1,721,208 research outputs found
Corrado Priami
No full text. In this study we extend the classical structural operational semantics to implement the possibility of having different views of the same system that are all consistent to one another and that can be recovered mechanically from a single, concrete representation. We apply this idea to concurrent and distributed systems, and especially to mobile agents. Our concrete representation is a transition system (called proved and defined in SOS style), whose transitions are labelled by encodings of their deduction trees. The labels of transitions allow us to retrieve all the main semantic models presented in the literature and also to define new semantics (e.g. a new causality). These semantics are retrieved from the proved transition system through relabelling functions that only maintain the relevant information in the labels of transitions. We show that our approach is robust: it scales up smoothly to higher-order process calculi and even to real programming languages like Facile. Its appl..
Pierpaolo Degano
No full textWe present here a laudatio that illustrates the distinguished career and the main scientific contributions of Pierpaolo Degano, in the volume of essays dedicated to him, on the occasion of his 65th birthday
Extended Transition Systems for Parametric Bisimulation
No full textn this work we have defined a parametric model for describing the semantics of finite states systems. It relies on the parametric theories of observation trees [5, 6] and proved trees [8]. A notion of parametric bisimulation is introduced over extended transition systems and it is shown that this equivalence coincide with the ones already presented in literature. The results presented in this paper are fundamental for a practical use of a parametric theory in automatic verification of systems.
Following the definitions given above, it is immediate to derive an algorithm for parametric bisimulation when incremental observations are considered. The extension to other observations is under development following the approach of decomposing any non-incremental observation into an incremental one and an abstraction function. The basic idea is use standard techniques from fix-point theory to prove properties on regular languages that may permit to make this decomposition effective
Comparison of Machine Learning Classifiers on Integrated Transcriptomic Data
No full textOmics data are being generated for different conditions, and can be a valuable resource for building novel predictive models for medical diagnosis. Given the reduced number of samples in each dataset, the application of Machine Learning (ML) models requires data integration. At the same time, multiple ML models are available, and the best option for data integration is not known. These challenges have been addressed typically in restricted settings, i.e., for one single disease at a time. However, a thorough comparison of models on integrated data, for different conditions, is still missing. In this paper we confront 7 classifiers on integrated data for 6 diseases, over 14 datasets. We compared the models on single and integrated datasets, employing different pre-processing techniques. We also evaluated the effect of feature selection, analyzing the robustness and relevance of the features extracted. We observed that, even if integration slightly reduces predictive power, the models are still able to produce good classifications. When testing generalization abilities on new datasets, sometimes the performance decreases drastically, depending on the disease studied
Stochastic modelling of diffusion systems. Video image simulation of tubulin diffusion in cytoplasm: a case study
No full textWe present a new mathematical model of diffusive processes in the cytoplasm. In this model, the movement of a molecule A from a region i to a region j of the space is represented as a first order reaction Ai ->k Aj , where the rate constant k depends on the diffusion coefficient. The diffusion coefficients are modeled as functions of the local concentration of the solutes, their intrinsic viscosities, their frictional coefficients and the temperature of the system. To demonstrate the method the simulation results of the diffusion of fluorescein-labeled tubulins in the cytoplasm are reported
Reflecting Mobile Ambients into the pi-calculus
No full textWe embed the transition system of the Mobile Ambients into the transition system of a subset of the π-calculus. The basic idea, applicable to other calculi as well, is to constrain the deduction of the π-calculus transitions with the suitable conditions that reflect the nesting of ambients
Language representability of finite P/T nets
No full textFinite-net Multi-CCS is a CCS-like calculus which is able to model atomic sequences of actions and, together with parallel composition, also multi-party synchronization. This calculus is equipped with a labeled transition system semantics and also with an unsafe P/T Petri net semantics, which is sound w.r.t. the transition system semantics. For any process p of the calculus, the net associated to p by the semantics has always a finite number of places, but it has a finite number of transitions only for so-called well-formed processes. The main result of the paper is that well-formed finite-net Multi-CCS processes are able to represent all finite, statically reduced, P/T Petri nets
Authentication Primitives for Refining Protocol Specifications
Full text linkWe propose a way to abstract from various specifications of authentication and to obtain idealized protocols "secure by construction". This feature enables us to prove that a cryptographic protocol is the correct implementation of the corresponding abstract protocol. Our proposal relies on the combination of two authentication primitives, proposed by the authors in to a simplified version of the spi calculus
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