1 / 13

Arcade: A formal, extensible, model-based dependability evaluation framework

Arcade: A formal, extensible, model-based dependability evaluation framework. Hichem Boudali 1 , Pepijn Crouzen 1,2 , Boudewijn R. Haverkort 1 , Matthias Kuntz 1 , Mari ë lle Stoelinga 1. 1 CS, Twente University, The Netherlands 2 CS, Saarland University, Germany. Motivation/Goals.

yves
Download Presentation

Arcade: A formal, extensible, model-based dependability evaluation framework

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Arcade:A formal, extensible, model-based dependability evaluation framework Hichem Boudali1, Pepijn Crouzen1,2, Boudewijn R. Haverkort1, Matthias Kuntz1, Mariëlle Stoelinga1 1CS, Twente University, The Netherlands 2CS, Saarland University, Germany AADL/UML workshop - Belfast

  2. Motivation/Goals • Approaches to dependability evaluation: • Low level (CTMC, SPN, SPA) • Dependability specific (fault trees) • Architecture-based (AADL, UML) • None is perfect, in terms of: • Modeling effort • Hierarchy & modularity • Expressiveness • (formal) Clear semantics • Effective solution techniques Our objective: To devise a formalism that scores high on all these aspects AADL/UML workshop - Belfast

  3. Our solution: Arcade methodology • Architectural approach (system design) • Expressive and extensible • Modular modeling • Formal semantics (based on I/O-IMC) • Efficient state-space generation (compositional-aggregation technique) AADL/UML workshop - Belfast

  4. What’s an I/O-IMC? • Combination of I/O automata and CTMC • Discrete state space • Markovian transitions • Interactive transitions • Action signature • ? - Input actions • ! - Output actions • ; - Internal actions • Behavior of the system results from the composition of its elements. • Well-defined composition operator & bisimulation equivalence (state minimization) λ failed! AADL/UML workshop - Belfast

  5. Sketch of the proposal Control System Process 1 Process 2 Dependability Annotation (User) Bus Processor 1 Processor 2 Result compositional-aggregation Dependability analysis Other analyses Std. solver AADL/UML workshop - Belfast

  6. Arcade: Current status • Use I/O-IMCs as the underlying formal semantics • At an architectural level, we have identified/defined: • (1) Basic (physical/logical) components (BC) • (2) Repair units (RU) • (3) Spare management units (SMU) • All kinds of behaviors/interactions/dependencies, e.g.: • Operational/failure modes • Repair and spare management policies • Functional dependencies • Textual syntax (ultimately graphical and integrate to an ADL) • To each component/unit corresponds a pre-defined basic I/O-IMC • Use I/O-IMCs’ machinery to carry out state-space generation (compositional-aggregation technique) and analysis AADL/UML workshop - Belfast

  7. Example & Results # of states: 98,056 # of transitions: 411,688 Unavailability (50 hours): 6.52100 ∙10-10 Unreliability (50 hours): 52.92420 ∙ 10-10 AADL/UML workshop - Belfast

  8. Arcade: Tool chain AADL/UML workshop - Belfast

  9. Arcade: A summary Architectural Dependability Evaluation with Arcade. Dependable Systems & Networks (DSN 2008), Anchorage, Alaska, USA. • Low modeling effort: • High level & Graphical • Standard features (BC, RU, SMU) • Tight to an ADL (alternative to AADL error annex) • Expressive/Extensible • Standard features, but also (well-structured) user-defined features • Formal semantics (I/O-IMCs) • Compositional & efficient SS generation • Hierarchical modeling AADL/UML workshop - Belfast

  10. Extra slides AADL/UML workshop - Belfast

  11. Arcade: Example 2 AADL/UML workshop - Belfast

  12. The State-Space Battle • Defined and used the I/O-IMC formalism to describe the semantics of each DFT element. • I/O-IMCs: CTMC + I/O transitions. • Semantics of the entire DFT arises naturally as the composition of its elements’ semantics. • Used the compositional-aggregation approach to combat the state-space explosion problem. • Lifted the restrictions  extended DFT formalism. AADL/UML workshop - Belfast

  13. The State-Space Battle Translation Composition + Hiding compositional-aggregation Repeat Aggregation (minimization) Result: System failure probability Aggregatedsystem CTMC CORAL AADL/UML workshop - Belfast

More Related