Visualization of generalized mean estimators using auxiliary information in survey sampling

Abstract

The mean estimators with ratio depend on multiple auxiliary variables and unknown parameters in a finite population setting. We propose a new generalized approach with matrices for modeling the mutivariate mean estimators with two auxiliary variables. Our approach brings naturally a graphical analysis for comparing mean estimators.     

商业银行个人金融服务的国际比较

目前,我国商业银行以代发工资、代收费等业务为突破口,已开发了近40个品种的个人金融服务业务。谁能提供更快捷、方便的金融服务,谁就会拥有更多的客户。进一步的对外开放,个人金融服务的巨大市场是中外银行竞争的焦点。个人金融服务市场从以往简单地通过银行储蓄存款获得利息并保障安全,已跳跃到支付结算、外汇买卖、临时透支、贷款融资、经营投资和综合理财等全方位、多层次的服务。这些对国内各家商业银行拓展个人金融服务提出了巨大的机遇和挑战。     

On the Convergence of the Monte Carlo Maximum Likelihood Method for Latent Variable Models

While much used in practice, latent variable models raise challenging estimation problems due to the intractability of their likelihood. Monte Carlo maximum likelihood (MCML), as proposed by Geyer & Thompson (1992 ), is a simulation-based approach to maximum likelihood approximation applicable to general latent variable models. MCML can be described as an importance sampling method in which the likelihood ratio is approximated by Monte Carlo averages of importance ratios simulated from the complete data model corresponding to an arbitrary value of the unknown parameter. This paper studies the asymptotic (in the number of observations) performance of the MCML method in the case of latent variable models with independent observations. This is in contrast with previous works on the same topic which only considered conditional convergence to the maximum likelihood estimator, for a fixed set of observations. A first important result is that when is fixed, the MCML method can only be consistent if the number of simulations grows exponentially fast with the number of observations. If on the other hand, is obtained from a consistent sequence of estimates of the unknown parameter, then the requirements on the number of simulations are shown to be much weaker.     

钢纤维混凝土基本性能试验研究

通过对30个立方体试块抗压强度试验,分析了钢纤维对普通混凝土的增强作用;通过对30个小梁试件三分点加载抗折试验,研究了体积率对钢纤维混凝土(SFRC)荷载-挠度关系及荷载-极限应变关系的影响.在脆性基体中掺入钢纤维,有效地提高了复合材料承受荷载时阻止裂缝引发与扩展的能力,达到对混凝土的增强效果,尤其是对于抗折强度的增强作用,使混凝土的破坏形式由脆性破坏变为塑性破坏.     

Empirical likelihood confidence intervals for the mean of a population containing many zero values

If a population contains many zero values and the sample size is not very large, the traditional normal approximation‐based confidence intervals for the population mean may have poor coverage probabilities. This problem is substantially reduced by constructing parametric likelihood ratio intervals when an appropriate mixture model can be found. In the context of survey sampling, however, there is a general preference for making minimal assumptions about the population under study. The authors have therefore investigated the coverage properties of nonparametric empirical likelihood confidence intervals for the population mean. They show that under a variety of hypothetical populations, these intervals often outperformed parametric likelihood intervals by having more balanced coverage rates and larger lower bounds. The authors illustrate their methodology using data from the Canadian Labour Force Survey for the year 2000.     

双波长比值法测定氯硝基苯异构体的含量

依据邻、间、对氯硝基苯三组分的比值光谱特征，以间氟硝基苯为参比组分，选择219nm、232nm和244nm、297nm作为邻氯硝基苯和对氯硝基苯的测定波长；以对氯硝基苯为参比组分．选择253nm、325nm作为间氟硝基苯的测定波长．测定邻、间、对氯硝基苯混合样品中三组分含量，结果显示。邻氯硝基苯在（3．73～74．34）mg／L，间氯硝基苯在（1．58～105．1）mg／L，对氯硝基苯在（0．36-107．1）mg／L范围具有良好的线性关系．回收率均在95．0％～110．0％之间．本法具有测定波长少、计算简单、光谱“分离”能力强。易于推广等特点．     

先进制造业基本特征刍议

本文结合当今先进制造业已具备的几个基本特征分析了我国制造业发展中存在的一些问题 ,并对如何解决这些问题提出了自己的观点与见解     

Adaptive tests of regression functions via multiscale generalized likelihood ratios

Many applications of nonparametric tests based on curve estimation involve selecting a smoothing parameter. The author proposes an adaptive test that combines several generalized likelihood ratio tests in order to get power performance nearly equal to whichever of the component tests is best. She derives the asymptotic joint distribution of the component tests and that of the proposed test under the null hypothesis. She also develops a simple method of selecting the smoothing parameters for the proposed test and presents two approximate methods for obtaining its P‐value. Finally, she evaluates the proposed test through simulations and illustrates its application to a set of real data.     

Interpreting DNA Mixtures with Related Contributors in Subdivided Populations

Abstract.  In this paper, we study the statistical interpretation of forensic DNA mixtures with related contributors in subdivided populations. Compact general formulae for match probabilities are obtained for two situations: a relative of one tested person is an unknown contributor of a DNA mixture; and two related unknowns are contributors. The effect of kinship and population structure is illustrated using a real case example.     

以核心竞争力为导向的企业并购策略研究

对在市场经济条件下企业核心竞争力形成的途径之一———并购进行研究。从并购企业的目标选择到具体实现并购以及并购后的整合等进行分析,指出并购是公司构筑核心竞争力的必由之路。