Multi-dimensional goal refinement in goal-oriented requirements engineering

In this paper, we propose a multi-dimensional extension of goal graphs in goal-oriented requirements engineering in order to support the understanding the relations between goals, i.e., goal refinements. Goals specify multiple concerns such as functions, strategies, and non-functions, and they are refined into sub goals from mixed views of these concerns. This intermixture of concerns in goals makes it difficult for a requirements analyst to understand and maintain goal graphs. In our approach, a goal graph is put in a multi-dimensional space, a concern corresponds to a coordinate axis in this space, and goals are refined into sub goals referring to the coordinates. Thus, the meaning of a goal refinement is explicitly provided by means of the coordinates used for the refinement. By tracing and focusing on the coordinates of goals, requirements analysts can understand goal refinements and modify unsuitable ones. We have developed a supporting tool and made an exploratory experiment to evaluate the usefulness of our approach.