On the selection of forecasting models

It is standard in applied work to select forecasting models by ranking candidate models by their prediction mean squared error (PMSE) in simulated out-of-sample (SOOS) forecasts. Alternatively, forecast models may be selected using information criteria (IC). We compare the asymptotic and finite-sample properties of these methods in terms of their ability to mimimize the true out-of-sample PMSE, allowing for possible misspecification of the forecast models under consideration. We show that under suitable conditions the IC method will be consistent for the best approximating model among the candidate models. In contrast, under standard assumptions the SOOS method, whether based on recursive or rolling regressions, will select overparameterized models with positive probability, resulting in excessive finite-sample PMSEs.     

谈高职数学中的“数学猜想法”

高职数学课程中常用的“数学猜想法”有:归纳猜想法、类比猜想法、几何直观猜想法、特殊化(一般化)猜想法、直觉猜想法、物理模拟猜想法、审美猜想法、实验猜想法等等,这些猜想方法既有联系,又有相对的独立性。恰当运用课程中的“数学猜想法,”发挥它在“思维的体操”中的作用,能够培养学生的创造性思维能力,提高学生的数学素养。     

Discussion and Analysis about Duration Method Based on Marginal Analysis

The selective principle of mutually exclusive project is the maximum of net present value, It is difficult to make decision when NPVA is equal to NPVLB. Some assistant analyses are put forward in ＂Enterprise Investment Decision Management＂. The scientific marginal analysis shows that the assistant analyses including the duration analysis are wrong. This problem can be solved by the classical marginal analysis.     

C4烃资源的生产、利用及发展设想

本文介绍了目前大庆石化公司炼油、乙烯装置碳四烃资源的生产及实际利用情况,并结合我国的实际情况对未来碳四烃的综合利用提出了一些设想和建议,最后对我院的高端基聚异丁烯的研制情况作一简单的介绍。     

Effects of EU dairy policy reform for Dutch dairy farming: a primal approach using GMM estimation

This paper estimates a production function for milk using ageneralised method of moments estimator to avoid the endogeneityproblem. Using the first-order conditions for profit maximisation,the economic effects for individual Dutch dairy farms of the2003 EU dairy policy reform are analysed. With an expected milkprice decrease of 21 per cent, profit decreases on average by22 per cent. EU direct payments compensate for roughly 53 percent of this fall in profit. The profit reduction means that69 per cent of all small farms have negative income from farming,compared with 15 per cent in the initial situation.     

中国会计国际化问题研究

顺序分配法是解决辅助生产费用分配时常采用的方法之一 ,该方法运用的关键在于确认辅助生产部门费用分配顺序 ;而要解决费用分配顺序 ,先必须解决顺序确定的标准。但现行成本会计在确定费用分配标准时 ,缺乏统一的科学的认识 ,致使实际运用顺序分配解决辅助生产费用分配时 ,排     

学习高等数学应处理好几个问题

学好高等数学要认清其重要性,弄清其特点,掌握与初等数学的不同点,缩短不适应期,完成从中学到大学学习的尽早过渡,应在听课和完成作业环节上重点研究学习方法.     

把案例教学引入英语课堂的必要性和可行性

中国加入WTO以后，要求高等教育培养出更多的适应经济全球化需要的、能够进入国际市场进行竞争的复合型人才．这种需求对于与之不相适应的教育观念、教育结构、人才培养模式、教育内容与方法等提出了严峻的挑战。在此大背景下．对案例教学——这种培养学生实际能力的教学方法．是否可以运用到大学英语教学中来的研究就显得尤为重要。该文从案例教学的性质特征出发．阐述了运用案例教学的必要性和可行性，有助于推动英语教学方法的改革。     

铁路货车周转时间计算方法研究

通过对现行铁路货车周转时间计算方法进行分析,指出由于定义的概念不清,存在车辆相关法误差较大、时间相关法可行性较差,且工作量计算不准确等问题。同时,根据运输生产和资产经营的要求,阐述了改进的计算方法和实现措施。     

中外科技合作模式评价实证研究

采用主成分分析法与熵权法，以江苏省13家典型中外科技合作企业为样本，对中外科技合作模式进行量化指标的实证分析，并得出结论：技术辐射型中外科技合作模式为中外科技合作的最优模式。