Performability Analysis of Guarded-Operation Duration: A Successive Model-Translation Approach

When making an engineering design decision, it is often necessary to consider its implications on both system performance and dependability. In this paper, we present a performability study that analyzes the guarded operation duration for onboard software upgrading. In particular, we define a “performability index” Y that quantifies the extent to which the guarded operation with a duration φ reduces the expected total performance degradation. In order to solve for Y , we progressively translate its formulation until it becomes an aggregate of constituent measures conducive to efficient reward model solutions. Based on the reward-mapping-enabled intermediate model, we specify reward structures in the composite base model which is built on three stochastic activity network reward models. We describe the model-translation approach and show its feasibility for design-oriented performability modeling.