We propose both an SOS transition rule format for the generative model of probabilistic processes, and an SOS transition rule format for the reactive model of the probabilistic processes. Our rule formats guarantee that probabilistic bisimulation is a congruence with respect to process algebra operations. Moreover, our rule format for generative process algebras guarantees that the probability of the moves of a given process, if there are any, sum up to 1, and the rule format for reactive process algebras guarantees that the probability of the moves of a given process labeled with the same action, if there are any, sum up to 1. We show that most operations of the probabilistic process algebras studied in the literature are captured by our formats, which, therefore, have practical applications.

We develop a model of parametric probabilistic transition Systems (PPTSs), where probabilities associated with transitions may be parameters. We show how to find instances of the parameters that satisfy a given property and instances that either maximize or minimize the probability of reaching a certain state. As an application, we model a probabilistic non-repudiation protocol with a PPTS. The theory we develop allows us to find instances that maximize the probability that the protocol ends in a fair state (no participant has an advantage over the others).

Abstract-We apply formal methods to lay and streamline theoretical foundations to reason about Cyber-Physical Systems (CPSs) and cyber-physical attacks. We focus on integrity and DoS attacks to sensors and actuators of CPSs, and on the timing aspects of these attacks. Our contributions are threefold:(1) we define a hybrid process calculus to model both CPSs and cyber-physical attacks; (2) we define a threat model of cyber-physical attacks and provide the means to assess attack tolerance/vulnerability with respect to a given attack; (3) we formalise how to estimate the impact of a successful attack on a CPS and investigate possible quantifications of the success chances of an attack. We illustrate definitions and results by means of a non-trivial engineering application.

Gossip protocols have been proposed as a robust and efficient method for disseminating information throughout large-scale networks. In this paper, we propose a compositional analysis technique to study formal probabilistic models of gossip protocols in the context of wireless sensor networks. We introduce a simple probabilistic timed process calculus for modelling wireless sensor networks. A simulation theory is developed to compare probabilistic protocols that have similar behaviour up to a certain probability. This theory is used to prove a number of algebraic laws which revealed to be very effective to evaluate the performances of gossip networks with and without communication collisions

We propose a process calculus for modelling systems in the Internet of Things paradigm. Our systems interact both with the physical environment, via sensors and actuators, and with smart devices, via short-range and Internet channels. The calculus is equipped with a standard notion of bisimilarity which is a fully abstract characterisation of a well-known contextual equivalence. We use our semantic proof-methods to prove run-time properties as well as system equalities of non-trivial IoT systems.

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Abstract. We propose an SOS transition rule format for the generative model of probabilistic processes. Transition rules are partitioned in several strata, giving rise to an ordering relation analogous to those introduced by Ulidowski and Phillips for classic process algebras. Our rule format guarantees that probabilistic bisimulation is a congruence w.r.t. process algebra operations. Moreover, our rule format guarantees that process algebra operations preserve semistochasticity of processes, i.e. the property that the sum of the probability of the moves of any process is either 0 or 1. Finally, we show that most of operations of the probabilistic process algebras studied in the literature are captured by our format, which, therefore, has practical applications.

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