RODES, a RObust DEsign Synthesis tool

Authors: Nicola Paoletti and his chums

Sensitivity-aware Pareto front for the Google File System model. Through an extended Pareto dominance relation we can include designs that are slightly suboptimal but with improved robustness (in red). RODES is a tool for the synthesis of optimal and robust designs for probabilistic systems. Synthesized designs (given as parametric Markov chains) are 1) robust to pre-specified levels of variation in the system parameters; 2) satisfy strict performance, reliability and other quality constraints; and 3) are Pareto optimal with respect to a set of quality optimisation criteria.

The resulting Pareto front consists of quality attribute regions induced by the parametric designs (see picture). The size and shape of these regions provide key insights into the system robustness since they capture the sensitivity of quality attributes to parameter changes (i.e, small regions = robust designs).

The method is based on a combination of GPU-accelerated parameter synthesis for Markov chains (to compute the quality attribute regions for fixed discrete parameters) through the PRISM-PSY tool, and multi-objective optimization based on an extended, sensitivity-aware dominance relation. RODES further extends the PRISM language with constructs to enable the specification of parametric models.

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