On the construction of multivariate permutation tests in the two–sample case

This paper is concerned with multivariate generalizations of two–sample rank tests, the bivariate Wilcoxon test in particular.     

温压战斗部爆炸冲击波毁伤小子样试验鉴定分析

针对温压战斗部爆炸冲击波毁伤的试验鉴定问题,提出冲击波毁伤的试验鉴定即为对毁伤参数所服从分布以及分布参数的统计推断问题,并进一步给出温压战斗部毁伤小子样试验鉴定的基本思路,重点对利用Bayes理论开展统计推断的方法进行了研究,介绍了两种验前分布的求取方法,并对Bayes估计理论进行了深入探讨,介绍了点估计和区间估计求取的具体方法。     

Optimal Estimation of the Parameters of the Gompertz Distribution Based on the Doubly Type II Censored Sample

In this paper, we develop exact confidence intervals and exactjoint confidence regions for the parameters of the Gompertzdistribution under the doubly type II censored sample. We alsoprovide optimal criteria for finding a best exact confidenceinterval and a best exact joint confidence region among theseinterval estimations. Finally, we give a numerical example toillustrate our proposed method. Furthermore,when compared to estimation of Chen (1997), our proposedmethod can get a better parameter estimation.     

浅谈粮食样品检测过程中的注意事项

粮食质量检验是粮食工作的重要组成部分,提高检测结果的准确性为保障人民群众吃上安全放心的粮食提供重要的依据。本文在多年粮食检测工作的基础上,对粮食检测过程中应注意的事项进行总结分析,为确保粮食质量检验结果的准确性提出浅显的见解。     

The Effect of Sample Size on the Mean Efficiency in DEA with an Application to Electricity Distribution in Australia,Sweden and New Zealand

This study examines the effect of sample size on the mean productive efficiency of firms when the efficiency is evaluated using the non-parametric approach of Data Envelopment Analysis. By employing Monte Carlo simulation, we show how the mean efficiency is related to the sample size. The paper discusses the implications for international comparisons. As an application, we investigate the efficiency of the electricity distribution industries in Australia, Sweden and New Zealand.     

A Measure of Representativeness of a Sample for Inferential Purposes

After defining the concept of representativeness of a random sample, the author proposes a measure of how much the observed sample represents its parent distribution. This measure is called Representativeness Index. The same measure, seen as a function of a sample and of a distribution, will be called Representativeness Function. For a given sample it provides the value of the index for the different distributions under examination, and for a given distribution it provides a measure of the representativeness of its possible samples. Such Representativeness Function can be used in an inferential framework just as the likelihood function, since it gives to any distribution the "experimental support" provided by the observed sample. This measure is distribution-free and it is shown to be a transformation of the wellknown Cramér–von Mises statistic. By using the properties of that statistic, criteria for providing set estimators and tests of hypotheses are introduced. The utilization of the representativeness function in many standard statistical problems is outlined through examples. The quality of the inferential decisions can be assessed with the usual techniques (MSE, power function, coverage probabilities). The most interesting examples turn out to be those of situations that are "non-regular", as for instance the estimation of parameters involved in the support of the parent distribution, or less explored (model choice).     

确定进口固体肥料份样数的方法

对确定进口固体肥料份样数的方法进行了初步探讨，提出并论了检验进口固体肥料的一般风险。     

首件封样作业法

文章提出了一种新的作业管理方法。此方法以首件加工的产品作为封样,确定批次产品的实物检验标准,以此规范操作者、质检员、工艺技术员、设备维修工、生产管理人员等生产过程诸影响因素的行为,以促进产品质量和工作质量的整体提升。     

小子样地铁备件需求量的贝叶斯预测模型改进研究

地铁备品备件的需求量预测有利于备件储备决策质量的提高,但是大量少样本备件的需求量预测不能采用常规的统计方法,经典贝叶斯预测模型有效利用先验信息进行预测,但是需要较多的数据,操作复杂,结果误差值较大。文章基于样本数据,通过实验的方式调整贝叶斯预测模型参数的计算方法,降低了数据要求,简化了贝叶斯模型操作的复杂程度,也提高了预测的精确度,在一定程度上提高了地铁备件管理的效率。     

岩矿样中金元素测定方法的进展

金在矿石中大多数以单质形式存在,常与各种矿物或矿石伴生,以金为主的矿石也常常伴生着银、锑、砷、铁、硫、碳等,目前,测定矿石中金含量的方法很多,本文就近代岩矿中金元素的测试分析技术作了较为全面的介绍,并综合总结了其优缺点。     

The Effect of Sample Size on the Mean Efficiency in DEA: Comment

Zhang and Bartels (1998) show formallyhow DEA efficiency scores are affected by sample size. They demonstratethat comparing measures of structural inefficiency between samplesof different sizes leads to biased results. This note arguesthat this type of sample size bias has much wider implicationsthan suggested by their example. Models which implicitly restrictthe comparison set like some models for non-discretionary variableslead to biased efficiency scores as well. A reanalysis of theBanker and Morey (1986b) data shows that the efficiency scoresderived there are significantly influenced by the variation insample size implicit in their model.     

抽样定理的System View仿真与实现

通过分析SystemView仿真软件的优势及主要的功能模块库和应用领域,重点通过通信系统中的抽样定理实例介绍了该软件的使用方法及注意事项。最后,总结该软件的教学应用效果及对相关课程教学的借鉴作用,特别适合通信系统的仿真与设计。     

小样本条件下的煤矿安全评价方法研究

研究煤矿安全评价问题的现状,针对传统的BP神经网络要获得可信度较高的评价模型需要大量的样本进行学习的缺点,采用V—fold Cross—validation技巧,利用MATLAB神经网络工具箱,建立基于BP神经网络的煤矿安全评价模型,利用实际指标数据研究小样本条件下的煤矿安全评价,并验证评价效果的有效性。     

Bartlett correction in the stable second‐order autoregressive model with intercept and trend

This paper derives the Bartlett factors that can be used to obtain higher‐order improvements for testing hypotheses about the autoregressive (AR) parameters in the stable AR(2) model with possible intercept and linear trend. The factors are obtained for testing hypotheses about individual parameters (φ₁ and φ₂) as well as their sum. Moreover, the effect of deterministic terms on the correction factors is found explicitly. All corrections are non‐decreasing in the AR parameters. Furthermore, the Bartlett corrections for φ₁ and φ₂ tend to infinity as φ₂ approaches 1, whereas the correction for φ₁ + φ₂ tends to infinity as φ₁ + φ₂ is close to 1. The effectiveness of these Bartlett corrections in finite samples is evaluated by simulations.     

变样本容量比例控制图设计及应用

针对单边休哈特比例控制图失控状态下平均报警时间长的问题,提出一种单边变样本容量比例控制图来监控两个正态变量间比例的偏移。采用马尔可夫链方法计算了该控制图的平均运行链长。在保证过程处于受控状态的统计性能基础上,使失控状态下的平均运行链长最小,从而获得控制图的最优决策变量和最优性能指标。仿真结果表明,单边变样本容量比例控制图的性能明显优于单边休哈特比例控制图。最后将该方法应用于港口皮带机配煤比例监控的问题,通过仿真实验说明了该方法能够对煤炭配比过程中的比例偏移做出有效反应。     

对产品样本容量的确定及模拟抽样的方法探讨

在一定精度的要求下,对产品合格率试验中样本容量的计算应用参数估计中的贝叶斯方法进行研究,并对贝叶斯估计方法与矩估计法作一比较,目的是为了减少用作实验的样本容量,并介绍如何使用利用计算机模拟实验抽样检验,确定样本容量的方法。     

Interval Estimation for the Two-Parameter Exponential Distribution Based on the Doubly Type II Censored Sample

The interval estimation of the scale parameter and the joint confidence region of the parameters of two-parameter exponential distribution under doubly Type II censoring is proposed. In addition, the simulation study for the performance of our methods is done in this paper. One biometrical example is also given to illustrate the proposed methods.     

移动商务与物流配送衔接策略探究——以京东商城为例

本文通过以京东商城为例,提出京东商城的移动商务与物流配送在配套合作中所采取的策略及存在的问题,分析其原因。旨在解决对于发展移动商务业务的企业,如何做好企业与物流配送的最优策略选择,增强企业竞争力。     

One-Sample Bayesian Predictive Interval of Future Ordered Observations for the Pareto Distribution

Nigm et al. (2003, statistics 37: 527–536) proposed Bayesian method to obtain predictive interval of future ordered observation Y _(j) (r < j≤ n ) based on the right type II censored samples Y ₍₁₎ < Y ₍₂₎ < ... < Y _(r) from the Pareto distribution. If some of Y ₍₁₎ < ... < Y _(r-1) are missing or false due to artificial negligence of typist or recorder, then Nigm et al.’s method may not be an appropriate choice. Moreover, the conditional probability density function (p.d.f.) of the ordered observation Y _(j) (r < j ≤ n ) given Y ₍₁₎ <Y ₍₂₎ < ... < Y _(r) is equivalent to the conditional p.d.f. of Y _(j) (r < j ≤ n ) given Y _(r). Therefore, we propose another Bayesian method to obtain predictive interval of future ordered observations based on the only ordered observation Y _(r), then compares the length of the predictive intervals when using the method of Nigm et al. (2003, statistics 37: 527–536) and our proposed method. Numerical examples are provided to illustrate these results.