA Triangle”

28          Copyright Katia Sycara
                                             ISRI-Seminar-05


     Multi Agent Systems
     Facilitator

                            Delegation of service
                               + preferences
     Requester                                             Facilitator
                                 Results of service
                                                                             Advertisement
                                                                             of capabilities
                                             Delegation          Results
                                             of service         of service

                                                          Provider 1         Provider n




29      Copyright Katia Sycara
                                     ISRI-Seminar-05


     Multi Agent Systems/Semantic Web Services
     Problem of Discovery

       Requester and provider have different views
          Provider sells Mutual Funds
          Requester wants Mutual Funds of European Companies
                     There is no exact match
       Matchmaker or Facilitator need to exploit the semantics of
       advertisements and requests to recognize partial matches




30          Copyright Katia Sycara
                                      ISRI-Seminar-05


     Semantic Web Services
     OWL-S Ontology

     OWL-S is an OWL ontology to describe Web services
     OWL-S has been accepted as a Note by W3C (12/1/2004)
     OWL-S leverages on OWL to
        Support capability based discovery of Web services
        Support automatic composition of Web services
        Support automatic invocation of Web services
        Support monitoring of the execution of Web services

Complete do not compete
        OWL-S does not aim to replace the Web services standards
        rather OWL-S attempts to provide a semantic layer
         • OWL-S relies on WSDL for Web service invocation (see Grounding)
         • OWL-s Expands UDDI for Web service discovery (OWL-S/UDDI mapping)

                         http://www.daml.org/services/owl-s/

31          Copyright Katia Sycara
                                      ISRI-Seminar-05

     Semantic Web Services
     Acknowledgements to the
     OWL-S Web Services Coalition
           BBN: Mark Burstein
           CMU: Katia Sycara, Massimo Paolucci, Naveen Srinivasan
           De Montfort University: Monika Solanki
           ISI: Jerry Hobbs
           U. Of Maryland: Bijan Parsia
           Nokia: Ora Lassila
           Southampton: Terry Payne
           Stanford KSL: Deborah McGuiness
           SRI: David Martin
           U. Of Toronto: Sheila McIlraith
           Vrije Universiteit: Marta Sabou
           Yale: Drew McDermott

32         Copyright Katia Sycara
                                      ISRI-Seminar-05

     Semantic Web Services
     Relation to Web Services Technology


                                                         Web Services
                                      OWL-S
                                                        Infrastructure
                Discovery
                                       Profile            UDDI API
               What it does
            Choreography
                                    Process Model         BPEL4WS
               How is done
               Invocation           Grounding+
                                                         WSDL/SOAP
             How to invoke          WSDL/SOAP




33         Copyright Katia Sycara
                                         ISRI-Seminar-05


     Semantic Web Services
     OWL-S Upper Ontology



                                                            •WS Capability specification to assist
                                                            Discovery
                                                            •Used for advertisement of service
                                                            Capabilities
                                                            •Used for requesting WS with desired
                                                            capabilities



      • Mapping to WSDL
           • communication protocol (RPC, HTTP, …)
                                                           • Control flow of the service
           • marshalling/serialization
                                                                 •Black/Grey/Glass Box view
           • transformation to and from XSD to OWL
                                                           • Protocol Specification
                                                           • Abstract Messages




34          Copyright Katia Sycara
                                      ISRI-Seminar-05


     Semantic Web Services
     Capability Description
           Preconditions
               Set of conditions that should hold prior to service invocation
           Inputs
               Set of necessary inputs that the requester should provide to invoke
               the service
           Outputs
               Results that the requester should expect after interaction with the
               service provider is completed
           Effects
               Set of statements that should hold true if the service is invoked
               successfully.
           Service type
               What kind of service is provided (eg selling vs distribution)
           Product
               Product associated with the service (eg travel vs books vs auto parts)
           Service Parameters (e.g. security, QoS etc)

35         Copyright Katia Sycara
                                             ISRI-Seminar-05

     Semantic Web Services
     CMU’s Matching Algorithm

        Matching of I/O of the request with I/O of the
        advertisement
        Four degrees of match                                                                    Thing




                                                            subsume
              Exact
              Subsume
              Plug-In                                                                  Vehicle           Price
              Fail
        Efficient implementation given correct indexing
        of advertisements                                                      Car               Truck




                                                            exact
              Linear complexity with some restrictions on
              the query
        Current work aims at generalizing matching                    Coupe            Sedan
        process to include preconditions/effects service
        and product types and service parameters

                                                            plug-in
                                                                              Luxury       Mid-Size

     Massimo Paolucci, Takahiro Kawamura, Terry R. Payne,
        Katia Sycara; "Semantic Matching of Web
        Services Capabilities." In Proceedings of the 1st
        International Semantic Web Conference (ISWC2002),
        2002

36            Copyright Katia Sycara
                                                ISRI-Seminar-05

 Semantic Web Services
 Integration of OWL-S Matchmaker and UDDI
                                                           • OWL-S Profile has been mapped
     Publish Port        Inquiry Port   Capability Port      to UDDI data structure
                                                                 • OWL-S Web services can be
                                                                   advertised in UDDI as any
                UDDI
          Business Registry
                                                                   other Web service
                                                            (see Paolucci et al 2002)
                 Green Pages
                                         OWL-S            • CMU OWL-S Matching engine has been
              Yellow Pages              Matching            integrated within UDDI server
           White Pages
                                         Engine           • CMU UDDI server provides
                                                                • Normal UDDI Publish/Inquiry ports
                                                                     • Complete interoperability with any
                                                                       UDDI Client
                                                                • Capability Port provides OWL-S based
     CMU UDDI is publicly available at                            capability requests
     www.daml.ri.cmu.edu/matchmaker                       (see Srinivasan et al 2004)
     or on SemWebCentral
     http://projects.semwebcentral.org/projects/mm-client/
     A variant of the CMU UDDI is in use at the NTT UDDI Business
     Registry (The main public UDDI in Japan) (see Kawamura et al
     2003, 2004)
37            Copyright Katia Sycara
                                    ISRI-Seminar-05


     Semantic Web Services
     Process Model



                                                      Process Model
                                                           Describes how a service
                                                           works: internal processes of
                                                           the service
                                                           Specifies service interaction
                                                           protocol
                                                           Specifies abstract messages:
                                                           ontological type of
                                                           information transmitted
                                                      Facilitates
                                                           Web service invocation
                                                           Composition of Web services
                                                           Monitoring of interaction




38         Copyright Katia Sycara
                                         ISRI-Seminar-05


     Semantic Web Services
     Definition of Process

       A Process represents a transformation (function). It is characterized by four
       parameters
           Inputs: the inputs that the process requires
           Preconditions: the conditions that are required for the process to run
           correctly
           Results: a process may have different outcomes depending on some
           condition
            • Condition: under what condition the result occurs
            • Outputs: the data that results from the execution of the process
            • Effects: real world changes resulting from the execution of the process




39          Copyright Katia Sycara
                                    ISRI-Seminar-05


     Semantic Web Services
     Composite Processes
         Composite Processes specify how processes work together to
        compute a complex function
         Composite processes define
          1. Control Flow
              Specify the temporal relations between the executions of the
              different sub-processes
          2. Data Flow
              Specify how the data produced by one process is transferred to
              another process




40         Copyright Katia Sycara
                                                   ISRI-Seminar-05


     Semantic Web Services
     Example of Composite Process
                                                                                Control Flow Links
                                    Airline        Sequence            Flight   Specify order of
                                                   BookFlight                   execution



                                                    Data-Flow Links
                                                 Specify transfer of data


            Perform                                              Perform
            Airline                                                             Select
            Depart          Get Flights           Flights            Flights                Flight
                                                                                Flight
            Arrive

                                                    Perform statements
                                              Specify the execution of a process

41         Copyright Katia Sycara
                                     ISRI-Seminar-05


     Semantic Web Services
     Control Flow
           Processes can be chained to form a workflow
           OWL-S supports the following control flow constructs
               Sequence/Unordered: to represent a list of processes that are
               executed in sequence or random order
               Conditionals: if-then-else statements
               Loops: while and repeat-until statements
               Multithreading and synchronization: split process in multiple
               threads, and rendezvous (joint) points
               Non-deterministic choices: (arbitrarily) select on process of a set




42         Copyright Katia Sycara
                                         ISRI-Seminar-05


     Semantic Web Services
     Data Flow
     Dataflow allows information that is transferred from process to process.
     OutputInput:
         The information produced by one process is transferred to another in the same
            control construct
     Input Input:
         The information received by a composite process is transferred to the sub-processes
     OutputOutput:
         The information produced by a subprocess is transferred to a super-process




43          Copyright Katia Sycara
                                    ISRI-Seminar-05


     Semantic Web Services
     Service Grounding


                                             Service Grounding
                                                 Provides a specification of service
                                                 access information.
                                                 Service Model + Grounding give
                                                 everything needed for using the
                                                 service
                                                 Builds upon WSDL to define
                                                 message structure and physical
                                                 binding layer




44         Copyright Katia Sycara
                                    ISRI-Seminar-05


     Semantic Web Services
     Mapping OWL-S /WSDL 1.1
           Operations correspond to
           Atomic Processes

           Input/Output messages
           correspond to Inputs/Outputs
           of processes




45         Copyright Katia Sycara
                                           ISRI-Seminar-05


     Semantic Web Services
     Example of Grounding
                                Airline   Sequence           Flight
                                          BookFlight




          Perform                                       Perform
           Airline                                                     Select
           Depart         Get Flights Flights            Flights                  Flight
                                                                       Flight
           Arrive



           Arrive
           Depart Get Flights Op Flights                 Flights       Select     Flight
           Airline                                                    Flight op

         WSDL

46         Copyright Katia Sycara
                                             ISRI-Seminar-05


     Semantic Web Services
     Result of using the Grounding
           Invocation mechanism for OWL-S
                Invocation based on WSDL
                Different types of invocation supported by WSDL can be used with OWL-S
           Clear separation between service description and
           invocation/implementation
                Service description is needed to reason about the service
                   • Decide how to use it
                   • Decide how what information to send and what to expect
                Service invocation may be based on SOAP and XSD types
                The crucial point is that the information that travels on the wire is the same
                information used in the ontologies
           Allows any web service to be represented using OWL-S
                For example: Amazon.com




47         Copyright Katia Sycara
                                          ISRI-Seminar-05


     Semantic Web Services
     Mapping OWL-S to WSDL
                          OWL-S invocation is based on the Grounding
                            Map atomic processes into WSDL operations
                            Use XSLT to map between XML Schema data structures and
                            Ontological Information
                            Invocation procedure totally separated from semantic
                            description of Web service
                              • Invocation may be modified without changing semantic
                                 description
                            Any Web service can be described in OWL-S without
                            modifying the WSDL description of the service
                              • Amazon’s Web service has been described in OWL-S
                                 maintaining Amazon’s XML-Schema data types




48         Copyright Katia Sycara
                                                  ISRI-Seminar-05


     Semantic Web Services
     OWL-S Virtual Machine

        OWL-S VM a generic processor for the OWL-S Process Model
          Uses OWL-S to represent service descriptions
          It can interact with any OWL-S Web service
          Based on the Process Model formal semantics (Ankolekar et al 2002)
          Implements grounding mapping to WSDL
          Uses OWL to represent information to exchange between Web services
          Actively adopts logic inference to reason about OWL-S and OWL
          ontologies
          Exploits Web services technology such as Axis and WSIF for actual
          invocation and message exchange


         Anupriya Ankolekar, Frank Huch, Katia Sycara. "Concurrent Execution Semantics for DAML-S with
            Subtypes." In The First International Semantic Web Conference (ISWC) , 2002.
         Massimo Paolucci, Anupriya Ankolekar, Naveen Srinivasan and Katia Sycara, "The DAML-S Virtual Machine," In
            Proceedings of the Second International Semantic Web Conference (ISWC) , 2003,


49         Copyright Katia Sycara
                                              ISRI-Seminar-05


     Semantic Web Services
     Architecture of CMU OWL-S VM

                                      Web Services
                                                 SOAP

       Provider                                         OWL-S VM
      Web Service
      Description                  Webservice Invocation
                                       Axis’s Web Service
                                      Invocation Framework
                                              OWLS
         WSDL                           WebServiceInvoker



                                      OWL-S Processor              Requester
         OWL-S
         Ground                     Grounding Execution Rules
           ing
                                  Process Model Execution Rules    APPLICATION
        OWL-S
        Process                    OWL Inference Engine
         Model                            OWL Jess KB
                                              Jess
                                              Jena


50       Copyright Katia Sycara
                                       ISRI-Seminar-05


     Semantic Web Services
     WSDL2OWL-S Converter
           Provides partial conversion from WSDL Web service
           descriptions to OWL-S descriptions
                Generates complete specification of Grounding
                Partial Specification of the Process Model
                   • Including Atomic Processes
                Partial Model of the Profile
           Resulting models require additional annotations to
           include semantic descriptions
           Combined with Java2WSDL to provide Java2OWL-S
           Web Based Interface

                    http://www.daml.ri.cmu.edu/wsdl2owls/
      Download: http://projects.semwebcentral.org/projects/wsdl2owl-s/

51         Copyright Katia Sycara
                                          ISRI-Seminar-05


     Semantic Web Services
     Process Model of AWS

     •WSDL2OWL-S
     used to generate
     OWL-S for
     Amazon’s Web                    Shop
     Service
     •OWL-S VM used to
     interact with                   Search
     Amazon Web                                             Reserve
     service




52          Copyright Katia Sycara
                                               ISRI-Seminar-05


     Semantic Web Services
     Performance
                                                                                        Data
                                                                   OWL-S VM        Transformation
       OWL-S VM client on
       browsing+reserving task
       Analyzed data by computing:
           Time required by OWL-S VM to
           execute Process Model
           Time required for data
                                                                         Amazon
           transformation to fit Amazon
           requirements                                                 Invocation
           Time required to invoke an
           operation on Amazon
       98 runs total over 4 days in varying load
       conditions
       Results in milliseconds
                                                                   VM        Data Trsfm   Invocation


                                                      Average           83       156          2797
                                                      percentage        3%       5%           92%

                                                      Strd dev       107         146          1314


53           Copyright Katia Sycara
                                    ISRI-Seminar-05


     Autonomous Semantic Web Services
     Problem of Composition

       No single Web service may achieve all goals of an agent
          Composition is the process of chaining results from different Web
          services automatically
       Planning problem
          How do the Web services fit together?
       Interoperation problem
          How does the information returned fit together?




54         Copyright Katia Sycara
                                           ISRI-Seminar-05


     Autonomous Semantic Web Services
     CMU Composition Architecture
          Exploits Retsina Architecture for WS composition
                OWL-S/UDDI Matchmaker for discovery
                Retsina planner to control the agent
                   • Use interleaving of planning and execution to allow communication while
                     planning
                OWL Reasoner
                OWL-S Virtual Machine to communicate and invoke Web Services




           Katia Sycara, Massimo Paolucci, Anupriya Ankolekar and Naveen Srinivasan, "Automated
               Discovery, Interaction and Composition of Semantic Web services," Journal of
               Web Semantics, Volume 1, Issue 1, September 2003, pp. 27-46

55         Copyright Katia Sycara
                                    ISRI-Seminar-05


     Autonomous Semantic Web Services
     Example of Composition

     Used in a number of applications:
     travel domain, supply chain
     management

     Supports composition and execution
     of Web Services

     Connection with autonomous agent
     technology




56        Copyright Katia Sycara
                                                      in collaboration with
                                              ISRI-Seminar-05


     Semantic Web Services
     Security and Policies
       No standard OWL-S representation for Security and Policies has been published yet
           But experimentation already under going
           Adoption of a solution will depend on WS security standards
       Security Experiments with
               • representing security capability/requirements for discovery
               • Representing security information in Process Model.
       Policies:
           Experiments combining OWL-S and Rei
           Rei statements included in Process Model to constrain the use of a Web service (see Kagal 2004)
       Recent work on Formal Verification of OWL-S Process Models provides a way to certify
       adherence to a policy



         Grit Denker, Lalana Kagal, Tim Finin, Massimo Paolucci, Naveen Srinivasan and Katia Sycara,
            "Security For DAML Web Services: Annotation and Matchmaking" In Proceedings of the
            Second International Semantic Web Conference (ISWC 2003), Sandial Island, Fl, USA, October
            2003, pp 335-350.
         Anupriya Ankolekar, Massimo Paolucci, and Katia Sycara
           Spinning the OWL-S Process Model -- Toward the Verification of the OWL-S Process
           Models In Proceedings of Workshop on Semantic Web Services:
           Preparing to Meet the World of Business Applications (ISWC 2004)

57          Copyright Katia Sycara
                                     ISRI-Seminar-05


     Semantic Web Services
     Production cycle of OWL-S WS

     1.   Developer generates Java code
     2.   Semi-automated transformation of Java into partial OWL-S description
           – WSDL is generate as by-product
     3.   User friendly OWL-S editor is used to complete the OWL-S description
     4.   UDDI client can be used for automatic advertisement in UDDI
     5.   Verification tools are available for correctness checking
     6.   Automatic client generation: integration with the OWL-S VM




58          Copyright Katia Sycara
                                                        ISRI-Seminar-05



     CMU OWL-S IDE (Eclipse based)
                                      OWL-S/UDDI                 UDDI          UDDI-data
                                      Matching Engine            Client         structure



                                                                              OWL-S2UDDI
                                           OWL-S               Profile         Converter
                                           Editor
                                                               Process        OWL-S            Java
                                           eclipse                             API             Code
                                                             Grounding
                                                                                  OWL-S          Java
                                                             OWL-S Files           VM
                                           Java                                                  Code
Legend:                                    Code
  Tools integrated in the OWL-S IDE
 10/22/04
                                                                                Spin Based
     Data Files                                                                 Verification

                              Apache’s                                            BBN’s
                            Java2WSDL                WSDL       WSDL2OWL-S
                                                                                  SWeDE
                             Converter               Code         Converter
                                                                                 OWL Editor


              http://projects.semwebcentral.org/projects/owl-s-ide/
59                Copyright Katia Sycara
                                 ISRI-Seminar-05



     Contributions of the three technologies
        Semantic Web: ontologies, metadata annotations and
        knowledge based inference
        Multi Agent Systems: goal-directedness, semantically
        meaningful communication protocols, cooperative and
        self interested reasoning mechanisms
         Web Services: industry standards and industry buy in




60      Copyright Katia Sycara
                                 ISRI-Seminar-05



     Future Evolution of Web Services
       Semantic Web Services: services whose description is
       in a machine understandable language with formal
       semantics
       Agent-based or Autonomous Semantic Web Services:
          goal-directed
          autonomous choice of partners
          based on own current internal goals, internal
          attitudes and their projection of their future needs.
          semantics support ASWS

        Semantic Web Services Interest Group created at W3C
        public-sws-ig@w3.org

61      Copyright Katia Sycara

								
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