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Decomposition Techniques (decomposition + techniques)

Distribution by Scientific Domains
Engineering62%

Kinds of Decomposition Techniques

  • domain decomposition techniques
    		•

    Selected Abstracts

    Gender Wage Differences in West Germany: A Cohort Analysis

    GERMAN ECONOMIC REVIEW, Issue 4 2002
    Bernd Fitzenberger
    A comprehensive descriptive analysis of gender wage differences over a long time period does not exist for West Germany. Using an empirical approach which explicitly takes into account changes of wage distributions for both males and females as well as life,cycle and birth cohort effects, we go beyond conventional decomposition techniques of the average gender wage gap. The paper provides stylized facts of the level and dynamics of the gender wage gap from 1975,95. The empirical analysis is based upon the IAB employment subsample. Our findings confirm the importance of distributional effects relating to skill level and employment status. While life,cycle wage growth is in general much lower for females compared to males, comparing their estimated time trends implies that the gender wage gap has narrowed substantially in the lower part of the wage distribution especially for low, and medium,skilled females but much less so in the upper part of the wage distribution. Surprisingly, we do not find any cohort effects for wages of female employees. [source]

    The Impact of Industrial Restructuring on Earnings Inequality: The Decline of Steel and Earnings in Pittsburgh

    GROWTH AND CHANGE, Issue 1 2004
    Patricia Beeson
    ABSTRACT Inter-industry employment shifts were largely responsible for changes in the income distribution in the Pittsburgh region during the 1980s. Kernel density estimators were used, together with decomposition techniques developed by DiNardo et al. (1996) to show that industry shifts were responsible for over 90 percent of the earnings reductions at some points on the earnings distribution. Most of the losses at the lower end of the distribution occurred in the early 1980s as the economy plunged into a deep recession. The recovery in the later part of the decade brought little improvement as earnings in the lower part of the distribution continued to fall with the increase in employment of part-time workers in the low-wage trade and service sectors. [source]

    Electron transport enhanced molecular dynamics for metals and semi-metals,

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8-9 2010
    Reese E. Jones
    Abstract In this work we extend classical molecular dynamics by coupling it with an electron transport model known as the two temperature model. This energy balance between free electrons and phonons was first proposed in 1956 by Kaganov et al. but has recently been utilized as a framework for coupling molecular dynamics to a continuum description of electron transport. Using finite element domain decomposition techniques from our previous work as a basis, we develop a coupling scheme that preserves energy and has local control of temperature and energy flux via a Gaussian isokinetic thermostat. Unlike the previous work on this subject, we employ an efficient, implicit time integrator for the fast electron transport which enables larger stable time steps than the explicit schemes commonly used. A number of example simulations are given that validate the method, including Joule heating of a copper nanowire and laser excitation of a suspended carbon nanotube with its ends embedded in a conducting substrate. Published in 2010 by John Wiley & Sons, Ltd. [source]

    Large eddy simulation of turbulent flows via domain decomposition techniques.

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2005
    Part 1: theory
    Abstract The present paper discusses large eddy simulations of incompressible turbulent flows in complex geometries. Attention is focused on the application of the Schur complement method for the solution of the elliptic equations arising from the fractional step procedure and/or the semi-implicit discretization of the momentum equations in velocity,pressure representation. Fast direct and iterative Poisson solvers are compared and their global efficiency evaluated both in serial and parallel architecture environments for model problems of physical relevance. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Large eddy simulation of turbulent flows via domain decomposition techniques.

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2005
    Part 2: applications
    Abstract The present paper discusses the application of large eddy simulation to incompressible turbulent flows in complex geometries. Algorithmic developments concerning the flow solver were provided in the companion paper (Int. J. Numer. Meth. Fluids, 2003; submitted), which addressed the development and validation of a multi-domain kernel suitable for the integration of the elliptic partial differential equations arising from the fractional step procedure applied to the incompressible Navier,Stokes equations. Numerical results for several test problems are compared to reference experimental and numerical data to demonstrate the potential of the method. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Solving high Reynolds-number viscous flows by the general BEM and domain decomposition method

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2005
    Yongyan Wu
    Abstract In this paper, the domain decomposition method (DDM) and the general boundary element method (GBEM) are applied to solve the laminar viscous flow in a driven square cavity, governed by the exact Navier,Stokes equations. The convergent numerical results at high Reynolds number Re = 7500 are obtained. We find that the DDM can considerably improve the efficiency of the GBEM, and that the combination of the domain decomposition techniques and the parallel computation can further greatly improve the efficiency of the GBEM. This verifies the great potential of the GBEM for strongly non-linear problems in science and engineering. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Predictive control of parabolic PDEs with state and control constraints

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 16 2006
    Stevan Dubljevic
    Abstract This work focuses on predictive control of linear parabolic partial differential equations (PDEs) with state and control constraints. Initially, the PDE is written as an infinite-dimensional system in an appropriate Hilbert space. Next, modal decomposition techniques are used to derive a finite-dimensional system that captures the dominant dynamics of the infinite-dimensional system, and express the infinite-dimensional state constraints in terms of the finite-dimensional system state constraints. A number of model predictive control (MPC) formulations, designed on the basis of different finite-dimensional approximations, are then presented and compared. The closed-loop stability properties of the infinite-dimensional system under the low order MPC controller designs are analysed, and sufficient conditions that guarantee stabilization and state constraint satisfaction for the infinite-dimensional system under the reduced order MPC formulations are derived. Other formulations are also presented which differ in the way the evolution of the fast eigenmodes is accounted for in the performance objective and state constraints. The impact of these differences on the ability of the predictive controller to enforce closed-loop stability and state constraints satisfaction in the infinite-dimensional system is analysed. Finally, the MPC formulations are applied through simulations to the problem of stabilizing the spatially-uniform unstable steady-state of a linear parabolic PDE subject to state and control constraints. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    New product introduction against a predator: A bilevel mixed-integer programming approach

    NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 8 2009
    J. Cole Smith
    Abstract We consider a scenario with two firms determining which products to develop and introduce to the market. In this problem, there exists a finite set of potential products and market segments. Each market segment has a preference list of products and will buy its most preferred product among those available. The firms play a Stackelberg game in which the leader firm first introduces a set of products, and the follower responds with its own set of products. The leader's goal is to maximize its profit subject to a product introduction budget, assuming that the follower will attempt to minimize the leader's profit using a budget of its own. We formulate this problem as a multistage integer program amenable to decomposition techniques. Using this formulation, we develop three variations of an exact mathematical programming method for solving the multistage problem, along with a family of heuristic procedures for estimating the follower solution. The efficacy of our approaches is demonstrated on randomly generated test instances. This article contributes to the operations research literature a multistage algorithm that directly addresses difficulties posed by degeneracy, and contributes to the product variety literature an exact optimization algorithm for a novel competitive product introduction problem. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 [source]