Executable specification-based system engineering

Standard system engineering techniques provide a robust approach to the design, creation and operation of systems but the reliance of these techniques on the generation of text documents reduces understanding of system interactions, makes it difficult to communicate design intent and desired behavior, provides no ability to analyze and assess implementation in the design phase, and can be plagued by errors during the transition from system engineering products to implementation. Model-based system engineering (MBSE) alleviates some of these issues by elevating models over standard documentation, but it still does not address many of the issues articulated above: The out-product of MBSE is still just documentation so the transition to implementation remains error prone, behavioral analysis can only be performed in limited instances, and MBSE tends to draw resources away from system engineering functions to maintain models that never keep up with actual design or implementation. This paper proposes a new technique of system engineering based on executable specification. Executable specification allows a user to specify a system in a formal language (i.e. the specification) and then bypass conventional implementation methods by directly executing the specification. Executable specification-based system engineering enables a system engineer to specify how the system will function, to analyze the behavior very early in the design phase, and to proceed to implementation without any transition issues since the system engineering diagrams developed within the executable specification framework are the actual implementation. The multiple benefits that can be realized by Executable Specification-based system engineering include: (1) Forcing the system engineers to understand and address the relationships between various sets of behaviors and constraints early in the project. (2) Enabling analysis of concept of operations and mission scenarios early in the project. (3) Elimina- - ting the errors in translation of system engineering products to implementation (4) Preventing models from lagging behind or misrepresenting the implementation; thereby preventing system decisions from being made based on out-of-date models. This paper articulates the concept of execution-based system engineering, outlines the benefits of using this technique, describes the execution-based system engineering process by walking through sample views of the system used to establish the specification, and finally presents an early prototype of an execution-based system engineering tool based on the outlined process.