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Semantic Web Services Sheila A. McIlraith, Tran Cao Son, and Honglei Zeng Stanford University 2001

Semantic Web Services Sheila A. McIlraith, Tran Cao Son, and Honglei Zeng Stanford University 2001. Presenter: Ali Fatolahi CSI 5389 Winter 2006. The Problem. Web Toward service provider Computers Moving inside devices Web usage Getting automated Web Page Change Needs an API Change.

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Semantic Web Services Sheila A. McIlraith, Tran Cao Son, and Honglei Zeng Stanford University 2001

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  1. Semantic Web ServicesSheila A. McIlraith, Tran Cao Son, and Honglei ZengStanford University2001 Presenter: Ali Fatolahi CSI 5389 Winter 2006 www.site.uottawa.ca/~afato092

  2. The Problem • Web • Toward service provider • Computers • Moving inside devices • Web usage • Getting automated • Web Page Change • Needs an API Change www.site.uottawa.ca/~afato092

  3. The Solution • Web Services need to be • Computer-Interpretable • Use-Apparent • Agent-Ready • Semantic Web Service is a Web Service • Unambiguous and Machine-Understandable • Properties, Capabilities, Interfaces, and Effects www.site.uottawa.ca/~afato092

  4. Realization • AI-Inspired Content Markup Languages • Ontology Interface Layer (OIL1) • DARPA Agent Markup Language (DAML2) • DAML +OIL3 • DAML –L4 • Still in Progress www.site.uottawa.ca/~afato092

  5. Approach of This Paper • An Agent-Independent Declarative API • Data and Metadata • Properties and Capabilities • Interface for Execution • Prerequisites and Consequences • Semantic Markup Exploiting Ontology • DAML Family • Distributed Knowledgebase (KB) www.site.uottawa.ca/~afato092

  6. Role of the Distributed KB • Enabling Agents to Perform Automatic • Discovery • Execution • Composition and Interoperation • A Means for Agents to • Populate their Local KBs • Reason about Web Services www.site.uottawa.ca/~afato092

  7. The Manual Web Service Usage • Use a search engine to find a service • Either read the web page associated with that service or execute the service • Fill out the forms and click the button • Inform the user about possible compositions • Interact with the user step by step • … www.site.uottawa.ca/~afato092

  8. The Automatic Web Service Usage • User just defines her objectives • An agent does everything using • WS Descriptions on WS Sites • Ontology-Enhanced Search Engines • Main Tasks in Automatic Mood • Discovery • Execution • Composition and Interoperation www.site.uottawa.ca/~afato092

  9. Automatic Discovery • Automatically Locating Web Services • Given Particular Service and Its Properties • Semantic Markup at the Web Sites • To Specify the Service • How to Find? • Service Registry • (Ontology-Enhanced) Search Engine www.site.uottawa.ca/~afato092

  10. Automatic Execution • Automatically Executing a Web Service • By a Computer Program or Agent • Semantic Markup of Web Services • A Declarative, Computer-Interpretable API for Executing Services • Tells the Agent What Input Is Necessary • What Information Will Be Returned • How to Execute and Interact With the Service www.site.uottawa.ca/~afato092

  11. Automatic Composition and Interoperation • Automatic • Selection • Composition • Interoperation • Given a High-Level Description of the Objective • Semantic Markup of Web Services • A software can manipulate this markup • Specification of the Objectives, Constraints, … www.site.uottawa.ca/~afato092

  12. State of the art • Today they are not automatic • Lack of Content Markup and a Suitable Markup Language • Academic Research • Agent matchmaking research (Lark5) • XML-based standards in industry • UDDI, WSDL, ebXML, … www.site.uottawa.ca/~afato092

  13. What distinguishes this paper? • Expressive Semantic Web Markup Language • Well-Defined Semantics • A Semantic Layer • Sitting On Top of WSDL • A Richer Level of Description • More Sophisticated Interactions • Reasoning www.site.uottawa.ca/~afato092

  14. Markup Strategy • Markup Subjects • Web Services • User and Group Constraints and Preferences • Agent Procedures • Markup Tool • DAML Ontology • Sharing Common Concepts • Specification and Reuse • Concept Mapping • Composition of New Concepts www.site.uottawa.ca/~afato092

  15. Ontology An Example Domain-Independent Service N includes 1 Primitive Service Complex Service Domain-Specific Buy Origin Destination Departure Date Customer Buy Ticket Buy Movie Ticket Buy Airline Ticket www.site.uottawa.ca/~afato092

  16. WS Discovery Markup • Associates properties with services • Relevant to Classification and Selection • Example: BuyUALTicket Service • Service-Independent Property Types • Company Name, The Service URL, Unique Service Identifier, The Intended Use, … • Service-Specific Property Types • Valid Methods of Payment, Travel Bonus Plans Accepted, … www.site.uottawa.ca/~afato092

  17. WS Execution Markup • Requires a dataflow model • Function Metaphor • Process or Conversation Model • It must enable the agent to • automatically construct and execute a Web service request • interpret and potentially respond to the service’s response. www.site.uottawa.ca/~afato092

  18. WS Composition Markup • AI-Based action metaphor • Plan Domain Description Language (PDDL6) • Parameters, Preconditions and Effects • Defines Consequences of WS Execution • Buying a Book • Credit Card will be debited • Each WS is conceived as an action • PDDL translation to AI action already exists www.site.uottawa.ca/~afato092

  19. Constraints and Preferences Markup • Bob Prefers to Drive if • Travel time is less than 3 hours • His company mandates him to • Travel by American Airlines • Markup Language: DAML-L • Agent Usage is more challenging than the Markup itself. www.site.uottawa.ca/~afato092

  20. Agent Technology • Model-Based Programming • Comprises a Model • The Agent’s KB • And a Program • The generic procedure we wish to execute • Agent Programming Language Golog • Congolog • Situation Calculus • Open Agent Architecture (OAA7) sends requests www.site.uottawa.ca/~afato092

  21. How it works? • User requests a generic procedure • Agent populates its local KB • adds the user’s constraints to its KB • provides a logical encoding of the preconditions and effects of the Web service actions • ConGolog instantiates user request into • a sequence of primitive actions • Agent finds appropriate service for each action • … www.site.uottawa.ca/~afato092

  22. Assessment • There is no sample of: • Situation Calculus • ConGolog • Semantic Markup • … • We just see the screen shots and general terms • But it’s a promising work! www.site.uottawa.ca/~afato092

  23. What’s up today? • Based on • J. Nandigam et al. “Semantic Web Services”.2005. [8] • People still trying out • Languages • Environments • Frameworks • Ontologies www.site.uottawa.ca/~afato092

  24. Some Ideas • What about WSFL? • For Procedures • Agent-Mediated Semantic WS Technology • Both the Good and the Bad • Semantic Web without Agents?! • Do not interrupt user please! • Opportunity for Agent Technology • Threat for Semantic Web Service www.site.uottawa.ca/~afato092

  25. Thank You, Any Question? ? www.site.uottawa.ca/~afato092

  26. References • F. van Harmelen and I. Horrocks, “FAQs on OIL: The Ontology Inference Layer,” IEEE Intelligent Systems, vol. 15, no. 6, Nov./Dec. 2000, pp. 69–72. • J. Hendler and D. McGuinness, “The DARPA Agent Markup Language,” IEEE Intelligent Systems, vol. 15, no. 6,Nov./Dec. 2000, pp. 72–73. • www.daml.org/2000/10/daml-oil • www.daml.org/2001/03/daml+oil-index.html • Somewhere in www.stanford.edu! • K. Sycara et al., “Dynamic Service Matchmaking among Agents in Open Information Environments,” J. ACM SIGMOD Record, vol. 28, no. 1, Mar. 1999, pp. 47–53. • M. Ghallab et al., PDDL: The Planning Domain Definition Language, Version 1.2, tech. report CVC TR–98–003/DCS TR–1165, Yale Center for Computational Vision and Control,Yale Univ.,New Haven, Conn., 1998. • D.L. Martin, A.J. Cheyer, and D.B. Moran, “The Open Agent Architecture: A Framework for Building Distributed Software Systems,” Applied Artificial Intelligence, vol. 13, nos. 1–2, Jan.–Mar. 1999, pp. 91–128. • Jagadeesh Nandigam, Venkat N Gudivada and Mrunalini Kalavala. “SEMANTIC WEB SERVICES” Proceedings of the CCSC: Midwestern Conference, JCSC 21, 1 (October 2005). pp. 50-63. www.site.uottawa.ca/~afato092

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