by Gemma Grau
Overview of the PRiM method
The PRiM methodology addresses i* modelling from the
process reengineering perspective, where the specification of a new system starts
from the observation of the current system and ends with the achievement of the
specification of the system-to-be. The PRiM methodology is composed of five phases
that are decomposed in steps:
PRiM is an iterative process that can be refined by going back on
the steps of its phases:
- In the first phase of PRiM, the current process is analysed and the information obtained is summarized into Detailed Interaction Scripts (DIS). DIS are tables that organize the information of each activity of the current system by means of its preconditions, postconditions, triggering events, and a list of the actors, actions and resources involved in the activity.
- In the second phase, the construction of the i* model begins with the identification of the actors of the system, and the i* model is built in two differentiated steps in order to distinguish the functionality performed by the stakeholders from their strategic intentionality. PRiM provides prescriptive rules for generating the Operational i* model of the system from the DIS and several guidelines for obtaining the intentional i* model based on the operational i* model .
- In the third phase, process alternatives are systematically generated by means of adding new actors to the system and reallocating the responsibilities between them.
- In the fourth phase the evaluation of the alternatives is done by choosing the appropriated properties. Once selected, metrics over the i* model are defined and used for evaluating thea i* models of the selected alternatives. Trade-off analysis is needed to select the most suitable solution.
- In the fifth phase, PRiM proposes to generate the specification of the new system from the i* model of the chosen alternative.