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Multiplicative Decomposition (multiplicative + decomposition)
Selected AbstractsA NEW MULTIPLICATIVE DECOMPOSITION FOR THE FOSTER,GREER,THORBECKE POVERTY INDICESBULLETIN OF ECONOMIC RESEARCH, Issue 3 2010Oihana Aristondo I30; I32; D63 ABSTRACT This paper shows that Foster,Greer,Thorbecke poverty indices can be written as the product of components summarizing the incidence, intensity and inequality dimensions of poverty and provides an empirical illustration of the decomposition using Spanish household budget surveys data. [source] Point process methodology for on-line spatio-temporal disease surveillanceENVIRONMETRICS, Issue 5 2005Peter Diggle Abstract We formulate the problem of on-line spatio-temporal disease surveillance in terms of predicting spatially and temporally localised excursions over a pre-specified threshold value for the spatially and temporally varying intensity of a point process in which each point represents an individual case of the disease in question. Our point process model is a non-stationary log-Gaussian Cox process in which the spatio-temporal intensity, ,(x,t), has a multiplicative decomposition into two deterministic components, one describing purely spatial and the other purely temporal variation in the normal disease incidence pattern, and an unobserved stochastic component representing spatially and temporally localised departures from the normal pattern. We give methods for estimating the parameters of the model, and for making probabilistic predictions of the current intensity. We describe an application to on-line spatio-temporal surveillance of non-specific gastroenteric disease in the county of Hampshire, UK. The results are presented as maps of exceedance probabilities, P{R(x,t)c|data}, where R(x,t) is the current realisation of the unobserved stochastic component of ,(x,t) and c is a pre-specified threshold. These maps are updated automatically in response to each day's incident data using a web-based reporting system. Copyright © 2005 John Wiley & Sons, Ltd. [source] Computational issues in large strain elasto-plasticity: an algorithm for mixed hardening and plastic spinINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 2 2005Francisco Javier Montáns Abstract In this paper an algorithm for large strain elasto-plasticity with isotropic hyperelasticity based on the multiplicative decomposition is formulated. The algorithm includes a (possible) constitutive equation for the plastic spin and mixed hardening in which the principal stress and principal backstress directions are not necessarily preserved. It is shown that if the principal trial stress directions are preserved during the plastic flow (as assumed in some algorithms) a plastic spin is inadvertently introduced for the kinematic/mixed hardening case. If the formulation is performed in the principal stress space, a rotation of the backstress is inadvertently introduced as well. The consistent linearization of the algorithm is also addressed in detail. Copyright © 2005 John Wiley & Sons, Ltd. [source] An arbitrary Lagrangian,Eulerian finite element method for finite strain plasticityINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2003Francisco Armero Abstract This paper presents a new arbitrary Lagrangian,Eulerian (ALE) finite element formulation for finite strain plasticity in non-linear solid mechanics. We consider the models of finite strain plasticity defined by the multiplicative decomposition of the deformation gradient in an elastic and a plastic part (F = FeFp), with the stresses given by a hyperelastic relation. In contrast with more classical ALE approaches based on plastic models of the hypoelastic type, the ALE formulation presented herein considers the direct interpolation of the motion of the material with respect to the reference mesh together with the motion of the spatial mesh with respect to this same reference mesh. This aspect is shown to be crucial for a simple treatment of the advection of the plastic internal variables and dynamic variables. In fact, this advection is carried out exactly through a particle tracking in the reference mesh, a calculation that can be accomplished very efficiently with the use of the connectivity graph of the fixed reference mesh. A staggered scheme defined by three steps (the smoothing, the advection and the Lagrangian steps) leads to an efficient method for the solution of the resulting equations. We present several representative numerical simulations that illustrate the performance of the newly proposed methods. Both quasi-static and dynamic conditions are considered in these model examples. Copyright © 2003 John Wiley & Sons, Ltd. [source] Classes of Anisotropic Finite Plasticity Models and their Implementation in a Brick-Type Shell ElementPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003N. Apel We discuss two constitutive models formulated in terms of logarithmic strains suitable for the description of elastoplastic material response. We consider two different approaches to the definition of the plastic deformation. The first is based on the introduction of a plastic map yielding a multiplicative decomposition of the deformation gradient into an elastic and plastic part. The second one uses an additive decomposition of the current metric. A quantitative analysis of both approaches by means of numerical examples of sheet metal forming processes are presented. [source] | ||||||||||