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991.
Samuel P. Schofield Mark A. Christon Vadim Dyadechko Rao V. Garimella Robert B. Lowrie Blair K. Swartz 《国际流体数值方法杂志》2010,63(8):931-952
This paper compares the numerical performance of the moment‐of‐fluid (MOF) interface reconstruction technique with Youngs, LVIRA, power diagram (PD), and Swartz interface reconstruction techniques in the context of a volume‐of‐fluid (VOF) based finite element projection method for the numerical simulation of variable‐density incompressible viscous flows. In pure advection tests with multiple materials MOF shows dramatic improvements in accuracy compared with the other methods. In incompressible flows where density differences determine the flow evolution, all the methods perform similarly for two material flows on structured grids. On unstructured grids, the second‐order MOF, LVIRA, and Swartz methods perform similarly and show improvement over the first‐order Youngs' and PD methods. For flow simulations with more than two materials, MOF shows increased accuracy in interface positions on coarse meshes. In most cases, the convergence and accuracy of the computed flow solution was not strongly affected by interface reconstruction method. Published in 2009 by John Wiley & Sons, Ltd. 相似文献
992.
Lucian Coroianu 《Numerical Functional Analysis & Optimization》2013,34(7):713-727
In this article, we investigate the local approximation and shape preserving properties in subintervals for the Meyer-König and Zeller max-product operators. The results obtained put in evidence that in the class of strictly positive continuous functions, the local properties of the nonlinear Meyer-König and Zeller max-product operators are much stronger and more general than those in the case of their linear counterparts. 相似文献
993.
In this paper we first prove the equivalence between the system of coupled Volterra gyrostats and a special class of energy-conserving
low-order models. We then extend the definition of the classical Volterra gyrostat to include nonlinear feedback, resulting
in a class of generalized Volterra gyrostats. Using this new class of gyrostats as a basic building block, we present an algorithm
for converting a general class of energy-conserving low-order models that routinely arise in fluid dynamics, turbulence, and
atmospheric sciences into a system of coupled generalized Volterra gyrostats with nonlinear feedback.
相似文献
994.
E. A. Nurminski 《Computational Mathematics and Mathematical Physics》2008,48(12):2154-2161
The behavior of Fejer processes with diminishing disturbances generated by a small shift in the argument of the Fejer operator is studied. It is shown that, if the operator is locally strongly Fejer, a diminishing disturbance does not prevent convergence to an attracting set. At the same time, such a disturbance can be used to furnish the process with additional properties that ensure convergence to certain subsets of the attracting set. In particular, based on this scheme, new parallel decomposition methods for optimization problems can be suggested that do not require that the constraints possess a specific structure. 相似文献
995.
基于亚洲艾滋病流行模型(Asian Epidemic Model,AEM)基本思想,建立我国艾滋病流行预测模型.利用该模型,估计某地1989—2007年艾滋病流行状况,同时设计不同行为改变方案,预测该地2008—2020年艾滋病流行趋势. 相似文献
996.
997.
We have used near IR spectrometry and multiple regression analysis to construct the calibration models for determining the
weight fractions of the major components of milk blends, and we have used the latter to study the feasibility of using a portable
spectrophotometer (designed at the Institute of Spectroscopy) based on a silicon CCD linear array as a working tool for monitoring
the quality of biotechnological products.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 274–279, March–April, 2008. 相似文献
998.
本文设计了一种极大单调算子零点的带误差项的新投影迭代算法,并在Banach空间中,利用Lyapunov泛函与广义投影映射等技巧,证明了迭代序列强收敛于极大单调算子零点的结论. 相似文献
999.
Conditions for the non-existence of a regular exceptional family of elements with respect to an isotone projection cone in
a Hilbert space will be presented. The obtained results will be used for generating existence theorems for a complementarity
problem with respect to an isotone projection cone in a Hilbert space. 相似文献
1000.
Benoît Jaillais Jean-Claude Boulet Jean-Michel Roger François Balfourier Pierre Berbezy Dominique Bertrand 《Analytica chimica acta》2012
Many scientific instruments produce multivariate images characterized by three-way tables, an element of which represents the intensity value at a spatial location for a given spectral channel. A problem frequently encountered is to attempt estimating the contributions of some compounds at each location of these images. Usual regression methods of calibration, such as PLS, require having a matrix of calibration X (n × p) and the corresponding vector y of the dependent variable (n × 1). X can be built up by sampling pixel-vectors in the images, but y is sometimes difficult to obtain, if the surface of the samples is formed by chemically heterogeneous regions. In this case, the quantitative analyses related to y may be difficult, if the pixels represent very small areas (for example on microscopic images) or very large ones (satellite images). This is for example the case when dealing with biological solid samples representing different tissues. Direct Calibration (DC), sometimes referred to as “spectral unmixing”, do not require having such a calibration set. However, it is indeed needed to have both a matrix of “perturbing” pixel-vectors (noted K) and a vector of the “pure” component spectrum to be analyzed (p), which are more easily obtainable. For estimating the contribution, the unknown pixel vector x and the pure spectrum p are first projected orthogonally onto K giving the vectors x⊥ onto p⊥, respectively. The contribution is then estimated by a second projection of x⊥ onto p⊥. A method, based on principal component analysis, for determining the optimal dimensions of K is proposed. DC was applied on a collection of multivariate images of kernel of wheat to estimate the proportion of three tissues, namely out-layers, “waxy” endosperm and normal endosperm. The eventual results are presented as images of wheat kernels in false colors associated to the estimated proportions of the tissues. It is shown that DC is appropriate for estimating contributions in situations in which the more usual methods of calibration cannot be applied. 相似文献