1. Using Semantic Web Services for Ad Hoc Collaboration in Virtual Teams Kay-Uwe Schmidt Kay-Uwe.Schmidt@fokus.fraunhofer.de Matthias Fluegge Matthias.Fluegge@fokus.fraunhofer.de

2. © Fraunhofer Institute FOKUS, Berlin, 2004 2 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

3. © Fraunhofer Institute FOKUS, Berlin, 2004 3 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

4. © Fraunhofer Institute FOKUS, Berlin, 2004 4 Virtualization of Teams  Team collaboration is a core issue for large organisations  Internet enabled virtual organizations and virtual teams  Groupware  Shared task management  Discussion forums  Document repositories  Shared calendars  Promise: Cost reductions and increased productivity

5. © Fraunhofer Institute FOKUS, Berlin, 2004 5 Drawbacks of Groupware Systems  Successful adoption of groupware is rare  Lack of a seamless integration with existing applications and work processes  Burden placed on users to effectively support the system is higher than perceived benefit

6. © Fraunhofer Institute FOKUS, Berlin, 2004 6 Electronic calendar with automatic meeting scheduling feature  Workflow  Check calendar for each potential participant,  Find a time convenient for all  Notify all participants of appointed date  Problem  Only few of the team members are likely to maintain their groupware calendars  No familiarity with the groupware and its features  Result  Scheduling program finds all times open and subsequent conflicts are preassigned  Solution  Utilization of the tools the users are accustomed to

7. © Fraunhofer Institute FOKUS, Berlin, 2004 7 Loose Coupling of Personal Information Managers (PIMs)  Common features of Personal Information Managers  Calendar  Scheduling  Address book  Task board  Email  Usually well-maintained by their owners  Loose coupling of PIMs  Data sharing of heterogeneous applications  Simple but efficient distributed groupware (team calendars, group address books, team to-do lists etc.)  Overcome shortcomings of centralistic groupware approaches

8. © Fraunhofer Institute FOKUS, Berlin, 2004 8 Communication through Web Services  Web services  Allow applications to collaborate over the internet irrespective of their concrete implementation  Web service interface as the only prerequisite for coupling PIMs  Standardization of ‘the one’ Web service interface unlikely  Huge number of competitors and implementations  Conclusion  For ad hoc communication based on different Web service interfaces a more generic approach is needed  Standardization of data formats – out of scope  vCalendar, iCalendar, RDFCalendar  vCard, iCard  …

9. © Fraunhofer Institute FOKUS, Berlin, 2004 9 Semantics for Web Services  Semantic Web gains momentum  Several research activities in the direction of Semantic Web enabled Web services  Adding Semantic Web support to Web services → automated collaboration of heterogeneous applications  Automation of  Web service discovery  Web service invocation  Web service composition and interoperation  Web service execution monitoring

10. © Fraunhofer Institute FOKUS, Berlin, 2004 10 Why Semantics ?  XML-based Web service standards (SOAP, WSDL, UDDI ) lack intrinsic formal semantics  Problem: Ad hoc collaboration between Web services that have not been designed to work together  WSDL not adequate for  Dynamic matchmaking and  Dynamic invocation of heterogeneous Web services  Semantic annotation of existing Web services

11. © Fraunhofer Institute FOKUS, Berlin, 2004 11 OWL-S  Semantic description of the whole spectrum of information necessary to find and execute Web services  Based on RDF and OWL  Four complementary ontologies  Service, Profile, Process and Grounding

12. © Fraunhofer Institute FOKUS, Berlin, 2004 12 OWL-S (cont‘d)  Service ontology  Upper ontology  Meta concepts  Sticking together the other ontologies  Profile ontology  Parameters, preconditions, effects  Properties  Process ontology  More detailed description of a Web service  Control and data flow  Grounding ontology  Linking the Profile and Process descriptions to a concrete Web service and its WSDL definition

13. © Fraunhofer Institute FOKUS, Berlin, 2004 13 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

14. © Fraunhofer Institute FOKUS, Berlin, 2004 14 The SemApp System  Addressing the appointment scheduling process in virtual teams  Workflow  Investigation of the schedules of team members  Making an appointment with certain team members based on the free times disclosed by their personal schedules  Technologies  Web services + Semantic Web  Detailed description  Appointment scheduling application that automatically collaborates with arbitrary personal calendars (Lotus Notes, Microsoft Outlook etc.) which provide semantically described Web services

15. © Fraunhofer Institute FOKUS, Berlin, 2004 15 System Architecture

16. © Fraunhofer Institute FOKUS, Berlin, 2004 16 Controller Component  Generating Web pages for user interaction  Controller role in MVC paradigm  Steering of the system interactions  Processing the input  Manipulating the data  Generating the output

17. © Fraunhofer Institute FOKUS, Berlin, 2004 17 Web Interface and Storage Engine  Web interface  Creation and modification of team / contact data  Manipulation of the associated PIMs  Storage Engine  Storing Team and contact data persistently  Factory pattern with one implementation (OWL file)

18. © Fraunhofer Institute FOKUS, Berlin, 2004 18 PIM Proxy  Encapsulating the communication with the Web services  Not a generic component  Aware of the PIM domain semantics  Two functions as interface to the Controller  Get the appointments of a given team member  Put an appointment to the personal schedule

19. © Fraunhofer Institute FOKUS, Berlin, 2004 19 Technical Details  J2EE web application: J2SE 1.4, Java Web Service Developer Pack (JWSDP) 1.3  OWL-S processing: Jena 2 by HP Labs  Web-based user interface: JavaServer Faces 1.0  Outlook Web service:.NET Framework 1.1  ZENO Web service: JWSDP 1.3 (JAX-RPC)

20. © Fraunhofer Institute FOKUS, Berlin, 2004 20 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

21. © Fraunhofer Institute FOKUS, Berlin, 2004 21 Ontologies  Definition  Ontologies ensure the common understanding of a problem domain through the definition of concepts, properties and the relations among them.  Functional ontology  Description and classification of Web service functionalities  Domain ontology  Definition of domain-specific concepts

22. © Fraunhofer Institute FOKUS, Berlin, 2004 22 Domain ontologies  Description of domain knowledge  Concepts used for describing appointments  Time data (Time Zone Database), appointment data (RDF Calendar), account data (Friend of a Friend)  Should be defined by widely accepted standardisation bodies  Reimplementaion of the ontologies for performance, granularity and consistency reasons  OWL Lite  Minimal set of concepts

23. © Fraunhofer Institute FOKUS, Berlin, 2004 23 Request and Advertisement  Request ontology  Containing all requirements a Web service has to satisfy in order to be recognized and invoked by the SemApp system  Two OWL ‑ S Profiles  Defined as instances of GetAppointments() and MakeAppointment() of the Profile hierarchy  Correspond to the functionality needed by the SemApp system  Definition of in- and output parameters by means of domain ontologies  Advertisement ontology  Profile description of a concrete Web service  Request and Advertisement are used for Matchmaking

24. © Fraunhofer Institute FOKUS, Berlin, 2004 24 Request (cont‘d)

25. © Fraunhofer Institute FOKUS, Berlin, 2004 25 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

26. © Fraunhofer Institute FOKUS, Berlin, 2004 26 Matchmaking Engine  Generic component  Compares service requests with service advertisements in order to find Web services that provide the functionalities needed by the SemApp system  Compares concepts instead of matching the method signatures by name  The following matches are recognized:  Exact match  Equivalent match  Sub class match  Super class match  Property match and  No match

27. © Fraunhofer Institute FOKUS, Berlin, 2004 27 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

28. © Fraunhofer Institute FOKUS, Berlin, 2004 28 Execution Engine  Generic component  Capable of executing arbitrary Web services in an ad hoc fashion  Prerequisites  Web service must conform to the WS-I Basic Profile 1.0  Web service must provide SOAP/HTTP binding  Web service must be described with OWL-S 1.0  Dependencies  SAAJ from the JWSDP 1.3  Apache’s Xalan  Hp Labs’ Jena 2 framework

29. © Fraunhofer Institute FOKUS, Berlin, 2004 29 Overview  Motivation  System Architecture  Ontologies  Matchmaking Engine  Execution Engine  Conclusions and Future Work

30. © Fraunhofer Institute FOKUS, Berlin, 2004 30 Conclusions and Future Work  Common applications may benefit from using Semantic Web services  Problems encountered  Frequently changing specifications, in particular OWL-S  Jena OWL reasoner not sufficiently stable, slow and rather greedy regarding memory and processing resources  RACER as substitute  Assignment of OWL-S concepts to XSD and vice versa  XSLT is labor intensive and error prone  Several serializations of one OWL graph can lead to semantically equal but syntactically different XML documents  Future activities  Applying the concepts presented on other groupware applications (team to-do lists, team chats, group address books etc.)  Extend matchmaker towards the consideration of effects, preconditions and properties  Incorporation of security issues

31. © Fraunhofer Institute FOKUS, Berlin, 2004 31 Thank you.