20 Rizzi
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Requirement-Driven.Approaches
Conversely, within a requirement-driven framework, in the absence of knowledge
of the source schema, the building of hierarchies cannot be automated; the main
assurance of a satisfactory result is the skill and experience of the designer, and the
designer??™s ability to interact with the domain experts. In this case it may be worth
adopting formal techniques for specifying requirements in order to more accurately
capture users??™ needs; for instance, the goal-oriented approach proposed by Giorgini,
Rizzi, and Garzetti (2005) is based on an extension of the Tropos formalism and
includes the following steps:
1. Create, in the Tropos formalism, an organizational model that represents the
stakeholders, their relationships, their goals as well as the relevant facts for
the organization and the attributes that describe them.
2. Create, in the Tropos formalism, a decisional model that expresses the analysis
goals of decision makers and their information needs.
3. Create preliminary fact schemata from the decisional model.
4. Edit the fact schemata, for instance, by detecting functional dependencies between
dimensions, recognizing optional dimensions, and unifying measures
that only differ for the aggregation operator.
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