Runtime Goal Models

Abstract—Goal models capture stakeholder requirements for a system-to-be, but also circumscribe a space of alternative specifications for fulfilling these requirements. Recent proposals for self-adaptive software systems rely on variants of goal models to support monitoring and adaptation functions. In such cases, goal models serve as mechanisms in terms of which systems reflect upon their requirements during their operation. We argue that existing proposals for using goal models at runtime are using design artifacts for purposes they were not intended, i.e., for reasoning about runtime system behavior. In this paper, we propose a conceptual distinction between Design-time Goal Models (DGMs)—used to design a system—and Runtime Goal Models (RGMs)—used to analyze a system’s runtime behavior with respect to its requirements. RGMs extend DGMs with additional state, behavioral and historical information about the fulfillment of goals. We propose a syntactic structure for RGMs, a method for deriving them from DGMs, and runtime algorithms that support their monitoring. Keywords—Runtime goal models; Requirements at runtime; Goal reasoning; Self-adaptive systems. I