Consumption Over the Life Cycle

This paper estimates a structural model of optimal life‐cycle consumption expenditures in the presence of realistic labor income uncertainty. We employ synthetic cohort techniques and Consumer Expenditure Survey data to construct average age‐profiles of consumption and income over the working lives of typical households across different education and occupation groups. The model fits the profiles quite well. In addition to providing reasonable estimates of the discount rate and risk aversion, we find that consumer behavior changes strikingly over the life cycle. Young consumers behave as buffer‐stock agents. Around age 40, the typical household starts accumulating liquid assets for retirement and its behavior mimics more closely that of a certainty equivalent consumer. Our methodology provides a natural decomposition of saving and wealth into its precautionary and life‐cycle components.     

招标与投标竞争系统决策模型及其应用

招投标理论所研究的首要问题是投标商的投标策略问题,其中最优报价尤为重要。本文利用两种方法-解析法和利润法,解决了独立投标中的最优报价问题。     

Combining forecasts of electricity consumption in China with time-varying weights updated by a high-order Markov chain model

Electricity consumption forecasting has been always playing a vital role in power system management and planning. Inaccurate prediction may cause wastes of scarce energy resource or electricity shortages. However, forecasting electricity consumption has proven to be a challenging task due to various unstable factors. Especially, China is undergoing a period of economic transition, which highlights this difficulty. This paper proposes a time-varying-weight combining method, i.e. High-order Markov chain based Time-varying Weighted Average (HM-TWA) method to predict the monthly electricity consumption in China. HM-TWA first calculates the in-sample time-varying combining weights by quadratic programming for the individual forecasts. Then it predicts the out-of-sample time-varying adaptive weights through extrapolating these in-sample weights using a high-order Markov chain model. Finally, the combined forecasts can be obtained. In addition, to ensure that the sample data have the same properties as the required forecasts, a reasonable multi-step-ahead forecasting scheme is designed for HM-TWA. The out-of-sample forecasting performance evaluation shows that HM-TWA outperforms the component models and traditional combining methods, and its effectiveness is further verified by comparing it with some other existing models.     

YAG:RE3+(RE=Eu,Tb)的制备及发光特性研究

利用柠檬酸-凝胶方法,以Y2O3,Eu2O3,Tb4O7和Al(NO3)3·9H2O作为初始原料,柠檬酸作为配位剂,成功制备出了Y3Al5O12:Eu3+(Tb3+)发光材料,其烧结温度为1?000℃,时间4?h.通过X射线衍射测试,表征Y3Al5O12为单相;计算其晶胞参数,发现晶胞体积v随着pH值的增大而增大.对Y3Al5O12:Eu3+(Tb3+)系列样品在紫外光谱区域和真空紫外光谱区域的发光性能进行了研究,结果表明:在真空紫外光谱区域激发下,Eu3+(Tb3+)的猝灭浓度比在紫外光谱区域激发下的低.     

显示问题式教材编纂法构想

传统的教材编纂法属于＂显示完美式教材编纂法＂,力求显示教材已将相应领域的问题都圆满解决,对于其中存在的问题不有意加以显示,甚至有意加以掩藏,故无法激发学生的创新意识、创新能力,甚或对创新有抑制作用。应采用＂显示问题式教材编纂法＂,力求将相应领域存在的各种问题显示出来,使学生产生创新的意念,明了创新的着力点,从而有力地促进学生创新能力的提高。     

双液注浆锚管加固在渗水软弱围岩浅埋偏压隧道中的应用

通过乌坑坝隧道北京端左线冲沟地段的施工实例，介绍渗水软弱围岩浅埋偏压隧道地表双液注浆锚管加固的施工方法，并对加固效果及其优缺点进行分析．     

观念·模式──谈高校校园规划设计思路的变化

在剖析以现代教育观念为背景的高校校园规划设计与传统做法存在的本质差别的基础上，阐述了当代高校校园规划设计的基本思路与方法．     

背越式跳高易犯错误及其纠正方法

通过对背跃式跳高的助跑、起跳、过杆和落地，各阶段容易产生的错误动作进行分析，找出易犯错误，分析原因，提出解决这些问题应采取的方法，为更好地学习背跃式跳高提供理论依据。     

素描教学的价值和意义

在素描教学中,由于对其体系的意义和价值缺乏基本认识,仍存在着单纯追求技法的倾向。素描教学方法说到底就是不断引导、启发学生进行观察实践和作画实践的过程,也是不断提高学生审美修养和悟性的过程。     

有限宽裂纹板受一对集中剪力时弹塑性解

针对运用断裂力学传统方法进行裂纹尖端的弹塑性应力场分析均为小范围塑性区的假定，不能准确反映塑性区应力情况的问题，利用裂纹线场分析方法，对理想弹塑性材料的有限宽平面板在裂纹面受到一对集中剪力作用时裂纹线附近的应力场及弹塑性边界进行了分析。不采用小范围塑性区的假设，直接通过将裂纹线附近弹塑性边界上弹性应力场与塑性应力场的匹配，获得了裂纹线附近弹塑性应力场的解析解以及弹塑性边界上单位法向量的表达式。用裂纹线分析方法可以准确地反映裂纹附近的弹塑性应力分布，该种方法的应用将成为断裂力学的一个重要发展方向，对石油天然气构造应力分析、材料力学分析具有参考价值。