4,882 research outputs found
Assessing the distortions of mandatory pensions on labor supply decisions and human capital accumulation : how to bridge the gap between economic theory and policy analysis
Get PDFMandatory pension systems play a major role in individual savings and labor supply decisions. In particular, it is well known that defined benefit pension schemes, which are not actuarially fair, can create incentives for early retirement and therefore reduce labor supply and the stock of human capital in a given country. This is an important policy issue in middle-income countries, with still low participation rates in the labor force, where the"window"opened by the demographic transition is already closed or will close in the near future. In these countries, policies to stimulate private sector growth, competitiveness, and employment creation should be accompanied by policies that increase labor force participation, raising the ratio of active to inactive population and therefore the potential for higher income per capita growth. Unfortunately, the analytical tools developed to assess pension reform options tend to focus on the financial sustainability of the schemes and the adequacy of benefits. Little attention is given in practice to the social costs imposed by distortions on the supply of labor. In part, this is given by the lack of analytical tools that, in the context of limited information regarding individual preferences and behavior, can be used to assess the magnitude of these distortions. This paper develops methodologies that can bridge the gap between economic theory and the practices of pension policy personnel under conditions of deep uncertainty regarding the variables driving individual behavioral responses to policy changes. First, the paper develops an indicator to predict the age-specific retirement probabilities induced by a particular pension system, given heterogeneous individual preferences over risk, consumption, and leisure. The paper then describes how this indicator can be used to project the size of the labor force by gender, age and skill level and therefore the dynamics of human capital accumulation. The integration of these two analytical tools allow us to show the impact of a particularpension reform proposals on the dynamics of labor supply, human capital and, given the dynamics of capital and total factor productivity, economic growth. Furthermore, the paper develops a set of life-cycle income measures for typical individual paths that allow us to measure the contribution of segmented pension schemes to the segmentation of the labor market. The methods are applied to the case of Morocco.,Labor Markets,Labor Policies,Pensions&Retirement Systems,Debt Markets
An isogeometric method for linear nearly-incompressible elasticity with local stress projection
Get PDFIn this paper, we propose an isogeometric method for solving the linear nearly-incompressible elasticity problem. The method is similar to the (B) over bar formulation where the volumetric strain is projected on a lower degree spline space in order to prevent volumetric locking. In our method, we adopt a local projection on a coarser mesh, chosen in order to guarantee optimal convergence. Moreover the locality of the projector allows to maintain the sparsity of the stiffness matrix, that is, the efficiency of the method. The analysis of the method is based on the inf-sup stability of the associated mixed formulation via a macro-element technique for spline functions. The numerical tests confirm the theory of the method. (C) 2016 Elsevier B.V. All rights reserved.MN
Modelling the Effect of Population Ageing on Government Social Expenditures
Get PDFThis paper reviews and extends a new framework, developed by Razin, Sadka, and Swagel, for capturing the effect of population ageing on public support for government social expenditures. Razin et al construct up an overlapping generations, median voter model, and investigate the empirical applicability of the model using panel data from 13 OECD countries. Their results suggest that population ageing will put downward pressure on per capita expenditures. These results rest, however, on an assumption that there is only one dependant age group: the old. This paper investigates the consequences of allowing for two such age groups: the young and the old. A replication of Razin et al’s empirical analysis, using two dependent age groups rather than one, suggests that population ageing will instead put upward pressure on per capita expenditures. Although these results are tentative, they illustrate the usefulness of including both youth dependency and old-age dependency in Razin et al’s framework.Social expenditures; Median voter models; Population Ageing
Iglesia de San Pablo del Monte: Tlaxcala
No full textLa construcción del templo de San Pablo del Monte se remonta al siglo XVI. En un primer momento estuvo dedicado a San Miguel Arcángel, y poco tiempo después fue brindado al apóstol San Pablo. El templo fungió como visita del convento franciscano de Puebla, junto con las poblaciones de San Miguel Tenancingo, San Francisco Papalotla y San Cosme Mazatecochco.</p
The Immersed Boundary Conformal Method for Kirchhoff–Love and Reissner–Mindlin shells
Get PDFThis work utilizes the Immersed Boundary Conformal Method (IBCM) to analyze linear elastic Kirchhoff-Love and Reissner-Mindlin shell structures within an immersed domain framework. Immersed boundary methods involve embedding complex geometries within a background grid, which allows for great flexibility in modeling intricate shapes and features despite simplicity of the approach. The IBCM method introduces additional layers conformal to boundaries, allowing for the strong imposition of Dirichlet boundary conditions and facilitating local refinement. In this study, the construction of boundary layers is combined with high degree spline-based approximation spaces to further increase efficiency. The Nitsche method, employing non-symmetric average operators, is used to couple the boundary layers with inner patch, while stabilizing the formulation with minimal penalty parameters. High-order quadrature rules are applied for integration over cut elements and patch interfaces. Numerical experiments demonstrate the efficiency and accuracy of the proposed formulation, highlighting its potential for complex shell structures modeled through Kirchhoff-Love and Reissner- Mindlin theories. These tests include the generation of conformal interfaces, the coupling Kirchhoff-Love and Reissner-Mindlin theories, and the simulation of a cylindrical shell with through-the-thickness crack
An interior penalty coupling strategy for isogeometric non-conformal Kirchhoff-Love shell patches
Get PDFThis work focuses on the coupling of trimmed shell patches using Isogeometric Analysis, based on higher continuity splines that seamlessly meet the requirement of Kirchhoff-Love-based discretizations. Weak enforcement of coupling conditions is achieved through the symmetric interior penalty method, where the fluxes are computed using their correct variationally consistent expression that was only recently proposed and is unprecedentedly adopted herein in the context of coupling conditions. The constitutive relationship accounts for generically laminated materials, although the proposed tests are conducted under the assumption of uniform thickness and lamination sequence. Numerical experiments assess the method for an isotropic and a laminated plate, as well as an isotropic hyperbolic paraboloid shell from the new shell obstacle course. The boundary conditions and domain force are chosen to reproduce manufactured analytical solutions, which are taken as reference to compute rigorous convergence curves in the L 2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} , H 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} , and H 2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} norms, that closely approach optimal ones predicted by theory. Additionally, we conduct a final test on a complex structure comprising five intersecting laminated cylindrical shells, whose geometry is directly imported from a STEP file. The results exhibit excellent agreement with those obtained through commercial software, showcasing the method's potential for real-world industrial applications.MN
Longevity Risk and Private Pensions
No full textThis paper examines how uncertainty regarding future mortality and life expectancy outcomes, i.e. longevity risk, affects employer-provided defined benefit (DB) private pension plans liabilities. For this purpose, it examines the different approaches that private pension plans follow in practice when incorporating longevity risk in their actuarial calculations. Unfortunately, most pension funds do not fully account for future improvements in mortality and life expectancy. The paper then presents estimations of the range of increase in the net present value of annuity payments for a theoretical DB pension fund. Finally, the paper discusses several policy issues on how to deal with longevity risk emphasising the need for a common approach. In this regard, it argues, following Antolin (2007), that to assess uncertainty and associated risks adequately, a stochastic approach to model mortality and life expectancy is preferable because it permits to attach probabilities to different forecasts.
A cost-effective isogeometric approach for composite plates based on a stress recovery procedure
Get PDFThis paper introduces a cost-effective strategy to simulate the behavior of laminated plates by means of isogeometric 3D solid elements. Exploiting the high continuity of spline functions and their properties, a proper out-of-plane stress state is recovered from a coarse displacement solution using a post-processing step based on the enforcement of equilibrium in strong form. Appealing results are obtained and the method is shown to be particularly effective on slender composite stacks with a large number of layers. These are indeed the cases where traditional (e.g., “layerwise”) approaches are more computationally heavy and where researchers are more inclined to look for alternatives, making the proposed method a very attractive solution.MN
A simple and effective method based on strain projections to alleviate locking in isogeometric solid shells
No full textIn this work, we focus on the family of shell formulations referred to as "solid shells", where the simulation of shell-type structures is performed by means of a mesh of 3D solid elements, with typically only one element through the thickness. We propose a novel approach for alleviating the various locking phenomena, which typically appear in thin structures, based on the projection of strains onto discontinuous coarser polynomial spaces defined at element level. In particular, we present and investigate two different formulations based on this approach. Several numerical experiments prove the very good performance of both formulations. The main advantages of the presented approach compared to existing solid shell formulations are its simplicity and numerical efficiency.MNS12 figure
Igatools: An isogeometric analysis library
Get PDFWe present the design of an object oriented general purpose library for isogeometric analysis, where the mathematical concepts of the isogeometric method and their relationships are directly mapped into classes and their interactions. The encapsulation of mathematical concepts into interacting building blocks gives flexibility to use the library in a wide range of scientific areas and applications. We provide a precise framework for a lot of loose, available information regarding the implementation of the isogeometric method, and also discuss the similarities and differences between this and the finite element method. We also describe how to implement this proposed design in a C++11 open source library, \textttigatools (http://www.igatools.org). The library uses advanced object oriented and generic programming techniques to ensure reusability, reliability, and maintainability of the source code. It includes isogeometric elements of the h-div and h-curl type, and supports the development of dimension independent code (including manifolds and tensor-valued spaces). We finally present a number of code examples to illustrate the flexibility and power of the library, including surface domains, nonlinear elasticity, and Navier--Stokes computations on nontrivial geometries.Fil: Pauletti, Miguel Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Matemática Aplicada del Litoral. Universidad Nacional del Litoral. Instituto de Matemática Aplicada del Litoral; ArgentinaFil: Martinelli, Massimiliano. Consiglio Nazionale delle Ricerche. Istituto di Matematica Applicata e Tecnologie Informatiche; ItaliaFil: Cavallini, Nicola. Scuola Internazionale Superiore di Studi Avanzati; ItaliaFil: Antolin, Pablo. Università degli Studi di Pavia. Dipartimento di Ingegneria Civile ed Architettura; Itali
- …
