On StocS: a stochastic extension of SCEL

Predicate-based communication allows components of a system to send messages and requests to ensembles of components that are determined at execution time through the evaluation of a predicate, in a multicast fashion. Predicate-based communication can greatly sim- plify the programming of autonomous and adaptive systems. We present a stochastically timed extension of the Software Component Ensemble Language (SCEL) that was introduced in previous work. Such an extension allows for quantitative modelling and analysis of system behaviour (e.g. performance) but rises a number of non-trivial design and formal semantics issues with different options as possible solutions at different levels of abstraction.