Analytical approximations for iterated bootstrap confidence intervals

Standard algorithms for the construction of iterated bootstrap confidence intervals are computationally very demanding, requiring nested levels of bootstrap resampling. We propose an alternative approach to constructing double bootstrap confidence intervals that involves replacing the inner level of resampling by an analytical approximation. This approximation is based on saddlepoint methods and a tail probability approximation of DiCiccio and Martin (1991). Our technique significantly reduces the computational expense of iterated bootstrap calculations. A formal algorithm for the construction of our approximate iterated bootstrap confidence intervals is presented, and some crucial practical issues arising in its implementation are discussed. Our procedure is illustrated in the case of constructing confidence intervals for ratios of means using both real and simulated data. We repeat an experiment of Schenker (1985) involving the construction of bootstrap confidence intervals for a variance and demonstrate that our technique makes feasible the construction of accurate bootstrap confidence intervals in that context. Finally, we investigate the use of our technique in a more complex setting, that of constructing confidence intervals for a correlation coefficient.     

论企业人力资源激励的历史演进及其启示

激励是企业人力资源开发的中心环节。一部企业管理发展史,实质上就是一部企业人力资源激励的演进史。由于激励基础、激励重点和主要激励手段的不同,从而产生了不同的管理理论,使得企业人力资源激励呈现出不同的发展阶段。研究企业激励的演进历史及其发展规律,对于提高我国企业激励水平,增强国际竞争力具有重要的现实意义。     

论英语专业教学中学生非智力因素的培养

非智力因素是保证成功进行各种活动的必要心理条件。在英语专业课程学习中,学生的非智力因素能够直接转化为学习动机,把学习当作自觉行为。教师应注重学生兴趣、情感、意志、性格等非智力因素的培养,讲究教学艺术,建立宽松互动的学习环境,使学生的非智力因素在学习中起到重要作用。     

论责任动机与偏好动机的共存

康德的责任动机理论是其备受争议的主张之一。人们通常认为康德的道义论强调责任动机,拒斥各种偏好动机,从而将情感等要素排除到道德动机范围之外。但是,在康德的道德动机理论中,责任动机和偏好动机的关系是共存的。     

CO_2增加与未来气温变化

近几十年来．由于人类活动导致大气中ＣＯ２含量呈明显上升趋势，预计到下世纪中叶ＣＯ２浓度将达到４５０ｐｐｍ左右，下世纪末，将达到工业革命前的两倍，各种数值模式表明，届时全球气温将升高１．５－４．５℃。     

最优验血方法的判定

本文对Ｎ个人验血的检验方法进行研究．得到如下结果：（１）设普查对象的阳性概率为ｐ，对当时，采用分组检验最优；当ｐ≥０．３０７８时，采用单个检验最优、（２）当采用分组检验时，分组人数或时，检验次数最少．     

治疗腰痛的气功功法和功理

本文扼要论述腰痛治疗三个层次的气功功法和功理.     

Sample selection in radiocarbon dating

Archaeologists working on the island of O'ahu, Hawai'i, use radiocarbon dating of samples of organic matter found trapped in fish-pond sediments to help them to learn about the chronology of the construction and use of the aquicultural systems created by the Polynesians. At one particular site, Loko Kuwili, 25 organic samples were obtained and funds were available to date an initial nine. However, on calibration to the calendar scale, the radiocarbon determinations provided date estimates that had very large variances. As a result, major issues of chronology remained unresolved and the archaeologists were faced with the prospect of another expensive programme of radiocarbon dating. This paper presents results of research that tackles the problems associated with selecting samples from those which are still available. Building on considerable recent research that utilizes Markov chain Monte Carlo methods to aid archaeologists in their radiocarbon calibration and interpretation, we adopt the standard Bayesian framework of risk functions, which allows us to assess the optimal samples to be sent for dating. Although rather computer intensive, our algorithms are simple to implement within the Bayesian radiocarbon framework that is already in place and produce results that are capable of direct interpretation by the archaeologists. By dating just three more samples from Loko Kuwili the expected variance on the date of greatest interest could be substantially reduced.     

宏观连续交通流数值模拟

应用交通流宏观连续模型,模拟上下游信号灯作异步周期变化的协调信号灯路段的交通流动,经数值计算比较,选择改进Ｍｕｒｍａｎ格式求解．结果表明：改进Ｍｕｒｍａｎ格式能准确捕捉交通流中无振荡“激波”位置．