Revisiting retesting in the estimation of proportions by group testing

In the estimation of a proportion p by group testing (pooled testing), retesting of units within positive groups has received little attention due to the minimal gain in precision compared to testing additional units. If acquisition of additional units is impractical or too expensive, and testing is not destructive, we show that retesting can be a useful option. We propose the retesting of a random grouping of units from positive groups, and compare it with nested halving procedures suggested by others. We develop an estimator of p for our proposed method, and examine its variance properties. Using simulation we compare retesting methods across a range of group testing situations, and show that for most realistic scenarios, our method is more efficient.     

On the mathematics of the Jeffreys–Lindley paradox

This paper is concerned with the well known Jeffreys–Lindley paradox. In a Bayesian set up, the so-called paradox arises when a point null hypothesis is tested and an objective prior is sought for the alternative hypothesis. In particular, the posterior for the null hypothesis tends to one when the uncertainty, i.e., the variance, for the parameter value goes to infinity. We argue that the appropriate way to deal with the paradox is to use simple mathematics, and that any philosophical argument is to be regarded as irrelevant.     

Hypothesis Testing in a Rayleigh Diffusion Model

Applying the large and moderate deviations for the log-likelihood ratio of the Rayleigh diffusion model, we give the negative regions in testing Rayleigh diffusion model and obtain the decay rates of the error probabilities.     

语义场理论对科技术语翻译的启示从——“水资源管理”一词的英汉互译谈起

科技术语在不同语言之间的翻译是一个复杂的语义匹配过程，如何在考虑相关术语使用现状的基础上将新产生的科技术语准确翻译为其它语言是科技工作者和术语研究者关注的重要问题。以语义场理论为分析框架，通过分析以"水资源管理"及其相关术语为代表的英汉互译，结果发现：不同科技术语在同一语义场所涵盖的语义范围将会随着相关研究深化带来的术语界定细化而发生相应的动态变化；新兴科技术语的翻译要充分考虑其所在语义场其它相关科技术语的翻译先例和使用现状所带来的影响，在翻译准确性和解读便利性之间做出适当的平衡。这是造成"水资源管理"及相关术语英汉互译处理极为复杂的重要原因之一，需要科技翻译者在工作实践中多加注意。     

Assessment of individual bioequivalence using sufficient bootstrap procedure

This paper proposes a sufficient bootstrap method, which uses only the unique observations in the resamples, to assess the individual bioequivalence under 2 × 4 randomized crossover design. The finite sample performance of the proposed method is illustrated by extensive Monte Carlo simulations as well as a real‐experimental data set, and the results are compared with those obtained by the traditional bootstrap technique. Our records reveal that the proposed method is a good competitor or even better than the classical percentile bootstrap confidence limits.     

Improved bonferroni procedures for testing overall and pairwise homogeneity hypotheses

Simes' (1986) improved Bonferroni test is verified by simulations ^?to control the α-level when testing the overall homogeneity hypothesis with all pairwise t statistics in a balanced parallel group design. Similarly, this result was found to hold (for practical purposes) in various underlying distributions other than the normal and in some unbalanced designs. To allow the use of step-up procedures based on pairwise t statistics, simulations were used to verify that Simes' test, when applied to testing multiple subset homogeneity hypotheses with pairwise t statistics also keeps the level ? α. Some robustness as above was found here too. Tables of the simulation results are provided and an example of a step-up Hommel-Shaffer type procedure with pairwise comparisons is given.     

积分变换求梁的变形

本文从求解梁挠度的二阶差分方程出发，通过Z变换，最后推导出计算挠度和转角的简单公式，使计算过程简化。对于变截面梁和复杂受载下，此法尤为简便。同时，这也是处理离散参数的数学方法—Z变换在力学中应用的初步尝试。     

水驱砂岩油藏孔喉结构变化的三维网络模拟

以长期水驱实验为基础，建立了等效水驱砂岩储层孔喉结构变化的三维网络模拟模型，结合三维微粒运移机制和有限差分求解方法，得到了长期水驱砂岩油藏孔喉结构变化规律：（1） 冲刷后喉道半径呈增加趋势，喉道半径变化范围变大，极小喉道半径呈微弱减小趋势；（2） 孔隙网络模型中冲刷半径扩大的孔道分布形式与原始孔隙网络结构密切相关，并非所有的大孔道都串联起来贯穿岩芯孔隙网络的两个端面，但入口端和出口端部分大孔道相互连通，形成端面上的大孔道网络群。网络模拟注水结果结合采油井测试，可为注水剖面的调整提供更加可靠的依据。     

絮凝床在茂名热电厂含油污水处理系统中的应用

絮凝床是中山大学开发的一种新型水处理设备．这种水处理技术在我省已用于包括含动、植物油类的污水处理工程中，１９９６年我院首次把这种设备用于茂名热电厂合油（矿物油）污水处理，工程建成投产以来取得了令人满意的效果。     

华庆地区长6深水沉积低渗透砂岩储层特征

通过大量岩芯、铸体薄片、扫面电镜及物性资料分析，对鄂尔多斯盆地华庆地区长6段砂岩的沉积特征、岩石学特征、孔渗特征、成岩作用类型、孔隙结构及孔隙类型等进行了深入研究。研究表明，以深水浊积砂体为主的长6储层具有沉积物粒度偏细、成分成熟度较低、结构成熟度中等的岩石学特点；储集空间主要是原生粒间孔隙和次生溶蚀孔隙，孔隙结构以中、小孔细喉型为主。研究区孔隙度与渗透率具有较好的正相关性，为一套典型的低孔、低渗到特低孔、特低渗的储层。