Theoretical perspectives of trade-off analysis using DEA

Because of the piecewise linear nature of the frontier in data envelopment analysis (DEA), estimated marginal rates of substitution are only valid for infinitesimal, or small finite, changes in one or more variables. Analysing the impacts of very small changes is not adequate for many situations, where the consequences of substantial changes in variables are of interest to for instance managers. This paper develops methods for evaluating larger, i.e. non-marginal, tradeoffs between variables in DEA. The methods are capable of handling both scalar and additive changes. Finally, the approaches for evaluating basic pairwise tradeoffs are generalised in order to enable assessment of the impact on one or more throughputs of the change in one or more of the other throughputs.     

汉英语码转换的句法特点和结构限制

通过分析实际语料验证波普拉克的“自由语素限制和对等限制”以及斯科顿的“主体语言构造模式”理论,可探讨汉英语码转换的句法特点和结构限制。研究得出,“主体语言构造模式”理论提出了更为合适的分析框架,更具有普遍性和说服力。     

物流中的时间约束模型

运用供应链管理过程中出现的最大最小时差,来讨论物流公司在货物配送过程中,如何较好地满足供应商或客户对时间的不同要求,以此来建立时间约束模型,解决调度中的问题。特别是针对客户对运输时间的要求为连续变化的情况,引入了参数规划的模型和解法。     

An estimating equation for parametric shared frailty models with marginal additive hazards

Summary.  Multivariate failure time data arise when data consist of clusters in which the failure times may be dependent. A popular approach to such data is the marginal proportional hazards model with estimation under the working independence assumption. In some contexts, however, it may be more reasonable to use the marginal additive hazards model. We derive asymptotic properties of the Lin and Ying estimators for the marginal additive hazards model for multivariate failure time data. Furthermore we suggest estimating equations for the regression parameters and association parameters in parametric shared frailty models with marginal additive hazards by using the Lin and Ying estimators. We give the large sample properties of the estimators arising from these estimating equations and investigate their small sample properties by Monte Carlo simulation. A real example is provided for illustration.     

课程先行性的研究与应用

文章描述了课程先行性的内涵,定义了由课程先行性所派生的先行性约束关系,分析了机械自动化专业各课系之间的先行性关系。根据机械自动化专业的教学课程系列,设计了课程先行性关系图,说明了课程先行性分析对教学计划制定的意义。     

Asymptotic normality for chi-bar-square distributions

Chi-bar-square distributions, which are mixtures of chi-square distributions, mixed over their degrees of freedom, often occur when testing hypotheses that involve inequality constraints. Here, necessary and sufficient conditions on the mixing or weighting distribution are found to ensure asymptotic normality of the corresponding chi-bar-square distribution. Essentially, asymptotic normality occurs for the chi-bar-square distribution if either the ratio of the mean to the variance of the mixing distribution goes to infinity, or the weighting distribution itself is asymptotically normal. Other than a combination of these two phenomena, this is also the only way for asymptotic normality to hold. Several examples of pertinent chi-bar-square distributions are shown to be asymptotically normal by the results in this paper.     

整体开发三峡黄金旅游带的路径探讨

重庆三峡黄金旅游带是旅游资源富集和市场潜力极大的区域。由于管理体制不顺,规划不系统,产品同质化严重,投入引导机制不健全,市场主体不明晰等多种原因,影响了旅游业的发展。本文从实际出发,分析了整体开发的可行性,并提出了创新体制、机制,实行集团化经营,打造旅游品牌,实施可持续发展等对策措施。     

英语轭式搭配的修辞特点及其汉译

本文概述了英语轭式搭配的特点及其修辞效果,并就轭式搭配的汉译进行了探讨,提出了用汉语的拈连,对偶,并列的四字格及排比句对轭式搭配作意义和修辞上的补偿.     

合作金融的制度视角

理论界对于是否要坚持合作金融一直存有争论,从这些争论中可以看出,我们对于合作金融的认识仍存在误区。本文在界定了合作金融的内涵之后,分析了合作金融产生的制度约束因素,并在此基础上提出了我国在利用合作金融时应注意的几个问题。     

信号方向误差对自适应阵的影响

讨论信号方向偏离约束方向(即信号方向误差)对线性约束自适应阵性能的影响.把输出信噪比看作是信号方向和输入信噪比的函数,研究了输出信噪比同信号方向和输入信噪比的关系.通过分析,结果发现在一定的输入信噪比下,要求的输出信噪比越大,信号方向误差就应越小;对具有一定方向误差的信号,输入信噪比越大,有用信号受到的抑制就越厉害;当干扰信号存在时,阵对信号方向误差的敏感度减少.