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121.
In this paper, we study two bivariate quartic spline spaces and , and present two classes of quasi-interpolation operators in the two spaces, respectively. Some results on the operators are given. 相似文献
122.
倪勤 《高等学校计算数学学报(英文版)》1997,(1)
In this paper we report a sparse truncated Newton algorithm for handling large-scale simple bound nonlinear constrained minimixation problem. The truncated Newton method is used to update the variables with indices outside of the active set, while the projected gradient method is used to update the active variables. At each iterative level, the search direction consists of three parts, one of which is a subspace truncated Newton direction, the other two are subspace gradient and modified gradient directions. The subspace truncated Newton direction is obtained by solving a sparse system of linear equations. The global convergence and quadratic convergence rate of the algorithm are proved and some numerical tests are given. 相似文献
123.
Sylvia Pulmannová 《Czechoslovak Mathematical Journal》2006,56(1):155-178
The notion of a partially ordered partial abelian monoid is introduced and extensions of partially ordered abelian monoids
by partially ordered abelian groups are studied. Conditions for the extensions to exist are found. The cases when both the
above mentioned structures have the Riesz decomposition property, or are lattice ordered, are treated. Some applications to
effect algebras and MV-algebras are shown. 相似文献
124.
《Magnetic resonance in chemistry : MRC》2003,41(11):933-938
1H multiple quantum (MQ) NMR spectra of toluene and p‐bromotoluene, partially aligned in a liquid crystalline solvent, were acquired using gradient‐assisted methods. The MQ spectra were analysed to give the dipolar couplings (Dij) and these were used to determine the molecular shape and average orientation of the of the spin systems. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
125.
A Detection Algorithm for the localisation of unknown fault lines of a surface from scattered data is given. The method is
based on a local approximation scheme using thin plate splines, and we show that this yields approximation of second order
accuracy instead of first order as in the global case. Furthermore, the Detection Algorithm works with triangulation methods,
and we show their utility for the approximation of the fault lines. The output of our method provides polygonal curves which
can be used for the purpose of constrained surface approximation.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
126.
In this paper we consider the transmission problem of viscoelastic waves. That is, we study the wave propagations over materials consisting of elastic and viscoelastic components. We show that for this types of materials the dissipation produced by the viscoelastic part is strong enough to produce exponential decay of the solution, no matter how small is its size. We also show that the linear model is well posed. 相似文献
127.
部分线性变系数模型中估计的渐进正态性 总被引:1,自引:1,他引:0
作为部分线性模型与变系数模型的推广,部分线性变系数模型是一类应用非常广泛的模型,本文基于Profile最小二乘方法给出了模型中参数分量与非参数分量的估计,并在异方差情形下证明了这些估计的渐进正态性. 相似文献
128.
We study a special case of the critical point (Morse) theory of distance functions namely, the gradient flow associated with the distance function to a finite point set in . The fixed points of this flow are exactly the critical points of the distance function. Our main result is a mathematical characterization and algorithms to compute the stable manifolds, i.e., the inflow regions, of the fixed points. It turns out that the stable manifolds form a polyhedral complex that shares many properties with the Delaunay triangulation of the same point set. We call the latter complex the flow complex of the point set. The flow complex is suited for geometric modeling tasks like surface reconstruction. 相似文献
129.
Jesper Møller 《Annals of the Institute of Statistical Mathematics》1989,41(3):565-581
Sufficient conditions for geometrical fast convergence of general spatial birth-and-death processes to equilibrium are established. 相似文献
130.
A strongly negative thixotropic behavior of solutions of partially hydrolyzed polyacrylamide in a glycerol-water mixture has been observed at high dilution. Using a Couette viscometer, time changes of viscosity at various shear rates were studied in detail. 相似文献