Empirical likelihood confidence intervals for the mean of a population containing many zero values

If a population contains many zero values and the sample size is not very large, the traditional normal approximation‐based confidence intervals for the population mean may have poor coverage probabilities. This problem is substantially reduced by constructing parametric likelihood ratio intervals when an appropriate mixture model can be found. In the context of survey sampling, however, there is a general preference for making minimal assumptions about the population under study. The authors have therefore investigated the coverage properties of nonparametric empirical likelihood confidence intervals for the population mean. They show that under a variety of hypothetical populations, these intervals often outperformed parametric likelihood intervals by having more balanced coverage rates and larger lower bounds. The authors illustrate their methodology using data from the Canadian Labour Force Survey for the year 2000.     

左江土白话声调变异成因探析

本文着重通过四个方面的讨论,指出语言地位的变化、语言间的接触及其趋同、语言的内部机制等内外因素的先后与共同作用是左江土白话声调变异的主要成因,并认为广西城镇的粤语将可能程度不同地发生这样的演变。     

论全球生产的网络化及其推动力量

在产业转移的浪潮中,世界经济局势发生了很大的变化。在经济全球化的过程中,市场经济规则在世界范围内被广泛接受。受惠于科技革命特别交通和信息技术的巨大进步,跨国公司得以在世界范围内寻找战略资源满足其趋利性动机,形成了全球生产网络。     

Data tilting for time series

Summary. We develop a general methodology for tilting time series data. Attention is focused on a large class of regression problems, where errors are expressed through autoregressive processes. The class has a range of important applications and in the context of our work may be used to illustrate the application of tilting methods to interval estimation in regression, robust statistical inference and estimation subject to constraints. The method can be viewed as 'empirical likelihood with nuisance parameters'.     

杭州汽轮机厂计算机集成制造系统——HTW-CIMS

本文介绍了杭州汽轮机厂计算机集成制造系统HTW-CIMS的总体方案以及开发和应用该系统时遵循的技术路线。     

浅析高校后勤社会化财务内控体系

目前,我国高校后勤社会化财务内部控制制度存在着理论滞后、实践不一的问题,解决这些问题应遵循合法性原则、成本效益原则、稳定性与灵活性相结合原则、全面性原则、规范化,程序化原则,采取完善内部控制制度,加大内部监控力度;完善外部监督机制,发挥外部监督作用;适时进行审首行动;果断采取有效隔离内部控制的对策,从而提高高校后勤社会化财务内部控制的有效性,使高校后勤财务内部控制制度能真正更好地保证我国高校后勤社会化的顺利、健康、快速发展。     

目前我国会计电算化存在的问题及发展方向

随着会计基础工作的加强,电子计算机日益深入地应用于会计核算和财务管理中。这使会计核算手段、管理方法都有了深刻的变化。但目前我国的会计电算化工作存在着一些问题。本文就这些问题提出了一些建议,并对未来的会计电算化的发展方向进行了分析。     

中古均田制度的农史观察

均田制是中国古代重要的土地制度之一,它的兴起与发展,与中古时代社会变迁与农业发展的宏观背景相联系:均田制与魏晋南北朝时期的民族大迁移、大融合相关联,既是中原既有生产关系与少数民族新型社会形态相结合的产物,也与民族迁徙而引发的农牧结构大调整和农牧技术的大发展密切相关。从这一视角出发亦可见均田制实施与隋唐盛世之联系。     

最少部件数的并联备份问题

如何快速提高系统的可靠度和最少部件数的并联备份问题,一直是系统可靠性问题中的研究热点。该文从系统的任意状态(k1,k2,L,kn)出发,讨论了上述问题,并证明了在子系统可靠度最小的位置上并联相同部件可使系统的可靠度提高最快,同时给出了最优算法和实例验证。     

Towards Enhancement of the Economy of a Thermal Power Generating System through Prediction of Plant Efficiency

The plant ‘Heat Rate’ (HR) is a measure of overall efficiency of a thermal power generating system. It depends on a large number of factors, some of which are non-measurable, while data relating to others are seldom available and recorded. However, coal quality (expressed in terms of ‘effective heat value’ (EHV) as kcal/kg) transpires to be one of the important factors that influences HR values and data on EHV are available in any thermal power generating system. In the present work, we propose a prediction interval of the HR values on the basis of only EHV, keeping in mind that coal quality is one of the important (but not the only) factors that have a pronounced effect on the combustion process and hence on HR. The underlying theory borrows the idea of providing simultaneous confidence interval (SCI) to the coefficients of a p-th p(≥1) order autoregressive model (AR(p)). The theory has been substantiated with the help of real life data from a power utility (after suitable base and scale transformation of the data to maintain the confidentiality of the classified document). Scope for formulating strategies to enhance the economy of a thermal power generating system has also been explored.