Sample Design and Allocation for Random Digit Dialling

Sample design and sample allocation methods are developed for random digit dialling in household telephone surveys. The proposed method is based on a two-way stratification of telephone numbers. A weighted probability proportional to size sample allocation technique is used, with auxiliary variables about the telephone coverage rates, within local telephone exchanges of each substrata. This makes the sampling design nearly “self-weighting” in residential numbers when the prior information is well assigned. A computer program generates random numbers for the local areas within the existing phone capacities. A simulation study has shown greater sample allocation gain by the weighted probabilities proportional to size measures over other sample allocation methods. The amount of dialling required to obtain the sample is less than for proportional allocation. A decrease is also observed on the gain in sample allocation for some methods through the increasing sample sizes.     

关于输配电价几个重要问题的探讨

我国电力企业将要由传统的垂直垄断的模式转变为网厂分开、竞价上网的模式。电网公司作为一个独立的经营实体分离开来,有着独立的收益需求。在市场运营过程中,通过输配电价取得收益就成了电网公司取得收益的主要手段。在输配电价的制订过程之中,管制方式、输配电成本、输电定价方法、价格水平及电网投资、输配电价价区、电网提供的辅助服务等六个问题十分重要。文中就这六个问题的解决作了一些有价值的探讨。     

铁离子、亚铁离子变化对工业锅炉酸洗的影响

介绍工业锅炉酸洗中铁离子的来源,并以实例说明酸洗中应强化对铁离子、亚铁离子(Fe3+、Fe2+)的化学监测,使锅炉酸洗安全进行,及终点的判断。     

MATLAB GUIDE在数字图像处理教学中的应用

MATLAB GUIDE(Graphical User Interfaces,图形用户界面)是为表现MATLAB中的基本功能而设计的演示程序。本文通过对数字图像处理中几个常用的设计例子,开发和利用MATLAB GUIDE的教学自动控制系统,展示了MATLAB GUIDE在数字图像处理课程辅助教学的优点。     

辅助生产计划成本分配法教学改进小议

辅助生产计划成本分配法在教学过程中往往出现学生困惑重重无法理解,而教师是努力解释却又无法解释清楚的困境。因此,在不考虑反映和考核辅助生产车间业绩的情况下,教师可以重新对计划成本分配法厘清思路,不需要交互分配,只需将生产费用按计划分配率根据外部各受益对象的实际耗用量直接分配,简化核算又不影响最终分配结果,使学生较快理解和掌握。     

基于遗传算法的锅炉水位控制器设计

文章分析了锅炉水位控制系统的基本原理及结构,针对传统PID控制器的不足之处设计了基于遗传算法的新型锅炉水位控制器,在此基础上搭建了锅炉水位控制系统。最后,通过仿真验证了该水位控制器在改善水位系统稳态误差及动态超调方面均具有较好的作用。     

1000MW机组塔式锅炉水冷壁垂直段组合安装方案浅析

本文以某电厂1000MW机组塔式锅炉水冷壁垂直段组合、安装为例,介绍塔式锅炉水冷壁垂直段组合、安装方案的确定过程,以其成功安装经验,对于同类型锅炉水冷壁安装具有一定借鉴意义。     

燃煤锅炉改造问题及节能环保改造措施

在现代社会的发展中,燃煤锅炉是工业发展中常用的供暖设备、供热设备,尤其在北方地区得到了十分广泛的应用。但是,在使用燃煤锅炉过程中,一定区域内会产生很多燃煤灰尘、SO2气体,现已成为很多地区的大气污染源之一。为了有效控制燃煤锅炉污染物排放量,相关部门需要实行烟气除尘、脱硫方式,做好燃煤锅炉节能改造工作,减少大气污染物的排放量。论文重点分析了燃煤锅炉改造问题及节能环保改造措施。     

浅谈营盘山隧道岩溶处理

本文主要通过对营盘山大型溶洞施工组织顺序上的调整和对施工工艺工法顺序的处理方法调整及选择方面介绍,希望对类似的溶洞处理的施工有一定借鉴意义。     

Linking of sample data to small areas

We consider methods for estimating the means of survey variables in domains of a finite population, where sample sizes are too small to obtain reliable direct estimates. We construct generalized compositions from the direct and traditional design-based synthetic estimators and propose the methodology for evaluating their coefficients. This methodology measures similarities among sample elements and estimates of the domain means. We propose the compositions for two cases of auxiliary information: domain-level characteristics are available; true means of auxiliary variables are available for the estimation domains, and unit-level auxiliary vectors are known for the sample elements. In the simulation study, we show where the generalized compositions improve the traditional synthetic and composite estimators.