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ICWS 2006

ICWS 2006. Incheon Paik, University of Aizu Daisuke Maruyama, University of Aizu Michael N. Huhns, University of South Carolina. A Framework for Intelligent Web Services: Combined HTN and CSP Approach. Presented by: Jingshan Huang Computer Science and Engineering Dept.

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ICWS 2006

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  1. ICWS 2006 Incheon Paik, University of Aizu Daisuke Maruyama, University of Aizu Michael N. Huhns, University of South Carolina A Framework for Intelligent Web Services: Combined HTN and CSP Approach Presented by: Jingshan Huang Computer Science and Engineering Dept. University of South Carolina ICWS 2006, Chicago

  2. Motivation • Solving real-life problems requires a set of appropriate services to be (1) composed via planning, (2) scheduled, and (3) executed. • HTN (Hierarchical Task Network) : Planning • CSP (Constraint Satisfaction Problem) : Scheduling • Problems of HTN-Only system • Cannot satisfy scheduling efficiently • Difficulty in finding an autonomous solution • Suggest a Novel WS Composition Engine: the HTN-CSP combined system ICWS 2006, Chicago

  3. Hierarchical Task Network (HTN) Planning • To produce a sequence of actions by task decomposition from large tasks • Similar to classical AI planning • Can produce plans to reach a final goal, but it is not suitable for scheduling • We chose SHOP2 as our basic planner ICWS 2006, Chicago

  4. Planning Domain Example : Method (transport ?p) task: : compound task (at ?p ?x) (destination ?p ?y) (available-truck ?t) preconditions: : primitive task : state subtasks: (dispatch ?t ?x) (!load ?t ?p) (!move ?t ?x ?y) (return ?t ?y) (dispatch ?t ?x) (return ?t ?y) task: task: subtasks: subtasks: (!reserve ?t) (!move ?t home ?x) (!move ?t ?x home) (!free ?t) ICWS 2006, Chicago

  5. Web Services Hotel Reservation WS Train Timetable WS Airplane Timetable WS … HTN-Only System Framework plan inputdata HTN Planner Input Domain Analyzer Web Service Executor planning problem ICWS 2006, Chicago

  6. Web Services Hotel Reservation WS Train Timetable WS Airplane Timetable WS … HTN-Only System Framework I'd like to make a trip next week.I want to departAizu-wakamatsu at 14:00 and arrive at San-Francisco. plan Departure Location = Aizuwakamatsu Departure Time = 14:00 Departure Date = Feb. 21, 2006 Arrival Location = San-Francisco inputdata HTN Planner Input Domain Analyzer Web Service Executor planning problem ICWS 2006, Chicago

  7. Web Services initial states: (departure-location aizu-wakamatsu) (departure-time _1400) (departure-date _20060221) (arrival-location san-francisco)) Hotel Reservation WS Train Timetable WS (trip) goal task: Airplane Timetable WS … HTN-Only System Framework plan inputdata HTN Planner Input Domain Analyzer Web Service Executor planning problem ICWS 2006, Chicago

  8. Web Services (travel ?from ?to) task: Hotel Reservation WS preconditions: Train Timetable WS . . . subtasks: Airplane Timetable WS (travel-by-train ?from ?via) (travel-by-airplane ?via ?to) … (available-train JR-Banetsu-West-Line aizu-wakamatsu _0600 koriyama _0712) . . . HTN-Only System Framework plan inputdata HTN Planner Input Domain Analyzer Web Service Executor planning problem ICWS 2006, Chicago

  9. Web Services Hotel Reservation WS Train Timetable WS Airplane Timetable WS … HTN-Only System Framework (!travel-by-train JR-Banetsu-West-Line aizu-wakamatsu _1413 _20060221 koriyama _1513 _ 20060221) (!travel-by-train Tsubasa-186 koriyama _1525 _ 20060221 tokyo _1648 _ 20060221) (!travel-by-train Narita-Express-37 tokyo _1703 _ 20060221 narita _1757 _ 20060221) (!travel-by-airplane ANA-B2 narita _2000 _ 20060221 san-francisco _1100 _ 20060221) plan inputdata HTN Planner Input Domain Analyzer Web Service Executor planning problem ICWS 2006, Chicago

  10. Problems with an HTN-Only System • Web service composition by a planner has limitations: • Inefficient for autonomous finding solution in planning • Not good for dealing user’s various requests • Weak in maintenance • Not efficient for scheduling ICWS 2006, Chicago

  11. Web Services Hotel Reservation WS Train Timetable WS Airplane Timetable WS … HTN-CSP Combined System Framework plan Web Service Executor inputdata HTN Planner Input Domain Analyzer CSP Constructor CSP Solver planning problem CSP representation CSP tuple ICWS 2006, Chicago

  12. CSP Constructor HTN Planner Domain Analyzer Goal Variable Representation Trip <Z, D, C> Z: variables D: domains C: constraints Domain Representation Sub-Goal Sub-Goal Shopping Constraint Representation ・ ・ ・ Trip Domain Trip Domain Knowledge Base Ontology Knowledge Base Ontology Knowledge Base Ontology Information needed for constructing CSP tuple Information needed for HTN planning Information needed for Domain Analysis Request Data defined with Ontology CSP Solver Web Service UDDI Master-Layer Sub-Layer Hotel Reservation Web Service Dynamic Request Hotel Label Assigner Robot with Situation Calculus Train Timeｔable Web Service Assigner Management Control Train Label Assigner Worldwide Web Service Constraint Check Airplane Timeｔable Web Service ・ ・ ・ ・ ・ ・ Knowledge Base Assigner Repository Constraint-satisfied Label Which assigner should be applied. ICWS 2006, Chicago

  13. Web Services Hotel Reservation WS Train Timetable WS Airplane Timetable WS … HTN-CSP Combined System Framework (riding-duration tokyo narita) = 0:54 (riding-duration koriyama tokyo) = 1:23 (riding-duration aizu-wakamatsu koriyama) = 1:00 (departure-time tokyo) = 17:03 (departure-time koriyama) = 15:25 (departure-time aizu-wakamatsu) = 14:13 (departure-date tokyo) = 2006/2/21 (departure-date koriyama) = 2006/2/21 (departure-date aizu-wakamatsu) = 2006/2/21 (arrival-time tokyo) = 16:48 (arrival-time narita) = 17:57 (arrival-time koriyama) = 15:13 (arrival-date tokyo) = 2006/2/21 (arrival-date narita) = 2006/2/21 (arrival-date koriyama) = 2006/2/21 (departure-time narita) = 20:00 (departure-date narita) = 2006/2/21 (arrival-time san-francisco) = 11:00 (arrival-date san-francisco) = 2006/2/21 plan Web Service Executor inputdata HTN Planner Input Domain Analyzer CSP Constructor CSP Solver planning problem CSP representation CSP tuple ICWS 2006, Chicago

  14. Performance Comparison Scenario ICWS 2006, Chicago

  15. Advantages of the HTN-CSP Combined System • Development Efficiency • Scheduling is already integrated • Flexibility • HTN-CSP combined system: • Can represent complex problems more easily • HTN-only system: • Might produce scenarios that are hard to solve • Extensibility • HTN-CSP combined system: • Features can be added easily • Many algorithms for solving CSPs available • HTN-only system: • To add new features, the planning domain must be rewritten in many cases ICWS 2006, Chicago

  16. Conclusion and Future Work • Suggested a combined HTN-CSP architecture for automatic Web service composition • Efficient for planning and scheduling • Future work • Automating HTN – CSP encoding • Fully automated problem solving (service composition) in a Semantic Web environment using this framework ICWS 2006, Chicago

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