Il contratto di lavoro subordinato a tempo determinato e la somministrazione di lavoro alla prova del decreto dignità = The fixed-term subordinate employment contract and the administration of work to the test of the dignity decree. WP C.S.D.L.E. “Massimo D’Antona”.IT – 380/2018

This paper deals with the recent reform of fixed-term contracts and agency work introduced by Law Decree law n° 87/2018, converted into Law n° 96/2018. It analyses the contents and the main implications of this reform. The analysis is divided into two parts, In the first part the author examines the news concerning fixed-term contracts: conditions to use; maximum duration; extensions and renewals. There is also analyzed the role of collective bargaining. In the second part the paper examines the news concerning agency work, with particular reference to the rules on fixed-term contracts applicable in this context

What do bus stops tell us? A long-term perspective on a family of objects (not only) designed and used for waiting

International audienceThe bus system is probably the oldest public transport system in the European cities. Directly linked to the processes of industrialization and urbanization, it has been operated during the 19 th century with horse-‐drawn vehicles, before getting motorized during the first decades of the 20 th century. By the way, the bus system has slightly become the slowest one, in comparison with the underground and the tramway, but also with the car. As a consequence, buses have built a peculiar relationship to speed, and more generally to time. This paper proposes to shed light on this relationship by addressing the problem of waiting for buses and the historical evolution of technical devices designed for this activity. Different generations of bus stops can be identified : small connexion stations with employees, bus poles, bus shelters of different scales, etc. These objects raise different questions. Who are the actors behind them and how are they conceived, designed and financed? What are the uses developed by people around them? How do they integrate the landscape of the city and become a constitutive element of the local identity

Simulation of Mono- and Bidisperse Gas-Particle Flow in a Riser with a Third-Order Quadrature-Based Moment Method

Gas-particle flows can be described by a kinetic equation for the particle phase coupled with the Navier−Stokes equations for the fluid phase through a momentum exchange term. The direct solution of the kinetic equation is prohibitive for most applications due to the high dimensionality of the space of independent variables. A viable alternative is represented by moment methods, where moments of the velocity distribution function are transported in space and time. In this work, a fully coupled third-order, quadrature-based moment method is applied to the simulation of mono- and bidisperse gas-particle flows in the riser of a circulating fluidized bed. Gaussian quadrature formulas are used to model the unclosed terms in the moment transport equations. A Bhatnagar−Gross−Krook (BGK) collision model is used in the monodisperse case, while the full Boltzmann integral is adopted in the bidisperse case. The predicted values of mean local phase velocities, rms velocities, and particle volume fractions are compared with the Euler−Lagrange simulations and experimental data from the literature. The local values of the time-average Stokes, Mach, and Knudsen numbers predicted by the simulation are reported and analyzed to justify the adoption of high-order moment methods as opposed to models based on hydrodynamic closures

Machine Learning-Based Elastic Cloud Resource Provisioning in the Solvency II Framework

The Solvency II Directive (Directive 2009/138/EC) is a European Directive issued in November 2009 and effective from January 2016, which has been enacted by the European Union to regulate the insurance and reinsurance sector through the discipline of risk management. Solvency II requires European insurance companies to conduct consistent evaluation and continuous monitoring of risks—a process which is computationally complex and extremely resource-intensive. To this end, companies are required to equip themselves with adequate IT infrastructures, facing a significant outlay. In this paper we present the design and the development of a Machine Learning-based approach to transparently deploy on a cloud environment the most resource-intensive portion of the Solvency II-related computation. Our proposal targets DISAR®, a Solvency II-oriented system initially designed to work on a grid of conventional computers. We show how our solution allows to reduce the overall expenses associated with the computation, without hampering the privacy of the companies’ data (making it suitable for conventional public cloud environments), and allowing to meet the strict temporal requirements required by the Directive. Additionally, the system is organized as a self-optimizing loop, which allows to use information gathered from actual (useful) computations, thus requiring a shorter training phase. We present an experimental study conducted on Amazon EC2 to assess the validity and the efficiency of our proposal

Optimal CCD readout by digital correlated double sampling

Digital correlated double sampling (DCDS), a readout technique for charge-coupled devices (CCD), is gaining popularity in astronomical applications. By using an oversampling ADC and a digital filter, a DCDS system can achieve a better performance than traditional analogue readout techniques at the expense of a more complex system analysis. Several attempts to analyse and optimize a DCDS system have been reported, but most of the work presented in the literature has been experimental. Some approximate analytical tools have been presented for independent parameters of the system, but the overall performance and trade-offs have not been yet modelled. Furthermore, there is disagreement among experimental results that cannot be explained by the analytical tools available. In this work, a theoretical analysis of a generic DCDS readout system is presented, including key aspects such as the signal conditioning stage, the ADC resolution, the sampling frequency and the digital filter implementation. By using a time-domain noise model, the effect of the digital filter is properly modelled as a discrete-time process, thus avoiding the imprecision of continuous-time approximations that have been used so far. As a result, an accurate, closed-form expression for the signal-to-noise ratio at the output of the readout system is reached. This expression can be easily optimized in order to meet a set of specifications for a given CCD, thus providing a systematic design methodology for an optimal readout system. Simulated results are presented to validate the theory, obtained with both time- and frequency-domain noise generation models for completeness.Comment: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record is available online via the DOI or at: http://mnras.oxfordjournals.org/content/455/2/1443.full.pd

Entretiens. Questions sur les archives ferroviaires

Entretiens d'Agnès Sander avec Henri Zuber et d'Arnaud Passalacqua avec Sébastien Mariani et Stéphanie FuchyInternational audienceLe chemin de fer a récemment offert l’exemple criant d’une actualité des questions historiques, lorsque des liens ont été tissés entre l’attribution de marchés ferroviaires aux États-Unis et l’établissement d’un discours historique sur les activités de la SNCF pendant la Seconde Guerre mondiale. Au-delà des arrière-pensées commerciales décelables dans cette affaire, l’épisode est venu rappeler l’importance que peut présenter, pour les acteurs contemporains, la conservation efficace d’archives anciennes. De même qu’elle ne fait pas de doute pour les chercheurs.En histoire des transports, le monde des chemins de fer est le premier à avoir suscité des travaux de recherche et constitue aujourd’hui un sujet d’intérêt toujours important. Longtemps, ses archives ont été essentiellement conservées par la SNCF, acteur monopolistique de ce système de mobilité depuis sa création en 1937. Mais, depuis la réforme ferroviaire de 1997, qui a vu la création de RFF, le monde ferroviaire s’est diversifié. Cette nouvelle structure, qui porte plusieurs missions dont la propriété du réseau ferré national et l’affectation des faisceaux de circulation aux différents opérateurs, a dû également trouver sa place dans le domaine des archives ferroviaires. Tandis que d’autres acteurs, privés, mènent désormais une activité ferroviaire, témoignant ainsi d’une diversification de ce paysage, au centre duquel demeure toutefois la SNCF.Dans ce nouveau contexte, quels sont les enjeux spécifiques à l’archivistique ferroviaire? Quelles sont les conditions particulières de ce monde reconfiguré depuis une quinzaine d’années? Comment deux entreprises aux caractéristiques différentes (ancienneté, taille, mission, etc.) trouvent-elles leur place dans cet espace partagé? Les services d’archives de la SNCF et de RFF répondent aux questions de Flux

Numerical simulation of turbulent gas-particle flow in a riser using a quadrature-based moment method

Gas-particle flows are used in many industrial applications in the energy, oil and gas fields, such as coal gasification, production of light hydrocarbons by fluid catalytic cracking, catalytic combustion and different treatments aiming to reduce or eliminate pollutants. The particle phase of a gas-particle flow is described by analogy to a granular gas, by finding an approximate solution of the kinetic equation in the velocity-based number density function. In the recent past, many studies have been published on the mathematical modeling of gas-particle flows using hydrodynamic models (e.g. Enwald et al. 1996), where Navier-Stokes-type equations are solved to describe the particle phase as a continuum, computing its stress tensor using moment closures from kinetic theory (Gidaspow 1994). These closures, however, are obtained assuming that the flow is dominated by collisions and near equilibrium, which corresponds to considering a very small particle-phase Knudsen number. This assumption leads to inconsistencies and erroneous predictions of physical phenomena when these models are applied to dilute fluid-particle flows, where rarefaction effects are not negligible. In these flows, the wall Knudsen layers extend inside the bulk of the fluid, and cannot be accounted for with the simple addition of partial-slip boundary conditions. Recently Desjardin et al. (2008) showed that two-fluid models are unable to correctly capture particle trajectory crossing, seriously compromising their ability to correctly describe any velocity moment for finite Stokes numbers. These authors clarified that the particle segregation captured by two-fluid models for finite Knudsen numbers is artificially high due to their mathematical formulation, which leads to the formation of delta-shocks. In order to overcome these shortcomings, Fox (2008) developed a third-order quadrature-based moment method for dilute gas-particle flows, which has been successfully coupled to a fluid solver to compute dilute and moderately dilute gas-particle flows by Passalacqua et al. (2010) in two dimensions. These authors validated their model against Euler-Lagrange and two-fluid simulations. In this work, the fully coupled quadrature-based fluid-particle code described in Passalacqua et al. (2010) is applied to simulate turbulent gas-particle flow in the riser described by He et al. (2009), using a three-dimensional configuration. This application shows the predictive capabilities and the robustness of the quadrature-based moment method to predict the behavior of gas-particle flows in accordance with experiments (He et al. 2009)

Reconfiguration of Distributed Information Fusion System ? A case study

Information Fusion Systems are now widely used in different fusion contexts, like scientific processing, sensor networks, video and image processing. One of the current trends in this area is to cope with distributed systems. In this context, we have defined and implemented a Dynamic Distributed Information Fusion System runtime model. It allows us to cope with dynamic execution supports while trying to maintain the functionalities of a given Dynamic Distributed Information Fusion System. The paper presents our system, the reconfiguration problems we are faced with and our solutions.Comment: 6 pages - Preprint versio