1,190 research outputs found
A Distributed Semantics for EMPA Based on Stochastic Contextual Nets
No full textthis paper is to define a new net semantics for EMPA in the label-oriented approach. Following the proposal of (Busi & Gorrieri, 1995a; Busi & Gorrieri, 1995b), we can define a label-oriented net semantics by exploiting inhibitor arcs as follows
On the expressive power of movement and restriction in pure mobile ambients
No full textAbstractPure mobile ambients is a process calculus suitable to focus on issues related to mobility, abstracting away from aspects concerning process communication. However, it incorporates name restriction (i.e. the (νn) binder) and ambient movement (i.e. the in and out capabilities) that can be seen as characteristics adapted, or directly borrowed, from the tradition of communication-based process calculi. For this reason, we retain that it is worth to investigate whether or not these features can be removed from pure mobile ambients without losing expressive power.To this aim, we consider two variants of pure mobile ambients which differ in the way infinite processes can be defined; the former exploits process replication, while the latter is more general and permits recursive process definition. We analyse whether or not the elimination of ambient movement and/or name restriction reduces the expressive power of these two calculi, using the decidability of process termination as a yardstick. We prove that name restriction can be removed from both calculi without reducing the expressive power. On the other hand, the elimination of both ambient movement and name restriction strictly reduces the expressive power of both calculi. As far as the elimination of only ambient movement is concerned, we prove an interesting discrimination result: process termination is undecidable under recursive process definition, while it turns out to be decidable under process replication
Emerging technologies in solid drug delivery: An interview with Nadia Passerini
No full textNadia Passerini is interviewed by Hannah Makin, Commission Editor. Nadia Passerini is Associate Professor of Pharmaceutical Technology at the University of Bologna (Bologna, Italy). She obtained the degree in Pharmaceutical Chemistry and Technology at the University of Bologna in 1992 and the PhD in Pharmaceutical Science in 1997. Her research focuses on the study of drug delivery systems, developing new technologies and new apparatus for the production of solid dosage forms (microparticles, granules and tablets), which can optimize the bioavailability of drugs according to the specific needs of the therapy. Furthermore, she is interested in the solid-state characterization of the produced delivery systems in order to correlate their physicochemical properties to the in vitro release of the drugs. Currently, her research focuses in particular on the production and characterization of microparticles produced by the spray congealing technology. She is author of over 50 international peer-reviewed publications and over 50 contributions (poster and oral presentations) to national and international conferences
Process discovery and Petri nets
No full textThe aim of the research domain known as process mining is to use process discovery to construct a process model as an abstract representation of event logs. The goal is to build a model (in terms of a Petri net) that can reproduce the logs under consideration, and does not allow different behaviours compared with those shown in the logs. In particular, process mining aims to verify the accuracy of the model design (represented as a Petri net), basically checking whether the same net can be rediscovered. However, the main mining methods proposed in the literature have some drawbacks: the classical α-algorithm is unable to rediscover various nets, while the region-based approach, which can mine them correctly, is too complex.
In this paper, we compare different approaches and propose some ideas to counter the weaknesses of the region-based approach
Integrating TwoTowers and GreatSPN through a Compact Net Semantics
No full textStochastic process algebras (SPAs) and stochastic Petri nets (SPNs) are two well known formal methods for the functional and performance modeling and analysis of computer, communication and software systems. Starting from the mappings from process algebras to Petri nets proposed in the literature to provide a truly concurrent semantic framework to concurrent programming languages, in this paper we define a new SPN semantics for SPAs in order to facilitate the integration and the cross fertilization between the two formalisms. We then prove that our net semantics is correct via a retrievability result. Afterwards, we demonstrate that it improves on the previously proposed net semantics with respect to the size of the resulting SPNs and on the standard interleaving semantics because of the detection of system symmetries. Furthermore, we illustrate its usefulness by showing how to reinterpret at the SPA level the results efficiently obtainable at the SPN level. Finally, we describe the implementation of our net semantics that has been realized to integrate the EMPAgr based software tool TwoTowers with the GSPN based software tool GreatSPN
Comparing Truly Concurrent Semantics for Contextual Place/Transition Nets with Inhibitor and Read Arcs
No full textThe paper is centered around the study and comparison of truly concurrent semantics for P/T nets with inhibitor and read arcs (called henceforth contextual P/T nets). We start proposing a causal semantics for P/T nets, that we prove to be equivalent to history preserving bisimulation defined on nonsequential processes. Then we develop a conservative extension of the causal semantics to contextual P/T nets and we prove this one to be finer than step semantics. Finally, a comparison of causal semantics with the process based semantics for contextual P/T systems proposed in [7] is carried out
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