大米市场价格波动态势及周期性特征分析

探索中国大米市场价格短期波动态势及周期性特征,以期为稳定农民的市场预期,提高其生产积极性提供参考。在对国内外大米市场价格波动分析的基础上,以2006年1月-2010年12月的中国大米市场价格周指数为样本,采用TARCH类模型,分析了中国大米市场价格的周期性特征。研究结果表明:中国大米市场价格具有显著的ARCH效应,其波动具有集簇性、非对称性、记忆性和持续性。提出政策建议:政府和相关主体可根据大米市场价格波动的特点,有针对性地对下期的大米市场价格进行预测,密切关注价格上行趋势,采取相应措施减缓中国大米市场价格短期剧烈波动。     

灰色周期关联度模型及其应用研究

灰色关联模型从统计序列几何形状的接近性和相似程序来判断其紧密程度,传统的灰色关联模型从统计序列的面积、斜率、变化速率等角度来计算其关联程度,这些关联模型受到统计序列横纵坐标(周期和振幅)的双重影响,这在分析统计序列间的单个因素间的关系时会产生其它因素的干扰。针对这一缺陷,本文提出了周期关联度模型,研究仅受周期因素影响的关联模型,证明该模型只与波形的波动周期和方向有关,不受曲线振幅的影响,且能表示出正负相关性,并应用该模型研究了GDP与居民消费间的周期关联性,取得了良好的效果。     

论生产力发展的阶段性要求

不同的国家和地区,生产力发展所处的阶段不同,发展要求也就不同,代表中国社会先进生产力发展要求必须充分把握我国生产力发展的阶段性特征。     

关于时变大系統之平稳振蕩

本文利用大系统分解理论来研究时变大系统之平稳振荡问题。首先通过构造一个特殊的函数,将一个微分大系统的有界性问题转化为一个代数不等的求解问题,由此得出用期解之存在性。然后,由上极限理论对大系统之非常稳定性进行研究,由此导出周期之唯一性。     

原子外层空轨道相对最稳定顺序周期性规则应用

本文介绍了原子外层空轨道相对最稳定顺序周期性规则和大周期概念与元素周期系的本质联系;元素周期律(特别是第二周期性)的解释;周期系各部分的相互联系和影响;未来元素的预测等.并对元素第二周期性原因、“镧系收缩后果”等问题作出新的解释.     

平面波垂直入射浸渍吸收剂蜂窝的反射特性(英文)

提出一个数值方法,计算当平面波垂直于蜂窝板入射时浸渍吸收剂的蜂窝的反射系数。在引入蜂窝壁表面阻抗后,借助于周期格林函数对无限大蜂窝表面建立了电场积分方程,用矩量法求解未知的表面电流。在8~12 GHz频段内,得到的不同蜂窝高度、不同吸收剂和不同浸渍厚度的数值结果表明,所提出的方法是高效的,可用于蜂窝制备和吸波结构的工作中。     

二阶常系数线性混合型周期系统的周期解

用Fourier分析的方法,给出了二阶常系数线性混合型周期系统的周期解存在且唯一的充要条件和一些充分条件.     

Threshold-range scaling of excitable cellular automata

Each cell of a two-dimensional lattice is painted one of colors, arranged in a color wheel. The colors advance (k tok+1 mod ) either automatically or by contact with at least a threshold number of successor colors in a prescribed local neighborhood. Discrete-time parallel systems of this sort in which color 0 updates by contact and the rest update automatically are called Greenberg-Hastings (GH) rules. A system in which all colors update by contact is called a cyclic cellular automation (CCA). Started from appropriate initial conditions, these models generate periodic traveling waves. Started from random configurations the same rules exhibit complex self-organization, typically characterized by nucleation of locally periodic ram's horns or spirals. Corresponding random processes give rise to a variety of forest fire equilibria that display large-scale stochastic wave fronts. This paper describes a framework, theoretically based, but relying on extensive interactive computer graphics experimentation, for investigation of the complex dynamics shared by excitable media in a broad spectrum of scientific contexts. By focusing on simple mathematical prototypes we hope to obtain a better understanding of the basic organizational principles underlying spatially distributed oscillating systems.     

On certain unbiased product estimators

When data on an auxiliary variate is available on all the units of the population, negatively correlated with the study variate, Robson (1957) and Murthy (1964) proposed product method of estimation for the estimation of the population total (mean) of the study variate. In this paper, we discuss a method given in Rao (1983) and obtain a simpler dervation of the class of unbiased product estimators for the case of Simple Random Sampling WithOut Replacement design as well as for the case of interpenetrating subsamples design which follows as a limiting case. Finally, we shall illustrate the results by means of two simple numerical example from live data.     

Mean Squared Error Matrix Comparisons of Some Restricted Almost Unbiased Estimators

In this article, we introduce two almost unbiased estimators for the vector of unknown parameters in a linear regression model when additional linear restrictions on the parameter vector are assumed to hold. Superiority of the two estimators under the mean squared error matrix (MSEM) is discussed. Furthermore, a numerical example and simulation study are given to illustrate some of the theoretical results.