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31.
阐述和分析CITE平台的通讯机制及产生故障的原因,并针对性地提出了解决方案。  相似文献   
32.
There are large differences across transition countries with respect to agricultural‐sector performance and corresponding scope of farm restructuring and shift to individual farming. In this article we analyze the impact of individualization on productivity growth within an augmented neoclassical growth model framework. This approach allows us to circumvent criticisms on the grounds of lack of theoretical and objective criteria for inclusion of explanatory variables. Furthermore, in the empirical analysis using a panel data covering 15 transition countries over the period 1990–2001 and applying a generalized method of moments with instrumental variable estimator we are able to control for the impact of various factors and the potential endogeneity of variables. Our estimation results are robust and support the view that the shift to individual farming, as well as the overall economic reforms, has positively contributed to the productivity growth in agriculture during the first decade of transition.  相似文献   
33.
我国武器装备通用ATS(自动测试系统)经历了从引进、仿制到自行研制的过程,但是目前通用ATS总的局面是通用ATS不通用,这种局面主要是由于国内对通用ATS实现技术缺乏统一认识造成的。基于此,本文研究了与开发通用ATS密切相关的标准/规范、硬件配置技术、接口技术、集成测试软件开发环境技术。本文的研究结果适用于所有开发通用ATS的项目。  相似文献   
34.
Probability theory in fuzzy sample spaces   总被引:2,自引:0,他引:2  
This paper tries to develop a neat and comprehensive probability theory for sample spaces where the events are fuzzy subsets of The investigations are focussed on the discussion how to equip those sample spaces with suitable -algebras and metrics. In the end we can point out a unified concept of random elements in the sample spaces under consideration which is linked with compatible metrics to express random errors. The result is supported by presenting a strong law of large numbers, a central limit theorem and a Glivenko-Cantelli theorem for these kinds of random elements, formulated simultaneously w.r.t. the selected metrics. As a by-product the line of reasoning, which is followed within the paper, enables us to generalize as well as to bring together already known results and concepts from literature.Acknowledgement. The author would like to thank the participants of the 23rd Linz Seminar on Fuzzy Set Theory for the intensive discussion of the paper. Especially he is indebted to Professors Diamond and Höhle whose remarks have helped to get deeper insights into the subject. Additionally, the author is grateful to one anonymous referee for careful reading and valuable proposals which have led to an improvement of the first draft.This paper was presented at the 23rd Linz Seminar on Fuzzy Set Theory, Linz, Austria, February 5–9, 2002.  相似文献   
35.
Robustness issues in multilevel regression analysis   总被引:8,自引:0,他引:8  
A multilevel problem concerns a population with a hierarchical structure. A sample from such a population can be described as a multistage sample. First, a sample of higher level units is drawn (e.g. schools or organizations), and next a sample of the sub‐units from the available units (e.g. pupils in schools or employees in organizations). In such samples, the individual observations are in general not completely independent. Multilevel analysis software accounts for this dependence and in recent years these programs have been widely accepted. Two problems that occur in the practice of multilevel modeling will be discussed. The first problem is the choice of the sample sizes at the different levels. What are sufficient sample sizes for accurate estimation? The second problem is the normality assumption of the level‐2 error distribution. When one wants to conduct tests of significance, the errors need to be normally distributed. What happens when this is not the case? In this paper, simulation studies are used to answer both questions. With respect to the first question, the results show that a small sample size at level two (meaning a sample of 50 or less) leads to biased estimates of the second‐level standard errors. The answer to the second question is that only the standard errors for the random effects at the second level are highly inaccurate if the distributional assumptions concerning the level‐2 errors are not fulfilled. Robust standard errors turn out to be more reliable than the asymptotic standard errors based on maximum likelihood.  相似文献   
36.
We examine the statistical performance of inequality indices in the presence of extreme values in the data and show that these indices are very sensitive to the properties of the income distribution. Estimation and inference can be dramatically affected, especially when the tail of the income distribution is heavy, even when standard bootstrap methods are employed. However, use of appropriate semiparametric methods for modelling the upper tail can greatly improve the performance of even those inequality indices that are normally considered particularly sensitive to extreme values.  相似文献   
37.
Demand for product characteristics is examined within the context of models that allow for both corner and interior solutions corresponding to zero and non-zero demand. Product attribute information is associated with marginal utility and curvature (satiation) parameters of various utility functions. Empirical applications demonstrate the need for incorporating characteristics in a fairly general way. We also compare our approach to an ideal point and pure Lancasterian versions of our nonlinear utility model. The data support our model over either the ideal point or Lancasterian variants.  相似文献   
38.
Scanner data for fast moving consumer goods typically amount to panels of time series where both N and T are large. To reduce the number of parameters and to shrink parameters towards plausible and interpretable values, Hierarchical Bayes models turn out to be useful. Such models contain in the second level a stochastic model to describe the parameters in the first level.  相似文献   
39.
不同企业下物流信息系统的实现   总被引:3,自引:0,他引:3  
韩玉麒  邹飞 《物流科技》2005,28(3):73-75
本文首先讨论了不同企业建立物流信息系统的前提要求,然后指出了不同企业下构建物流信息系统的基本原则和模式,并提出了在国内的特殊环境下企业构建物流信息系统的几点建议。  相似文献   
40.
分析了供应链和供应链管理的基础,并针对一个MIS的模块结构实例,给出基于Internet/Intranet的供应链管理信息系统的一个例子。  相似文献   
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