1,879 research outputs found

    Using HCMM Thermal Data to Improve Classification of MSS Data

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    Spectral overlap between urban and rural land use/land cover categories can lead to unacceptable map accuracy levels in the classification of LANDSAT multispectral scanner (MSS) data. The four MSS bands used alone are not always adequate to distinguish among various land uses and cover types having similar spectral responses. The use of thermal data from the Heat Capacity Mapping Mission (HCMM) satellite as a means of improving MSS land cover classification accuracies for urban versus rural categories was investigated. The approaches used to integrate the HCMM data are described

    Adaptive Meshing for Deep-drawing Process

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    The paper incorporates the concept of adaptive meshing for finite-element analysis of the deep-drawing process. In adaptive meshing, the mesh is automatically refined both in the areas of insufficient accuracy and sharp stress gradients. The Zienkiewicz-Zhu error estimator based upon the difference between the finite-element solution and the corresponding smoothened solution is used to judge the accuracy both at the element and the global levels. The post-processing for determining more accurate solutions is done by fitting a higher order polynomial expansion to the finite-element solution in nodal patches. An illustrative problem is solved and the adaptive refinement at differention is presented

    Finite Element Simulation of Sheet Metal Forming Processes

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    In the present study, the survey of research work on finite element analysis of metal forming processes has been carried out. A classification of formulations dealing with geometry and material nonlinearity in the context of finite element simulation of forming operations has been recapitulated. The procedures based upon shell and continuum approaches and methods of dealing withfrictional contact, are described. Topics of current interest on finite element analysis such as error estimation, projection of error, and adaptive mesh refinement have been reviewed

    Importance-performance analysis of UK and US bank customer perceptions of service delivery technologies

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    Importance-performance analysis is utilised to compare the perceptions held by bank customers regarding selected service delivery technologies (SDTs) such as automated teller machines (ATMs), telephone banking and internet banking. Bank patrons in the United Kingdom and the United States are surveyed to examine which service delivery factors they consider to be most important toward assessing the performance of SDTs offered by banking institutions. Customer views are plotted onto importance-performance grids which offer banking strategists a straightforward, graphic illustration of service factors that patrons consider to be salient and well-addressed by current installations of bank SDTs in each respective nation. The grids also offer heuristic decision guides for translating customer perceptions into strategic allocations of organisational investments toward SDT

    Kinetic models for dilute solutions of dumbbells in non-homogeneous flows revisited

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    We propose a two fluid theory to model a dilute polymer solution assuming that it consists of two phases, polymer and solvent, with two distinct macroscopic velocities. The solvent phase velocity is governed by the macroscopic Navier-Stokes equations with the addition of a force term describing the interaction between the two phases. The polymer phase is described on the mesoscopic level using a dumbbell model and its macroscopic velocity is obtained through averaging. We start by writing down the full phase-space distribution function for the dumbbells and then obtain the inertialess limits for the Fokker-Planck equation and for the averaged friction force acting between the phases from a rigorous asymptotic analysis. The resulting equations are relevant to the modelling of strongly non-homogeneous flows, while the standard kinetic model is recovered in the locally homogeneous case

    Sufficient Covariate, Propensity Variable and Doubly Robust Estimation

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    Statistical causal inference from observational studies often requires adjustment for a possibly multi-dimensional variable, where dimension reduction is crucial. The propensity score, first introduced by Rosenbaum and Rubin, is a popular approach to such reduction. We address causal inference within Dawid's decision-theoretic framework, where it is essential to pay attention to sufficient covariates and their properties. We examine the role of a propensity variable in a normal linear model. We investigate both population-based and sample-based linear regressions, with adjustments for a multivariate covariate and for a propensity variable. In addition, we study the augmented inverse probability weighted estimator, involving a combination of a response model and a propensity model. In a linear regression with homoscedasticity, a propensity variable is proved to provide the same estimated causal effect as multivariate adjustment. An estimated propensity variable may, but need not, yield better precision than the true propensity variable. The augmented inverse probability weighted estimator is doubly robust and can improve precision if the propensity model is correctly specified
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