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Orthogonal main-effect plans for two and three factors in small blocks are obtained from the dual of adjusted orthogonal row-column
designs. The method for constructing efficient plans is presented, and a relationship between the average efficiency factors
of the row-column design and the corresponding main effects is given for the two-factor case.
Orthogonal Main Effect. 相似文献
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HXD2C型机车是中国北车同车公司自主创新的新型电力机车,具有技术先进、网络化程度高、维护方便快捷等优势。本文针对近两年该型车在高坡重载运输任务中发生的问题进行浅析,总结探索可行的应对措施。 相似文献
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A common exercise in empirical studies is a “robustness check”, where the researcher examines how certain “core” regression coefficient estimates behave when the regression specification is modified by adding or removing regressors. If the coefficients are plausible and robust, this is commonly interpreted as evidence of structural validity. Here, we study when and how one can infer structural validity from coefficient robustness and plausibility. As we show, there are numerous pitfalls, as commonly implemented robustness checks give neither necessary nor sufficient evidence for structural validity. Indeed, if not conducted properly, robustness checks can be completely uninformative or entirely misleading. We discuss how critical and non-critical core variables can be properly specified and how non-core variables for the comparison regression can be chosen to ensure that robustness checks are indeed structurally informative. We provide a straightforward new Hausman (1978) type test of robustness for the critical core coefficients, additional diagnostics that can help explain why robustness test rejection occurs, and a new estimator, the Feasible Optimally combined GLS (FOGLeSs) estimator, that makes relatively efficient use of the robustness check regressions. A new procedure for Matlab, testrob, embodies these methods. 相似文献
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文中首先分析了目前大型百货电商常用的分拣方式,指出了其存在的不足;随后详细剖析了自动分拣系统可适用于大型百货电商的原因,同时给出了实施瓶颈;最后提出来大型百货电商实施自动分拣系统的对策。 相似文献
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Performance of empirical Bayes estimators of random coefficients in multilevel analysis: Some results for the random intercept-only model 总被引:1,自引:0,他引:1
Math J. J. M. Candel 《Statistica Neerlandica》2004,58(2):197-219
For a multilevel model with two levels and only a random intercept, the quality of different estimators of the random intercept is examined. Analytical results are given for the marginal model interpretation where negative estimates of the variance components are allowed for. Except for four or five level-2 units, the Empirical Bayes Estimator (EBE) has a lower average Bayes risk than the Ordinary Least Squares Estimator (OLSE). The EBEs based on restricted maximum likelihood (REML) estimators of the variance components have a lower Bayes risk than the EBEs based on maximum likelihood (ML) estimators. For the hierarchical model interpretation, where estimates of the variance components are restricted being positive, Monte Carlo simulations were done. In this case the EBE has a lower average Bayes risk than the OLSE, also for four or five level-2 units. For large numbers of level-1 (30) or level-2 units (100), the performances of REML-based and ML-based EBEs are comparable. For small numbers of level-1 (10) and level-2 units (25), the REML-based EBEs have a lower Bayes risk than ML-based EBEs only for high intraclass correlations (0.5). 相似文献
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Anthony C. Atkinson 《Metrika》2005,62(2-3):127-138
Often the responses from mechanistic models have to be transformed to achieve error distributions that are symmetric and have
constant variance. Because of the nature of the relationship between the response and the mechanistic model, it is necessary
to transform both sides of the model. Expressions are given for the parameter sensitivities in the transformed model and examples
given of optimum designs for particular values of λ, together with the efficiency of these designs as λ varies. Approaches
to finding designs robust to variations in λ are indicated and exemplified. 相似文献
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硅酸铁锂是一种锂离子电子的正极材料,由于其晶胞在理论上可允许可逆脱嵌两个锂原子,使得其理论比容量有巨大的提升空间,加上原料易得、无污染及成本低的优势,受到了人们的重视。正极材料掺杂被认为是改善其导电性能的有效途径。论文通过运用基于第一性原理方法的计算机仿真技术,对铬掺杂硅酸铁锂的结构和导电性能的影响进行了计算机仿真研究,结果表明未掺杂的硅酸铁锂其带隙快读为2.44eV,掺杂铬之后硅酸铁锂带隙减小为2.31eV,表明铬掺杂可提高硅酸铁锂的导电性能。 相似文献
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家电制造企业物流外包策略及实施研究 总被引:1,自引:0,他引:1
通过分析物流外包的必要性以及外包过程中的障碍和问题,对家电制造企业如何做好物流业务外包、实施策略以及基于家电制造企业物流业务外包的管理及运行机制进行探讨和研究。 相似文献
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A general method for construction of E(s
2)-optimal, two-level supersaturated designs (SSDs) with the equal occurrence property, from supplementary difference sets
is introduced. It is proved that SSDs constructed in this way are E(s
2)-optimal. Comparisons are made with previous works and it is shown that the proposed method gives promising results for the
construction of E(s
2)-optimal large SSDs. 相似文献
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针对特低渗透油藏,在模拟实际油藏条件下开展水驱、CO2驱和水/CO2交替驱室内实验研究。结果表明:在相同条件下,水/CO2交替驱的采收率比CO2驱高22.63%,比水驱采收率高27.22%。水驱见水早,含水率上升快,注入压力高;CO2驱虽然注入压力低,但CO2气窜非常严重;水/CO2交替驱注入压力比CO2驱高,但远远低于水驱压力。水/CO2交替驱见气和见水时间较CO2驱和水驱晚,而且气油比和含水率上升速度慢。因此利用CO2驱油时,应首先选择水/CO2交替驱。 相似文献
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B2C电子商务中退货策略 总被引:2,自引:0,他引:2
退货策略对于B2C电子商务运营商意义深刻,如何合理地运用这一策略值得探讨.本文首先对这一问题建立了定量分析模型,然后分析了这一模型下最优的策略组合,最后,对模型中的诸参数进行分析,旨在找础这些因素对决策变量的影响,并得出一些指导建议,以期对企业管理实践有所帮助. 相似文献
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CO2 Multipliers in Multi-region Input-Output Models 总被引:1,自引:0,他引:1
In order to achieve equitable reduction targets, international trade has to be taken into account when assessing nations' responsibility for abating climate change. Especially for open economies such as Denmark, greenhouse gases embodied in internationally traded commodities can have a considerable influence on the national 'greenhouse gas responsibility'. We set up a five-region input-output model including Denmark, Germany, Sweden and Norway in order to calculate CO2 multipliers and trade balances. We investigate multidirectional feedback between these countries, and hence the error inherent in a single-region input-output model. We also examine the effect of aggregation on the model results. In the case of Denmark, an 11 Mt CO2 trade surplus resulting from a single-region model turns into balance when multidirectional trade is considered. Moreover, aggregated models are likely to result in significant errors. Therefore, both the type and the degree of aggregation used for modelling CO2 responsibilities could have a major bearing in international negotiations. 相似文献
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B2C电子商务模式中逆向物流的管理 总被引:4,自引:0,他引:4
本文首先讨论了B2C电子商务模式下正向物流与逆向物流的区别,然后分析了B2C电子商务模式下逆向物流管理的基本思路及方法.管理好逆向物流是采用B2C电子商务模式的企业寻求降低成本、提高客户满意度、提升竞争能力的有效途径. 相似文献
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文章介绍了利用WebField GCS-2在糖厂结晶罐结晶过程的自动控制系统的设计方法。 相似文献
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互联网的应用普及,改变了人们传统的购物模式。这种新兴的经济环境,迫使企业为了寻求新的竞争优势,不得不把目光投向了企业的外部顾客。在当今B2C电子商务模式迅猛发展的形势下,对顾客感知价值及其内涵的研究就显得尤为重要,它有助于B2C电子商务企业找到提升顾客感知价值的途径。文章首先回顾了国内外有关顾客感知价值的文献研究,然后结合我国电子商务的发展环境,对B2C环境下的顾客感知价值进行了分析,并就企业提升顾客的感知价值给出一些浅见。 相似文献
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针对桂林电子科技大学现有后勤管理系统相对落后的问题,采用B/S架构,运用开源框架Struts-Spring-Hibernate构建基于J2EE的高校后勤管理系统。该系统将开源框架与Ajax技术相结合,可实现系统的异步提交,减轻网络通信和服务器端的负担;以后勤管理数据为研究对象,通过数据仓库、OLAP、数据挖掘技术的综合运用发现后勤管理系统中的有用信息,为管理高层提供辅助决策支持,具有较强的实用价值。 相似文献