Maria Grazia Vigliotti

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Mobile Ambients (MA) have acquired a fundamental role in modelling mobility in systems with mobile code and mobile devices, and in computation over administrative domains. We present the stochastic version of Mobile Ambients, called Stochastic Mobile Ambients (SMA), where we extend MA with time and probabilities. Inspired by previous models, PEPA and Sπ, we(More)
Palamidessi has shown that the π-calculus with mixed choice is powerful enough to solve the leader election problem on a symmetric ring of processes. We show that this is also possible in the calculus of Mobile Ambients (MA), without using communication or restriction. Following Palamidessi's methods, we deduce that there is no encoding satisfying certain(More)
We compare the expressive power of process calculi by studying the problem of electing a leader in a symmetric network of processes. We consider the π-calculus with mixed choice, separate choice and internal mobility, value-passing CCS and Mobile Ambients, together with other ambient calculi (Safe Ambients, the Push and Pull Ambient Calculus and Boxed(More)
We define a new, output-based encoding of the λ-calculus into the asynchronous π-calculus – enriched with pairing – that has its origin in mathematical logic, and show that this encoding respects one-step spine-reduction up to substitution, and that normal substitution is respected up to similarity. We will also show that it fully encodes lazy reduction of(More)
The calculus of Mobile Ambients has been introduced for expressing mobility and mobile computation. In this paper we present a probabilistic version of Mobile Am-bients by augmenting the syntax of the original Ambient Calculus with a (guarded) probabilistic choice operator. To allow for the representation of both the proba-bilistic behaviour introduced(More)
In this paper we provide a general method to derive product-form solutions for stochastic models. We take inspiration from the Reversed Compound Agent Theorem and we provide a different formulation using labeled automata, a generalization which encompasses a bigger class of product-form solutions, and a new proof based on the solution of the system of(More)
The Ambient Calculus offers many ways in which processes can interact and be observed. In the context of Levi and Sangiorgi's Safe Mobile Ambients (SA), the extra co-capabilities required for interaction complicate the fundamental observations. We show that different formulations of barbs lead to the same barbed congruence. We prove this by following Honda(More)
In biological phenomena like osmosis, the rate of flow of water molecules in or out of biological compartments depends on the solute concentration and on other forces, like hydrostatic pressure. A similar example is the passive transport of ions in and out the cell membrane. In this paper, we address the problem of faithfully modelling these kind of(More)