Threshold Estimation for Stochastic Processes with Small Noise

Consider a process satisfying a stochastic differential equation with unknown drift parameter, and suppose that discrete observations are given. It is known that a simple least squares estimator (LSE) can be consistent but numerically unstable in the sense of large standard deviations under finite samples when the noise process has jumps. We propose a filter to cut large shocks from data and construct the same LSE from data selected by the filter. The proposed estimator can be asymptotically equivalent to the usual LSE, whose asymptotic distribution strongly depends on the noise process. However, in numerical study, it looked asymptotically normal in an example where filter was chosen suitably, and the noise was a Lévy process. We will try to justify this phenomenon mathematically, under certain restricted assumptions.     

Model comparison of linear and nonlinear Bayesian structural equation models with dichotomous data

In this article, dichotomous variables are used to compare between linear and nonlinear Bayesian structural equation models. Gibbs sampling method is applied for estimation and model comparison. Statistical inferences that involve estimation of parameters and their standard deviations and residuals analysis for testing the selected model are discussed. Hidden continuous normal distribution (censored normal distribution) is used to solve the problem of dichotomous variables. The proposed procedure is illustrated by a simulation data obtained from R program. Analyses are done by using R2WinBUGS package in R-program.     

The effect of different data structures,sample sizes on model fit measures

In this study, our aim was to investigate the changes of different data structures and different sample sizes on the structural equation modeling and the influence of these factors on the model fit measures. Examining the created structural equation modeling under different data structures and sample sizes, the evaluation of model fit measures were performed with a simulation study. As a result of the simulation study, optimization and negative variance estimation problems have been encountered depending on the sample size and changing correlations. It was observed that these problems disappeared either by increasing the sample size or the correlations between the variables in factor. For upcoming studies, the choice of RMSEA and IFI model fit measures can be suggested in all sample sizes and the correlation values for data sets are ensured the multivariate normal distribution assumption.     

Schematic saturated orthogonal arrays obtained by using the contractive replacement method

This paper presents a general method of constructing schematic saturated orthogonal arrays of strength two. We consider a class of mixed saturated orthogonal arrays produced from saturated symmetric orthogonal arrays by using the contractive replacement method, study the Hamming distances of the rows, construct their association schemes, and prove that they are schematic. Some examples are given to illustrate this construction method.     

Decomposition of the main effects and interaction term by using orthogonal polynomials in multiple non symmetrical correspondence analysis

The multiple non symmetric correspondence analysis (MNSCA) is a useful technique for analyzing a two-way contingency table. In more complex cases, the predictor variables are more than one. In this paper, the MNSCA, along with the decomposition of the Gray–Williams Tau index, in main effects and interaction term, is used to analyze a contingency table with two predictor categorical variables and an ordinal response variable. The Multiple-Tau index is a measure of association that contains both main effects and interaction term. The main effects represent the change in the response variables due to the change in the level/categories of the predictor variables, considering the effects of their addition, while the interaction effect represents the combined effect of predictor categorical variables on the ordinal response variable. Moreover, for ordinal scale variables, we propose a further decomposition in order to check the existence of power components by using Emerson's orthogonal polynomials.     

“空间、空间生产”五问——对张之沧教授几个观点的质疑

既然空间是物质的存在方式,它就不可能具有主观性、意识性,也不可能是精神的存在方式。先在的、外在于人类实践的自然空间不可能是人创造的。我们在改造自然的同时,也改变了自然事物的原有空间形式,新的空间形式是适合于人类生活的。但我们不能创造物质本身,只能改变物质的具体形态,因而,我们也不能创造空间本身,只能创造具体事物的空间形式。社会存在是物质的高级存在方式,社会存在的空间形式可以称之为社会空间。但"社会空间"不表示这种空间具有社会性。社会存在包含着自然存在,不是自然存在的存在是非存在。社会空间实际上是社会存在的自然物质基础具有的空间形式。空间是物质的自然属性而非社会属性,"社会空间"不具有社会性。空间的生产只是生产的一个方面,不能用"空间生产"的概念代替"物质生活资料的生产"和"生产方式"的概念,应当从生产方式来理解人类历史和帝国主义、霸权主义在空间上的扩张、争夺。     

陕西省物流业的投入产出分析研究

运用投入产出法对陕西省三次产业和物流业做投入产出、产业关联、产业波及效应等进行分析,计算出各产业部门的直接消耗系数、列昂惕夫逆矩阵、直接前向关联指数和直接后向关联指数、影响力和感应度系数。得出陕西省物流业与其他三次产业的技术经济关系,最后根据陕西省物流业存在的一些问题提出促进陕西物流业发展的建议和对策。     

海南建省以来区域经济差异的测度与评价

采用Theil指数分析、基尼系数分析和局域空间自相关分析等方法,系统测度1988-2011年海南区域经济差异,以此为基础分析海南建省以来区域经济差异的时序变化及空间格局动态。结果显示,海南建省以来区域经济差异呈现先扩大后缩小、继而转平稳波动的阶段性变化,但总体上明显扩大;海南区域经济差异以4类区域间差异为主导,其空间格局总体上呈现内陆与沿海间及沿海内部差异型;海南区域经济差异在量上未突破偏小的非相对合理状态。这些表明,目前海南相对发达区域经济增长水平不高,海南整体经济增长水平偏低,经济增长缺少实力强的增长极带动。推动海南经济快速稳定增长和区域经济协调发展,以支撑海南国际旅游岛建设,必须遵循经济增长的空间规律,强化实施增长极战略,集中有限的力量重点发展海口、三亚、儋州、文昌、澄迈和琼海,在此基础上培育三个有明显辐射带动作用的增长极或核心区,避免遍地开花式的低效率开发和重复建设。     

两个不同品牌洗衣粉抑菌效果的测定与研究

为了比较汰渍、碧浪两种不同品牌洗衣粉的抑菌效果,本试验采用滤纸片琼脂平板扩散法,将待洲样品溶液转移至接种有大肠杆菌(Escherichia coli)、枯草芽孢杆菌(Bacillus Subtilis)和金黄色葡萄球菌(Staphylococcus aureus)敏感菌株的培养基上,经培养后测定其抑菌圈的大小,以判断其抑菌能力的强弱.通过对抑菌圈直径的比较和两个均数的差异显著性分析,发现汰溃、碧浪两种洗衣粉的押菌效果差异不显著.     

基于熵值法的东陇海产业带区域发展能力评价与建设策略

以市区和县域为研究单元,从经济发展推动力、社会发展支撑力、资源环境承载力三个方面构建区域发展能力指标体系.采用熵值法进行量化分析并进行发展能力评价.从省域层面看,该区域发展能力明显弱于省平均水平;从区域内部看,发展能力差距明显,综合发展能力优势集中在东陇海产业带的双核及轴线上.在区域发展能力评价的基础上,提出区域发展能力的建设策略:整合空间结构,深化区域分工,完善基础设施,涵养资源环境.