by Gemma Grau
Phase 2: Construction of the i* Model
One of the key points of our method is to obtain reliable and
repeatable i* models is to be as prescriptive as possible when building them.
For doing so PRiM proposes several steps, rules and guidelines.
Building the operational i* model
- The i* model is constructed in two different steps in order to allow two
different levels of abstraction: the operational and the intentional.
- The operational i* model is composed by descriptive goals, the ones obtained by
the observation of the current process.
- The resulting i* model is composed mainly by task, resource and some goal dependencies.
- The models can be automatically generated from the information stored in the DIS.
- The tool allows to rename the elements (bottom of the screenshot) and to generate the model.
- As a main difference with other i* modelling tools, J-PRiM does not show the models in a graphic, but in a tree-hierarchy.
- As the models can grow quickly, this allows to manage scalability of the models. With this purpose in mind it is possible to focus on certain elements of the models (an actor, an activity, an intentional element or a dependency).
- At the left of the screenshot, we can see the actors are decomposed into SR elements. which are in turn decomposed into other SR elements and SR dependencies.
Building the intentional i* model
- The intentional i* model contains the organization goals over the process,
that is the prescriptive goals.
- This goals are obtained by analysing the operational i* model but it is mainly
composed by goals and softgoals.
- The Intentional i* model can not be generated automatically but the method
proposes a set of guidelines in order to guide its construction:
- Obtaining the main intentionality behind the activity.
For each activity state which is the final goal to achieve by executing the
activity and which actors are the ones that need to attain the goal and the
ones that can provide it.
- Decomposition of goals into subgoals.
It is also possible to analyse the already existing goals and to decompose
them into subgoals.
- Quality-attributed analysis of the dependencies.
Some of the dependums can be qualified according to some quality attributes
they should provide. This analysis can be done by performing inquire questions
using the ISO/IEC 9126 as a guide.