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models. Moreover, the extended i* metamodel also
defines a new abstraction (the alternative) to allow
the generation of several different views of the same
model. In particular, each view focuses in a
particular routine to accomplish something, reducing
the complexity of the model and, therefore,
improving its readability and understandability.
6 CONCLUSIONS
In this paper we propose an extension of the i*
modelling language by adding new constructs to the
i* metamodel to improve the understandability of
the i* models. By doing so, we have added two
attributes to the task-decomposition link to define
the order in which the components of a decomposed
task are required. Moreover, a new abstraction has
been added to the metamodel, called alternative, to
suppress specific sub graphs in the SR model and,
therefore, produce simpler views of the same SR
model. In fact, each view focuses on a specific
routine to achieve a dependency. These views may
reduce the complexity of i* models, increasing their
readability, maintainability and scalability. In fact, it
is now necessary to carry out experiments with some
available metrics (Ramos et al., 2008) (Franch,
2006) to estimate the degree of amount complexity
reduction using our approach.
Currently, we are working on the inclusion of
routines identification and their association with
viewpoints (Sommerville et al., 1998) in i* models.
Finally, we plan to evolve the current i* support tool
(Yu and Yu, 2000) to include the new constructs of
the extended metamodel. Moreover, the new
constructs requires the formal specification of
constraints to be considered when specifying i*
models. Currently, these constraints are being
specified in OCL (OMG, 2006) and will be
presented in future work.
ACKNOWLEDGEMENTS
This work was supported by CAPES/GRICES Proc.
129/05.
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