Your search for: 'author:("Barbuti, Roberto")' has returned 14 results. (0.008s) Save search

Authors: Barbuti, Roberto | Tesei, Luca

Article Type: Research Article

Abstract: We present a notion of non-interference which embodies the notion of time. It is useful to verify the strength of a system against attacks depending on the frequency of certain actions. In particular we give a decidable definition of non-interference which can be checked by using existing verification tools. We show an application example of our notion of non-interference by defining a variant of the classical Fischer's mutual exclusion protocol and by analyzing its strength against attacks.

Citation: Fundamenta Informaticae, vol. 54, no. 2-3, pp. 137-150, 2003

Authors: Barbuti, Roberto | Cataudella, Stefano

Article Type: Research Article

Abstract: In this paper we present a use of abstract interpretation techniques for reducing synchronization overhead in an object calculus. First we present the new raconcς calculus, an extension of an already existing calculus for supporting reentrant locks. Then we use an abstract form of this calculus to check when synchronization operations may be safely eliminated from statements. Thus our approach may be used to improve performance in object oriented languages by eliminating locks, without the risks caused by "manual" optimizations performed by programmers.

Citation: Fundamenta Informaticae, vol. 67, no. 1-3, pp. 1-12, 2005

Authors: Barbuti, Roberto | De Francesco, Nicoletta | Tesei, Luca

Article Type: Research Article

Abstract: In this paper we propose a model, timed automata with non-instantaneous actions, which allows representing in a suitable way real-time systems. Timed automata with non-instantaneous actions extend the timed automata model by dropping the assumption that actions are instantaneous: in our model an action can take some time to be completed. We investigate the expressiveness of the new model, comparing it with classical timed automata. In particular, we study the set of timed languages which can be accepted by timed automata with non-instantaneous actions. We prove that timed automata with non-instantaneous actions are more expressive than timed automata and less …expressive than timed automata with ϵ edges. Moreover we define the parallel composition of timed automata with non-instantaneous actions. We point out how the specification by means of a parallel timed automaton with non-instantaneous actions is, in some cases, more convenient to represent reality. Show more

Keywords: real-time systems, timed automata, timed languages

Citation: Fundamenta Informaticae, vol. 47, no. 3-4, pp. 189-200, 2001

Authors: Barbuti, Roberto | Cataudella, Stefano | Tesei, Luca

Article Type: Research Article

Abstract: In this paper we investigate the use of abstract interpretation techniques for statically preventing race conditions. To this purpose we enrich the concurrent object calculus concζ by annotating terms with the set of "locks" owned at any time. We use an abstract form of the object calculus to check the absence of race conditions. We show that abstract interpretation is more flexible than type analyses, and it allows to certify as "race free" a larger class of programs.

Keywords:

Citation: Fundamenta Informaticae, vol. 60, no. 1-4, pp. 67-79, 2004

Authors: Barbuti, Roberto | Gori, Roberta | Levi, Francesca | Milazzo, Paolo

Article Type: Research Article

Abstract: Reaction systems are a qualitative formalism for modeling systems of biochemical reactions characterized by the non-permanency of the elements: molecules disappear if not produced by any enabled reaction. Reaction systems execute in an environment that provides new molecules at each step. Brijder, Ehrenfeucht and Rozemberg introduced the idea of predictors . A predictor of a molecule s , for a given n , is the set of molecules to be observed in the environment to determine whether s is produced or not at step n by the system. We introduced the notion of formula based predictor , that is a …propositional logic formula that precisely characterizes environments that lead to the production of s after n steps. In this paper we revise the notion of formula based predictor by defining a specialized version that assumes the environment to provide molecules according to what expressed by a temporal logic formula. As an application, we use specialized formula based predictors to give theoretical grounds to previously obtained results on a model of gene regulation. Show more

DOI: 10.3233/FI-2016-1403

Citation: Fundamenta Informaticae, vol. 147, no. 2-3, pp. 173-191, 2016

Authors: Barbuti, Roberto | Levi, Francesca | Milazzo, Paolo | Scatena, Guido

Article Type: Research Article

Abstract: Maximally parallel semantics have been proposed for many formalisms as an alternative to the standard interleaving semantics for some modelling scenarios. Nevertheless, in the probabilistic setting an affirmed interpretation of maximal parallelism still lacks. We define a synchronous maximally parallel probabilistic semantics for multiset rewriting tailored to describe, simulate and verify biological systems evolving with maximally parallel steps. Each step of the proposed semantics is parallel as each reaction can happen multiple times, and it is maximal as it leaves no enabled reaction i.e. as many reactions as possible are executed. We define a maximally parallel probabilistic semantics in terms …of Discrete Time Markov Chain for systems described by stochastic multiset rewriting. We propose a simple, maximally parallel, model of Caenorhabditis elegans vulval development on which we show probabilistic simulations results. Show more

DOI: 10.3233/FI-2011-575

Citation: Fundamenta Informaticae, vol. 112, no. 1, pp. 1-17, 2011

Authors: Barbuti, Roberto | Maggiolo-Schettini, Andrea | Milazzo, Paolo | Gruska, Damas P.

Article Type: Research Article

Abstract: A formal model for diagnostics of biological systems modelled as P systems is presented. We assume the presence of some biologically motivated changes (frequently pathological) in the systems behavior and investigate when these changes could be diagnosed by an external observer by exploiting some techniques originally developed for reasoning on system security.

DOI: 10.3233/FI-2010-294

Citation: Fundamenta Informaticae, vol. 102, no. 1, pp. 19-34, 2010

Authors: Barbuti, Roberto | Maggiolo-Schettini, Andrea | Milazzo, Paolo | Tesei, Luca

Article Type: Research Article

Abstract: To study systems whose dynamics changes with time, an extension of timed P systems is introduced in which evolution rules may vary with time. The proposed model is a timed automaton with a discrete time domain and in which each state is a timed P system. A result on expressive power and on features of the formalism sufficient for full expressiveness is proved and, as an application example, the model of an ecological system is given.

DOI: 10.3233/FI-2009-114

Citation: Fundamenta Informaticae, vol. 94, no. 1, pp. 1-19, 2009

Authors: Barbuti, Roberto | Maggiolo-Schettini, Andrea | Milazzo, Paolo | Troina, Angelo

Article Type: Research Article

Abstract: The paper presents the Calculus of Looping Sequences (CLS) suitable to describe microbiological systems and their evolution. The terms of the calculus are constructed by basic constituent elements and operators of sequencing, looping, containment and parallel composition. The looping operator allows tying up the ends of a sequence, thus creating a circular sequence which can represent a membrane. We show that a membrane calculus recently proposed can be encoded into CLS. We use our calculus to model interactions among bacteria and bacteriophage viruses, and to reason on their properties.

Citation: Fundamenta Informaticae, vol. 72, no. 1-3, pp. 21-35, 2006

Authors: Barbuti, Roberto | Maggiolo-Schettini, Andrea | Milazzo, Paolo | Tini, Simone

Article Type: Research Article

Abstract: P Systems are computing devices inspired by the structure and the functioning of a living cell. A P System consists of a hierarchy of membranes, each of them containing a multiset of objects, a set of evolution rules, and possibly other membranes. Evolution rules are applied to the objects of the same membrane with maximal parallelism. In this paper we present an extension of P Systems, called P Systems with Membrane Channels (PMC Systems), in which membranes are enriched with channels and objects can pass through a membrane only if there are channels on the membrane that enable such a …passage. We show that PMC Systems are universal even if only the simplest form of evolution rules is considered, and we give two application examples. Show more

DOI: 10.3233/FI-2009-0085

Citation: Fundamenta Informaticae, vol. 93, no. 1-3, pp. 17-31, 2009