AN EXTRAPOLATION METHODFOR FINITE ELEMENT APPROXIMATION OF INTEGRODIFFERENTIAL EQUATIONS WITH PARAMETERS

In this paper,we discuss the accelerating convergence method for finite elementapproximation of integro-differential equations with parameters.As applications,we give theerror estimates of finite element for the first kind of Fredholm integral equation,particularlyfor the Volterra integral equation with kernel condition k(x,x)=0.     

A super-resolution algorithm for spectral estimation and time series extrapolation

Recent developments in the signal processing field of electrical engineering have resulted in several frequency domain methods of extrapolating a time series. Insight gained in testing one such method, the Papoulis algorithm, has been used to suggest modifications which greatly improve its performance under most operating conditions where real data are concerned. The modified Papoulis method thus developed has been applied to electricity load forecasting over the short and medium term, as well as to world economic and energy data, to assess the cyclic structure present in each series about a trend.     

What is mechanistic evidence,and why do we need it for evidence-based policy?

It has recently been argued that successful evidence-based policy should rely on two kinds of evidence: statistical and mechanistic. The former is held to be evidence that a policy brings about the desired outcome, and the latter concerns how it does so. Although agreeing with the spirit of this proposal, we argue that the underlying conception of mechanistic evidence as evidence that is different in kind from correlational, difference-making or statistical evidence, does not correctly capture the role that information about mechanisms should play in evidence-based policy. We offer an alternative account of mechanistic evidence as information concerning the causal pathway connecting the policy intervention to its outcome. Not only can this be analyzed as evidence of difference-making, it is also to be found at any level and is obtainable by a broad range of methods, both experimental and observational. Using behavioral policy as an illustration, we draw the implications of this revised understanding of mechanistic evidence for debates concerning policy extrapolation, evidence hierarchies, and evidence integration.     

高维解析信号的外推

文献［２］给出了一维解析信号的外推方法，本文讨论了高维解析信号的外推问题并得到了相应的结果。     

外推法计算高温气体恒压摩尔热容

恒压摩尔热容是化工热力学中计算过程热力学性质变化所需的基础数据,但手册中通常难以查到计算气体在高温范围恒压摩尔热容所需的数据。文中提出一种计算气体在高温范围的恒压摩尔热容的方法:首先从手册数据适用的温度范围的上限起按一定的温度间隔逐点外推,再用五点曲线平滑法处理各点数据,然后将所得各点数据用线性回归方法处理得到恒压摩尔热容与温度的函数关系式: Cp,m=a0+a1T+a2T2+a3T3+a4T4,用以计算气体在高温范围的恒压摩尔热容。对CO气体,将用此方法计算的结果与用统计热力学方法计算的结果进行了比较,二者具有很好的一致性。     

Judgemental revision of sales forecasts: A longitudinal eetension

When quantitative models are used for short-term multi-item sales forecasts it is possible that the managers who use such forecasts may disagree with at least some of the estimates obtained, and wish to change them so that they become more consistent with their own (subjective) evaluation of the marketplace. This study reports on an analysis of the effectiveness of judgemental revision of sales forecasts over six quarterly forecasting periods. The results give general support for the practice of forecast manipulation as a means of improving forecasting accuracy. It is also observed that the effectiveness of revision activity varies across different time periods.     

Towards a taxonomy of forecast error measures a factor-comparative investigation of forecast error dimensions

This study explores the nature of information conveyed by 14 error measures drawn from the literature, using real-life forecasting data from 691 individual product items over six quarterly periods. Principal components analysis is used to derive factor solutions that are subsequently compared for two forecasting methods, a version of Holt's exponential smoothing, and the random walk model (Naive 1). The results reveal four underlying forecast error dimensions that are stable across the two factor solutions. The potentially confounding influence of sales volume on the derived error dimensions is also explored via correlation analysis.     

Judgemental revision of sales forecasts: Effectiveness of forecast selection

When managers make revisions to sales forecasts initially generated by a rational quantitative model it is important that the particular forecasts selected for adjustment are those which would benefit most from the adjustment process (i.e. realize high errors). This study reports an empirical investigation on this issue, spanning six quarterly forecasting periods and incorporating forecasting data on over 850 products. The results show that the errors of the forecasts chosen for revision are, in general, higher than those which were not chosen. In addition, it is shown that managesrs tend to revise forecasts which are initially low, hence possibily introducing some degree of bias into the overall forecasts.     

矩形二次有限元解的外推

设u∈W~5,∞~(Ω)∩H_0~1(Ω)是模型问题-△u=f,u|_(0Ω)=0的解,u~h∈S~h是u的二次有限元逼近我们得到了下面的外推估计:■其中Z_0是粗h一网格的任何角节点。     

多级模板匹配的外推技术

本文提出一种可应用于多级模板匹配算法的外推技术;分析了配准点外推估计的无偏性、定位精度的改善和计算的简单性;导出了外推参数的计算公式。理论分析和实验结果表明,对于三种基本算法,外推技术能在几乎不增加计算量的情况下达到比常规算法更高的定位精度。而且,精度的提高能够不受加性噪声和几何失真的影响。