Search results for "Exchange"
showing 10 items of 2035 documents
Effect of Boundary Conditions on the Hydrogen Absorption in a Metal Hydride Reactor
2018
In this paper, a numerical study of the heat and mass transfer in a metal hydride reactor is presented. The reaction within the metal hydride reactor is exothermic. That makes the hydriding process less effective. Thus, a cooling system is needed to reduce the temperature in order to increase the amount of the absorbed hydrogen. The geometry of the studied reactor is cylindrical with (H=3cm) of height and (R=5cm) of radius. A heat exchanger is considered in the lateral and base walls. The transfer is considered two-dimensional and transient. The governing equations of the transfer phenomenon are based on the conservation principle of mass, momentum and energy. Using the finite volume method…
A gap analysis of Internet-of-Things platforms
2016
We are experiencing an abundance of Internet-of-Things (IoT) middleware solutions that provide connectivity for sensors and actuators to the Internet. To gain a widespread adoption, these middleware solutions, referred to as platforms, have to meet the expectations of different players in the IoT ecosystem, including device providers, application developers, and end-users, among others. In this article, we evaluate a representative sample of these platforms, both proprietary and open-source, on the basis of their ability to meet the expectations of different IoT users. The evaluation is thus more focused on how ready and usable these platforms are for IoT ecosystem players, rather than on t…
Constrained Role Mining
2013
Role Based Access Control (RBAC) is a very popular access control model, for long time investigated and widely deployed in the security architecture of different enterprises. To implement RBAC, roles have to be firstly identified within the considered organization. Usually the process of (automatically) defining the roles in a bottom up way, starting from the permissions assigned to each user, is called {\it role mining}. In literature, the role mining problem has been formally analyzed and several techniques have been proposed in order to obtain a set of valid roles. Recently, the problem of defining different kind of constraints on the number and the size of the roles included in the resu…
An exploratory study of COVID-19 misinformation on Twitter.
2020
During the COVID-19 pandemic, social media has become a home ground for misinformation. To tackle this infodemic, scientific oversight, as well as a better understanding by practitioners in crisis management, is needed. We have conducted an exploratory study into the propagation, authors and content of misinformation on Twitter around the topic of COVID-19 in order to gain early insights. We have collected all tweets mentioned in the verdicts of fact-checked claims related to COVID-19 by over 92 professional fact-checking organisations between January and mid-July 2020 and share this corpus with the community. This resulted in 1 500 tweets relating to 1 274 false and 276 partially false cla…
Bayesian inference for the extremal dependence
2016
A simple approach for modeling multivariate extremes is to consider the vector of component-wise maxima and their max-stable distributions. The extremal dependence can be inferred by estimating the angular measure or, alternatively, the Pickands dependence function. We propose a nonparametric Bayesian model that allows, in the bivariate case, the simultaneous estimation of both functional representations through the use of polynomials in the Bernstein form. The constraints required to provide a valid extremal dependence are addressed in a straightforward manner, by placing a prior on the coefficients of the Bernstein polynomials which gives probability one to the set of valid functions. The…
The limit order book on different time scales
2007
Financial markets can be described on several time scales. We use data from the limit order book of the London Stock Exchange (LSE) to compare how the fluctuation dominated microstructure crosses over to a more systematic global behavior.
Orbital Rotations induced by Charges of Polarons and Defects in Doped Vanadates
2020
We explore the competiton of doped holes and defects that leads to the loss of orbital order in vanadate perovskites. In compounds such as La$_{1-{\sf x}}$Ca$_{\,\sf x}$VO$_3$ spin and orbital order result from super-exchange interactions described by an extended three-orbital degenerate Hubbard-Hund model for the vanadium $t_{2g}$ electrons. Long-range Coulomb potentials of charged Ca$^{2+}$ defects and $e$-$e$ interactions control the emergence of defect states inside the Mott gap. The quadrupolar components of the Coulomb fields of doped holes induce anisotropic orbital rotations of degenerate orbitals. These rotations modify the spin-orbital polaron clouds and compete with orbital rotat…
Social media as a strategic marketing tool in the Sicilian wine industry: Evidence from Facebook
2017
Abstract Over the last few years, many companies have integrated social media, and social networking sites in particular, into their communication and media plan, leading to a deep transformation of the organizational models and changing the companies׳ marketing dynamics. This study has dual aims: first, to recognize and validate the firm׳s social media (SM) efforts in its use of the Facebook platform; second, to examine the relationships among the firm׳s SM efforts and some firm and managerial characteristics. In order to achieve these research aims, data on 45 wineries were collected and analysed, using a model that considers three different dimensions of the firms׳ activity on the social…
What is the role of social media in several overtones of CSR communication? The case of the wine industry in the Southern Italian regions
2019
Purpose The purpose of this paper is to understand whether the companies most involved in communicating their responsible behaviour externally are those most active on the social media (SM) platform, with a philanthropic purpose rather than strictly aimed at economic aspects. Design/methodology/approach The authors, first, assess firms’ efforts on the SM platform using the model proposed by Chung et al. (2014), and, second, the authors analyze the content of messages in order to verify what dimensions of the corporate social responsibility (CSR) they contain. A multivariate modelling has been performed in order to verify whether the wineries that take most care to communicate their respons…
An Economic Viewpoint on Capitalism Bashing
2016
Abstract In this paper I discuss two long disputed notions: that capitalism without crises is a fallacy respectively that capitalism bashing, however severe, will not endanger the system itself. Yet proving both is not an easy task since the capitalism issue has always been a cupellation of theory, ideology and political precepts, which are controversial and hard to disentangle. That capitalism detractors are numberless is a truism. Yet criticism against capitalism, however fierce, has always been clearly delineated. Not any more: globalization has rendered the picture dangerously fuzzy. It is now hard to ascertain whether someone who will harangue about the ostensible evils of globalizatio…