Variable-specific resolutions for feature interactions

Systems assembled from independently developed features suffer from feature interactions, in which features affect one another's behaviour in surprising ways. The feature-interaction problem states that the number of potential interactions is exponential in the number of features in a system. Resolution strategies offer general strategies that resolve entire classes of interactions, thereby reducing the work of the developer who is charged with the task of resolving interactions. In this paper, we focus on resolving interactions due to conflict. We present an approach, language, and implementation based on resolution modules in which the developer can specify an appropriate resolution for each variable under conflict. We performed a case study involving 24 automotive features, and found that the number of resolutions to be specified was much smaller than the number of possible feature interactions (6 resolutions for 24 features), that what constitutes an appropriate resolution strategy is different for different variables, and that the subset of situation calculus we used was sufficient to construct nontrivial resolution strategies for six distinct output variables.