Abstract. Goal models have been used in Requirements Engineering (RE) to elicit, model and analyse stakeholder requirements. In a goal model, stakeholder requirements are represented as root-level goals that are iteratively refined through AND/OR-refinements to eventually yield a specification consisting of functions the system-to-be needs to implement, as well non-functional requirements and domain assumptions. The association of a function to a goal is called operationalization in the sense that the function specifies how a goal can be made operational. We focus on the concept of operationalization and propose several extensions to account for operationalizations of non-functional and adaptation requirements, as well as behavioural specifications..

Abstract. Variability is essential for adaptive software systems, because it captures the space of alternative adaptations a system is capable of when it needs to adapt. In this work, we propose to capture variability for an adaptation space in terms of a three dimensional model. The first dimension captures requirements through goals and reflects all possible ways of achieving these goals. The second dimension captures supported variations of a system’s architectural structure, modeled in terms of con-nectors and components. The third dimension describes supported sys-tem behaviors, by modeling possible sequences for goal fulfillment and task execution. Of course, the three dimensions of a variability model are inter-twined as choices made with respect to one dimension have impact on the other two. Therefore, we propose an incremental design method-ology for variability models that keeps the three dimensions aligned and consistent. We illustrate our proposal with a case study involving the meeting scheduling system exemplar.