改进运动规律凸轮基圆半径的确定

本文针对凸轮机构推杆作改进梯形加速度、改进正弦加速度和３－４－５次多项式运动规律的情况，研究对心式盘形凸轮机构凸轮基圆半径的确定方法，并利用数值计算方法绘制了基圆半径系数β（ｒ＿０／ｈ）的线图．本文是对已有的用于四种基本运动规律确定基圆半径的诺模图￣［３］和补充诺模图［６］的进一步的发展．     

一道IMO试题的探源及启发

本文通过对一道IMO竞赛题的探索和研究，发现了此竞赛题可转化为三角形三边长的三角不等式，从而提出了一些新颖的不等式。     

关于Deutsch定理的注记

本文就任意n阶非负分块矩阵,给出了谱半径的估计公式,推广了Deutsch定理.     

求解线性互补问题的AOR算法

建立了求解线性互补问题的加速松驰迭代算法，并在一定条件下，证明了新算法的收敛性。     

Cluster analysis of massive datasets in astronomy

Clusters of galaxies are a useful proxy to trace the distribution of mass in the universe. By measuring the mass of clusters of galaxies on different scales, one can follow the evolution of the mass distribution (Martínez and Saar, Statistics of the Galaxy Distribution, 2002). It can be shown that finding galaxy clusters is equivalent to finding density contour clusters (Hartigan, Clustering Algorithms, 1975): connected components of the level set S _c ≡{f>c} where f is a probability density function. Cuevas et al. (Can. J. Stat. 28, 367–382, 2000; Comput. Stat. Data Anal. 36, 441–459, 2001) proposed a nonparametric method for density contour clusters, attempting to find density contour clusters by the minimal spanning tree. While their algorithm is conceptually simple, it requires intensive computations for large datasets. We propose a more efficient clustering method based on their algorithm with the Fast Fourier Transform (FFT). The method is applied to a study of galaxy clustering on large astronomical sky survey data.     

多源多目标环境下配送中心服务半径的确定（模型研究）

面对日益高效、快速及个性化的客户配送服务需求,配送中心服务半径的科学决策和确定十分必要。本文在分析配送中心服务半径基本含义及其影响因素的基础上,针对多源多目标环境下配送中心服务半径提出了相应的数学模型,并通过数学模型对实体环境进行模拟研究,确定了一个区域内多个配送中心配送多种商品给若干客户时的服务半径。通过本研究,旨在为配送中心服务半径的科学决策提供借鉴。     

连续梁桥平转施工过程稳定影响因素分析

如何确保桥梁平转过程的稳定是平转施工控制的关键，但目前关于桥梁平转过程中影响转体稳定因素的研究还不够系统和深入。为此，以长安高速公路微子立交桥为依托工程，建立数值分析模型，较全面地分析了转体速度、环境风速及墩高等参数对桥梁平转过程稳定的影响。研究表明：桥梁平转过程中的稳定不仅与转速和环境风速有关，而且受转体结构自振特性影响较大，因此应根据其自身结构动力特性判定其最不利的转速和环境风速，并加以避免。     

Autocontours: Dynamic Specification Testing

We propose a new battery of dynamic specification tests for the joint hypothesis of iid-ness and density function based on the fundamental properties of independent random variables with identical distributions. We introduce a device—the autocontour—whose shape is very sensitive to departures from the null in either direction, thus providing superior power. The tests are parametric with asymptotic t and chi-squared limiting distributions and standard convergence rates. They do not require a transformation of the original data or a Kolmogorov style assessment of goodness-of-fit, explicitly account for parameter uncertainty, and have superior finite sample properties. An application to autoregressive conditional duration (ACD) models for trade durations shows that the difficulty with the assumed densities lies on the probability assigned to very small durations. Supplemental materials for this article are available online.     

三维平衡轮换的多水平抽样调查设计研究综述及应用

现行的多水平抽样调查使用的各种形式的轮换模式,在西方各国均得到了广泛应用,但也存在着一系列问题。鉴此,通过对各种形式轮换模式的归纳统一和理论化综述研究,最终归纳出三维平衡多水平轮换模式设计方法,即将多水平轮换模式设计与后续的抽样估计方法研究统一起来,不但能够削减各类轮换偏差的负面影响,还能准确度量轮换样本之间的相关关系,并在多水平调查下得出更加准确的连续性抽样数据。此套设计方法具有极大的推广价值。     

Dimension Reduction in Regressions through Weighted Variance Estimation

Because sliced inverse regression (SIR) using the conditional mean of the inverse regression fails to recover the central subspace when the inverse regression mean degenerates, sliced average variance estimation (SAVE) using the conditional variance was proposed in the sufficient dimension reduction literature. However, the efficacy of SAVE depends heavily upon the number of slices. In the present article, we introduce a class of weighted variance estimation (WVE), which, similar to SAVE and simple contour regression (SCR), uses the conditional variance of the inverse regression to recover the central subspace. The strong consistency and the asymptotic normality of the kernel estimation of WVE are established under mild regularity conditions. Finite sample studies are carried out for comparison with existing methods and an application to a real data is presented for illustration.