The Spatial Durbin Model and the Common Factor Tests

Abstract

The spatial Durbin model occupies an interesting position in the field of spatial econometrics. It is the reduced form of a model with cross-sectional dependence in the errors and it may be used as the nesting equation in a more general approach of model selection. Specifically, in this equation we obtain the common factor tests (of which the likelihood ratio is the best known) whose objective is to discriminate between substantive and residual dependence in an apparently misspecified equation. Our paper tries to delve deeper into the role of the spatial Durbin model in the problem of specifying a spatial econometric model. We include a Monte Carlo study related to the performance of the common factor tests presented in the paper in small sample sizes.     

Efficient estimation of forecast uncertainty based on recent forecast errors

Multi-step-ahead forecasts of the forecast uncertainty of an individual forecaster are often based on the horizon-specific sample means of his recent squared forecast errors, where the number of past forecast errors available decreases one-to-one with the forecast horizon. In this paper, the efficiency gains from the joint estimation of forecast uncertainty for all horizons in such samples are investigated. If the forecast uncertainty is estimated by seemingly unrelated regressions, it turns out that the covariance matrix of the squared forecast errors does not have to be estimated, but simply needs to have a certain structure, which is a very useful property in small samples. Considering optimal and non-optimal forecasts, it is found that the efficiency gains can be substantial for longer horizons in small samples. The superior performance of the seemingly-unrelated-regressions approach is confirmed in several empirical applications.     

输送机中心轴线标定及测量精度分析

通过对带式输送机安装中心轴线标定方法进行理论分析,推导出边长和角度实测的精度相关公式,同时输送机的施工安装工艺对测量标定中心轴线提出了较高的要求,为我们提出了在实际工作中的具体做法和应注意的几个问题。     

无机非金属材料本科毕业生就业跟踪调查分析

无机非金属材料本科毕业生数量大幅度上升,而企业招聘人数越来越少,日益激烈的竞争压力使得大学生面临越来越严峻的就业形势。而无机本科毕业生的就业形势和已就业学生的发展情况是本文研究的焦点,所以以e-mail邮件、电话调查和走访的方式对洛阳理工学院无机毕业生及其就业单位进行就业跟踪调查。就这次调查研究的基本情况和统计结果进行分析,目的是了解该校的专业教育、就业指导等与毕业生就业和岗位发展的关系,为该校改进教学方法和调整就业指导策略提供决策数据。     

全国农村与城镇居民人均收入的协整分析

中国农村居民人均收入和城镇居民人均收入的关系,反映了中国乡镇经济的基本特征。运用协整分析方法和误差修正模型理论,对1978—2010年全国农村居民人均收入和城镇居民人均收入的年度数据进行实证分析,分析结果表明,中国农村居民人均收入和城镇居民人均收入之间存在着一个长期稳定的均衡关系,并且建立协整模型和误差修正模型,采用Granger因果检验,得出城镇居民人均收入是农村居民人均收入的原因,并从研究结论中提出针对性的建议。     

Food Package Familiarity and Perceived Amount of Verbal Information: The Moderating Effect of Frugal Behavior

ABSTRACT

This paper discusses the moderating effect of frugal behavior on the relationship between food package familiarity and the perceived amount of verbal information. Two experiments were conducted on food packaging to analyze two central points: (a) the relationship between food package familiarity and the perceived amount of verbal information and (b) the moderating effect of frugal behavior on this relationship. The studies demonstrate the negative influence of food package familiarity on the perceived amount of verbal information. We demonstrate that the greater (smaller) the familiarity with food packaging is, the smaller (greater) the visual attention to the verbal information will be. Second, we show that frugal behavior moderates this behavior. Our experiment shows that a greater (smaller) tendency toward frugal behavior tends to have a positive (maintain negative) effect on the relationship between food package familiarity and the perceived amount of verbal information.     

视觉导航关键技术及应用研究

由于视觉导航技术的应用越来越普及,因此,有必要对视觉导航中的关键技术及应用进行研究。文章对其中的图像处理技术和定位与跟踪技术进行了详细研究,并与此相对应,介绍的相关的应用。     

角速度传感器误差校正研究

某角速度传感器的输入与输出成近似线性关系,测量输出的电压值即可得到目标运动的角速度。为了提高测量的精度,通过对角速度传感器零位和灵敏度的误差进行校正,可得到更为精确的目标运动角速度。实验表明,该校正方法能有效提高角速度传感器的测量精度,有一定的实用性。     

煤质化验中的误差的控制

煤质化验是一项技术性强、环节较多的工作,在采样、制备、化验的过程中,因煤的不均匀性,造成各个工作环节产生偏差。要对煤质常规化验操作化验员存在的突出问题进行分析,以保证煤质化验的测值准确,获得理想可靠的结果。本文主要阐述了煤质化验中采样、制样、干燥、分析等环节的误差控制。     

A number‐of‐modes reference rule for density estimation under multimodality

We consider kernel density estimation for univariate distributions. The question of interest is as follows: given that the data analyst has some background knowledge on the modality of the data (for instance, ‘data of this type are usually bimodal’), what is the adequate bandwidth to choose? We answer this question by extending Silverman's idea of ‘normal‐reference’ to that of ‘reference to a Gaussian mixture’. The concept is illustrated in the light of real data examples.