Likelihood-based Estimation of the Regression Model with Scrambled Responses

A significant problem in the collection of responses to potentially sensitive questions, such as relating to illegal, immoral or embarrassing activities, is non-sampling error due to refusal to respond or false responses. Eichhorn & Hayre (1983) suggested the use of scrambled responses to reduce this form of bias. This paper considers a linear regression model in which the dependent variable is unobserved but for which the sum or product with a scrambling random variable of known distribution, is known. The performance of two likelihood-based estimators is investigated, namely of a Bayesian estimator achieved through a Markov chain Monte Carlo (MCMC) sampling scheme, and a classical maximum-likelihood estimator. These two estimators and an estimator suggested by Singh, Joarder & King (1996) are compared. Monte Carlo results show that the Bayesian estimator out-performs the classical estimators in all cases, and the relative performance of the Bayesian estimator improves as the responses become more scrambled.     

Estimating the location of the cauchy distribution by numerical global optimization

The log-likelihood function (LLF) of the single (location) parameter Cauchy distribution can exhibit up to n relative maxima, where n is the sample size. To compute the maximum likelihood estimate of the location parameter, previously published methods have advocated scanning the LLF over a suf-ficiently large portion of the real line to locate the absolute maximum. This note shows that, given an easily derived upper bound on the second derivative of the negative LLF, Brent's univariate numerical global optimization method can be used to locate the absolute maximum among several relative maxima of the LLF without performing an exhaustive search over the real line.     

辛二酰氯的合成及其理论计算

以辛二酸为原料,经酰化反应合成得到辛二酰氯,考察了反应时间和反应温度对产物产率的影响,并借助密度泛函量子力学程序对反应前后产物空间结构的变化进行研究.实验结果显示:反应时间24 h,反应温度80℃,辛二酰氯产率为94.7％;结构优化后的辛二酰氯HOMO与LUMO轨道上的电子密度下降,且向亚甲基方向偏移.     

一个数值积分公式

以函数Ｔａｙｌｏｒ展开式为基点，导出一个数值积分公式；并给出相应的误差公式；最后用实例展示公式使用程序及对公式的评估。     

A comment on sample size calculations for binomial confidence intervals

In this article we examine sample size calculations for a binomial proportion based on the confidence interval width of the Agresti–Coull, Wald and Wilson Score intervals. We pointed out that the commonly used methods based on known and fixed standard errors cannot guarantee the desired confidence interval width given a hypothesized proportion. Therefore, a new adjusted sample size calculation method was introduced, which is based on the conditional expectation of the width of the confidence interval given the hypothesized proportion. With the reduced sample size, the coverage probability can still maintain at the nominal level and is very competitive to the converge probability for the original sample size.     

克拉玛依九9 区齐古组稠油提高开发效果研究

克拉玛依油田九9 区齐古组油藏由于埋藏浅，地层胶结疏松，汽窜出砂严重，影响了油井的生产效果。针对该油藏逐步进入蒸汽吞吐的中后期，采出程度高，油井高含水，产能低，边底水侵入，开采难度加大，产量递减加快，开发效益下降等现状，为了改善油藏整体开发效果，选择该油藏有代表性的井组，利用数值模拟方法对其进行下步开发方案设计与指标预测。数值模拟结果符合油田开发实际。研究表明：克拉玛依油田九9 区齐古组油藏吞吐生产后转连续蒸汽驱对改善生产效果，提高采收率具有一定的积极的作用。     

特低渗透油藏压裂水平井新型布井方式研究

考虑长庆油田特低渗油藏地貌特征和储层各向异性，提出了一种压裂水平井新型布井方式。从钻井和油藏两个角度论证新型布井的可行性。丛式井技术可确保压裂水平井新型布井的顺利实施。利用油藏数值模拟方法，分别从单井产能、阶段采出程度、含水率、波及面积等方面评价了压裂水平井新型布井在交错、菱形和矩形井网中的开发效果。研究表明，新型布井与常规布井在交错井网中具有相同的开发效果；菱形和矩形井网中，新型布井可以提高阶段采出程度、单井产能和相对波及面积，降低相同采出程度对应的含水率。新型布井在菱形井网（矩形井网）30 a 的相对波及面积和采出程度分别提高6.00%（10.00%）和0.96%（1.60%），含水率95% 的采出程度提高1.05%（1.50%）     

列管式换热器中管程介质流动均匀性数值模拟与优化

在双管程烟一水介质的列管式换热器中,针对烟气在管程中流量分布不均匀对换热效果的不利影响,利用 FLUENT软件对管程结构进行模拟与优化。考虑折返通道高度h、两管程间距L、换热管列数r、管内径d和管节距S 5个 主要特征尺寸对流动均匀性的影响,采用正交试验方法进行数值模拟试验。通过极差和方差分析,得出影响烟气流动均 匀性的显著因素是d,其次是r和h,而不显著因素是L和.。在模拟参数范围内,得到管程结构的最优组合参数：h为60 mm,L为20 mm,r为4,d为7 mm,S为11.6 mm[l. 45(d+1)]。优化后的各管程中流动均匀性明显得到改善     

水平裂缝井压后产量影响因素分析

针对目前对水平裂缝井产量的影响因素认识不够充分和增产效果评价不够完善,对水平裂缝井产量的影响因素和增产效果评价进行了深入的研究。结合油藏工程理论和数值模拟技术,考虑裂缝导流能力随时间的变化和地层弹性膨胀能等因素对压后产量的影响,以水平裂缝井在生产过程中的渗流特性为理论前提,采用二维柱坐标模型,建立了含水油藏水平裂缝井中油藏-裂缝系统的压力方程和饱和度方程,采用有限差分法对压力方程和饱和度方程进行差分离散求解。实例计算表明：建立的水平裂缝井压后产能预测模型,可以分析影响水平裂缝井产量的地层因素和裂缝因素,计算压后增产效果。对于优化浅层油气藏压裂设计方案具有一定的指导意义。     

“写作即翻译”与同伴反馈法结合之实证研究

同伴反馈法在英语写作教学中有着不可替代的作用,但是自身也有其局限性,为了弥补其重技巧、轻能力、指导性的不足,本文基于"同伴反馈"与"写作即翻译"教学法的结合,对学生进行了一次系统的问卷调查,并通过定量统计与定性分析,以期从现象与本质两方面了解学生对两种教学法结合的态度。结论表明:总体上学生对该教学手段持肯定态度,部分学生提出了建议,少数学生持否定或中立态度。此实验为本教学法的后期改进与完善提供了理论与数据上的参考。