An ASSL Approach to Handling Uncertainty in Self-adaptive Systems

Both modularity and loose-coupling properties inherent to the self-adaptive systems offer the opportunity for ad-hoc service compositions, dynamic change and adaptation. To provide such a dynamic and self-adapting behavior, developers emphasize special self-management policies. ASSL (Autonomic System Specification Language) is a formal tool where such policies might be formally specified, validated and implemented. Intrinsically, the ASSL-developed policies are very strict and may impose quite restrictive behavior, which sometimes is undesirable. To solve the problem, we are currently developing special mechanisms for ASSL that help to specify policies that might evolve in order to satisfy system goals changing in the course of system adaptation. This paper presents our work on a mechanism imposing special loose self-management policies introducing flexibility into the self-adapting behavior.