The Impact of Government-Sponsored Training Programs on the Labor Market Transitions of Disadvantaged Men

The analysis focuses on the impact of government-sponsored training programs aimed at disadvantaged male youths on their labour market transitions. The richness of the data at our disposal allows us to recreate very detailed individual histories over a relatively long period. We use a continuous time duration model to estimate the density of duration times in as many as seven states, controlling for the endogeneity of an individual s training status. We investigate the sensitivity of the parameter estimates by comparing a typical non-parametric specification with a series of parametric two-factor loading models, as well as a parametric three-factor loading model. Our results show that young, poorly educated males who participate in welfare training programs do worse on the labour market than those who do not participate. On the other hand, participation in unemployment training programs provides them some benefits. In general, we find that duration times in any of the seven states considered are sensitive to variations in program parameters such as welfare benefits, policy variables such as the minimum wage rate, and in the economic environment as proxied by the unemployment rate. Dans cet article, nous cherchons à déterminer l'impact des mesures actives d'insertion sur les transitions des jeunes prestataires masculins de l'aide de dernier recours sur le marché du travail. La richesse des données à notre disposition nous permet de recréer de façon très détaillée l'historique de chaque prestataire sur une période relativement longue. Nous avons recours à un modèle de durée en temps continue pour estimer la densité des durées observées dans plus de sept états différents. L'endogénéité de la présence dans une mesure active est explicitement prise en compte. Nous analysons la sensibilité des paramètres estimés en comparant les résultats d'un modèle non-paramétrique standard avec ceux de plusieurs modèles paramétriques à deux ou trois facteurs de charge. Nos résultats montrent que les jeunes hommes peu scolarisés qui participent à des mesures actives destinées aux prestataires d'aide de dernier recours ont davantage de difficultés à s'intégrer au marché du travail que ceux qui ne participent pas à des telles mesures. En revanche, les mesures d'insertion offertes dans le cadre du programme d'assurance-emploi semblent donner de meilleurs résultats. De façon générale, la durée dans chacun des sept états considérés est sensible aux variables considérées dans l'analyse, soient les prestations d'aide de dernier recours, le salaire minimum, et le taux de chômage.Multi-state multi-episods duration model, non-parametric heterogeneity, training programs, welfare, Modèle de durée multi-états multi-épisodes, hétérogénéité non-paramétrique, mesures active d'insertion, aide de dernier recours

The Impact of Government-Sponsored Training Programs on the Labor Market Transitions of Disadvantaged Men

Dans ce travail, nous cherchons à déterminer l'impact des mesures actives d'insertion sur les transitions des jeunes prestataires masculins de l'aide de dernier recours sur le marché du travail. La richesse des données à notre disposition nous permet de recréer de façon très détaillée l'historique de chaque prestataire sur une période relativement longue. Nous avons recours à un modèle de durée en temps continue pour estimer la densité des durées observées dans plus de sept états différents. L'endogénéité de la présence dans une mesure active est explicitement prise en compte. Nous analysons la sensibilité des paramètres estimés en comparant les résultats d'un modèle non-paramétrique standard avec ceux de plusieurs modèles paramétriques à deux ou trois facteurs de charge. Nos résultats montrent que les jeunes hommes peu scolarisés qui participent à des mesures actives destinées aux prestataires d'aide de dernier recours ont davantage de difficultés à s'intégrer au marché du travail que ceux qui ne participent pas à des telles mesures. En revanche, les mesures d'insertion offertes dans le cadre du programme d'assurance-emploi semblent donner de meilleurs résultats. De façon générale, la durée dans chacun des sept états considérés est sensible aux variables considérées dans l'analyse, soient les prestations d'aide de dernier recours, le salaire minimum, et le taux de chômage. The analysis focuses on the impact of government-sponsored training programs aimed at disadvantaged male youths on their labour market transitions. The richness of the data at our disposal allows us to recreate very detailed individual histories over a relatively long period. We use a continuous time duration model to estimate the density of duration times in as many as seven states, controlling for the endogeneity of an individual's training status. We investigate the sensitivity of the parameter estimates by comparing a typical non-parametric specification with a series of parametric two-factor loading models, as well as a parametric three-factor loading model. Our results show that young, poorly educated males who participate in welfare training programs do worse on the labour market than those who do not participate. On the other hand, participation in unemployment training programs provides them some benefits. In general, we find that duration times in any of the seven states considered are sensitive to variations in program parameters such as welfare benefits, policy variables such as the minimum wage rate, and in the economic environment as proxied by the unemployment rate.Modèle de durée multi-états multi-épisodes, hétérogénéité non-paramétrique, mesures active d'insertion, aide de dernier recours, multi-state multi-episods duration model, non-parametric heterogeneity, training programs, welfare

Experimenting with Gnutella Communities

Computer networks and distributed systems in general may be regarded as communities where the individual components, be they entire systems, application software or users, interact in a shared environment. Such communities dynamically evolve with components or nodes joning and leaving the system. Their own individual activities affect the community's behaviour and vice-versa. This paper discusses various experiments undertaken to investigate the behaviour of a real system, the Gnutella network, which represents such a community. Gnutella is a distributed Peer-to-Peer data-sharing system without any central control. It turns out that most interactions between nodes do not last long and much of their activity is devoted to finding appropriate partners in the network. Good connections lasting longer appear only as rare events. For example, out of 42,000 connections only 57 hosts were found to available on a regular basis. This means that, in contrast to the common belief that this kind of peer-to-peer networks or sub-communities are always large, they are actually quite small. However, those sub-communities examplify very dynamic behaviour because their actual composition can change very quickly. The experimental results presented have been obtained from a Java implementation of Gnutella running in the open Internet environment, and thus in unknown and quickly changing network structures heavily dependent on chance. Les réseaux informatique ainsi que les systèmes distribués peuvent être considérés comme des communautés où les composantes - que ce soit des systèmes complets, des programmes ou des usagers - interagissent dans un environnement partagé. Ces communautés sont dynamiques car des éléments peuvent s'y joindre ou quitter en tout temps. L'article présente les résultats d'une suite d'expériences et de mesures faites sur Gnutella, un système peer-to-peer à grande échelle qui opère sans aucun contrôle centralisé. Nous avons remarqué qu'une grande partie des messages échangés sont erronés ou redondants et que les interactions entre n?uds ne durent pas très longtemps. En particulier, des connexions durant plus d'une minute sont des phénomènes rares. Les n?uds passent donc la majorité de leur temps à remplacer les partenaires perdus et, contrairement à l'idée répandue que les réseaux peer-to-peer sont immenses, nous avons noté que les communautés effectives étaient assez limitées. Gnutella est un environnement très dynamique avec peu de stabilité. Par exemple, de 42,000 sites avec lesquels nous avons établi une connexion, il a seulement été possible de re-communiquer de façon régulière avec 57. Dans un tel environnement, la chance joue un rôle important dans la performance observée; mais nous avons élaboré un protocole expérimental permettant de comparer diverses options.Gnutella, peer-to-peer networks, Internet communities, distributed systems, protocols, Gnutella, réseaux peer-to-peer, communautés virtuelles, internet, systèmes distribués, protocoles de télécommunication

MYOAN : an implementation of the KOAN shared virtual memory on the Intel paragon

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How do the grains slide in fine-grained zirconia polycrystals at high temperature?

Degradation of mechanical properties of zirconia polycrystals is hardly discussed in terms of solution-precipitation grain-boundary sliding due to experimental controversies over imaging of intergranular amorphous phases at high and room temperatures. Here, the authors applied the techniques of mechanical spectroscopy and transmission electron microscopy (TEM) to shed light on the amorphization of grain interfaces at high temperature where the interface-reaction determines the behaviour of fine-grained zirconia polycrystals. They present mechanical spectroscopy results, which yield evidences of an intergranular amorphous phase in silica doped and high-purity zirconia at high temperature. Quenching of zirconia polycrystals reveals an intergranular amorphous phase on TEM images at room temperature.Comment: 12 pages, 3 figure

Prophylactic anti-coagulation in cancer palliative care: a prospective randomised study

Goals: The objective of this study was to determine utility of prophylactic anti-coagulation in cancer patients hospitalised for palliative care in a specialised centre. Materials and methods: Prospective 1:1 open randomised study was designed. Twenty patients aged 55 to 88years with advanced cancer and an estimated life expectancy of less than 6months were assigned to either receive treatment with 2,850/3,800U (70kg) of daily subcutaneous nadroparin or no treatment. Suspicion of venous thrombo-embolism (deep vein thrombosis and pulmonary embolism) was confirmed by echo-Doppler examination of the lower limbs and/or by spiral computed tomography scan of the lungs. Bleeding episodes were recorded. Platelet count was measured on days 7 and 14. Survival time from study entry was determined. Main results: One venous thrombo-embolism and one major bleeding occurred in the group receiving nadroparin, whereas two minor bleedings occurred in the control group. At 3months, nine of ten participants had died in the control group vs five of ten in the group receiving nadroparin (P = 0.141). Five participants could be discharged home (P = 0.141). Conclusions: Decision to administer prophylactic nadroparin in hospitalised cancer patients under palliative care remains a challenge. Better mobility score at admission and the likelihood to be discharged home may be useful for practical purposes. The observation of a potential influence of prophylactic nadroparin on survival deserves further studie

Shack-Hartmann multiple spots with diffractive lenses

International audienceIn this Letter we aim to bring an understanding to the apparition of multiple spots when using a Shack-Hartmann (SH) wavefront sensor behind diffractive lenses. In contrast to previous work, this phenomenon is described in terms of diffractive orders. It is illustrated with Zemax simulations, where three kinds of diffractive lenses (monofocal, bifocal, and trifocal) are set behind a microlens array. The presence of multiple spots is related to the phase jump of the diffractive profile and also to the number of steps seen through the microlens pupil. The possibility of assessing the optical quality of such lenses using SH measurements is discussed, in particular within the field of ophthalmology, where the need for precautions is underline

A scalable dynamic parking allocation framework

International audienceCities suffer from high traffic c ongestion of which one of the main causes is the unorganized pursuit for available parking. Apart from traffic congestion, the blind search for a parking slot causes financial and environmental losses. We consider a general parking allocation scenario in which the GPS data of a set of vehicles, such as the current locations and destinations of the vehicles, are available to a central agency which will guide the vehicles toward a designated parking lot, instead of the entered destination. In its natural form, the parking allocation problem is dynamic, i.e., its input is continuously updated. Therefore, standard static allocation and assignment rules do not apply in this case. In this paper, we propose a framework capable of tackling these real-time updates. From a methodological point of view, solving the dynamic version of the parking allocation problem represents a quantum leap compared with solving the static version. We achieve this goal by solving a sequence of 0-1 programming models over the planning horizon, and we develop several parking policies. The proposed policies are empirically compared on real data gathered from three European cities: Belgrade, Luxembourg, and Lyon. The results show that our framework is scalable and can improve the quality of the allocation, in particular when parking capacities are low

The parking allocation problem for connected vehicles

International audienceIn this paper, we propose a parking allocation model that takes into account the basic constraints and objectives of a problem where parking lots are assigned to vehicles. We assume vehicles are connected and can exchange information with a central intelligence. Vehicle arrival times can be provided by a GPS device, and the estimated number of available parking slots, at each future time moment and for each parking lot is used as an input. Our initial model is static and may be viewed as a variant of the generalized assignment problem. However, the model can be rerun, and the algorithm can handle dynamic changes by frequently solving the static model, each time producing an updated solution. In practice this approach is feasible only if reliable quality solutions of the static model are obtained within a few seconds since the GPS can continuously provide new input regarding the vehicle’s positioning and its destinations. We propose a 0–1 programming model to compute exact solutions, together with a variable neighborhood search-based heuristic to obtain approximate solutions for larger instances. Computational results on randomly generated instances are provided to evaluate the performance of the proposed approaches