On accelerating sequential procedures for estimating exponential populations

In this study, we accelerate the purely sequential procedure due to Anscombe(1953), Chow and Robbins(1965) to reduce the number of sampling operations required to carry out the estimation process. The method is proposed while estimating the location parameter(s) of the exponential distribution(s). We also develop theory for the asymptotic characteristic of the associated stopping variables. Our findings are applicable to both point as well as confidence interval estimation problems. Other interesting results are also given.     

Bayesian estimation of parameters of mixed geometric failure models from Type I group censored sample

The estimation problem of the parameters of a mixed geometric lifetime model, using Bayesian approach and Type I group censored sample, will be investigated in the case of two subpopulations. The Bayes estimates are derived for squared error, minimum expected, general entropy and linex loss functions under informative and diffuse priors. A practical example given by Nelson (W.B. Nelson, Hazard plotting methods for analysis of the life data with different failure models, J. Qual. Technol. 2 (1970), pp. 126–149) is considered. A simulation study is carried out along with risk.     

Efficiency of lattice conditional independence models for multinormal samples with non-monotone missing data

For multivariate normal data with non-monotone (i.e. arbitrary) missing data patterns, lattice conditional independence (LCI) models determined by the observed data patterns can be used to obtain closed-form MLEs (Andersson and Perlman, 1991, 1993). In this paper, three procedures — LCI models, the EM algorithm, and the complete-data method — are compared by means of a Monte Carlo experiment. When the LCI model is accepted by the LR test, the LCI estimate is more efficient than those based on the EM algorithm and the complete-data method. When the LCI model is not accepted, the LCI estimate may lose efficiency but still may be more efficient than the EM estimate if the observed data is sparse. When the LCI model appears too restrictive, it may be possible to obtain a less restrictive LCI model by.discarding only a small portion of the incomplete observations. LCI models appear to be especially useful when the observed data is sparse, even in cases where the suitability of the LCI model is uncertain.     

EDITOR's NOTES

Abstract

Over the past 20 years investigators have explored the incidence, experience, and extent of grieving following miscarriage for heterosexual partnered women and, to some degree, for men. Prior investigations confirm an increase in disturbed emotions following unexpected pregnancy loss and suggest a variety of predisposing social and obstetrical factors that lead to such responses. Little is known, however, about the ways in which lesbian women experience and respond to miscarriage. An argument is made that given the increased number of lesbian women attempting pregnancy through alternative methods of conception, research is warranted that explores their experiences and potentially unique caring needs following miscarriage.     

Construction of stationary state distributions for loss systems

A stationary state distribution will be constructed for a loss system G/G/m/0 without additional restrictive conditions. It will be shown by examples that for a given input there may exist several stationary state distributions. A sufficient and necessary criterion for the uniqueness will be formulated.     

天气指数农业保险探究——以河北省农村为例

近年世界范围内极端天气事件频繁发生，对粮食安全造成了重大威胁。利用金融创新工具应对天气灾害，保障粮食安全成为国际研究的热点问题。为了解天气指数农业保险的需求情况，对河北省正定县和灵寿县40个行政村的400个农户进行了调查问卷。调查结果显示，一旦爆发天气灾害，大多数农民依靠储蓄、抵押贷款、紧急贷款、社会援助或亲属救济来恢复灾后生产与建设，但很多农民已经表示了对天气指数农业保险的极大兴趣；对那些熟悉保险的农户和容易遭受洪涝和干旱天气的农户进行相关分析，结果证明了这类群体对于天气指数农业保险的兴趣更加浓厚。     

Intergenerational Yearnings and Other “Acts of Perversion”: Or Where Would I Be Without Lesbian Drumming?

This article explores the (il)legibilities of race, gender, sexuality, and interracial solidarity between two feminist generations. Using the words of Judy Grahn and Pat Parker, the author juxtaposes her own experience and writings as a queer, Black, feminist, born in 1971 with their dyke, feminist writings of the same period, asking “Where Would I Be, Without You?” Central to this question is a queer re-imagining of queer past and future in an effort to understand the potential for interracial, feminist solidarity in the twenty-first century.     

Efficiency of the generalized difference-based Liu estimators in semiparametric regression models with correlated errors

In this paper, a generalized difference-based estimator is introduced for the vector parameter β in the semiparametric regression model when the errors are correlated. A generalized difference-based Liu estimator is defined for the vector parameter β in the semiparametric regression model. Under the linear nonstochastic constraint Rβ=r, the generalized restricted difference-based Liu estimator is given. The risk function for the β?_GRD(η) associated with weighted balanced loss function is presented. The performance of the proposed estimators is evaluated by a simulated data set.     

An Objective Bayesian Criterion to Determine Model Prior Probabilities

We discuss the problem of selecting among alternative parametric models within the Bayesian framework. For model selection problems, which involve non‐nested models, the common objective choice of a prior on the model space is the uniform distribution. The same applies to situations where the models are nested. It is our contention that assigning equal prior probability to each model is over simplistic. Consequently, we introduce a novel approach to objectively determine model prior probabilities, conditionally, on the choice of priors for the parameters of the models. The idea is based on the notion of the worth of having each model within the selection process. At the heart of the procedure is the measure of this worth using the Kullback–Leibler divergence between densities from different models.     

社会生活中主体有德行为选择的可能性分析

实现道德选择中的有德行为是社会有序化的关键。有德行为是对他人和社会有道德价值的选择行为。其内涵包括主体的意志自由、利于人的意识和利于人的事实,其实质是主体的道德修养和对时下情景的正确判断。主体的意志不自由、多重道德价值评价的存在、道德价值之间的冲突等,会带来主体有德选择的困境。因此,合理的社会舆论、面对多重评价时坚持“价值量大小”的优先序列原则,以及发生价值间冲突时坚持“底线伦理至上”的原则,可以使主体走出有德选择的困境,实现有德行为。