Human Capital and Growth Cycles

This paper studies the dynamic interaction between human capital accumulation and economic growth. Capital market imperfections and an indivisibility in human capital investment prevent poor agents from accumulating skills, the acquisition of which positively affects technological progress. More productive technologies in turn require more sophisticated qualification and involve higher training costs. The equilibrium dynamics can be characterized by the joint evolution of productivity growth, the schooling costs, and the income distribution. Under our assumptions, individual incomes follow a non-linear Markov chain. This non-linearity generates endogenous fluctuations of schooling activities and the rate at which productivity improvements occur. We thank an anonymous referee for many helpful suggestions. Support from the German Research Foundation (DFG) under grant KA1519/2-2 is gratefully acknowledged.     

基于时间约束的多源多品种随机配送系统模型

在基于时间竞争的随机需求环境下,配送系统设计除了使系统总费用的期望值最小外,还要考虑系统稳定性和服务水平等方面的要求。在说明了建模的假设条件后,建立了考虑随机需求和时间约束的多源配送系统随机模型。通过等价变换,将随机模型转化为确定性等价问题,从而方便了问题的求解。     

Distributional aspects of the divisibility of money: an example

Summary. I highlight the importance of the distributional aspects of moneys divisibility by comparing a search-theoretic model with random transfers of indivisible money balances, to one with deterministic transfers of partially divisible balances. Randomization allows price flexibility, as if money were fully divisible. Partial divisibility does not, but allows money redistributions. An example of the relevance of such extensive margin aspects of divisibility is provided.JEL Classification Numbers: D30, D83, E40.I thank Dean Corbae and seminars participants at the Federal Reserve Bank of Richmond, University of Texas at Austin, Purdue University, the Midwest Macroeconomics Meetings, the Central Bank Institute of the Federal Reserve Bank of Cleveland, and the meetings of the Society for the Advancement of Economic Theory, where this work has been presented during the years 2002 and 2003.     

商业物流的现状调研和对策思考

随着市场竞争的不断加剧．作为企业第三利润源的物流越来越受到各个企业的重视。物流服务范围很广，可分为采购物流、生产物流、销售物流、商业物流和逆向物流等等。不同的物流服务对物流运营商提出了不同的要求。本文通过市场调研．对我国商业物流的现状进行系统的实证分析．总结商业物流的特性与发展规律，探讨商业物流存在的问题和面临的挑战，并提出改进的建议。     

基于启发式算法的成品油配送计划研究

通过对成品油配送计划特点的研究与分析，建立了成品油配送计划编制的数学模型；并设计了模型求解方案；通过对实验结果的分析，证明本文设计的算法快速、有效、稳定。     

越库作业调度问题及其启发式算法研究

主要研究两台机器环境下的以加权完工时间和为目标函数的越库调度问题。首先针对两机器越库调度问题进行研究与分析,给出该问题最优解的若干性质;其次,基于最优解的性质,提出求解该问题的启发式算法,并在此基础上对所给算法进行改进;最后,通过数值实验与动态规划算法比较,证明所给算法及其改进算法的有效性。     

模糊聚类分析在配送中心订货策略中的应用

针对传统ABC分类方法的局限性,提出了面向订货策略的物料模糊聚类分析方法,以物料订货量和物料单价作为聚类指标,对物料进行模糊聚类分析,对于不同类别的物料实施不同的订货策略。给出了一个模糊聚类应用于订货策略的实例,并与基于ABC分类的库存控制系统进行了对比,表明基于多因素模糊聚类的库存控制系统能有效降低库存成本。     

村镇连锁经营配送系统关键技术问题分析

论文充分考虑村镇连锁经营配送系统的影响因素．对村镇连锁经营配送系统中的配送中心规划仿真技术和城乡双向物流问题进行深入的技术分析．同时提出了典型的村镇连锁经营管理与配送决策模型。     

Exceptional Convergence of the Sample Variance

The case is investigated when Hoeffding's one sample U–statistic theorem for the sample variance S² is not applicable. It is shown that this occurs only when the parent distribution is the two–point distribution with jumps of equal magnitude. For this exceptional case the standardised S² is shown to converge in distribution to (1 – V )√2, where V has chi–square distribution with one degree of freedom.     

价值、财富与分配"新四说"

目前，学术界在商品价值、社会财富和分配关系的基本理论研究方面仍没有取得共识。为了清晰地使有关价值、财富与分配的各种现象和本质联系都可得到圆满的科学说明，笔者提出“新四说”：各种生产性活劳动创造商品价值——活劳动价值说；全生产要素或经济要素创造社会财富或商品使用价值——全要素财富说；多种产权关系决定按资和按劳等多种分配方式——多产权分配说；按生产要素贡献分配的形式是要素所有者创造价值和财富并据此参与分配，而实质是按生产要素产权分配——按要素贡献的分配形式与实质说(按贡分配形质说)。