Software Engineering

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10.2 
Functional architecture ontology
be broken down into two or more subfunctions. The designation of a function as a 
component indicates that it involves a lower level of functional detail to unambigu-
ously express the manner by which the data processing or transformation is per-
formed. Several layers of decomposition may be necessary to establish a noncomplex 
solution.
10.2.2 
Functional unit
Functional units represent elements at the lowest level of the hierarchy. A func-
tional unit signifies that no further decomposition is necessary to unambiguously 
express the solution. Functional units can be recognized when the design or imple-
mentation of the function can be easily comprehended. Functional units should per-
form a single, noncomplex task; should receive data items as input from a limited 
number of sources; and should output data processing results to a limited number of 
receiving functions or external elements.