Identification of asymmetric prediction intervals through causal forces

When causal forces are specified, the expected direction of the trend can be compared with the trend based on extrapolation. Series in which the expected trend conflicts with the extrapolated trend are called contrary series. We hypothesized that contrary series would have asymmetric forecast errors, with larger errors in the direction of the expected trend. Using annual series that contained minimal information about causality, we examined 671 contrary forecasts. As expected, most (81%) of the errors were in the direction of the causal forces. Also as expected, the asymmetries were more likely for longer forecast horizons; for six‐year‐ahead forecasts, 89% of the forecasts were in the expected direction. The asymmetries were often substantial. Contrary series should be flagged and treated separately when prediction intervals are estimated, perhaps by shifting the interval in the direction of the causal forces. Copyright © 2001 John Wiley & Sons, Ltd.     

R^n空间中闭光滑流形上的线性奇异积分方程

本文给出了高斯奇异积分的合成和反演公式,并且证明了R~n空间中闭光滑流形上的线性奇异积分方程的有关结果。     

连续闭映射与拓扑空间的分离性

讨论了连续闭映射对拓扑空间的分离性：T0、T1、T2、正则、正规、全正规是否保持或逆保持的问题。     

抽象二阶边值问题正解的存在性

讨论了有序Banach空间中的非线性二阶Dirichlet边值问题正解的存在性，并在非线性项满足一个易检验的序条件下，应用凝聚映射的拓扑度理论获得了该问题正解的存在性结果．     

Local to unity,long‐horizon forecasting thresholds for model selection in the AR(1)

This article introduces a novel framework for analysing long‐horizon forecasting of the near non‐stationary AR(1) model. Using the local to unity specification of the autoregressive parameter, I derive the asymptotic distributions of long‐horizon forecast errors both for the unrestricted AR(1), estimated using an ordinary least squares (OLS) regression, and for the random walk (RW). I then identify functions, relating local to unity ‘drift’ to forecast horizon, such that OLS and RW forecasts share the same expected square error. OLS forecasts are preferred on one side of these ‘forecasting thresholds’, while RW forecasts are preferred on the other. In addition to explaining the relative performance of forecasts from these two models, these thresholds prove useful in developing model selection criteria that help a forecaster reduce error. Copyright © 2004 John Wiley & Sons, Ltd.     

高校办公室管理职能的创新

在追求和谐发展的今天,高校办公室要拓宽办公室职能,树立以人为本的思想,围绕学校中心,承担好收集信息、辅助决策、沟通协调、传播信息、提供服务等职责。     

一类生化反应中的数学模型

讨论一类生化反应模型的闭轨的存在性，不存在性和唯一性。     

集值线性算子的闭图性质

设，Ｘ，Ｙ为实拓扑线性空间，Ｔ：Ｘ－Ｙ是Ｘ互Ｙ的一个集值线性算子，本文给出了算子Ｔ具有闭图象的一些等价格条件，并推广了经典的闭图象定理。     

Wppl-空间的遗传性

就wppl-空间进行了研究，举了一个实例说明wppl-空间不具有遗传性，同时证明了wppl-空间具有闭遗传性．     

强磁场中NO分子的模型势与闭合轨道

我们采用一种全新的方法来计算强外磁场中高里德堡态NO分子的模型势，此势把多通道的几何对称性考虑进去，以致此势在长程区和短程区都是适用的．利用哈密顿量的经典正则方程，我们还得到各通道的经典闭合轨道，从而为NO分子回归谱的计算做好准备．