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我国住户调查轮换样本的确定机制 被引量:2
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作者 刘建平 张国校 《统计研究》 CSSCI 北大核心 2016年第3期3-10,共8页
本文提出了住户调查中受样本轮换作用的6个重要方面,结合国外住户调查的经验,对国内有关制度及研究中的问题进行了讨论。通过构建一个适合复杂样本分析的方差-成本模型,结合数据模拟和比较静态分析方法,从6个方面综合考虑轮换样本的影响... 本文提出了住户调查中受样本轮换作用的6个重要方面,结合国外住户调查的经验,对国内有关制度及研究中的问题进行了讨论。通过构建一个适合复杂样本分析的方差-成本模型,结合数据模拟和比较静态分析方法,从6个方面综合考虑轮换样本的影响,从而得出有效样本轮换率和样本轮换频率的确定机制。 展开更多
关键词 住户调查 样本轮换 方差-成本模型
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基于挣值分析法的电网企业信息化项目管控策略研究 被引量:2
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作者 方宽 黄杰韬 +1 位作者 黄慧欣 林俊 《现代电子技术》 北大核心 2017年第21期183-186,共4页
提出基于挣值分析法的信息化项目管控策略,首先引入定量评估机制来周期性地计算成本及进度的偏差值;其次引入挣值分析法来衡量当前项目实施情况,并创新性地提出进度方差及成本方差两个参数,衡量已存在偏差相对于初始计划值的归一化比值... 提出基于挣值分析法的信息化项目管控策略,首先引入定量评估机制来周期性地计算成本及进度的偏差值;其次引入挣值分析法来衡量当前项目实施情况,并创新性地提出进度方差及成本方差两个参数,衡量已存在偏差相对于初始计划值的归一化比值,从项目整体实施角度得到各个偏差的相对严重程度;最后基于已完成的偏差评估对项目实施节点的进度进行预测,从而引入对应的纠正措施,灵活保障电网企业信息化建设项目的实施及质量管控。 展开更多
关键词 电网企业 信息化建设 挣值分析法 成本方差 进度方差
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Effect of Substitution of Fermented Kapok Seed (Ceiba petandra) to Soybean Meal on Production and Egg Quality from Native Laying Hens
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作者 Erman Syahruddin Rita Herawaty Azhar Ibrahim 《Journal of Agricultural Science and Technology(A)》 2015年第10期833-838,共6页
This study aimed to determine the level of use of fermented kapok seed to substitute 100% soybean meal in native laying hen rations without adverse effect on laying hen production. Two hundred and forty laying hens ag... This study aimed to determine the level of use of fermented kapok seed to substitute 100% soybean meal in native laying hen rations without adverse effect on laying hen production. Two hundred and forty laying hens aged 20 weeks were used in this experiment. The completely randomized design was assigned with six treatments to replace 0, 20%, 40%, 60%, 80% and 100% of soybean meal with fermented kapok seed with four replications. The variables measured were feed intake, feed conversion and income over feed cost (gross profit), as well as variables related to egg production (hen day production and egg weight), thickness of eggshell and yolk color index for quality of eggs. Data were analyzed statistically using analysis of variance (ANOVA), and if the result shows a marked influence, it will be followed by Duncans test (DMRT). The results showed that the performance of laying hen had not been affected significantly by substituting soybean meal with fermented kapok seed. Feed intake, feed conversion and egg production is not influenced either. In summary, the use of fermented kapok seed to substitute soybean meal in the ration can be up to 100% in the diet of laying chicken. 展开更多
关键词 Fermented kapok seed (Ceiba petandra) SUBSTITUTION hen day production native laying hen.
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A comprehensive investigation of loading variance influence on fuel consumption and gas emissions in mine haulage operation 被引量:5
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作者 Soofastaei A. Aminossadati S.M. +1 位作者 Kizil M.S. Knights P. 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第6期995-1001,共7页
The data collected from haul truck payload management systems at various surface mines show that the payload variance is significant and must be considered in analysing the mine productivity, diesel energy consumption... The data collected from haul truck payload management systems at various surface mines show that the payload variance is significant and must be considered in analysing the mine productivity, diesel energy consumption, greenhouse gas emissions and associated costs. The aim of this study is to determine the energy and cost saving opportunities for truck haulage operations associated with the payload variance in surface mines. The results indicate that there is a non-linear relationship between the payload variance and the fuel consumption, greenhouse gas emissions and associated costs. A correlation model, which is independent of haul road conditions, has been developed between the payload variance and the cost saving using the data from an Australian surface coal mine. The results of analysis for this particular mine show that a significant saving of fuel and greenhouse gas emissions costs is possible if the standard deviation of payload is reduced from the maximum to minimum value. 展开更多
关键词 Energy consumption Haul truck Surface mine Greenhouse gas emissions Cost
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An Extension of the Dimension-Reduced Projection 4DVar
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作者 SHEN Si LIU Juan-Juan WANG Bin 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第4期324-329,共6页
This paper extends the dimension-reduced projection four-dimensional variational assimilation method(DRP-4DVar) by adding a nonlinear correction process,thereby forming the DRP-4DVar with a nonlinear correction, which... This paper extends the dimension-reduced projection four-dimensional variational assimilation method(DRP-4DVar) by adding a nonlinear correction process,thereby forming the DRP-4DVar with a nonlinear correction, which shall hereafter be referred to as the NC-DRP-4DVar. A preliminary test is conducted using the Lorenz-96 model in one single-window experiment and several multiple-window experiments. The results of the single-window experiment show that compared with the adjoint-based traditional 4DVar, the final convergence of the cost function for the NC-DRP-4DVar is almost the same as that using the traditional 4DVar, but with much less computation. Furthermore, the 30-window assimilation experiments demonstrate that the NC-DRP-4DVar can alleviate the linearity approximation error and reduce the root mean square error significantly. 展开更多
关键词 data assimilation linear approximation nonlinear correction OSSE
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