Optimal Bootstrap Sample Size in Construction of Percentile Confidence Bounds

In traditional bootstrap applications the size of a bootstrap sample equals the parent sample size, n say. Recent studies have shown that using a bootstrap sample size different from n may sometimes provide a more satisfactory solution. In this paper we apply the latter approach to correct for coverage error in construction of bootstrap confidence bounds. We show that the coverage error of a bootstrap percentile method confidence bound, which is of order O ( n ^−2/2) typically, can be reduced to O ( n ⁻¹) by use of an optimal bootstrap sample size. A simulation study is conducted to illustrate our findings, which also suggest that the new method yields intervals of shorter length and greater stability compared to competitors of similar coverage accuracy.     

基于系统动力学的中小型科技企业成长机制研究

中小型科技企业的成长是自身功能系统与外部环境系统间的非线性时间维反馈过程.通过运用系统动力学的理论和方法,构建了含有79个反馈回路的中小型科技企业成长机制模型.模型分析表明完善的中小型科技企业成长机制应包含内生成长机制和外生成长机制两部分,内生成长机制是根本动力,外生成长机制是中小型科技企业成长的必要条件和补充,它们的协调互补决定了中小型科技企业的成长能力和成长空间.     

汽车保险杠注射模设计与制造

将部分型芯做成活动型芯与塑件一并顶出 ,利用人工将塑件取下的办法解决一些常规模具机构不能使用的问题。在模具的加工上 ,模具的成形部件是在三维中进行的实体设计 ,实现了设计 -编程 -加工的一体化     

纳米稀土固体超强酸SO4^2-／TiO2／La^3＋的制备及催化合成尿囊素的研究

用纳米稀土固体超强酸 SO42-/TiO2/La3 为催化剂,以尿素和乙二醛为原料合成了尿囊素.考察了原料配比、pH值、活化温度、硫酸浓度对催化剂催化活性,以及原料配比、反应温度、反应时间、催化荆用量对尿囊素合成的影响.     

上海股票市场分形特征的实证研究

以有效市场假说为基础的现代资本市场理论被越来越多的实践证明与现实情况不符,而分形理论则考虑到资本市场的复杂性和EMH的缺陷,以非线性范式为分析基础,解释了有效市场理论无法解释的许多市场现象,为更深入地分析资本市场提供了新的思路和方法。文章以上海股票市场为例,用分形理论对上海股市的分形特征进行了研究,其结果表明上海股票市场具有明显的分形特征。     

Interrupted aspirations: research and policy on Gitano education in a time of recession,in Spain

During the past decade, Gitano students’ school success and its cultural, social and emotional consequences have been largely unexplored, particularly in a new context: the deep economic crisis in Spain. This study reviews and analyses the evolution of the research production and the changing contexts of policy trends affecting the ‘Roma education issue’ as they have developed in Spain during the past decade (2004–2014). The authors take as a starting point the groundbreaking study published in 2004 that focused on trajectories of educational achievement and continuity among Gitano youth, and go on to reconstruct the approaches undertaken by qualitative, quantitative and evaluation research since then, in relation to their contributions to improve policy recommendations. The role played by Spanish and European social and educational strategies addressed to the Gitano/Roma population is critically explored to challenge the controversial notion of a ‘Spanish model of Roma integration’. Finally, the authors argue that the deterioration of public education and the virtual disappearance of social benefits in recent years, in addition to the worrying actions taken against Roma citizens in the EU, are to account for the interrupted aspirations of a whole generation of Gitano/Roma youth.     

A comparative study of series arima/mlp hybrid models for stock price forecasting

ABSTRACT

Series hybrid models are one of the most widely-used hybrid models that in which a time series is assumed to be composed of two linear and nonlinear components. In this paper, the performance of two types of these hybrid models is evaluated for predicting stock prices in order to introduce the more reliable series hybrid model. For this purpose, ARIMA and MLPs are elected for constructing series hybrid models. Empirical results for forecasting three benchmark data sets indicate that despite of more popularity of the conventional ARIMA-ANN model, the ANN-ARIMA hybrid model can overall achieved more accurate results.     

Making autism through Ocean Heaven (海洋天堂, Haiyang tiantang) and the possibilities of realizing disability differently

This article focuses on a filmic portrayal of issues relating to autism in a Chinese context, using this as a prism through which to consider how meanings associated with disability in general, and the autistic spectrum in particular, are produced. Instead of perpetuating a reductive positive/negative approach to representation, the article focuses on the fluid and dynamic ways in which author and audience co-produce texts relating to disability in ways which are invariably influenced by, and reproducing of, specific socio-cultural and discursive circumstances. Meaning-making in relation to disability is, however, ongoing and there is potential to realize disability differently.     

Influence of Parenting Behavior on Psychosocial Adjustment in Early Adolescence: Mediated by Anger Regulation and Moderated by Gender

Emotion regulation (ER)—one of the most important developmental tasks in early adolescence—has been proposed to mediate the relation between parenting and adolescents’ psychosocial adjustment. The aim of this study was to examine the influence of parental psychological control and autonomy support on adolescents’ problem and prosocial behavior (Strengths and Difficulties Questionnaire), as well as to examine the mediating role of adolescents’ anger regulation and the moderating effect of gender. We collected three‐year longitudinal questionnaire data from N = 923 parents and their (at first assessment) 9‐ to 13‐year‐old children. Path‐analysis results mainly support the mediating role of adolescents’ adaptive and maladaptive anger regulation and suggest parental autonomy support to be beneficial for regulatory abilities and psychosocial adjustment, whereas the opposite was found for psychological control. Gender differences were found for parent report data, but not for adolescent report data. Practical and theoretical implications are discussed.     

基于Pro/E的转换接头CAD/CAPP系统设计

钻柱转换接头是石油产品中的一类标准件,但在实际工作中,因需要不同而频繁变化且种类繁多。根据转换接头的特点,建立结构数据库,用VB语言编程,以Pro/E和AutoCAD为开发平台,完成了转换接头的CAD/CAPP集成系统软件设计。该软件利用Pro/PROGRAM实现转换接头的参数化设计,能自动生成转换接头的三维实体图、二维工程图、机械加工工艺过程卡和机械加工工序卡。