1. METEOR-S METEOR-S Project Entry for SWS Challenge Phase II Using Planning for Process Mediation John Harney, Karthik Gomadam, John Miller, Amit Sheth, Kunal Verma, Zixin Wu LSDIS LabLSDIS Lab, University of Georgia

2. The problem of Process Mediation ClientService Provider I want to do something I can give you these Mediator This is how to do it. First step, second step, etc.

3. Process Mediation –SWS Challenge 2006

4. Using Planning in Process Mediation Planning Problem –Find an execution path of services (tasks) given some state of the world to achieve a goal –Classical planning algorithms use combinatorial search, backtracking and branching to secure a plan Plan No Plan

5. Using Planning in Web Service Composition Planning Problem –With many operations available, planning using these techniques: Becomes computationally complex (at times infeasible) Gives less desirable plans –Need a method that alleviates planner complexity and retrieves “smart” plans

6. Interaction Protocol Approach for Process Mediation Client Service Provider(s)Mediator Interaction Protocol Requirement Create Interaction Protocol Planning Execute Validation WSDL-S

7. Interaction Protocol Approach for Process Mediation Bottom-up (Process Synthesization) –Construct a plan given: Client’s requirements i.e. preconditions/input, postconditions/output (goals) Provider’s available operations (preconditions/input, effects/output) “Pseudo”-operations – combined operations determined by the provider; encapsulate human knowledge.

8. Interaction Protocol Approach Consists of four phases: 1.Client presents requirements via semantic template 2.Provider creates a (set of) valid pseudo- operations 3.Planner synthesizes processes using provider defined interaction protocol (pseudo- operations) as well as other operations 4.Final plan validated and used by consumer (final BPEL process is deployed)

9. Compose the solution on the fly Constraints for planning come from: 1.Semantic requirements (preconditions, post-conditions, input, and output ) from the client (WSDL-S) 2.Precondition, effect, input, and output from the providers (WSDL-S) 3.Interaction protocol from the providers

10. Interaction Protocol Approach Client’s requirements can be captured in Semantic Template (WSDL-S) For the SWS Challenge 2006:

11. Interaction Protocol Approach Besides the semantic annotation for “regular” operatioins, Service Provider specify the Interaction Protocol which is a set of pseudo- operations mooncompany:OMServicePortType:createNewOrder ; mooncompany:OMServicePortType:addLineItem * ; mooncompany:OMServicePortType:closeOrder

12. Interaction Protocol Approach Planner uses GraphPlan algorithm –Represents possible plans using expandable graph data structure –Alternating layers of ground literals and actions (ground instances of operators) –Represents the literals and actions that might occur at each time step –Attempts to extract plan when goal level of literals is reached

13. Interaction Protocol Approach GraphPlan example (Preconditions -> “A ^ B” Goal -> “E”) –If preconditions exist for operation: Operation placed in sequential path Effects of operation placed in new state –Expansion continues until goal is reached –Plan is composed by backtracking to the initial level through operations Initial state Goal literal operation A O1O1 O1O1 O2O2 O1O1 O2O2 O3O3 O4O4 A B C D E A B C D B A B C Plan → O 1,O 2,O 4

14. Interaction Protocol Approach Graphplan Example with pseudo-operations –Pseudo-operations reduce graph complexity (execution path length, number of actions, etc) with human defined super-operations Initial state Goal literal Atomic operation Psuedo operation O4O4 O3O3 O1O1 O2O2 A C C D B A A B C D E PO 1 Plan → PO 1, O 4

15. Interaction Protocol Approach GraphPlan extended –Must also check whether output of one operation semantically matches the input of the next operation in sequence Need to refer both to ontology InputOutput O1O1 O2O2

16. Interaction Protocol Approach GraphPlan extracts a sequential “backbone” execution path that can be converted to BPEL –Includes pseudo-operation conversion Plan w/ IP PO 1 O4O4 O1O1 O2O2 O4O4 Plan w/ Atomic Operations BPEL … …

17. Service Provider 2 (POM) Create Add Close authToken Contact shipTo billTo orderId authToken orderId item orderId lineItemId authToken orderId ItemNo Search Customer CompanyName CustId Service Provider 1 (CRM) Solution –Process synthesized using client’s requirements and internal planning. –Service provider provides pre-defined pseudo operations to make planning easier.

18. Architecture

19. Demo Open ProcessMediator.swf in IE or Firefox (requires Flash)ProcessMediator.swf Inputs: –Client Template: Blue_SemanticTemplate.wsdlsBlue_SemanticTemplate.wsdls –Provider Services: CRMService.wsdls, OMService.wsdlsCRMService.wsdls OMService.wsdls Output –generatedProcess.bpelgeneratedProcess.bpel

20. The End Thanks