1 research outputs found
Stochastic Activity Networks Templates: Supporting Variability in Performability Models
Model-based evaluation is extensively used to estimate performance and
reliability of dependable systems. Traditionally, those systems were small and
self-contained, and the main challenge for model-based evaluation has been the
efficiency of the solution process. Recently, the problem of specifying and
maintaining complex models has increasingly gained attention, as modern systems
are characterized by many components and complex interactions. Components share
similarities, but also exhibit variations in their behavior due to different
configurations or roles in the system. From the modeling perspective,
variations lead to replicating and altering a small set of base models multiple
times. Variability is taken into account only informally, by defining a sample
model and explaining its possible variations. In this paper we address the
problem of including variability in performability models, focusing on
Stochastic Activity Networks (SANs). We introduce the formal definition of
Stochastic Activity Networks Templates (SAN-T), a formalism based on SANs with
the addition of variability aspects. Differently from other approaches,
parameters can also affect the structure of the model, like the number of cases
of activities. We apply the SAN-T formalism to the modeling of the backbone
network of an environmental monitoring infrastructure. In particular, we show
how existing SAN models from the literature can be generalized using the newly
introduced formalism