1,721,028 research outputs found
Stochastic Petri net semantics for stochastic process algebras
No full textWe define a stochastic Petri net (SPN) semantics for stochastic process algebras (SPAs), a recently introduced formalism that offers a novel approach for performance modeling. The proposed semantics is evaluated in terms of three criteria: concurrency and retrievability, as defined by Olderog (1987, 1991) for untimed net semantics, and Markov equivalence for the stochastic aspects
On the Aggregation Techniques in Stochastic Petri Nets and Stochastic Process Algebras
No full textStochastic Petri Nets and Stochastic Process Algebras can both be used for the qualitative and quantitative analysis of parallel and distributed systems. However, sometimes and complexity of the system can make such analysis infeasible, due to the large size of the state space underlying the model. To overcome this problem different aggregation techniques have been proposed in both formalisms. Two of them are compared in this paper
Modelling Mobility with PEPA Nets
No full textWe explain the use of PEPA nets in documenting high-level designs of mobile code and mobile computing systems. This modelling language (which allows the modeller to differentiate between location changing and state-changing operations in the system, and to quantify their computational expense for use in predictive performance analysis) is applied to the problem of modelling the canonical mobile code design paradigms which are in practical application today, as described in [2]
AulaWeb, Web-based Learning as a Commodity - The Experience of the University of Genova
No full textStarting from the academic year 2005/2006, the University of Genova has foster the use of AulaWeb, a virtual environment based on the open source software Moodle, to promote the introduction of web-based technologies in the traditional educational process. We describe the experience of the past four years presenting the approach we have followed to encourage the use of AulaWeb among faculties, the numbers of users we have reached, an Instructional Design course we have organised to promote educational technology
Exploiting Symmetries in Stochastic Process Algebras
No full textStochastic Process Algebras have been introduced to enable compositional performance analysis of parallel and distributed systems. As with other high level modelling formalisms, state space explosion is a frequently observed problem, especially if the system consists of many cooperating components. However, if the components are identical replicas of each others, the state space can be reduced by means of equivalence preserving aggregation. This paper introduces symmetric parallel composition, an operator to specify sets of identical replicas cooperating in parallel. Its operational semantics is consistent with usual parallel composition whereas the state space explosion problem is drastically reduced. We illustrate this beneficial effect, and provide an interpretation of symmetric parallel composition in terms of Petri Nets
Open Data for the masses - Unleashing personal data into the wild
No full textIn these years the public administration is undergoing a deep transformation, driven by a greater demand for transparency and efficiency in a participative framework involving nonprofit organizations, businesses, and citizens, with the modern network infrastructures as a common medium. The Open Data movement is considered to be one of the keys of this change. In this position paper we argue that the work done so far in the Open Data field, i.e. offering massive public datasets, is just a preliminary answer. We argue that a few open standards concerning online authorization, access control, and data exportation, are emerging; these standards, if adopted by the public administration (but also business companies and any other organization), will trigger the release of a much wider and more useful wave of open data, able to sustain a new generation of helpful online personalized services, based on personal data whose ownership is given back to individual people
Stochastic Process Algebras: a New Approach to Performance Modeling
No full textIn this chapter we present an introduction to the novel approach to performance modeling provided by stochastic process algebras (SPA). Like queueing networks and stochastic Petri nets, and their variants, these formal languages can be regarded as high-level model specification languages for low-level stochastic models. The advantages of SPAs are that they incorporate the attractive features of process algebras and thus bring to the area of performance modeling several attributes which are not offered by the existing formalisms. Perhaps the most important such feature is the compositionality which is inherent in the models and can be exploited during their analysis. Throughout this chapter we will present several simple examples which illustrate this and several other aspects of the SPA approach to performance modeling
Problematiche per la gestione di un servizio basato su Moodle in un contesto universitario di medie dimensioni
No full textIl lavoro descrive l’esperienza di uso di Moodle all’Università degli Studi di Genova, presso la quale è attivo dal 2005 un servizio di supporto alla didattica a livello di Ateneo. Viene descritta AulaWeb, la piattaforma Moodle installata a Genova, la gestione del servizio e le diverse tipologie di utenti che vi accedono. Sono inoltre presentati i risultati di un questionario somministrato agli studenti al termine del primo anno di sperimentazione e descritte le iniziative intraprese per soddisfare le richieste pervenute dagli studenti
Training educators: plan for replicating the experience
No full textThis paper reports on a short survey and a training course offered to the faculty members of the University of Genova with the aim of driving the users of the university Learning Management System in the transition from Moodle 1.9 to Moodle 2, transition that took place in August 2012. The survey has been administered to lectures and staff to understand their needs and gather subscriptions before the actual starting of the training course. A similar process is now in progress in the context of the Bishkek Academy of Finance and Economics (Kyrgyzstan), where the same survey has been recently delivered. Results obtained in both institutions are presented. Indeed, although we are aware of the fact that these two universities represent two different contexts, being geographically far, different in size, and with different diffusion of ICT, we think we can take advantage of the experience of the University of Genova to transfer some practices on the organization and delivery of training courses in the Bishkek Academy of Finance and Economics
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