钢筋混凝土抗震结构的多目标多级优化设计

本文同时将多目标和多级优化设计理论应用于钢筋混凝土框架结构的抗震设计中，把整个优化过程分为两级优化来处理，第一级优化以结构的整体位移和结构重量两个目标函数为第一级优化目标进行优化设计。第二级优化以结构的延性为目标函数，对截面进行最优配筋计算，并计算了钢筋混凝土框架结构的算例。结果表明，本文提出的理论和计算方法是合理的。     

基于Excel的飞机舱门结构强度自动化计算技术

文章通过Excel软件内置的计算函数和强大的VBA语言编程功能，编制了舱门框梁结构强度自动化计算程序，具有完成多工况、多截面的批量处理能力，实现了该类构件强度的自动计算，在设定目标的前提下还可以对设计参数进行优化，有效减轻结构重量。     

预应力混凝土简支梁设计与分析

结合某一办公楼屋面预应力钢筋混凝土梁的设计,介绍了预应力梁的工作机理,进行了该梁的截面和材料的选取及配筋计算,采用ANSYS有限元软件进行了预应力钢筋混凝土梁的挠度验算,最后验算了简支梁的裂缝,可为初级设计人员的设计提供参考和借鉴。     

核爆等效静载作用下工字型钢梁截面优化设计

应用ANSYS有限元分析程序建立了工字型截面钢粱的参数化有限元模型和优化数学模型,用ANSYS参数化设计语言编制了有限元分析文件及优化控制文件,对梁截面进行优化分析,得到了工宇型钢梁的最优截面型式,该方法优化效果显著,且计算效率高。     

基于有限元的预应力混凝土梁桥的优化分析

介绍了结构优化设计的基本原理和在Ansys软件中的实现过程，在有限元分析中钢筋混凝土模型和预应力模型的实现方案，及如何在Ansys软件中建立钢筋混凝土单元模型和预应力单元模型。并讨论在优化过程中各参数选取时要考虑的因素。最后提供了一个预应力混凝土简支T型梁的优化计算模型，从而提供了基于有限元的预应力混凝土梁桥优化分析的具体实现方法，为更复杂的优化计算提供了计算基础。     

分析变截面梁受弯变形的样条有限点法

对于变截面梁受弯变形位移的计算,文章利用样条函数构造位移函数,对样条节点之间的梁段进行刚度离散,先求出各梁段独立的势能泛函,再根据能量守恒原则及"势能求和",利用变分原理使问题得以求解.本法满足一定的工程精度要求,易于编程,适用于桥梁、房屋等大跨度变截面梁结构的位移计算,具有一定的工程实际参考价值.     

基于遗传算法的钢筋混凝土梁离散优化设计

首先给出钢筋混凝土矩形截面简支梁的离散优化模型，进而给出了简化的数学模型，设计了相应的适应度函数，用改进遗传算法来寻求最优设计方案，取得了较好的效果。     

分析变截面梁受弯变形的样条有限点法

对于变截面梁受弯变形位移的计算,文章利用样条函数构造位移函数,对样条节点之间的梁段进行刚度离散,先求出各梁段独立的势能泛函,再根据能量守恒原则及“势能求和”,利用变分原理使问题得以求解。本法满足一定的工程精度要求,易于编程,适用于桥梁、房屋等大跨度变截面梁结构的位移计算,具有一定的工程实际参考价值。     

在役RC框架结构截面的灵敏度分析及其应用

本文给出了钢筋混凝土框架结构截面约束的重要度和灵敏度概念以及相应的计算方法，并将结果用于在役结构震前维修加固的优化决策。     

坡折梁板屋盖的荷载效应交互作用及其分离式模型分析

现浇钢筋混凝土坡折梁板屋盖可进行梁板分离假设,建立计算模型。通过折板对圈梁的拉结传递水平推力交互到折梁支座,从而减少折梁的跨中正弯矩,达到减少折梁截面有效高度的目的。     

DEA在仓库运作管理中的应用

数据包络分析能对决策单元的有效性进行评价。本文应用数据包络分析的C2R模型,对仓库的运作效率进行研究。选取某部的8个备件仓库为样本,基于C2R模型计算结果,得到一些有价值的仓库运作管理方面的信息。     

Efficiency analysis of Norwegian district courts

This paper examines the efficiency of the Norwegian district courts with the aim of suggesting ways of improving this efficiency. Pooling the observations for the period 1983 to 1988 efficiency measures are calculated for each court using the nonparametric data envelopment analysis (DEA) method. The results show estimates of overmanning due to technical inefficiency. Comparisons are made between the specialized city courts and the generalized rural courts. When using the yearly observations Malmquist indices are calculated to estimate the rate of productivity change. Finally the paper addresses the questions of how the information from DEA can be used by the courts to become more efficient.The editor of this paper was Knox Lovell.     

中国各地区集约经济运营绩效的DEA评价

DEA方法是进行相对有效性评价的一种方法。其最先提出并被广泛应用的C2R模型可同时判断决策单元是否同时满足技术有效和规模有效。通过利用DEA模型对我国30个地区的集约经营效率进行了分析评价,并探讨了制约我国各地区集约经济发展的重要因素及其对策问题。     

Indirect productivity measurement

Caves, Christensen and Diewert [1982a] showed that the Törnqvist productivity index is superlative in a considerably more general sense than had been previously believed. We examine the allocative and technical efficiency hypotheses on which their finding rests. We show that the allocative efficiency hypothesis can be modified, which makes the Törnqvist index superlative in a wider sense than even Caves, Christensen and Diewert showed, since it is consistent with a type of allocative efficiency other than the standard cost minimization and revenue maximization hypotheses considered by Caves, Christensen and Diewert. We also show that if the technical efficiency hypothesis is relaxed, the CCD result may no longer hold, and the distance functions that form the basis of the Malmquist productivity indexes, and hence of the Törnqvist productivity index, must be calculated. We then show how to calculate the underlying distance functions, and we argue that there are real advantages to doing so.The refereeing process of this paper was handled through N.R. Adam.     

DEA方法在供应链绩效评价中的应用

阐述了供应链绩效评价的特征及重要性。叙述了数据包络分析方法(DEA)方法的基本原理和模型,进而利用DEA中的C2R模型和C2GS2模型对供应链绩效进行评价分析。算例分析表明该方法可以有效地评价不同供应链体系的相对规模性和技术有效性,找出其非DEA有效的影响因素,并通过在生产前沿面上的投影分析,给出了改进措施。评价过程与结果均较客观、合理。     

A novel method for computing single output for DEA with application in hospital efficiency

There are two main methods for measuring the efficiency of decision-making units (DMUs): data envelopment analysis (DEA) and stochastic frontier analysis (SFA). Each of these methods has advantages and disadvantages. DEA is more popular in the literature due to its simplicity, as it does not require any pre-assumption and can be used for measuring the efficiency of DMUs with multiple inputs and multiple outputs, whereas SFA is a parametric approach that is applicable to multiple inputs and a single output. Since many applied studies feature multiple output variables, SFA cannot be used in such cases. In this research, a unique method to transform multiple outputs to a virtual single output is proposed. We are thus able to obtain efficiency scores from calculated virtual single output by the proposed method that are close (or even the same depending on targeted parameters at the expense of computation time and resources) to the efficiency scores obtained from multiple outputs of DEA. This will enable us to use SFA with a virtual single output. The proposed method is validated using a simulation study, and its usefulness is demonstrated with real application by using a hospital dataset from Turkey.     

论工作流程中各环节的“界”定

随着企业的不断发展,分工越来越细化,企业的工作流程被细分为若干个工作环节。为了避免分工不明确、权责不清晰的弊端,我们必须要对工作流程中不同环节的"边界"进行界定,以提高工作效率。"抽屉式"管理已经风靡于现代管理学界的人力资源管理,我们同样可以借鉴"抽屉式"管理的方法来实现对工作流程中各环节的"界"定。     

Visualizing Efficiency and Reference Relations in Data Envelopment Analysis with an Application to the Branches of a German Bank

The interest in Data Envelopment Analysis (DEA) as a method for analyzing the productivity of homogeneous Decision Making Units (DMUs) has significantly increased in recent years. One of the main goals of DEA is to measure for each DMU its production efficiency relative to the other DMUs under analysis. Apart from a relative efficiency score, DEA also provides reference DMUs for inefficient DMUs. An inefficient DMU has, in general, more than one reference DMU, and an efficient DMU may be a reference unit for a large number of inefficient DMUs. These reference and efficiency relations describe a net which connects efficient and inefficient DMUs. We visualize this net by applying Sammons mapping. Such a visualization provides a very compact representation of the respective reference and efficiency relations and it helps to identify for an inefficient DMU efficient DMUs respectively DMUs with a high efficiency score which have a similar structure and can therefore be used as models. Furthermore, it can also be applied to visualize potential outliers in a very efficient way.JEL Classification: C14, C61, D24, M2     

Multiple Comparisons with the Best: Bayesian Precision Measures of Efficiency Rankings

A large literature measures the allocative and technical efficiency of a set of firms using econometric techniques to estimate stochastic production frontiers or distance functions. Typically, researchers compute only the precision of individual efficiency rankings. Recently, Horrace and Schmidt (Journal of Applied Economics 15, 1–26, 2000) have applied sampling theoretic statistical techniques known as multiple comparisons with a control (MCC) and multiple comparisons with the best (MCB) to make statistical comparisons of efficiency rankings. As an alternative, this paper offers a Bayesian multiple comparison procedure that we argue is simpler to implement, gives the researcher increased flexibility over the type of comparison, and provides greater, and more intuitive, information content. For these methods and a parametric bootstrap technique, we carry out multiple comparisons of technical efficiency rankings for a set of U.S. electric generating firms, estimated using a distance function framework. We find that the Bayesian method provides substantially more precise inferences than obtained using the MCB and MCC methods.Jel Classification: C11, C32, D24.     

Self‐Interest vs. Greed and the Limitations of the Invisible Hand

Markets can only function well if there is an appropriate legal framework to restrict the behavior of market participants; however, the legal framework is inevitably inadequate. A “greedy” market participant that seeks to gain at the expense of others can usually find some way to do so. This might be done within the legal framework, or it might involve a violation of the law that is difficult to enforce. Since the legal system does not generally guarantee that markets can function efficiently, there is a role for other institutions to foster a more enlightened self‐interest as a social norm and thus improve efficiency.