The Workshop on Process Algebra and Stochastically Timed Activities is an informal meeting on the theme of modelling with stochastic process algebras (SPAs). These process algebras have been used in performance modelling of computer and telecommunication systems and also in the verification of computer systems where the duration of activities is approximated by drawing from specified random distributions.

More recently, process algebras such as PEPA have been applied to modelling biological systems and interpreted via an alternative semantics based on ordinary differential equations (ODEs). The PASTA workshop includes both finite-state Markovian and continuous-state non-Markovian approaches. The methods and techniques of interest include solution of Markov models, stochastic simulation, and numerical integration of ODEs.

As always, we seek high-quality papers on any aspect of modelling with stochastic process algebras and related formalisms. Topics of interest include, among others:

• comparisons of discrete and continuous modelling approaches
• semantics and theory of SPAs
• comparisons with other modelling formalisms
• methodologies for application of SPAs in or outside computing
• tools to support SPA-based modelling and analysis
• applications and case studies