NASA Perspective on Recent Trends in Executable Models “This is an important development since it requires minimal configuration, can be used earlier in the lifecycle and can evolve as the design matures.” “Executable UML is the next logical, and perhaps inevitable, evolutionary step in the ever-rising level of abstraction at which programmers express software solutions. Someday soon, the idea of writing an application in Java or C++ will seem as absurd as writing an application in assembler does today.” Rather than elaborate an analysis product into a design product and then write code, application developers of the future will use tools to translate abstract application constructs into executable entities. Modern transmission consist not only from mechanical parts but also from electronics. State machine shall be in the context of the system which behavior it describes Transmission control unit (Figure 1) controls gearbox and switch between gears based on many car parameters.įigure 6. ![]() Behavior descriptions need to be contained underneath the element which is executed. Executable element can only have one main behavior. Recommendation for the main behavior which controls other behaviors is to use State Machine Diagram. ![]() State Machine diagram can be enriched with other behaviors e.g. start activity on enter to state, or execute code as effect of switch between states. We defined behavior description and connected to structure. Now we want to enrich model with more parameters and want to do additional static and dynamic calculations. For these tasks we need to create parametric diagrams. Parametric diagram connects SysML Constraint blocks as a network of reusable constraints that represent mathematical expressions, which constrain the physical properties of a system. SysML parametric diagrams provide a way to integrate engineering analysis models described in mathematical equations and constraints, with design models describing the structural and behavioral aspects of systems. Our goal will be to calculate vehicle speed from engine Revolutions per Minute (RPM). We will use following four (Figure 7) mathematical expressions. System characteristics and requirement relation We will formalize them in SysML constraint blocks.įigure 14. ![]() Note that in simple cases manual requirement refinement with constraint block is not required. Natural language analysis capability available in modern modeling tools recognize text pattern based one predefined and customizable ones and create constraint automatically.
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