3 rd International Workshop on Web Services and Formal Methods

1. 3rd International Workshop onWeb Services and Formal Methods Report on WS-FM 2006, Vienna Andreas Duscher

2. Content • Key Data • Topics • Program • Overview of Presented Papers

3. WS-FM 2006 • held at Vienna University of Technology, during September 8-9, 2006 • in conjunction with the 4th International Conference on Business Process Management BPM 2006 • Featured 15 papers selected among 40 submissions • Three invited papers "... bringing together researchers working on Web Services and Formal Methods"Web Services and Formal Methods, Proceedings, Springer, September 2006.

4. WS-FM 2006 • Co-chairs of Program Committee • Gianluigi Zavattaro, Mario Bravetti (University of Bologna) • Chair of Organizing Committee • Manuel Nùñez (University of Madrid)

5. Topics • Protocols and standards for Web Services (WS) • Languages and description methodologies for Choreography, Orchestration and Workflow • Coordination techniques for WS • Semantic-based dynamic WS discovery • Security, performance evaluation, and QoS of WS

6. September, 8th 8.45Start of registrations 9.15Opening by the chairs 9.30-10.30Invited talk DecSerFlow: Towards a Truly Declarative Service Flow Language 11.00-12.30Session: Service Choreography Towards the Formal Model and Verification of Web Service Choreography Description Language Execution Semantics for Service Choreographies Choreography Conformance Analysis: Asynchronous Communications and Information Alignment 14.30-16.00Session: Security and performance analysis Verified Reference Implementations of WS-Security Protocols Application of Model Checking to AXML System's Security : A Case Study Evaluating the Scalability of a Web Service-based Distributed E-Learning and Course Management System 16.30-18.00Session: Service composition A formal account of contracts for Web services A Formal Approach to Service Component Architecture Analysis and Verification of Time Requirements applied to the Web Services Composition

7. September, 9th 9.30-10.30Invited talk SCC: a Service Centered Calculus 11.00-12.30Session: Service orchestration Towards a Unifying Theory for Web Services Composition Orc Features into Petri nets and the Join Calculus From BPEL Processes to YAWL Workflows 14.30-15.30Invited talk Service QoS composition at the level of part names 16.00-17.30Session: Service discovery and invocation Semantic Querying of Mathematical Web Service Descriptions Computational Logic for Run-Time Verification of Web Services Choreographies: exploiting the SOCS-SI tool Dynamic Constraint-based Invocation of Web Services

8. Rebhi Baraka, Wolfgang Schreiner Motivation Mathbroker Framework (Registry and Querying Facilities for Mathematical WS) Querying for Mathematical WS only possible on the syntactic structure of MSDL documents Result Extension for semantic querying Semantic Querying of Mathematical Web Service Descriptions

9. Semantic Querying of Mathematical Web Service Descriptions

10. A Formal Approach to Service Component Architecture José Luiz Fiadeiro, Laura Bocchi (University of Leicester) Antónia Lopes (University of Lisbon)

11. A Formal Approach to Service Component Architecture • Service Component Architecture (SCA): • Set of industry specifications for building applications and systems • Builds on open standards (e.g. Web Services) • Initiated by major software vendors (IBM, Oracle, BEA, ...)

12. A Formal Approach to Service Component Architecture • Motivation • Describing mathematical semantics of SCA • Uniform and general model of service behaviour,independent of languages and technologies • Other approaches (WSMF, OWL-S) see services as blackbox • Result • Core set of primitives for interaction • Language SRML-P that • captures the essence of SCA modelling paradigm • operates on a higher level of abstraction

13. A Formal Approach to Service Component Architecture Business Role Wire External Interface (provides) External Interface (requires)

14. A Formal Approach to Service Component Architecture Core set of primitives for describing interaction

15. A Formal Approach to Service Component Architecture Language SRML-P: Business Role Supplier

16. A Formal Approach to Service Component Architecture Language SRML-P: Business Protocol Warehouse

17. Dynamic Constraint-Based Invocation of Web Services Diletta Cacciagrano, Flavio Corradini, Rosario Culmone, Leonardo Vito (University of Camerino)

18. Dynamic Constraint-Based Invocation of Web Services • Motivation • Web Service Description Language (WSDL): describes a collection of methods and their parameter signature, together with information about parameter syntax • no dynamic constraints about invocation parameters can be expressed • ontologies are not suitable for only describing constraints • Result • Enriched WSDL documents, that specify static and dynamic integrity constraints • Software framework that consists of several open source technologies

19. Dynamic Constraint-Based Invocation of Web Services Enriched WSDL • CLiX (Constraint Language in XML) • based on First-Order-Logic and XPath • simple and syntactic approach <items> <item id="1"> <price currency="EUR">224</price> </item> <item id="2"> <price currency="YEN">8432</price> </item> </items> <clix:forall var="price" in="/items/item/price"> <clix:equal op1="$price/@currency" op2="'EUR'"/> </clix:forall>

20. Client Server Client Stub Service Marshalling Unmarshalling Marshalling Unmarshalling CLiX Validator SOAP Request Dynamic Constraint-Based Invocation of Web Services Software framework • OpenCLiXML (validates CLiX expressions) • WSDL2Java (generates client stubs)

21. Conclusion • In particular • A Formal Approach to Service Component Architecture • declarative approach for describing service interactions and component models • Dynamic Constraint-Based Invocation of Web Services • a combination of existing software frameworks • a new (not ontology-based) approach • Generally • a lot of interesting talks and nice people http://www.cs.unibo.it/projects/ws-fm06/