1. Semantic Web Services Peter Bartalos

2. 2 Dr. Jorge Cardoso and Dr. Amit Sheth http://dme.uma.pt/jcardoso/Books/Semantic-Web-Services-Processes-and-Applications/

3. 3 Semantic Web  Machine understandable Web content  Not a separate Web but an extension  (semantic) meta-data  RDF, OWL

4. 4 Web Service “A Web service is a software system identified by a URI, whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems. These systems may then interact with the Web service in a manner prescribed by its definition, using XML based messages conveyed by Internet protocols"

5. 5 Web Service “A Web service is a software system identified by a URI, whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems. These systems may then interact with the Web service in a manner prescribed by its definition, using XML based messages conveyed by Internet protocols"

6. 6 Semantic Web services  Semantic Web services are the result of the evolution of the syntactic definition of Web services and the semantic Web Bussler et al 2003: A Conceptual Architecture for Semantic Web Enabled Web ServicesA Conceptual Architecture for Semantic Web Enabled Web Services

7. 7 Semantic Web services  Web services are: Modular Self-describing Self-contained Accessible over the Internet  Described using WSDL WSDL - Web Services Description Language Provide operational information Does not contain semantic descriptions It specifies the structure of message components using XML Schema constructs

8. 8 Semantic Web services  Solution: Mapping concepts in a Web service description to ontological concepts OWL-SOWL-S, WSMO, SWSF, WSDL-S, SAWSDLWSMOSWSFWSDL-SSAWSDL

9. 9 Semantic Web services  Submissions to the W3C: OWL-S WSMO WSDL-S OWL-SOWL-S, WSMO, SWSF, WSDL-S, SAWSDLWSMOSWSFWSDL-SSAWSDL

10. 10 Semantic Web service discovery  Discovery The procedure of finding a set of appropriate Web services  Problem How to efficiently discover Web services  Currently Universal Description Discovery and Integration (UDDI) Relatively inefficient Does not take into account the semantics of Web services Web Service DiscoveryWeb Service Discovery, Verma et al 2003: MWSDIMWSDI Downloadable Tool: Lumina - Semantic Web Service DiscoveryLumina - Semantic Web Service Discovery

11. 11 Semantic Web service discovery  MWSDI Multiple registries discovery Ontologies used  Organized registries  Semantic classification  OWL-S based approach Logic inference is used for matching services  … Web Service DiscoveryWeb Service Discovery, Verma et al 2003: MWSDIMWSDI Downloadable Tool: Lumina - Semantic Web Service DiscoveryLumina - Semantic Web Service Discovery

12. 12 Semantic Web Process  Web Services are application’s functionalities available on the Internet. Examples: Zip Code, Booking Flights, etc.  Single services has a limited utility For traveling, it is not sufficient to book a Flight  We must take care about booking the hotel, getting entertained, rental car, etc  Web Services Composition Collection of services in order to achieve a particular goal

13. 13 Problem …  To achieve a given objective – sell my car, I may need more than one Web Service: Car Valuation service – WS1 Car Auction Service – WS2 Online Financial service – WS3  All three WS need to interact seamlessly To achieve my goal Satya Sanket Sahoo

14. 14 Semantic Web Process OWL-SOWL-S, WSMO, SWSF, WSDL-S, SAWSDLWSMOSWSFWSDL-SSAWSDL  Web Process Combine individual services to achieve a more complex goal Advantage  enables modular design  Implements the control and data flow between services For example, Service A, B and C. B is dependent on A’s output message. A and C can be invoked at the same time

15. 15 Web Services Composition  Necessity to achieve a predetermined goal that cannot be realized by a standalone service  Problem’s Description Travel Service  Composed of 3 atomic services: Airplane service, Hotel service and Car rental service The execution order of these 3 tasks is determined by a planner Proposed Environment involves these phases:  Planning  Discovery  Optimization (Concerns this work)  Execution

16. 16 Web Services Composition  WS discovery  WS selection Also non-functional criteria QoS Multi-objective optimization approach  WS composition Andrews T. et al. Specification: BPEL4WS - Business Process Execution Language for Web Services - Version 1.1.BPEL4WS - Business Process Execution Language for Web Services - Version 1.1 OWL-S Coalition. OWL-S: Semantic Markup for Web Services.OWL-S: Semantic Markup for Web Services

17. 17 Web Services Composition  Models to Compose Web Services BPEL4WS – Business Process Execution Language for Web Services Abstract and executable processes Andrews T. et al. Specification: BPEL4WS - Business Process Execution Language for Web Services - Version 1.1.BPEL4WS - Business Process Execution Language for Web Services - Version 1.1 OWL-S Coalition. OWL-S: Semantic Markup for Web Services.OWL-S: Semantic Markup for Web Services

18. 18  Two categories of Web Services Composition: Workflow composition  Static workflow composition: EFlow (Casati, Ilnicki, et al. 2000)  Dynamic workflow composition: PPM (Polymorphic Process Model) (Schuster, Georgakopoulos, et al. 2000) Web Services Composition

19. 19 Automatic approaches to WS composition  AI Planning Golog – Logic Programming Language Planning Domain Definition Language (PDDL) – action value Rule-based plan generation – SWORD (Ponnekanti and Fox, 2002) Hierarchical Task Network (HTN) – SHOP2 (Wu, Sirin, et al. 2003)  Approach considering the user preferences  Software agents

20. 20 Approaches to WS composition  What about WS composition supported by Collaboration?