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31.
ADAPTIVE MESHLESS METHOD BASED ON LOCAL FIT TECHNOLOGY 总被引:1,自引:0,他引:1
LouLuliang ZengPan 《Acta Mechanica Solida Sinica》2005,18(2):164-172
An h-adaptive meshless method is proposed in this paper. The error estimation is based on local fit technology, usually confined to Voronoi Cells. The error is achieved by comparison of the computational results with smoothed ones, which are projected with Taylor series. Voronoi Cells are introduced not only for integration of potential energy but also for guidance of refinement.New nodes are placed within those cells with high estimated error. At the end of the paper, two numerical examples with severe stress gradient are analyzed. Through adaptive analysis accurate results are obtained at critical subdomains, which validates the efficiency of the method. 相似文献
32.
Developing chemicals that inhibit checkpoint kinase 1 (Chk1) is a promising adjuvant therapeutic to improve the efficacy and selectivity of DNA-targeting agents. Reliable prediction of binding-free energy and binding affinity of Chk1 inhibitors can provide a guide for rational drug design. In this study, multiple docking strategies and Prime/Molecular Mechanics Generalized Born Surface Area (Prime/MM-GBSA) calculation were applied to predict the binding mode and free energy for a series of benzoisoquinolinones as Chk1 inhibitors. Reliable docking results were obtained using induced-fit docking and quantum mechanics/molecular mechanics (QM/MM) docking, which showed superior performance on both ligand binding pose and docking score accuracy to the rigid-receptor docking. Then, the Prime/MM-GBSA method based on the docking complex was used to predict the binding-free energy. The combined use of QM/MM docking and Prime/MM-GBSA method could give a high correlation between the predicted binding-free energy and experimentally determined pIC(50) . The molecular docking combined with Prime/MM-GBSA simulation can not only be used to rapidly and accurately predict the binding-free energy of novel Chk1 inhibitors but also provide a novel strategy for lead discovery and optimization targeting Chk1. 相似文献
33.
Jean-Louis Féménias 《Journal of Molecular Spectroscopy》2005,232(1):80-101
Applications of the χ2 test, the F test, the Durbin-Watson d test, and the f (or Sign) test, to examples of correlated data treatment, show important drawbacks with the d test and (apparently) with the f test. An analytical approach based on residual analysis suggests an improvement in their use that leads to better results at lowest order; it also points out a distinction between goodness-of-fit tests, as the f test, and goodness-of-modeling tests, as the χ2 and F tests. The residual analysis method is applied to the same examples; it looks faster, simpler, and often more accurate than the classical ones. 相似文献
34.
35.
非圆截面环流器FY-1实验(Ⅰ)——被动运行部分 总被引:1,自引:1,他引:0
本文简略地描述了FY-1装置结构、等离子体基本参数的测量和等离子体位形的调试,初步考察了硬X射线产额与工作气压的关系。实验分析表明,FY-1装置已形成的等离子体环流放电属于逃逸放电。在场成形线圈作被动运行时,通过改变其回路连接方式和外串电感值,可适当调节等离子体平衡位置和位形。MHD平衡计算与实验测量拟合结果表明,等离子体截面可调节为不同截面积和拉长比(k=1.1—1.4)的椭圆。 相似文献
36.
D. Zwick 《Advances in Computational Mathematics》1994,2(4):375-391
We characterize the solution of the following problem and describe an algorithm for numerically solving it. Two sets ofN points in the plane, labeled 1,...,N, are given: a fixed set of nominal points and a set of measured points. We wish to transform the messured points as a whole,
by translation and rotation, so that the maximal distance between corresponding points in the two sets is minimized. This
algorthm provides an accept-reject criterion that may be used together with a coordinate measuring machine to determine if
two mating parts will fit, or if a part is sufficiently close to its ideal measurements. A weighted version, suitable for
point-dependent tolerances, is also discussed, as is optimal joint scalling of the data. 相似文献
37.
38.
关于正态分布的等距分组 总被引:1,自引:0,他引:1
一组数据进行等距分组,到底分多少组?美国人斯特.杰斯(sturges)给出经验公式:n=1+3.322lgN又有a=R/n=R/1+3.322lgN.这里n-组数,N-单位数a-组距,R-全距,a的确定,经验公式远远不够,只能作参考.为此对正态分布进行研究.得到下列结果:1)一组数据,计算均值μ及方差σ~2,得出似合密度,由a与σ~2关系.得出a的上界公式.2)给出找出a的算法.这个算法,简单实用且用途广泛. 相似文献
39.
This study sets out a framework to evaluate the goodness of fit of stochastic mortality models and applies it to six different models estimated using English & Welsh male mortality data over ages 64-89 and years 1961-2007. The methodology exploits the structure of each model to obtain various residual series that are predicted to be iid standard normal under the null hypothesis of model adequacy. Goodness of fit can then be assessed using conventional tests of the predictions of iid standard normality. The models considered are: Lee and Carter’s (1992) one-factor model, a version of Renshaw and Haberman’s (2006) extension of the Lee-Carter model to allow for a cohort-effect, the age-period-cohort model, which is a simplified version of the Renshaw-Haberman model, the 2006 Cairns-Blake-Dowd two-factor model and two generalized versions of the latter that allow for a cohort-effect. For the data set considered, there are some notable differences amongst the different models, but none of the models performs well in all tests and no model clearly dominates the others. 相似文献
40.
A convertible bond is a security that the holder can convert into a specified number of underlying shares. We enrich the standard model by introducing some default risk of the issuer. Once default has occured payments stop immediately. In the context of a reduced form model with infinite time horizon driven by a Brownian motion, analytical formulae for the no-arbitrage price of this American contingent claim are obtained and characterised in terms of solutions of free boundary problems. It turns out that the default risk changes the structure of the optimal stopping strategy essentially. Especially, the continuation region may become a disconnected subset of the state space. 相似文献