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 Automatic Web Service Orchestration using AI Planners

 Automatic Web Service Orchestration using AI Planners. Antonio Kantek COMS E6125  Web Enhanced Information Management Professor Gail Kaiser. Overview. * Automatic and Semi-Automatic WS Orchestration * AI Planners and How They Work * Web Services and Semantic Web

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 Automatic Web Service Orchestration using AI Planners

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  1.  Automatic Web Service Orchestration using AI Planners Antonio Kantek COMS E6125  Web Enhanced Information Management Professor Gail Kaiser

  2. Overview * Automatic and Semi-Automatic WS Orchestration * AI Planners and How They Work * Web Services and Semantic Web * Building and Executing Plans for WS Orchestration * Real World Challenges

  3. AI Planners * Defining a problem as a graph search:     - Global Problem Solver (1959) [1]     - Combinatorial Explosion     - Block World * Planners based on Simple Graph Search: DFS, BFS, A*, etc     - Vertices correspond to states     - Edges correspond to actions     - Actions are defined in terms of pre / pos condition       and main action * Fast Forward Heuristics (2001) [2] and Modern Planners

  4. AI Planning

  5. AI Planning * PDDL (Planning Domain Description Language) [3] (define (domain VACATION_TRIP)          (:requirements ...          (:predicates (AMOUNT_MONEY ?2500)                       (FLIGHT_CLASS ?BUSINESS)               ...)          (:action BUY_FLIGHT_TICKET                [:parameters (?TICKET_PRICE)]                [:precondition AMOUNT_MONEY > 2500]                [:effect EFFECT_FORMULA (AMOUNT_MONEY - TICKET_PRICE) ]           )          (:action BOOK_HOTEL_ROOM            ...)          ...)

  6. OWL-S and Semantic Web * Extending WSDL with Semantic Web (OWL-S) <rdf:RDF          ...      >     <owl:Ontology rdf:FLIGHT_RESERVATION="">           <owl:versionInfo>VacationTrip.owl version 1.0</owl:versionInfo>           <rdfs:comment>                This ontology represents the OWL-S service that describes a web services             for booking flight tickets.           </rdfs:comment>        <owl:imports rdf:resource="&service;" />           <owl:imports rdf:resource="&flight_class;" />           <owl:imports rdf:resource="&ticket_price;" />           <owl:imports rdf:resource="&destiny;" />        ...     </owl:Ontology>

  7. Planning and PDDL  (define (domain VACATION_TRIP)      (:requirements ...      (:predicates (AMOUNT_MONEY ?2500)                (FLIGHT_CLASS ?BUSINESS)        ...)     (:action BUY_FLIGHT_TICKET            [:parameters (?TICKET_PRICE)]            [:precondition AMOUNT_MONEY > 2500]            [:effect EFFECT_FORMULA (AMOUNT_MONEY - TICKET_PRICE) ]      )      (:action BOOK_HOTEL_ROOM     ...)   ...)

  8. AI Planning and Web Services

  9. WS Planner Architecture

  10. Real World Challenges * Assumptions like execution atomic type, instantaneous actions with deterministic effects, omniscience are no longer true * Services are not 100% reliable     - They may fail or they may return unexpected results     - They may take an unexpected amount of time to run     - Partially executed action and rollback * Internet domain is complex     - Way more complex than world block     - Security and authentication

  11. Real World Challenges * Automatic WS Orchestration: Planning and Grouding * Semi-Automatic WS Orchestration: Planning only * Extending Planners by Adding Parallel Execution [4] * "Close World Assumption" no longer valid * Defining and Respecting Real World Constraints * Hierarchical Planning and Task decomposition

  12. Final Considerations * Planners are not the only solution for Automatic and Semi-Automatic WS Orchestration     - Golog [5]     - IBM's WSBPEL * Automatic WS Orchestration may work better for closed environments * Semi-Automatic more recommended for an open environment like Internet

  13. Questions ? Comments ? ak2765@columbia.edu

  14. Thanks !

  15. References [1] Newell, A.; Shaw, J.C.; Simon, H.A. (1959). Report on a general problem-solving program. Proceedings of the International Conference on Information Processing. pp. 256-264. [2] Hoffmann, Jorg (2001). The FF Planning System: Fast Plan Generation Through Heuristic Search. Journal of Artificial Intelligence Research 14 (2001), 253-302.  [3] Ghallab, M., Howe, A., Knoblock, C., McDermott, D., Ram, A., Veloso, M., Weld, D., and Wilkins, D. (1998). PDDL the planning domain definition language. In Proc. of AIPS-98 Planning Committee. 

  16. References [4] McDermott, D. (2002). Estimated-Regression Planning for Interactions with Web Services. In AIPS 2001. [5] McIlraith, S. A. and Son, T. C. (2002). Adapting Golog for Composition of Semantic Web Services. In KR2002, pages 482–493. 

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