Unwinding biological systems

Unwinding conditions have been fruitfully exploited in Information Flow Security to define persistent security properties. In this paper we investigate their meaning and possible uses in the analysis of biological systems. In particular, we elaborate on the notion of robustness and propose some instances of unwinding over the process algebra Bio-PEPA and over hybrid automata. We exploit such instances to analyse two case-studies: Neurospora crassa circadian system and Influenza kinetics models

A semantic equivalence for Bio-PEPA based on discretisation of continuous values

AbstractBio-PEPA is a process algebra for modelling biological systems. An important aspect of Bio-PEPA is the ability it provides to discretise concentrations resulting in a smaller, more manageable state space. The discretisation is based on a step size which determines the size of each discrete level and also the number of levels. This paper considers the relationship between two discretisations of the same Bio-PEPA model that differ only in the step size and hence the number of levels, by using the idea of equivalence from concurrency and process algebra. We present a novel behavioural semantic equivalence, compression bisimilarity, and investigate when this equates two discretisations of the same model and the circumstances in which this equivalence is a congruence with respect to the synchronisation operator