1. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU1 Semantic Web Services Atilla ELÇİ Dept. of Computer Engineering Eastern Mediterranean University

2. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU2 Semantic Web Services- A Survey  SWS intro  WSMO Approach: European approach  OWL-S Approach: W3C  SWSF Approach  IRS-III Approach  WSDL-S Approach  Grounding: semantic vs syntactic description of services  Davies et al. Ch. 10.

3. SWS intro  Current WS tech based on SOAP messaging, WSDL, and UDDI technology is syntactic requiring manual process.  FYI: see references for leads on How to WS.  A different framework is required for semantic Web services: Conceptual model Lang for formal syntax & semantics Execution environment  In order to enable fully flexible automated e- business, Semantic Web Services promise to automate tasks such as discovery, mediation, selection, composition, and invocation of services. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU3

4. WSMO Approach: schematics  Components of Web Services Modelling Ontology (WSMO) Ref. Fig. 10.1WSMO 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU4

5. WSMO Approach  Design principles: Web compliance: w/ W3C specs Ontology-based: data model Strict decoupling: independently specified resources Centrality of mediation: mediation provided centrally Ontological role separation: parts played by users/components Description vs implementation: seperated concerns Execution semantics: reference implementation (WSMX) Service vs Web service: separation of tool & result 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU5

6. Conceptual model of WSMO  Meta Object Facility (MOF): a meta-meta model language Used in defining elements of WSMO ontology An abstract lang & framework for technology neutral meta-models: specify, contruct, manage Four layers of MOF:  Meta meta-model: the language used for WSMO  Meta model: WSMO itself (class, subClass, Attribute, type, cardinality,...)  Model: actual ontologies, WSs, goals, mediators specs  Info: actual data described by the model (grounding)  Exs: ontologies, Web services, goals, mediators: Described by non-functional properties Using mostly DC namespace elements 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU6

7. WS Descr.: TheLanguage WSML  The Web Service Modelling Language (WSML) is a merger of: Description logics Logic programming F-Logic  Used in service description through: Ontology description: syntax & semantics Declarative functional description of goals & services: syntactical framework (with implied Hoare-style semantics). => Transaction Logic? Description of dynamics: choreagraphy & orchestration. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU7

8. WSML variants 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU8

9. WSML Example: Amazon cart  Ex. code in 10.2.2.2 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU9

10. The Execution Environment  The Web Services Modelling Execution Environment (WSMX) for Web services: Discovery Selection Mediation, and Invocation.  A test bed of ideas and a reference implementation of WSMO.  WSMX info model: see Sourceforge WSMX info model  Developed for the Eclipse Framework open source IDE.Eclipse Framework  Ref. Fig. 10.3 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU10

11. WSMX Architecture 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU11

12. OWL-S Approach  Revolves around the OWL-S: OWL Web Service Ontology Part of the DAML ProgramDAML Program A language for describing semantically rich Web services Based on OWL  Consists of the subontologies of “service” concept: Profile:  What a service does?  Service presents ServiceProfile. Process model:  How it works?  Service describedBy ServiceModel. Grounding:  How to access it?  Service supports ServiceGrounding. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU12

13. OWL-S: Sub-ontologies of Service  ServiceProfile: Profile sub-ontology. What a service does? Advertising Constructing service requests Matchmaking  ServiceModel: Process model sub-ontology. How it works? Invocation Enactment Composition Monitoring Recovery  ServiceGrounding: Grounding sub-ontology. Accessing the service Data sources to message formats Protocols 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU13

14. OWL-S ServiceProfile  Service is a function of: The organization that provides the service:  Admin contact info The function the service computes:  Info xformation: I/O params  State change caused: Pre/post-conditions Characteristics of the service:  Quality, category, and user-declared service parameters 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU14

15. OWL-S ServiceProfile: IOPE  The function part simply lists the IOPE: inputs, outputs, preconditions, effects No schema here to describe them. Simply links them to the Process Model part. Properties of the Profile Class:  hasParameter  hasInput  hasOutput  hasPrecondition  hasResult 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU15

16. OWL-S ServiceModel: Process  Process: Defines how to interact with the service not the function code of the service.  In a way, more detailed verison of the function part of ServiceProfile!  Processes and IOPEs are linked by the following properties: hasParticipant -> Participant class (client, service) hasInput -> Input class hasOutput -> Output class hasLocal -> Local class hasPrecondition -> Condition class (required for exec.) hasResult -> Result class (effects, outputs) 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU16

17. OWL-S ServiceModel: Process kinds  Atomic processes: Single step process: I -> O Involves no sub-process  Composite processes: Multi-step process With state memory Decomposable into atomic, simple, or composite processes.  Simple Processes. A (utility) view of atomic/composite process. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU17

18. Control Structures: Decomposing a Composite Process  Sequence  Split: Like threads to be executed concurrently Completes when all component processes are scheduled.  Split + Join: Like Split but completes when all component processes complete execution  Choice: Selecting a control construct to execute  Any-Order: Unspecified sequential order of execution  If-Then_Else: Just as common format  Iterate: Non-conditional looping  Repeat-While and Repeat-Until: Conditional looping 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU18

19. OWL-S: Examples:  BravoAirProcess.owl BravoAirProcess.owl  VehiclePartPriceService.owl VehiclePartPriceService.owl  How to do SWS: doc by Duygudoc 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU19

20. SWSF Approach 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU20

21. IRS-III Approach 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU21

22. WSDL-S Approach 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU22

23. Conclusions 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU23

24. Books on SWS  Modeling Semantic Web Services: The Web Service Modeling Language by Jos de Bruijn Modeling Semantic Web Services: The Web Service Modeling Language Price: $59.95 Release Date: June 1, 2008 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU24

25. Conferences: summer schools  4TH REASONING WEB SUMMER SCHOOL (RW 2008):RW 2008 7-11 September, 2008, San Servolo Island, Venice. Appl Deadline: May 16, 2008.  PROGRAM 1. Foundations of Knowledge representation and Reasoning 2. Representing Knowledge with Controlled Natural Language Processing 3. Semantic Multimedia 4. Semantic techniques for Social Networks 5. Semantic techniques for Bioinformatics 6. Semantic Web Services  REGISTRATION FEE: 750 EUR which covers: - the volume of LECTURE NOTES published by Springer, - accommodation at San Servolo Island, - all meals, - social event. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU25

26. Conferences: summer schools  ICCL Summer School 2008: COMPUTATIONAL LOGIC AND COGNITIVE SCIENCE ICCL Summer School 2008 Technische Universität Dresden August 24 -- September 6, 2008  6th INTERNATIONAL SUMMER SCHOOL IN FORMAL LANGUAGES AND APPLICATIONS (formerly International PhD School in Formal Languages and Applications) FORMAL LANGUAGES AND APPLICATIONS Tarragona, Spain, July 21 - August 2, 2008 Organized by Research Group on Mathematical Linguistics Rovira i Virgili University 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU26

27. Conferences: summer schools  THE SIXTH EUROPEAN SUMMER SCHOOL ON ONTOLOGICAL ENGINEERING AND THE SEMANTIC WEB (SSSW-2008) SSSW-2008 Cercedilla, near Madrid, Spain. 6-12 July, 2008. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU27

28. 11/05/08 rev 22/5/08CmpE 588 Spring 2008 EMU28 References  John Davies, Rudi Studer, Paul Warren (Editors): Semantic Web Technologies: Trends and Research in Ontology-based Systems, John Wiley & Sons (July 11, 2006). ISBN: 0470025964. Ch. 10.: pp. 191-236.  Web Services- How To: see the following: Deitel & al.: Ch. 21 in C# HTP, Pearson 2002. W3Schools: Web Services TutorialWeb Services Tutorial W3C Web Services Activity.Web Services Activity Hugo Haas: Tutorial: Foundations And Future Directions of Web ServicesTutorial: Foundations And Future Directions of Web Services  W3C Semantic Web Tools Wiki page:Semantic Web Tools Check Jena, SemWeb, Protégé, Swoop, etc.