1 TDT Modeling of Information Systems, Autumn 2006 Model-driven development (MDA), Software Oriented Architecture (SOA) and semantic web (exemplified by WSMO) Draft of presentation John Krogstie Professor, IDI, NTNU Senior Researcher, SINTEF ICT

2 TDT Modeling of Information Systems, Autumn 2006 Q Overview of lectures today and Wednesday Overview on SOA and MDA / MDD, based on material produced in the Athena EU-project More details based on the articles today Articles A14 White, S. A. Introduction to BPMNWhite, S. A. Introduction to BPMN A15. Pasley, J. How BPEL and SOA is changing web services development, IEEE Internet computing May-June 2005Pasley, J. How BPEL and SOA is changing web services development, IEEE Internet computing May-June 2005 A16. de Bruijn, J, Fensel, D., Keller, U. and Lara, R. Using the web-service modelling ontology to enable semantic e- business, Communication of ACM Dec 2005de Bruijn, J, Fensel, D., Keller, U. and Lara, R. Using the web-service modelling ontology to enable semantic e- business, Communication of ACM Dec 2005 A17. France, R.B., Gosh, S. Dinh-Trong, T, and Solberg, A. Model-driven development using UML2.0: Promises and Pitfalls, IEEE Computer February 2006 France, R.B., Gosh, S. Dinh-Trong, T, and Solberg, A. Model-driven development using UML2.0: Promises and Pitfalls, IEEE Computer February 2006 A18. Jones, V., Rensik, A. and Briksma, E. Modelling mobile health systems: an application of augmented MDA for the extended healthcare enterpriseJones, V., Rensik, A. and Briksma, E. Modelling mobile health systems: an application of augmented MDA for the extended healthcare enterprise

3 TDT Modeling of Information Systems, Autumn 2006 Q BPMN – based on a presentation by Steven White

4 TDT Modeling of Information Systems, Autumn 2006 Q Business process management (BPM) services

5 TDT Modeling of Information Systems, Autumn 2006 Q

6 Q

7 Q

8 Q

9 Q

10 TDT Modeling of Information Systems, Autumn 2006 Q

11 TDT Modeling of Information Systems, Autumn 2006 Q

12 TDT Modeling of Information Systems, Autumn 2006 Q

13 TDT Modeling of Information Systems, Autumn 2006 Q

14 TDT Modeling of Information Systems, Autumn 2006 Q

15 TDT Modeling of Information Systems, Autumn 2006 Q

16 TDT Modeling of Information Systems, Autumn 2006 Q

17 TDT Modeling of Information Systems, Autumn 2006 Q

18 TDT Modeling of Information Systems, Autumn 2006 Q

19 TDT Modeling of Information Systems, Autumn 2006 Q

20 TDT Modeling of Information Systems, Autumn 2006 Q

21 TDT Modeling of Information Systems, Autumn 2006 Q

22 TDT Modeling of Information Systems, Autumn 2006 Q

23 TDT Modeling of Information Systems, Autumn 2006 Q

24 TDT Modeling of Information Systems, Autumn 2006 Q

25 TDT Modeling of Information Systems, Autumn 2006 Q

26 TDT Modeling of Information Systems, Autumn 2006 Q Model-driven development (MDD) CIM Business Context Models PIM Model trans- formation Software Specification Models PSM Software Realisation Models Model trans- formation Model-driven approach to system engineering where models are used in understanding design construction deployment operation maintenance modification Model transformation tools and services are used to align the different models. Business-driven approach to system engineering where models are refined from business needs to software solutions Computation independent model (CIM) capturing business context and business requirements Platform independent model (PIM) focusing on software services independent of IT technology Platform specific model (PSM) focusing on the IT technology realisation of the software services

27 TDT Modeling of Information Systems, Autumn 2006 Q Current MDA Architecture CIM models PIM System models PSM System models System QVT MOF2Txt Enterprise modeling expert System modeling expert System realisation installation expert UML2.0 MOF2.0 XMI2.0 Ontology ODM BPDM OrgMM BSVR OWL ATL MOFScript EMF Java API MTF (IBM) QVT (MOF2Txt)

28 TDT Modeling of Information Systems, Autumn 2006 A17. France, R.B., Gosh, S. Dinh-Trong, T, and Solberg, A. Model-driven development using UML2.0: Promises and Pitfalls, IEEE Computer February 2006 Navigating the metamuddle France, R.B., Gosh, S. Dinh-Trong, T, and Solberg, A. Model-driven development using UML2.0: Promises and Pitfalls, IEEE Computer February 2006 Arnor Solberg, Robert France, Raghu Reddy Colorado State University and SINTEF Norway

29 TDT Modeling of Information Systems, Autumn 2006 Q Claim The complexity of the current UML 2 metamodel make the understanding, using, extending and evolving the metamodel difficult pages specification  large and fragmented Available as a model in Rational Rose  Only for visualization, no manipulation features available (e.g. queries)  Poorly documented This is a risk factor for MDD in general and MDA in particular!

30 TDT Modeling of Information Systems, Autumn 2006 Q This is a problem since.. MDD require development teams to understand, use and extend metamodels Configuring and tailoring MDD frameworks need to be done for each domain and even System Family to be able to succeed with MDD. Defining domain specific modeling concepts (for example by means of profiles), specification of metamodel mappings (transformations) and model composition will be main tasks Task for Domain and System Family architects. No out of the box tools to buy from vendors. Tailoring is needed

31 TDT Modeling of Information Systems, Autumn 2006 Q Conceptual transformation model Source (e.g., UML domain/PF subset/profile) > Source2Target Scheme > Source implementation > Target (e.g. CORBA UML profile) > Transformation (e.g. MOF2.0 QVT) > Target Transformation >

32 TDT Modeling of Information Systems, Autumn 2006 Q Good news and bad news Good news is In practice only part of the UML is used  Subset of diagrams  Subset of concepts -> Should not need to have the full knowledge of the UML metamodel to use “your” part of UML Bad news Need to manually navigate the metamuddle to extract the concepts you want to use

33 TDT Modeling of Information Systems, Autumn 2006 A glimpse into the story Illustrative Example Mapping of Simple UML interactions models (e.g. to UML profile for CORBA)

34 TDT Modeling of Information Systems, Autumn 2006 Q Simple metamodel for UML interactions Want to extract the Lifeline and Message concepts and their relationships. These are core concepts for modeling interactions so you would expect to find their properties and relationships quite easily in the standard  Examination of the Interactions section in the UML specification, reveals that the information required in this simple view is not available in one place in the metamodel.

35 TDT Modeling of Information Systems, Autumn 2006 Q Lifeline fragment (no obvious relation to Message)

36 TDT Modeling of Information Systems, Autumn 2006 Q Message fragment (no lifeline)

37 TDT Modeling of Information Systems, Autumn 2006 Q Problems of UML Large and complex Specification fragmented Leads to accidental complexity As opposed to inherent problem complexity This is a risk factor for the MDA vision! Furthermore how do you evolve the UML model in a consistent manner? How can one be sure that required changes are incorporated consistently across the metamodel? How can one determine the impact that a change will have on other metamodel elements? In particular, how can one ensure that the changes do not result in a metamodel that defines inconsistent or nonsensical language constructs? It will be extremely difficult to evolve the UML 2.0 metamodel to reflect changes in the UML standard using only manual techniques.

38 TDT Modeling of Information Systems, Autumn 2006 Q Suggestions Need user oriented views into the metamuddle At least a simple view of the metamodel for each diagram type that describes only the concepts and relationships that appears in the diagram Use aspect oriented techniques e.g. to Provide views of the set of diagram types that only contain concepts that are visible in the diagrams (abstract concepts such as NamedElement will not appear in such diagrams, but derived properties will) Define aspects presenting views of abstract concepts reflecting language and UML-specific concerns such as name space management, element typing, connectivity of elements, and execution semantics. Make it easier to evolve (e.g., change aspects, new aspects)

39 TDT Modeling of Information Systems, Autumn 2006 Q Tool support At least Tool that allows developers to query the metamodel, to extract views of the metamodel E.g., get all relationships and properties of a metamodel concept  Including the derived ones Some tools provide some of this capability already  Xactium  Megamodelling, ATL (Jean Bezivin) Better Tool that take UML models as input and automatically extract the metamodel for this set of input models  Implicit model checking (compliance checking)

40 TDT Modeling of Information Systems, Autumn 2006 Q Conclusion

41 TDT Modeling of Information Systems, Autumn 2006 Q Questions How do we eliminate accidental complexity such as the one illustrated in this presentation Other examples exists, e.g., the QVT specification Is this a unavoidable for new, immature fields? Problem is to include the users in the evolution of the field when there is too much accidental complexity involved when using it

42 TDT Modeling of Information Systems, Autumn 2006 Q Conclusion and further work MDD framework that facilitates: Horizontal separation  Handling crosscutting features distributed across a model  Emphasis on QoS during model specification and transformation  Simplify transformations Vertical separation of concerns  Abstractions e.g., to manage diversity and evolution of platforms Future work More case studies  Different platforms,  Repository of models and mappings of common middleware concerns Profile for specifying model weaving Usage of framework for adaptive systems and adaptive middleware (E.g., Madam middleware)  Increase flexibility and ease evolution of adaptive systems

43 TDT Modeling of Information Systems, Autumn 2006 WSMO overview As basis for A16. de Bruijn, J, Fensel, D., Keller, U. and Lara, R. Using the web-service modelling ontology to enable semantic e-business, Communication of ACM Dec 2005de Bruijn, J, Fensel, D., Keller, U. and Lara, R. Using the web-service modelling ontology to enable semantic e-business, Communication of ACM Dec 2005

44 TDT Modeling of Information Systems, Autumn 2006 Q Contents Mission of WSMO WSMO Standard

45 TDT Modeling of Information Systems, Autumn 2006 Q Mission of WSMO Web Service Modeling Ontology WSMO is a conceptual model for relevant aspects related to Semantic Web Services

46 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard Provide the formal semantics of the information used by all other components Semantic description of Web Services: - Capability (functional) - Interface (usage) Specify objectives that a client may have when consulting a Web Service Connectors between components with mediation facilities (de-coupling)

47 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard - Ontologies Non functional properties Used mediators Importing / re-using ontologies as modular approach for ontology design. OO Mediators:  handles all ontology management issues (access, namespaces, etc.)  ontology integration (merging / alignment) => Modularization & De-coupling Axioms The set of axioms that belong to the represented ontology. Concepts The set of concepts that belong to the represented ontology. Relations The set of relations that belong to the represented ontology. Instances The set of instances that belong to the represented ontology.

48 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard - Goals Non functional properties Used mediators import ontologies using OO Mediators. GG Mediator: Goal definition by reusing an already existing goal. Post-conditions describe the state of the information space that is desired. Effects Effects describe the state of the world that is desired.

49 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard - Mediators Principle of De-coupling for handling complexity & heterogeneity => Mediators: WSMO components are never allowed to touch each other without a mediator in-between.

50 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard - Mediators

51 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard - Mediators Non functional properties Source component the connected entity / entities Target component the connecting entity / entities Mediation Service links to Mediation Facility needed to resolve heterogeneity Reduction describes the differences between the connected entities only in WG or GG

52 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard – Web Service Non functional properties Used mediators OO Mediators for importing ontologies as the formalized terminology for describing the Web Service Capability functional description (WHAT), 1:1 Interfaces description of usability & composition (HOW), 1:n Semantic Description of Web Services to allow (semi-)automated usage of Web Services

53 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard – Capability Non functional properties Used mediators OO Mediator: importing ontologies as terminology definition WG Mediator: link to a Goal that is solved by the Web Service Pre-conditions what a web service expects in order to be able to provide its service, i.e. conditions over the input Assumptions Conditions on the state of the world that has to hold before the Web Service can be executed Post-conditions describes the computational result in relation to the input of the Web Service, and conditions on it Effects Conditions on the state of the world that hold after execution of the Web Service (i.e. changes in the state of the world)

54 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard – Interfaces describes how the functionality of the service can be achieved provides a twofold view on the operationalization of the Web Service: 1. Choreography defines how to communicate with the web service in order to consume its functionality. 2. Orchestration defines how the overall functionality is achieved by the cooperation of more elementary service providers. Choreography & Orchestration = different decompositions of process/capabilities to the top (service requester) and to the bottom (other service providers). This distinction reflects the difference between communication and cooperation.

55 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard – Interfaces

56 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard – Interfaces Non functional properties Used mediators OO Mediators for importing ontologies as terminology definitions Choreography provides the necessary information for the user to communicate with the web service. described by an instantiated Message Exchange Pattern Orchestration describes a service makes use of other web service or goals in order to achieve it's capability. specifies the composition of Web Services used by a Web Service described as an instantiated Problem Solving Pattern.

57 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Standard – Language F-Logic combines the advantages of conceptual high-level approaches typical for frame-based language and the expressiveness, the compact syntax, and the well defined semantics from logics. it provides a standard model theory it is a full first order logic language it provides second order syntax while staying in the first order logic semantics it has a minimal model semantics implemented inference engines are already available.

58 TDT Modeling of Information Systems, Autumn 2006 Q WSMO Working drafts at:

59 TDT Modeling of Information Systems, Autumn 2006 Model-driven development (MDA), Software Oriented Architecture (SOA) and semantic web (exemplified by WSMO) John Krogstie Professor, IDI, NTNU Senior Researcher, SINTEF ICT