Beginners Guide to Model-Based Systems Engineering

12/18/2018

N2 (“N-squared”) Diagrams

• Represent the logical data flow for a system or segment • Structured variant of data flow diagram • Highlight what’s there and what’s not • Identify implied interfaces (when grouped with allocation shown) • Reflects only functions and the corresponding data flow • No structure • No sequencing • Shown in box & line or matrix layout • Suitable for general audiences • More often used for analysis (including clustering) than communication • Foundation for DSM (design structure matrix)

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Key Semantics of N2 Diagrams

• Functions shown on the diagonal • Number and name standard • Allocation optional (often shown for clustering) • Items • Name only (sometimes “X”) • Inputs shown in the column • Outputs shown in the row • “Externals” shown in the top row / right column • Arrowheads show directionality only (items input / output at function) • Regions around diagonal have implied meaning • Above implies feedforward • Below implies feedback

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