Multi-phase sampling under cost constraints

Multi-phase sampling (M-PhS) scheme is useful when the interest is in the estimation of the population mean of an expensive variable strictly connected with other cheaper (auxiliary) variables. The MSE is an accuracy measure of an estimator. Usually it decreases as the sample size increases. In practice the sample size cannot become arbitrarily large for possible cost constraints. From a practical point of view it would be useful to know the sample sizes which guarantee the best accuracy of the estimates for fixed costs. These “optimum” sample sizes can be, in some cases, computable but not admissible. In other cases, they can be neither admissible nor computable. The main goal of this paper is to propose a solution for both these situations. It will be clear that in both situations the solution is to consider a M-PhS scheme with one or more phases less.     

H-likelihood: problems and solutions

In recent issues of this journal it has been asserted in two papers that the use of h-likelihood is wrong, in the sense of giving unsatisfactory estimates of some parameters for binary data (Kuk and Cheng, 1999; Waddington and Thompson, 2004) or theoretically unsound (Kuk and Cheng, 1999). We wish to refute both these assertions.     

Nonconglomerative coherent conditional probabilities in statistical inference

Noteworthy connections among conglomerability, countable additivity and coherence are discussed in detail, reaching the conclusion that nonconglomerable conditional probabilities must not be doomed and play a significant role in statistical inference. Extended and updated version of a contributed paper presented at the International Conference on “Information Processing and Management of Uncertainty in knowledge-based systems”, IPMU 2004, Perugia, Italy.     

项目风险分析与管理

本文在分析比较传统风险分析方法的基础上,提出了一个更为有效的风险分析方法,即“交叉分析-蒙特卡罗模拟”综合模型。并利用此模型对H集团的某技改投资项目进行了案例分析。在此基础上,提出了建立项目风险防范预警系统的风险管理模式。     

四川盆地西北部蕈菌资源

1986年以来在四川盆地西北部采集到205种草菌,其中包括省内新记录种60种,国内新记录种4种。根据G.C.Ainsworth等(1973)的分类系统分类并命名。所有标本保藏在四川锦阳农业专科学校真菌标本室。     

股份制改革是增强国营企业活力创造“深圳效益”的重要途径

本文分析了深圳特区前10年经济高速发展和经济效益滞后的矛盾,认为特区国营企业经济效益不高是影响特区经济效益严重滞后的主要原因之一。在此基础上,提出深圳特区要在90年代创造出“深圳效益”,必须在已取得的改革成果的基础上,加快国营企业股份制改革的进程。文章还从股份制改革的理论和实践两个方面阐述了特区国营企业股份制改革的可行性和必要性。     

隆线溞(Daphnia carinata king)的呼吸代谢测定

本文用Winkler法测定隆线溞(Caphnia carinata king)不同龄期个体的耗氧量及二幼龄个体在不同温度下的耗氧量。测得幼龄与成龄两阶段,其耗氧量分别以4.88×10~(-2)与1.695×10~(-1)的速率随体重增加而增大,耗氧率则分别随体重的增加而逐渐降低;在常温下,隆线溞耗氧量Y与温度X呈Y=3.69×10~(-3)×1.07~x的指数函数关系,由此得到,17℃—19℃是隆线搔生长速率快而耗氧量较小的最适人工培养温度。     

六端口技术自校准方法解的不唯一性证明

本文就六端口技术自校准方法进行了分析讨论,用解析方法和计算机模拟方法分别证明了自校准方法解的不唯一性.从而否定了自校准方法是六端口技术最突出的优点之一这个传统概念.     

离心式叶轮机任意旋成面栅后区长度处理

文章揭示了叶轮栅后区长度L_3太长时,会使栅后区出气角β_2无法选择而造成无解的事实;表明在β_2变化的适当范围内,叶型后缘两侧速度差△Λ与β_2之间呈线性关系,而且该线性变化范围随L_3的增长而缩小;获得了随L_3作线性变化的规律。文章最后提出了离心式叶轮机任意旋成面叶栅流场的简单求解方法。     

回旋管及回旋潘尼管的动力学理论

本文发展了目前回旋管的动力学理论。用动力学方法,描述了回旋潘尼管的不稳定性机理,求解了偶极电流。这样,本文提出的理论,不仅可以更为精确地描写回旋管,而且可以描写新近出现的回旋潘尼管。