Research Heaven,West Virginia

A Compositional Approach for A Compositional Approach for Validation of Formal Models Validation of Formal Models

Bojan Cukic, Dejan Desovski

West Virginia University

NASA OSMA SAS '04

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Research Heaven,West Virginia

Approach

• Using test coverage measures, decompose the formal specification model. – Abstract the thoroughly tested parts, use model checking on

the rest of the specification.

• Demonstrate that visual interfaces hide the complexity of the specification model. – Develop methodology for creation of visual interfaces. – Use them for representing the coverage metrics too.

• Extend the SCR toolset – Monitoring specification test coverage. – Automatic decomposition of the specification. – Compositional verification.

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Research Heaven,West Virginia

Importance/benefits

Verification and validation of formal models suffers from significant practical drawbacks. Practical and automated assurance of specifications is an open

research problem.

Integration of model testing and visual specification interfaces. Facilitates variable and interaction abstraction. Abstractions reducing the state-space of the models.

A compositional framework for verification and validation of system specification models. Exploit the ease of testing, and the completeness of the model

checking.

Extending a mature toolset (SCR).

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Research Heaven,West Virginia

Relevance to NASA

• Incomplete, inconsistent, unstable system requirements a major mission assurance problem. – Brian O’Connor’s address at NASA IV&V, June 04.

• Proposed approach to be evaluated on NASA case studies. – Fault Protection Engine (FPE) System at JPL. – Other case studies wanted/needed.

• Ongoing case studies on formal specification.

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Research Heaven,West Virginia

Accomplishments

• Test coverage of SCR specification constructs study completed.– Formally defined

coverage criteria applicable to SCR specifications.

– SCR’s simulator utilized for automated coverage tracking.

– Coverage tracking tool developed, applied to Safety Injection System.

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Research Heaven,West Virginia

Next Steps

Continue the research on SCR specification test coverage, visualization, abstraction, additional case studies. Develop a methodology for building visual

interfaces of generic SCR specifications. Investigate visual interfaces suitable for

specification verification and validation. Integrate visualization toolset with the coverage

tracking tool.

Research on automated specification abstraction from test coverage metrics.