Reusing Modeling Elements in IV&V

1. Reusing Modeling Elements in IV&V Thomas Otani Naval Postgraduate School John Ryan Reuse Working Group Lead 2009 NASA Independent Verification and Validation (IVV) Annual Workshop

2. Outline • The IV&V Reuse Working Group • The System Reference Model (SRM) • Reuse in SRM • Reusable Modeling Elements • SRM Reuse Framework • Intermediate Reuse Repository • Conclusion Sept 15 - Reusing Modeling Elements

3. The Reuse Working Group • Objectives • Provide reusable modeling artifacts to support in NASA IVV efforts to: • Reduce labor cost and time of product deliverables • Reduce duplication of modeling artifacts • Increase scope, flexibility, and responsiveness • Leverage previous understandings of systems and behaviors Sept 15 - Reusing Modeling Elements

4. The Reuse Working Group • Previous Goals • Define the definition and attributes of reuse and use artifacts • Define how reuse integrates with the product lines • Define the process and requirements for a Reuse Repository • Current Goals • To demonstrate the feasibility and value of reuse through focused projects • To increase the supply and availability of reusable artifacts • To increase community capability and interest to leverage existing artifacts Sept 15 - Reusing Modeling Elements

5. The Reuse Working Group • Scope The WG will define and recommend areas within modeling, validation, and verification activities for reuse, and will provide support (analytical, development, management, and training) to enable reuse within those activities across projects. • Focus on: • Reuse of existing artifacts • Reuse of newly developed artifacts derived from existing artifacts • Developing initial modeling, assertion, and report templates • Reuse of modeling artifacts (Initially) • Reuse for science and exploration mission projects Sept 15 - Reusing Modeling Elements

6. System Reference Model • We advocate the use of System Reference Model (SRM) for the IV&V team to capture its understanding of the problem domain • The SRM contains • Written Use Cases • UML artifacts and • a set of formal assertions and accompanying test scenarios to model precisely the required behavior of the system Sept 15 - Reusing Modeling Elements

7. Executable SRM • We advocate that the SRM be executable for it to be truly useful • Executable SRM includes a computer-aided tool to validate behavior specifications • Software automation is the key to the successful validation (and verification) of the behaviors of complex systems • Traditional manual process is woefully inadequate in locating subtle errors in increasingly complex software-intensive systems of systems Sept 15 - Reusing Modeling Elements

8. Reuse in SRM • Two types of reuse in SRM: • Adoption Reuse • An existing artifact (e.g. activity diagram) is reused in another product • Instantiation Reuse • A concrete artifact is created from a generic template • An idea of generic assertion template was presented at IEEE SSIRI 2008 Sept 15 - Reusing Modeling Elements

9. Sample Assertion Template Resusing Modeling Elements

10. Test Scenario Patterns • These are the types of test patterns that must accompany every assertion • Obvious Success • Obvious Failure • Event Repetitions • Time-interval Repetitions • Overlapping Time-interval Repetitions Resusing Modeling Elements

11. More Reusable Modeling Elements • Behavioral and structural products for conceptual system and subsystem views • Written Use Cases, Use Case Diagrams, Activity Diagrams, Sequence Diagrams, Communication Diagrams, State Diagrams, Class Diagrams • Goals, Constraints, External Actors/Stakeholders, Some Internal Actors, Actions/Functions • Reuse by Context: Subsystem, Behavior, Design Choices, Mission Characterizations • Note: The actions/functions in Behavioral Diagrams may be reusable but not necessarily in the sequence defined in the diagrams Sept 15 - Reusing Modeling Elements

12. More Reusable Modeling Elements • SysGoals Product • PBRA Products • Assertions • Behavioral and structural products associated with design subsystem component views • Other Reports, References, Templates Sept 15 - Reusing Modeling Elements

13. Example: SysGoals Product • Characterize/Classify Missions by: • Mission Type: Orbiter/Lander • Location/Destination: Earth Orbit, Non-Earth Planetary Orbit • Orbit Type: LEO, Polar, Geocentric, etc. • Number of Orbiters, Solo/Cluster • Overall Objectives and Science Requirements • Communication Signal Bands and Availability • Autonomous vs. Commanded Operations • Length of Mission • Launch and Landing Plans • Environment/Conditions • Environmental Limitations and Safety Precautions • Capabilities, Limitations, and Risks Sept 15 - Reusing Modeling Elements

14. Modeling Reuse with Classifications • Identify Commonalities and Differences • Associate Goals to Characterizations • Associate Sub Goals to Characterizations • Develop Reusable SysGoal Products in respect to context by characterization Common and Generic Goals, Behaviors, Actions, Actors, etc. Additional and Specific Goals, Behaviors, etc. for Classification Sept 15 - Reusing Modeling Elements

15. NEAP Project Sept 15 - Reusing Modeling Elements

16. Reuse Process Reuse Repository Discovery Search Packaging Validation Classification Adaptation/ Integration Sept 15 - Reusing Modeling Elements

17. SRM Reuse Framework • Three initial use cases to identify the actors and behaviors of the desired reuse library: • Add SRM artifacts to the reuse library • Browse the reuse library • Retrieve and reuse SRM artifacts Sept 15 - Reusing Modeling Elements

18. Use Case: Add SRM Artifacts Sept 15 - Reusing Modeling Elements

19. Use Case: Browse Artifacts Sept 15 - Reusing Modeling Elements

20. Use Case: Browse by Activity Sept 15 - Reusing Modeling Elements

21. Use Case: Retrieve and Reuse Sept 15 - Reusing Modeling Elements

22. Conceptual Model Sept 15 - Reusing Modeling Elements

23. Elements in the Prototype Sept 15 - Reusing Modeling Elements

24. Intermediate Reuse Repository • Reuse Working Group is using svn to control new reuse artifacts within a Together Project: • The Reuse Repository • Working Group acts as current librarian to define or accept new reuse additions • The Reuse Repository will provide different folder views to browse by: [contexts] • Behavior • Product • Subsystem (associate reusable products) • Design Component (associated reusable products) • Project • {All contexts may be further decomposed by classifications} Sept 15 - Reusing Modeling Elements

25. A Prototype Beyond svn • Eclipse plugin • Must integrate with other tools used by the IV&V team • First prototype will support • Only basic searches by id and name • Backend database is object-oriented • Artifacts maintained in the XML format Resusing Modeling Elements

26. Conclusion • Short-term Goal • Implement the prototype Intermediate Reuse Repository using svn • Evaluate the prototype for its effectiveness • Promote the use of Intermediate Reuse Repository with a pilot project • Start the construction of a basic proof-of-concept prototype that supports only a limited number of elements in the reuse conceptual model • Long-term Goal • Meet the Objectives and Goals of the Reuse Working Group • Reuse (of modeling elements) becomes a fully integrated aspect of the IV&V workflow Sept 15 - Reusing Modeling Elements

27. Questions? Sept 15 - Reusing Modeling Elements