Covariance structural models of the relationship between the design and customer domains

This paper addresses the problem of modelling and mapping of difficult to quantify customer needs to technical requirements and subsequently to design parameters. Proposed is a covariance structural equation model, which incorporates a confirmatory and a structural component. The former is used for the decomposition of the qualitative customer needs, modelled as latent variables, onto a generally larger number of measurable technical requirements. The structural component maps the technical requirements to design parameters. The concept is illustrated by an example. The model is confined to the linear dependence between the variables, but in general the approach can handle a number of non-linear relations through variable transformation. The conclusion is that the proposed synthetic procedure, named SEMDES (Structural Equation Models for the Design of Engineering Systems) represents a sufficiently rich and generic structure capable of bridging the gap between the customer and the design domains.