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191.
T. Håvie 《BIT Numerical Mathematics》1969,9(4):338-350
In this paper we discuss a modification of the Clenshaw-Curtis quadrature formula. It is shown that for integrals, where the integrand may be expanded in a sufficiently rapid convergent Chebyshev series, we may split the sequence of calculated approximations into two sequences, one which approximates the integral from above and one which approximates it from below. Thus, at any step during the calculation we obtain both upper and lower bounds for the true value of the integral.Work performed while the author was working as a visiting scientist at CERN/Geneve. 相似文献
192.
The paper reports the results of work on the construction of LISP programs for various symbolic operations in complex analysis, including the evaluation of integrals around closed contours by the use of Cauchy's Theorem. It is concluded that the only difficulty in the way of the preparation of programs for all of the important and useful textbook calculations in complex analysis is that large amounts of fast storage in the computer are needed. 相似文献
193.
R. D. Brownrigg 《Journal of Optimization Theory and Applications》1979,28(2):163-184
This paper presents a potentially parallel iterative algorithm for the solution of the unconstrainedN-stage decision problem of dynamic programming. The basis of the algorithm is the use of variable-metric minimization techniques to develop a quadratic approximation to the cost function at each stage. The algorithm is applied to various problems, and comparisons with other algorithms are made.This research forms part of the author's PhD program, and is supported by the Department of Scientific and Industrial Research of the New Zealand Government. The author is indebted to Dr. B. A. Murtagh, PhD supervisor, for his encouragement and support during the preparation of this paper. 相似文献
194.
Elena?F.?ShekaEmail author Ekaterina?A.?Nikitina Valentin?A.?Zayets Ilya?Ya.?Ginzburg Joop?Schoonman 《Journal of nanoparticle research》2005,7(2-3):171-186
The current paper presents results of a quantum-chemical study of the surface structure of nanoparticles of both rutile and anatase crystallographic modifications. Different stages of the surface relaxation are discussed. Water adsorption is considered. The calculations were performed in the spd-basis by using semi-empirical quantum-chemical codes, both sequential and parallel. The results are mainly addressed to the study of the interface formed by titania nanoparticles and a set of carboxylated species, namely, benzoic, bi-isonicotinic acids as well as tris-(2,2′-dcbipyridine) Fe(II) complex placed on the surface of either rutile or anatase polymorphs.This revised version was published online in August 2005 with a corrected issue number. 相似文献
195.
Xu J 《Molecular diversity》2005,9(1-3):45-49
A 1H-azeto[2,1-d][1,5]benzothiazepin-1-one, -lactam derivatives of dihydrobenzothiazepines library derived from reactions of 2,4-disubstituted 2,3-dihydro-1,5-benzothiazepines and acyl chlorides, including phthalimidoacetyl chloride, chloroacetyl chloride, dichloroacetyl chloride and phenoxyacetyl chloride, was built up through parallel solution-phase synthesis. Stereochemistry of 1H-azeto[2,1-d][1,5]benzothiazepin-1-ones in the reaction process is discussed. 相似文献
196.
Andreas?GerndtEmail author Marc?Schirski Torsten?Kuhlen Christian?Bischof 《Journal of Mathematical Modelling and Algorithms》2005,4(1):35-52
The use of Virtual Reality (VR) techniques for the investigation of complex flow phenomena offers distinct advantages in comparison to conventional visualization techniques. Especially for unsteady flows, VR methodology provides an intuitive approach for the exploration of simulated fluid flows. However, the visualization of Computational Fluid Dynamics (CFD) data is often too time-consuming to be carried out in real-time, and thus violates essential constraints concerning real-time interaction and visualization. To overcome this obstacle, we make use of the fact that typically a multi-block approach is employed for domain decomposition, and we use the corresponding data structures for the computation of path lines and for parallelization. In this paper, we present the synthesis of fragmented multi-block data sets and our implementation of an accurate path line integration scheme in order to speed up path line computations. We report on the results of our efforts and describe a combination of this algorithm with a highly efficient visualization approach of large amounts of particle traces, thus considerably improving interactivity when exploring large scale CFD data sets.Mathematics Subject Classifications (2000) 76Mxx, 76M27, 76M28, 65M55, 65L05, 65L06, 65D05, 65Y05, 68U05. 相似文献
197.
This paper proposes and analyzes a class of multigrid smoothers called the parallel multiplicative (PM) smoother by subspace decomposition techniques. It shows that the well known additive and multiplicative smoothers and the JSOR smoother are special cases of the PM smoother, and their smoothing properties can be obtained directly from the PM analysis. Moreover, numerical results are presented in this paper to show that the JSOR smoother is more robust and effective than the damped Jacobi smoother on current MIMD parallel computers.
AMS subject classification (2000) 65N55, 65Y05.Received May 2004. Revised September 2004. Communicated by Per Lötstedt.Dexuan Xie: This work was partially supported by the National Science Foundation through grant DMS-0241236. 相似文献
198.
TANG Dexiang GE Wei WANG Xiaowei MA Jingsen GUO Li & LI Jinghai Multi-phase Reaction Laboratory Institute of Process Engineering Chinese Academy of Sciences Beijing China 《中国科学B辑(英文版)》2004,47(5):434-442
Particle methods such as SPH (smoothed particlehydrodynamics)[1,2], DEM (distinct-element model)[3],DPD (dissipative particle dynamics)[4— and pseudo- 6]particle modeling (PPM)[7,8] are getting more and morepopular as numerical methods in material science andfluid dynamics, due to their flexibility in simulatingcomplicated phenomena like fluid-solid coupling,multi-phase flow and large deformation and rupture insolid materials. However, a comm… 相似文献
199.
Recently, Gill and Chien introduced a new radial quadrature for multiexponential integrands (MultiExp grid) to deal with the radial part of the numerical integration. In this article, the MultiExp grid is studied and used to integrate the charge density. The MultiExp grid, along with an optimal pruning scheme, performed very well both in terms of accuracy and efficiency compared to other radial mappings commonly used in Density Functional Theory. 相似文献
200.
LiWei Hai-liangYang 《应用数学学报(英文版)》2004,20(3):495-506
In this paper we first consider a risk process in which claim inter-arrival times and the time untilthe first claim have an Erlang (2) distribution.An explicit solution is derived for the probability of ultimateruin,given an initial reserve of u when the claim size follows a Pareto distribution.Follow Ramsay,Laplacetransforms and exponential integrals are used to derive the solution,which involves a single integral of realvalued functions along the positive real line,and the integrand is not of an oscillating kind.Then we showthat the ultimate ruin probability can be expressed as the sum of expected values of functions of two differentGamma random variables.Finally,the results are extended to the Erlang(n) case.Numerical examples aregiven to illustrate the main results. 相似文献