The Integrated‐Iterative‐Incremental System Development Model

This chapter introduces the capabilities‐based integrated‐iterative‐incremental (I‐cubed or I
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) system development model that integrates incremental development of physical elements and iterative development of software elements for software‐enabled physical systems. It provides the opportunity for readers to gain an understanding of capabilities‐based requirements definition and model‐based and simulation systems engineering (M&SBSE) system realization. Business/mission analysis and stakeholder's requirements/system capabilities definition are grouped together in I
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Phase 1 to indicate an iterative approach to analysis and definition. As indicated, system capabilities are derived from stakeholders' requirements and system requirements are defined for each of the system capabilities. Simulated elements, interfaces, and connections are replaced for each of the capabilities realized during each incremental subphase. Depending on the nature of a capability being realized, realization of a physical element may proceed ahead of realizing the software needed for the capability. Decomposing a complex system capability into smaller units may facilitate synchronization of element realizations.