Employing fuzzy logic in feature diagrams to model variability in software product-lines

The possible features of software product line members may vary according to the needs of particular market segments or purposes. The assessment of what will be common and what will be variable may, e.g., result from market strategies. Customer profiles may be used to model an otherwise anonymous market, each requiring in turn a specific sets of variant features. Identical feature sets may be prioritized in different ways for specific customer groups. The paper proposes a system description based on a feature diagram tree, annotated with weighted variant features in the product line context. The principle how some variant features may be described on the basis of fuzzy logic is introduced and discussed. As the proposed description also integrates the external cross-tree constraints, it leads to an improved homogeneity of the descriptive logic. This opens the opportunity to integrate additional tools into the scenario, e.g., generators or support for constraint based reasoning. The use of the proposed approach is demonstrated by the example of a simple car description.