I am studying a book about software design called: Nonfunctional Requirements in Systems Analysis and Design which talks about the Axiomatic Design Methodology.
This methodology has two axioms. One of them is the Independence axiom.
There is something however I did not manage to understand. It says about this methodology :
Each functional requirement should be satisfied without affecting any other functional requirement. During the conceptualization process the functional requirements are transformed from the functional domain where they state what, to the physical domain where they will be met by how. The mapping should be one design parameter (DP) to one functional requirement (FR).
The relevance of the independence axiom has additional utility in that individual designs may be evaluated, not qualitatively, but quantitatively, based on the relationship to an ideal design. The ideal design is one where the number of DPs are equal to the number of FRs, where the FRs are kept independent of one another. All design alternatives may be evaluated against the concept of an ideal design.
The book suggests the ideal design has one design parameter to one functional requirement. But what exactly is considered a design parameter within the software engineering scope and this methodology ?