WSMO-Full – Some thoughts

1. WSMO-Full – Some thoughts Chris Preist

2. Opening Comments…. • OWL-S was feature-driven rather than concept-driven…. • The (implicit) conceptual architecture is ‘web services as plan fragments.’ • WSMF provides central conceptual pillars, but no conceptual architecture. • Let’s make a clear, semi-formal conceptual architecture for WSMO.

3. What am I presenting? • Conceptual architectural model, not features (But still informal, provisional…) • The conceptual model can be applied to WSMO-lite, WSMO-std or WSMO-full • However, to do it ‘properly’ (in e-commerce) will require extra features beyond either WSMO-std or OWL-S.

4. Where does the model come from? • Use cases developed over several years of analysis of eCommerce case studies. • Linked to work in the agent community, and HP’s Service Oriented Architecture work. (e-Speak) • Particularly based on analysis of SWWS Case Studies 7 and 8. • Weakness: needs input from beyond eCommerce.

5. What does ‘service’ mean? • A ‘good or service’ at the application level: information, train ticket, book, bandwidth provision etc. • An ‘agent’ which carries out tasks on behalf of its owner: Amazon book-selling service. (‘e-Service’) • A set of WSDL operations which implement some behaviours. (Web service)

6. ‘Semantic e-Services’ • For e-Commerce to succeed, we need to annotate e-Services (however they are implemented) with semantics at the application level, and group them according to service provider. • This accords with the W3C Web Services Architecture

8. Messages…. • I believe that WSMO needs a clear conceptual architecture to motivate its features • Such an architecture should relate to abstract use cases developed from concrete case studies • I propose an early version of this

9. What next…. • I am working on SWWS conceptual architecture (Due end April) (Extending W3C-WSA) • Based on analysis of the 4 case studies • I welcome feedback and input. • Particularly example use cases (from case studies) which should be supported by the conceptual architecture. • Maybe basis for WSMO architecture?

10. Use Case Flow (I) • Client formulates a goal which needs to be achieved Discovery Phase • Client locates Service Providers which may help him to achieve the goal • May include contacting some Service Provider Registry • Client contacts some of potential Service Providers Product Definition/Negotiation Phase • For each provider: • Client contacts each Service Provider and presents his goal • Provider will ask additional questions about the need of the Client • This may be an iterative process until Client and the Service provider agree on the Product Definition • This phase may involve negotiation as well • Client chooses one Service Provider • Client makes a contract with the Service Provider

11. Use Case Flow (II) Delivery Phase • Client requests the start of the service • During service delivery messages may be exchanged, e.g. to check the status of the service delivery • After service is delivered, payment will take place • May also occur before, after, or in stages, depending on the contract

12. Use Case Addendum • To achieve his goal, Client may need to contact several Service Providers • Each service provider is capable of achieving only a part of the Client’s goal • Client has to coordinate activities of the Service Providers • Each Service Provider uses a different protocol: there is a need for mediation