Modelling (pre-)Design Activities With a Multi-Stakeholder Perspective - Principia Designae: Pre-Design, Design, and Post-Design - page 174

Fig. 12.3 Extended FBS model (Cascini et al. 2013 ) : Needs Identification (a) and Requirements
Definition (b)

investigates customer needs N e , thus producing N i • Process I variables

(interpretation).
• Process II transforms N i into R i variables (transformation). These R i are a
preliminary set of requirements, useful to better categorize the gathered needs.
• Process III transforms the initial expected requirements Re i into Ne i variables
(transformation). This step ensures that needs not provided by customers, but
necessary, have the chance to be taken into consideration.
• Process IV transforms Ne i into N e variables (transformation) to validate the
expected requirements with the customers. In case of negative feedback, the
emerging external needs N e can be analysed and interpreted to reformulate the
requirements (through processes I and II).

In the proposed Needs Identification step, processes I and II correspond to
analysis, while III and IV correspond to synthesis. This means, in general, that
Needs Identification consists initially in an analysis process that creates a mental
link between the captured Needs and possible Requirements in a sort of feasibility
analysis. The process of synthesis produces a list of needs that can be deducted by
the expectations of the designer (in the form of Requirements) and can be validated
by the customer. Therefore, according to these alternative transitions, the identified
Ne can be directly provided by the customer and/or can be anticipated by the
designer who proposes the list of needs description to the customer.

12.4.2 Requirements Definition

Once that the Needs intended to fulfil have been identified, the design process
moves to the definition of the design specification, i.e., the list of requirements to be