Functional Analysis and Allocation, in thesystems engineering process, bridges the gap betweenrequirements engineering and design. This step in the process transforms stakeholder requirements into a logical[1] and functional architecture,[2] and provides the inputs to the design, integration, and verification activities.[3][4]
Functional decomposition is used to break down top-level functions into lower-level sub-functions to provide a hierarchical structure of the functionality.
Like functional decomposition, FAST is used to decompose a system's functions into sub-functions. In addition, it analyzes the logical relationships between those functions. The methodology uses theFAST diagram in order to assist the brainstorming process. For each top level function, the diagram maps "how" the function is achieved, "why" the function is needed, and which functions support the main function.
Use case analysis
Use case analysis is used for both functional requirement identification, and the refinement of those requirements.[7]
^"SEBoK".Guide to the Systems Engineering Body of Knowledge (SEBoK).
^abNASA.NASA Systems Engineering Handbook, NASA/SP-2016-6105 Rev2. Washington, DC: NASA Headquarters, Office of the Chief Engineer, 2016. Available atNASA NTRS.
^INCOSE.INCOSE Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities. Version 4.0. San Diego, CA: International Council on Systems Engineering (INCOSE), 2015.
^SAVE International.Value Methodology Standard (VMS), 2007. Also see Miles, L. D.Techniques of Value Analysis and Engineering. McGraw-Hill, 1961.
