Supporting decision-making for selfadaptive systems: From goal models to dynamic decision networks

Abstract. [Context / Motivation] Different modeling techniques have been used to model requirements and decision-making of self-adaptive systems (SASs). Specifically, goal models have been prolific in support-ing decision-making depending on partial and total fulfilment of func-tional (goals) and non-functional requirements (softgoals). Different goal-realization strategies can have different effects on softgoals which are specified with weighted contribution-links. The final decision about what strategy to use is based, among other reasons, on a utility function that takes into account the weighted sum of the different effects on softgoals. [Questions/Problems] One of the main challenges about decision-making in self-adaptive systems is to deal with uncertainty during run-time. New techniques are needed to systematically revise the current model when empirical evidence becomes available from the deployment. [Principal ideas/results] In this paper we enrich the decision-making supported by goal models by using Dynamic Decision Networks (DDNs). Goal realization strategies and their impact on softgoals have a corre-spondence with decision alternatives and conditional probabilities and expected utilities in the DDNs respectively. Our novel approach allows the specification of preferences over the softgoals and supports reasoning about partial satisfaction of softgoals using probabilities. We report re-sults of the application of the approach on two different cases. Our early results suggest the decision-making process of SASs can be improved by using DDNs