3499 research outputs found
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Un indicatore di sintesi dell'economicità aziendale: il valore economico del capitale
No full textIn questa parte del volume di esaminano i concetti di capitale economico e le principali logiche di determinazione di questa grandezz
Il Made in Tuscany come competenza identitaria e distintiva dell'azienda familiare
No full textIL capitolo tratta della potenziale strategico insito nel Made in Tuscany e indaga alcune possible vie di sfruttamento
Conclusioni
No full textIl commento scientifico è conclusivo dell'intera trattazione scientifica e sofferma l'attenzione su Impatto strategico e implicazioni operative derivanti dai cambiamenti in atto nel governo strategico dell'azienda familiare
Piecewise affine regression via recursive multiple least squares and multicategory discrimination
No full textIn nonlinear regression choosing an adequate model structure is often a challenging problem. While simple models (such as linear functions) may not be able to capture the underlying relationship among the variables, over-parametrized models described by a large set of nonlinear basis functions tend to overfit the training data, leading to poor generalization on unseen data. Piecewise-affine (PWA) models can describe nonlinear and possible discontinuous relationships while maintaining simple local affine regressor-to-output mappings, with extreme flexibility when the polyhedral partitioning of the regressor space is learned from data rather than fixed a priori. In this paper, we propose a novel and numerically very efficient two-stage approach for {PWA} regression based on a combined use of (i) recursive multi-model least-squares techniques for clustering and fitting linear functions to data, and (ii) linear multi-category discrimination, either offline (batch) via a Newton-like algorithm for computing a solution of unconstrained optimization problems with objective functions having a piecewise smooth gradient, or online (recursive) via averaged stochastic gradient descent
Festivalization of fantasy culture and the growing phenomenon of comic-cons: Lucca Comics & Games
No full textPreface for the special issue on Interaction and Concurrency Experience 2014
No full textThis special issue contains extended versions of selected papers from the 7th Interaction and Concurrency Experience workshop (ICE 2014). The workshop was held in Berlin (Germany) on June 6th, 2014. ICE workshops form a series of international scientific meetings oriented to theoretical computer science researchers with special interest in models, verification, tools, and programming primitives for complex interactions.
The general scope of the venue includes theoretical and applied aspects of interactions and the synchronization mechanisms used among components of concurrent/distributed systems, related to several areas of computer science in the broad spectrum ranging from formal specification and analysis to studies inspired by emerging computational models.
The authors of the most prominent papers presented at ICE 2014 were invited to submit an extended version to this special issue. In order to guarantee the fairness and quality of the selection process, each submission received at least three reviews. The review process has also ensured that the accepted articles significantly extend and improve the original workshop contributions.
This special issue features three articles:
• Declarative event based models of concurrency and refinement in psi-calculi, by Håkon Normann, Christian Johansen and Thomas Hildebrandt. In this paper the authors show an exploration of declarative event-based specifications open to runtime refinement aiming at a declarative model with support for adaptation.
• Contracts as games on event structures, by Massimo Bartoletti, Tiziana Cimoli, G. Michele Pinna and Roberto Zunino. This work presents an event structure based interpretation of contracts, allowing to study the rights and obligations of contract participants in a natural setting.
• Relating two automata-based models of orchestration and choreography, by Davide Basile, Pierpaolo Degano, Gian Luigi Ferrari and Emilio Tuosto. This paper presents a comparison between local contract-based specifications coordinated by orchestrators with communicating machines that have decentralized coordination.
We want to thank all the authors who contributed to this volume. We would like to thank all the members of the Program Committee of ICE, who helped us in the selection of the papers and who helped the authors to improve their contributions in several ways. Additional referees were involved in the review of the papers invited for this special issue and we thank their timely contributions. We would also like to thank the editors of JLAMP, for their support during the whole editorial process
Dynamic role authorization in multiparty conversations
No full textProtocols in distributed settings usually rely on the interaction of several parties and often identify the roles involved in communications. Roles may have a behavioral interpretation, as they do not necessarily correspond to sites or physical devices. Notions of role authorization thus become necessary to consider settings in which, e.g., different sites may be authorized to act on behalf of a single role, or in which one site may be authorized to act on behalf of different roles. This flexibility must be equipped with ways of controlling the roles that the different parties are authorized to represent, including the challenging case in which role authorizations are determined only at runtime. We present a typed framework for the analysis of multiparty interaction with dynamic role authorization and delegation. Building on previous work on conversation types with role assignment, our formal model is based on an extension of the π-calculus in which the basic resources are pairs channel-role, which denote the access right of interacting along a given channel representing the given role. To specify dynamic authorization control, our process model includes (1) a novel scoping construct for authorization domains, and (2) communication primitives for authorizations, which allow to pass around authorizations to act on a given channel. An authorization error then corresponds to an action involving a channel and a role not enclosed by an appropriate authorization scope. We introduce a typing discipline that ensures that processes never reduce to authorization errors, including when parties dynamically acquire authorizations
Investigating the interplay between fundamentals of national research systems: Performance, investments and international collaborations
No full textAbstract We discuss, at the macro-level of nations, the contribution of research funding and rate of international collaboration to research performance, with important implications for the “science of science policy”. In particular, we cross-correlate suitable measures of these quantities with a scientometric-based assessment of scientific success, studying both the average performance of nations and their temporal dynamics in the space defined by these variables during the last decade. We find significant differences among nations in terms of efficiency in turning (financial) input into bibliometrically measurable output, and we confirm that growth of international collaboration positively correlate with scientific success—with significant benefits brought by {EU} integration policies. Various geo-cultural clusters of nations naturally emerge from our analysis. We critically discuss the factors that potentially determine the observed patterns
Percolation properties of the free volume generated by two rough surfaces in contact
No full textThe mechanism of fluid leakage trough the free volume between rough surfaces in
contact is relevant in physics and in many engineering applications. In the present study, the
normal contact problem between randomly generated fractal rough surfaces is solved using the
boundary element method. Then, an algorithm for the evaluation of the network involved in
the percolation of fluid is proposed. Numerical results are synthetically collected in diagrams
relating the free volume involved in the percolation to the dimensionless statistical parameters
of the rough surfac
Distress propagation in complex networks: the case of non-linear DebtRank
No full textWe consider a dynamical model of distress propagation on complex networks, which we apply to the study of financial contagion in networks of banks connected to each other by direct exposures. The model that we consider is an extension of the DebtRank algorithm, recently introduced in the literature. The mechanics of distress propagation is very simple: When a bank suffers a loss, distress propagates to its creditors, who in turn suffer losses, and so on. The original DebtRank assumes that losses are propagated linearly between connected banks. Here we relax this assumption and introduce a one-parameter family of non-linear propagation functions. As a case study, we apply this algorithm to a data-set of 183 European banks, and we study how the stability of the system depends on the non-linearity parameter under different stress-test scenarios. We find that the system is characterized by a transition between a regime where small shocks can be amplified and a regime where shocks do not propagate, and that the overall the stability of the system increases between 2008 and 2013