LTSA-PCA: tool support for compositional reliability analysis

Software systems are often constructed by combining new and existing services and components. Models of such systems should therefore be compositional in order to reflect the architectural structure. We present herein an extension of the LTSA model checker. It supports the specification, visualisation and failure analysis of composable, probabilistic behaviour of component-based systems, modelled as Probabilistic Component Automata (PCA). To evaluate aspects such as the probability of system failure, a DTMC model can be automatically constructed from the composition of the PCA representations of each component and analysed in tools such as PRISM. Before composition, we reduce each PCA to its interface behaviour in order to mitigate state explosion associated with composite representations. Moreover, existing behavioural analysis techniques in LTSA can be applied to PCA representations to verify the compatibility of interface behaviour between components with matching provided-required interfaces. A video highlighting the main features of the tool can be found at: http://youtu.be/moIkx8JHE7o.