级数收敛的概念评注

从级数、函数列的收敛理论出发,建立数项级数和函数项级数的收敛理论,即数项级数的收敛归结为它的部分和数列收敛是数学分析(高等数学)教学中很重要的一个环节;本文就是从级数收敛的定义出发来分析和探讨级数收敛的概念的.     

关于调和级数发散性的几种证明方法

调和级数是一个具体的、重要的数项级数,在级数理论中具有重要的地位.本文给出几种证明其发散性的不同方法,这对于熟悉调和级数,理解级数敛散性,掌握级数敛散性判定定理具有重要意义.     

利用伴随信息改善预测精度

本文指出了利用时间序列及其伴随序列的信息来获得最佳预测的方法。通常,伴随时间序列是输入时间序列,如果输出的变化趋于输入变化之所料,则称伴随时间序列为输出时间序列的“导前指示器”。     

关于函数的Fourier级数系统展开方法

设f(x)在区间[a,b]上满足Dirichlet充分条件,则f(x)在[a,b]上既可以展开成正弦函数,也可以展开成余弦函数。     

微分法在一类特殊常数项级数求和中的应用

本文介绍了一种通过构造幂级数求解常数项级数和的方法。该方法运用逐项微分法将幂级数的收敛和函数转化为相应的常系数线性微分方程,求出微分方程的通解从而得到相应常数项级数之和。并给出了相应的定理和例题来说明这一方法。     

Application of uncertainty reasoning based on cloud model in time series prediction

INTRODUCTIONTimeseriespredictionhasbeensuccessfullyusedinseveralapplicationareas,suchasmeteo rologicalforecasting (Andrei,1972 ) ,loadpre dictioninpowersystem (OuandLi,1999) ,marketprediction (Gilesetal.,1997) ,net worktrafficprediction (Edwardsetal.,1997…     

The Inveterate Tinkerer 15. Miscellaneous Fluid Instabilities

In this series of articles, the author discusses various phenomena in fluid dynamics, which may be investigated via tabletop experiments using low-cost or home-made instruments. The fifteenth article in this series demonstrates some fluid instabilities.     

The Inveterate Tinkerer 11. Marangoni Effect

In this series of articles, the authors discuss various phenomena in fluid dynamics, which may be investigated via tabletop experiments using low-cost or home-made instruments. The eleventh article in this series demonstrates the Marangoni effect.     

光山方言指示代词三分及相关问题

光山方言属中原官话,其指示代词有三系：＂这[te31]＂系、＂恁[n3′1]＂系和＂那[la31]＂系,中指＂恁＂系较有特色。文章结合语例对光山方言的三分指示代词进行了较为详尽的区分和描述,也考察了光山方言中指代词＂恁＂与人称代词＂你＂的音义关系,为有关语言学者进一步研究汉语指示代词的三分现象提供参考。     

CHARACTERISTIC FUNCTIONS OF BILINEAR TIME SERIES MODEL

Bilinear time series models are of importance to nonlinear time seriesanalysis.In this paper,the autocovariance function and the relation between linearand general bilinear time series models are derived.With the help of Volterra seriesexpansion,the impulse response function and frequency characteristic function of thegeneral bilinear time series model are also derived.     

The Inveterate Tinkerer

In this series of articles, the author discusses various phenomena in fluid dynamics, which may be investigated via tabletop experiments using low-cost or home-made instruments. The twelfth article in this series demonstrates some experiments with air bubbles in liquids.     

从“性”到“情”：女权主义，孰真孰假？——比较电视剧《欲望都市》和《好想好想谈恋爱》

电视作为一种文化的载体,在传播文化的同时,本身又体现了其所属社会的文化特征。本文通过比较美国电视剧《欲望都市》和该剧在中国的翻版《好想好想谈恋爱》中的女性主角在对待性以及男人和婚姻的态度上的异同,从而得出两剧在宣言女权主义这一问题上的根本差异,进而分析了造成这种差异的社会文化层面上的原因。     

基于时域卷积与双向GRU神经网络的时序预测模型

随着物联网技术和5G技术的发展,各类智能设备收集的时序数据规模急剧增长,为了利用深度学习技术对大规模时序数据进行预测,提出一种基于深度神经网络的时序预测模型。该模型首先利用时域卷积神经网络层对时序数据进行预处理,然后利用双向GRU神经网络层提取时序数据的前向特征和后向特征,最后对时序数据进行预测。在真实数据集上的实验结果表明,该模型相比传统长短期记忆网络模型,预测准确度提高了近70%,预测速度提高了近10%,可更好地满足对大规模时序数据的预测需求。     

“修正的克强指数”与GDP增长率时间序列建模分析

本文基于2008²011年的月度时间序列数据,建立了一元时间序列模型和二元时间序列的动态回归ARIMAX模型,运用ADF检验对各变量数据的平稳性进行检验,采用AIC、SBC准则选择相对最优模型.结果表明,可引入"修正的克强指数"对GDP增长率进行二元时间序列分析,并且建立的ARIMAX模型优于一元时间序列模型.     

The Inveterate Tinkerer

In this series of articles, the authors discuss various phenomena in fluid dynamics, which may be investigated via tabletop experiments using low-cost or home-made instruments. The thirteenth article in this series demonstrates some experiments with Hele–Shaw cells.     

正项级数敛散性判别法的综合探究

级数的中心问题是要判别其敛散性,在这方面已有许多丰富的研究成果。在已有结论的基础上归纳总结了正项级数敛散性判别法的技巧和方法,对有关判别法之间的强弱进行了归纳总结,并通过实例对正项级数敛散性判别进行梳理和强弱比较。     

Application of uncertainty reasoning based on cloud model in time series prediction

Time series prediction has been successfully used in several application areas, such as meteorological forecasting, market prediction, network traffic forecasting, etc., and a number of techniques have been developed for modeling and predicting time series. In the traditional exponential smoothing method, a fixed weight is assigned to data history, and the trend changes of time series are ignored. In this paper, an uncertainty reasoning method, based on cloud model, is employed in time series prediction, which uses cloud logic controller to adjust the smoothing coefficient of the simple exponential smoothing method dynamically to fit the current trend of the time series. The validity of this solution was proved by experiments on various data sets. Project (No. 2001AA112030) supported by the National Hi-Tech Development Program (863) of China     

p维向量型随机Dirichlet级数的增长性

通过引入辅助级数∑n=1^∞Une-Eλn^n，分别研究了P维向量型随机Dirichlet级数在收敛平面和收敛半平面上的增长性，证明了p维向量型随机Dirichlet级数和辅助级数在一定条件下增长级a．s．相等．     

The Formulas of Finding Sum of Several Infinite Series

We use the methed of seperating term,and easily obtain the following sum of two kinds of infinite series.write them here     

混沌时间序列的相关性及其应用

混沌时间序列分析不同于传统的时间序列分析,本质上是非线性动力学分析,在观念和方法上都有革命性的创新。探讨混沌时间序列的相关性及其应用。