Diasporas

Migration flows are shaped by a complex combination of self-selection and out-selection mechanisms. In this paper, the authors analyze how existing diasporas (the stock of people born in a country and living in another one) affect the size and human-capital structure of current migration flows. The analysis exploits a bilateral data set on international migration by educational attainment from 195 countries to 30 developed countries in 1990 and 2000. Based on simple micro-foundations and controlling for various determinants of migration, the analysis finds that diasporas increase migration flows, lower the average educational level and lead to higher concentration of low-skill migrants. Interestingly, diasporas explain the majority of the variability of migration flows and selection. This suggests that, without changing the generosity of family reunion programs, education-based selection rules are likely to have a moderate impact. The results are highly robust to the econometric techniques, accounting for the large proportion of zeros and endogeneity problems.Population Policies,Voluntary and Involuntary Resettlement,Human Migrations&Resettlements,Anthropology,International Migration

Diasporas

Migration flows are shaped by a complex combination of self-selection and out-selection mechanisms. In this paper, we analyze how existing diasporas (the stock of people born in a country and living in an another one) affect the size and human-capital structure of current migration flows. Our analysis exploits a bilateral data set on international migration by educational attainment from 195 countries to 30 OECD countries in 1990 and 2000. Based on simple micro-foundations and controlling for various determinants of migration, we find diasporas increase migration flows, lower their average educational level and lead to higher concentration of low-skill migrants. Interestingly, diasporas explain majority of the variability of migration flows and selection. This suggests that, without changing the generosity of family reunion programs, education-based selection rules are likely to have moderate impact. Our results are highly robust to the econometric techniques, accounting for the large proportion of zeros and endogeneity problems.migration, self-selection, network/diaspora externalities

Petroleum Reservoir Simulation Using 3-D Finite Element Method With Parallel Implementation.

Modeling fluid flow around wellbores with conventional reservoir simulators is inaccurate because radial flow occurs in the vicinity of the wellbore and these simulators use cartesian coordinates. In this research, we present a more accurate wellbore simulation by incorporating the finite element method (FEM) to simulate the radial flow in the vicinity of the wellbore and interfacing this finite element wellbore model with an existing finite difference method (FDM) reservoir simulator. Although this technique was developed for a vertical well, it could also be used to accurately model a horizontal wellbore. This hybrid solution is for three dimensional---triphasic fluid flow and allows a more rigorous treatment of the near-well flow. The reservoir region, where flow geometry is linear, is simulated with the cartesian grid using finite differences. The reservoir simulator used for this research was the US Department of Energy\u27s Black Oil Applied Simulation Tool (BOAST II). Two problems furnished by the Department of Energy were used to test the effectiveness of our solution. The first was a single stratum three phase system. The second was a three strata three phase gas injection problem. Finally, our stand alone model could actually be interfaced with almost any other finite difference fluid flow simulator; whether it is for petroleum reservoirs, underground water, or hazardous waste management

Conception d'architectures de calcul à hautes performances pour la comparaison de séquences génétiques

Concepts de base et problématique du domaine de comparaison de séquences -- Cycle de vie -- Information génétique -- Projet du génome humain et bases de données génétiques -- Alignement de séquences génétiques -- Principes de la programmation dynamique -- Accélération matérielle de traitement -- Parallélisme logiciel/matériel et transformations -- Classification des systèmes HPC -- Les accélérateurs FPGA, ASIC, et autres -- Choix de la technologie du support matériel -- Parallélisation de l'application : comparaison de séquences génétiques -- Méthodologie -- Parallélisation logicielle -- Parallélisation avec le standard OpenMP (mémoire partagée) -- Parallélisation MPI (mémoire distribuée) -- Apport de la parallélisation logicielle -- Parallélisation matériel -- Performances et analyses des résultats -- Performance du PE_1x1 par rapport aux systèmes existants -- Étude comparative de performances entre les différents éléments réalisés : coût matériel et accélération du traitement -- Détermination des points de Pareto de l'espace de conception -- Validation du choix de l'unité de traitement la plus performante