具有非负密度的粘性不可压缩流体运动的初边值问题的广义解的唯一性

本文讨论了一类具有非负密度的不可压缩流体运动的初边值问题,用积分估值法证明了这一模型广义解的唯一性.     

On the Bootstrap of the Maximum Score Estimator

This paper shows that the bootstrap does not consistently estimate the asymptotic distribution of the maximum score estimator. The theory developed also applies to other estimators within a cube‐root convergence class. For some single‐parameter estimators in this class, the results suggest a simple method for inference based upon the bootstrap.     

Statistical inference for start-up demonstration tests with rejection of units upon observing d failures

In this paper, we consider the statistical inference for the success probability in the case of start-up demonstration tests in which rejection of units is possible when a pre-fixed number of failures is observed before the required number of consecutive successes are achieved for acceptance of the unit. Since the expected value of the stopping time is not a monotone function of the unknown parameter, the method of moments is not useful in this situation. Therefore, we discuss two estimation methods for the success probability: (1) the maximum likelihood estimation (MLE) via the expectation-maximization (EM) algorithm and (2) Bayesian estimation with a beta prior. We examine the small-sample properties of the MLE and Bayesian estimator. Finally, we present an example to illustrate the method of inference discussed here.     

双重分层抽样中的校正估计

校正估计法已被大量运用于抽样调查中,它利用辅助信息构造的校正权重提高了对总体总值（或均值）的估计精度。本文提出了分层抽样中的校正组合比率估计量,并推广到分层双重抽样中。同时给出新估计量的近似方差表达式。最后利用计算机随机模拟验证较正估计量对估计精度的改进。     

基于平衡单水平轮换的连续性抽样估计方法研究

内容提要：针对现存的各种单水平轮换模式和估计方法,本文提出一套统一的平衡单水平轮换模式。在此轮换模式下,引入两类相关关系,运用线性无偏估计方法,并通过使不同类型估计量方差的加权总和最小的方法确定最优系数,从而得到最优线性无偏估计量,不仅能够减少甚至消除估计量偏差的影响,还能使得连续性调查的整体抽样误差最小,适合估计各种类型的估计量。     

Efficient estimation for the proportional hazards model with bivariate current status data

We consider efficient estimation of regression and association parameters jointly for bivariate current status data with the marginal proportional hazards model. Current status data occur in many fields including demographical studies and tumorigenicity experiments and several approaches have been proposed for regression analysis of univariate current status data. We discuss bivariate current status data and propose an efficient score estimation approach for the problem. In the approach, the copula model is used for joint survival function with the survival times assumed to follow the proportional hazards model marginally. Simulation studies are performed to evaluate the proposed estimates and suggest that the approach works well in practical situations. A real life data application is provided for illustration.     

Loaning Supplementary Benefit and the Introduction of the Social Fund

This paper discusses an episode in social security policy making that has until now remained unexplored. This is the review, at the request of then Labour Secretary of State for Social Services, Richard Crossman MP, in the latter months of 1969 and early 1970 into the possibility of introducing loans to the Supplementary Benefit system as a replacement for some exceptional needs and exceptional circumstances payments. The paper examines files held at the National Archives to discuss the nature and extent of the proposed scheme and the objections of civil servants to loaning Supplementary Benefit. The paper demonstrates how the worst‐case scenario outlined by civil servants in 1970 was introduced some 15 years later as Social Fund loans. The paper then discusses economic, ideological and social change that provided the context for the introduction of loans as part of the Social Fund in the 1980s.     

剩磁法估测三相交流异步电动机转速的分析

介绍一种用剩磁法估测三个交流异步电动机转速的新方法,并就这种方法的有关问题进行了初步分析。     

Improving coverage accuracy of nonparametric prediction intervals

Methods are suggested for improving the coverage accuracy of intervals for predicting future values of a random variable drawn from a sampled distribution. It is shown that properties of solutions to such problems may be quite unexpected. For example, the bootstrap and the jackknife perform very poorly when used to calibrate coverage, although the jackknife estimator of the true coverage is virtually unbiased. A version of the smoothed bootstrap can be employed for successful calibration, however. Interpolation among adjacent order statistics can also be an effective way of calibrating, although even there the results are unexpected. In particular, whereas the coverage error can be reduced from O ( n ^-1) to orders O ( n ^-2) and O ( n ^-3) (where n denotes the sample size) by interpolating among two and three order statistics respectively, the next two orders of reduction require interpolation among five and eight order statistics respectively.     

公司促销费用的最优估计

一个公司究竟需要多少促销费用,才能达到预期的促销效果,本文认为公司处在不同发展阶段和不同市场,应具有不同的促销费用,并运用定性与定量相结合的分析方法讨论了成长型公司促销费用的最优估计问题。