Toward Semantic Web E-Commerce

1. Toward Semantic Web E-Commerce Massimo Paolucci, Katia Sycara, Takuya Nishimura, Naveen Srinivasan

2. Overview • Present DAML-S VM a generic processor for the DAML-S Process Model that can be used to interact with any DAML-S Web service • Process Model semantics • Architecture of the DAML-S VM • Example of execution using Amazon’s Web service • Performance evaluation

3. Crucial Problems • Capability based discovery • Web services should find each other on the basis of what they do • Semantic interoperation • Web services “understand” the information that they exchange and use it to solve their problems

4. Requirements of Interaction • Shared Knowledge of interaction protocols: • What information the provider needs • When does it need it • Shared understanding of content of messages • Ontologies that act like “dictionaries” • Logic framework for correct interpretation • Agreement on ports and low level details

5. Provider publishes Process Model Grounding, WSDL Requester uses them to initiate the interaction with the provider Web Services Interaction Process Model Requester Provider Grounding WSDL

6. Process Model • Detailed view of the Web Service • Provides description of how the Web service accomplishes its tasks • Interaction protocol • Specifies when Web service requires inputs from requesters • Specifies what information (and when) Web service sends to the requesters

7. Operationally • Process Model describes a workflow • Atomic Processes • Composite Processes • Sequence, Split&joint • Conditionals, Non-deterministic choices • Loops

8. Process • Processes are defined by • Inputs that they require • Outputs that they generate • Preconditions that should be satisfied for the correct execution of the process • Effects that result from the execution of the process

9. Process Model Execution Rules Based on formal execution semantics (Ankolekar et al 2002) executed(atomic(Process))  executedGrounding(Process) executed(sequence(Process,List))  executed(first(List)), executed(sequence(Process,rest(List))) executed(split(Process,List))  exec(first(List)), exec(split(Process,rest(List))) executed(splitJoint(Process,List))  exec(first(List)), exec(splitJoint(Process,rest(List))), complete(first(List)), complete(splitJoint(Process,rest(List))) executed(if(Cond,ThenProcess,ElseProcess))  ( Cond, executed(ThenProcess) ) XOR executed(ElseProcess) executed(choice(Process,List))  executed(oneOf(List))

10. Grounding • Specify mapping to WSDL • Atomic Processes map to Operations • Inputs/Outputs described as messages • Specify XSLT transformations for mapping to and from DAML and XSD types

11. Book author title publisher price Book author Person name age title publisher Company name address price Transforming XSD to DAML XSD DAML

12. DAML-S Virtual Machine Web Services SOAP Provider Web Service Description DAML-S VM Webservice Invocation Axis’s Web Service Invocation Framework Requester WSDL DAMLS WebServiceInvoker APPLICATION DAML-S Processor DAML-S Ground ing Grounding Execution Rules Process Model Execution Rules DAML-S Process Model DAML Inference Engine DAML Jess KB Jess Jena

13. Features DAML-S VM • DAML-S VM a generic processor for the DAML-S Process Model • It can interact with any DAML-S Web service • Uses only DAML-S as representation of Web services • Based on the Process Model formal semantics • Shows how to integrates DAML-S within Web services technology such as Axis and WSIF

14. DAMLzon: DAML-S for Amazon.com • WSDL2DAML-S used to generate DAML-S for Amazon’s Web Service • DAML-S VM used to interact with Amazon Web service Book Search Reserve Book Process Model for Amazon.com

15. WSDL2DAML-S • WSDL2DAMLS allows easy translation of WSDL documents in DAML-S • Automatic generation of Grounding • Partial generation of Process Model and Profile • Up to 80% of work required to generate a DAML-S description is done automatically • Combined with Java2WSDL to provide Java2DAML-S

16. <damls> </damls> <wsdl> </wsdl> <ProcessModel> </ProcessModel> <portType> </portType> <operation> </operation> <AtomicProcess> </ AtomicProcess > <input> </input> <inputs> </inputs> <output> </output> <outputs> </outputs> <fault> </fault> WSDL2DAML-S

17. Example WSDL2DAML-S To Be Specified • Atomic Processes are generated automatically • Need to be specified • Composite Processes • mapping XSD to DAML Generated Automatically Process Model for Amazon.com

18. Performance Measures • We compared the performance of using DAML-S in its interaction with Amazon.com • Two experiments • Compared Amazon client with DAML-S VM client on browsing task • Used DAML-S VM client on browsing+reserving task • Analyzed distribution of time

19. Compared Amazon client with DAML-S VM client on browsing task 98 runs total over 4 days in varying load conditions Results in milliseconds Results Experiment 1 Distribution

20. Results Experiment 2 • DAML-S VM client on browsing+reserving task • No client for Browsing+Reserving provided by Amazon • Analyzed data by computing: • Time required by DAML-S VM to execute Process Model • Time required for data transformation to fit Amazon requirements • Time required to invoke an operation on Amazon • 98 runs total over 4 days in varying load conditions • Results in milliseconds

21. Conclusion • DAML-SVM is a generic DAML-S port that can be used to interact with any Web DAML-S service • It conforms with the DAML-S semantics • It is based on DAML inference engine • The use of DAML-S does not result in a performance penalty