G（3）的存在性定理及其结构规律

给出了３度平面图的两个存在性定理的简洁证明，以矩阵列举法迅速得到所有的异构类，并举例说明结论的意义．     

浅析电信运营商在3G中的经营策略

随着电信业的发展,以3G为依托的一个巨大产业链已经开始形成,并将推动、促进新的电信市场格局的构建.面对这种形势,电信运营商应当采取有效的竞争策略,主动应对、打好品牌战略、挖掘用户潜在需求、建立有效的监管机制,从而为企业营造一个可持续发展的生态环境.     

基于光纤光栅传感阵列及双目视觉的内窥镜三维显形系统的研究

内窥镜柔性杆在体内的形状显示是一种新型的技术,在这种技术的帮助下,当病人的结肠处于一种不正确的位置上或者说在进境的过程中内窥镜柔性杆的形状形成了扭曲,而形状扭曲会导致内窥镜检查的不安全性,如果预先知道这种状况的发生,就能给诊断带来安全性。本文主要研究了一种基于光纤光栅传感阵列的内窥镜柔性杆的形状及双目视觉的内窥镜镜手柄部分的姿态检测方法,这两种方法的集成构成了整个内窥镜的显形系统。详细的分析包括基于光纤光栅传感器信息的检测原理以及空间曲线重建算法,内窥镜手柄部分相对于世界坐标系的位姿估计。实验结果证明了提出方法的有效性。比较以前的研究,形状重建的精度已经提高到了4.5mm。通过加入内窥镜手柄的位姿检测,整个三维形状显示子系统变得更加有效和更实用化。     

Rate of strong uniform convergence of k-NN density estimates

Let f_n(x) be the univariate k-nearest neighbor (k-NN) density estimate proposed by Loftsgaarden and Quesenberry (1965). By using similar techniques as in Bahadur's representation of sample quantiles (1966), and by the recent results on the oscillation of empirical processes by Stute (1982), we derive the rate of strong uniform convergence of f_n(x) on some suitably chosen interval J_δ. Some comparison with the kernel estimates is given, as well as the choice of the bandwidth sequence relative to the sample size.     

Non-parametric recursive estimates of a probability density function and its derivatives

Recursive estimates of a probability density function (pdf) are known. This paper presents recursive estimates of a derivative of any desired order of a pdf. Let f be a pdf on the real line and p?0 be any desired integer. Based on a random sample of size n from f, estimators f^(p)_n of f^(p), the pth order derivatives of f, are exhibited. These estimators are of the form $\text{n}{}^{\mathrm{?1}}\text{∑n}\text{j=1}\text{δ}{}_{\mathrm{jp}}$, where δ_jp depends only on p and the jth observation in the sample, and hence can be computed recursively as the sample size increases. These estimators are shown to be asymptotically unbiased, mean square consistent and strongly consistent, both at a point and uniformly on the real line. For pointwise properties, the conditions on f^(p) have been weakened with a little stronger assumption on the kernel function.     

The ideological context of child welfare

This paper examines consequences for child development and well-being of the prevailing institutional order and ideology of the United States and concludes that child development in our country is severely obstructed because of socially structured violence which permeates our way of life. The paper ends with comments on prospects for social transformation which seems necessary to assure the development and well-being of every child.     

Rank-order tests for the parallelism of several regression surfaces

For testing the hypothesis that several (s?2) linear regression surfaces X_ki=α_k+β_kc_ki+Z_ki (k=1,…,s) are parallel to one another, i.e., β₁=?=β_s, a class of rank-order tests are considered. The tests are shown to be asymptotically distribution-free, and their asymptotic efficiency relative to the general likelihood ratio test is derived. Asymptotic optimality in the sense of Wald is also discussed.     

Binary-image restoration

We consider the problem of binary-image restoration. The image being restored is not random, and we make no assumption about the nature of its contents. The estimate of the colour at each site is a fixed (the same for all sites) function of the data available in a neighbourhood of that site. Under this restriction, the estimate minimizing the overall mean squared error of prediction is the conditional expectation of the true colour given the observations in the neighbourhood of a site. The computation of this conditional expectation leads to the formal definition of the local characteristics of an image, namely, the frequency with which each pattern appears in the true unobserved image. When the “true” distribution of the patterns is unknown, it can be estimated from the records. The conditional expectation described above can then be evaluated using the estimated distribution of the patterns, and this procedure leads to a very natural estimate of the colour at each site. We propose two unbiased and consistent estimates for the distribution of patterns when the noise is a Gaussian white noise. Since the size of realistic images is very large, the estimated pattern distribution is usually close to the true one. This suggests that the estimated conditional expectation can be expected to be nearly optimal. An interesting feature of the proposed restoration methods is that they do not require prior knowledge of the local or global properties of the true underlying image. Several examples based on synthetic images show that the new methods perform fairly well for a variety of images with different degrees of colour continuity or textures.     

On nonparametric profile analysis of several multivariate samples

A unified development is offered for asymptotically distribution-free profile analysis of several multivariate samples. This includes as special cases procedures based on generalized U-statistics and also those based on linear rank statistics. Furthermore, it includes as special cases analysis of location profiles and also scalar profiles. Finally, asymptotic power and consistency properties are discussed for tests of hypotheses and subhypotheses of interest.     

A class of tests for testing ‘new is better than used’

A class of tests is proposed for testing H₀ F?(x) = e^?λx, λ > 0, x≥0 vs. H₁ F?(x + y) ≤ F?(x)F?(y), x, y≥0, with strict inequality for some x, y ≥ 0 (F = new is better than used). Efficiency comparisons of some tests within the class are made and a new test is proposed on the basis of these comparisons. Consistency and the asymptotic normality of the class of tests is proved under fairly broad conditions on the underlying entities.