On Some Nonparametric Tests of Dispersion

Let X and Y be random variables with distribution functions F and G and medians ζand η, respectively. X will be said to be more dispersed about the median than Y if F(x+ζ) – F(–x+ζ) G (x+η) – G (–x+η)for all x > O, with sharp inequality holding for some positive x. Asymptotically nonparametric tests for the hypothesis that F (x+ζ) = G (x+η) against alternatives of the above type (for ζ and η unknown), provided F(x+ζ) (but not necessarily G (x+η)) is symmetric and Fand G have bounded densities, are constructed from a subclass Of SUKHATME'S modified generalized U - statistics [12]. One simple test of this subclass turns out to be the MANN-WHITNEY test as performed on the |X_i–ζ| and | Y_j–η| where ζ and η are the corresponding sample medians. Consistency and PITMAN efficiencies of some of the tests proposed are discussed under two families of alternatives in which the Y's differ from the X's through departure from symmetry as well as by being more (less) dispersed: a model of “heterogeneous response” and the wellknown gross error model. The usual scale alternatives are also studied and the relationship of our tests to those previously given in the literature is pointed out.     

Some Improved Tests for Multivariate One-Sided Hypotheses

Multivariate one-sided hypothesis-testing problems are very common in clinical trials with multiple endpoints. The likelihood ratio test (LRT) and union-intersection test (UIT) are widely used for testing such problems. It is argued that, for many important multivariate one-sided testing problems, the LRT and UIT fail to adapt to the presence of subregions of varying dimensionalities on the boundary of the null parameter space and thus give undesirable results. Several improved tests are proposed that do adapt to the varying dimensionalities and hence reflect the evidence provided by the data more accurately than the LRT and UIT. Moreover, the proposed tests are often less biased and more powerful than the LRT and UIT.     

提高机加工柔性生产效率的几点思考

通过对发动机机加工柔性生产线换型运行进行分析,找到了影响机加工换型的主要原因,同时从加工工艺、刀具、工装夹具设备、测量系统等方面对柔性生产的影响因素进行了分析和总结,并通过具体运行实际和实验研究,得出了一些关于提高机加工柔性生产效率影响因素的结论及这些影响因素对效率提升的办法。     

提高机加工柔性生产效率的几点思考

通过对发动机机加工柔性生产线换型运行进行分析,找到了影响机加工换型的主要原因,同时从加工工艺、刀具、工装夹具设备、测量系统等方面对柔性生产的影响因素进行了分析和总结,并通过具体运行实际和实验研究,得出了一些关于提高机加工柔性生产效率影响因素的结论及这些影响因素对效率提升的办法。     

提高机加工柔性生产效率的几点思考

通过对发动机机加工柔性生产线换型运行进行分析,找到了影响机加工换型的主要原因,同时从加工工艺、刀具、工装夹具设备、潮量系统等方面对柔性生产的影响因素进行了分析和总结,并通过具体运行实际和实验研究,得出了一些关于提高机加工柔性生产效率影响因素的结论及这些影响因素对效率提升的办法.     

The Political Uses of Some Economic Ideas: The Trade‐Off Between Efficiency and Equality

The notion of a trade‐off between efficiency and equality is pervasive in many disciplines across the social sciences. Moreover, an imprecise notion of this well‐known dilemma is an integral part of the discourse of politicians and policy‐makers. The scientific status of the idea of a trade‐off between efficiency and equality is, however, a matter of contention. Philosophical dissections of the idea have already deflated the analytical cogency of most of its versions, while the economic literature trying to assess the empirical relation between growth and equality has shown contradicting results. This article, by focusing on the role this idea plays both in the discourse and strategy of social‐democratic parties, and in the social science explanations of their trajectories, argues that the pervasiveness of the notion of the trade‐off between efficiency and equality is best explained in terms of the political functions it can fulfill.     

The Performance of Structural Change Tests

This paper provides analytical and Monte Carlo studies of the effect of different types of structural change (residual variance, process mean and process persistence) on the performance of the Chow/Wald stability test. We focus on the first-order autoregressive model, which has been used to estimate and assess changes in inflation persistence. Our results show that the autoregressive model is a difficult subject for the Chow test.     

Tests for model specification in the presence of alternative hypotheses: Some further results

In Davidson and MacKinnon (1981), two of the present authors proposed a novel and very simple procedure for testing the specification of a nonlinear regression model against the evidence provided by a non-nested alternative. In this paper we extend their results in several directions. First, we relax a number of the assumptions of the previous paper; we admit the possibility that the nonlinear regression functions may depend on lagged dependent variables, and we do not require that the error terms be normally distributed. Second, we show how the earlier procedure may straightforwardly be generalized to the case where the two non-nested models involve different transformations of the dependent variable. Finally, we propose a simple procedure for testing non-nested linear regression models which have endogenous variables on the right-hand side, and have therefore been estimated by two-stage least squares.     

On the Use of Value Efficiency Analysis and Some Further Developments

The purpose of this paper is to discuss the use of Value Efficiency Analysis (VEA) in efficiency evaluation when preference information is taken into account. Value efficiency analysis is an approach, which applies the ideas developed for Multiple Objective Linear Programming (MOLP) to Data Envelopment Analysis (DEA). Preference information is given through the desirable structure of input- and output-values. The same values can be used for all units under evaluation or the values can be specific for each unit. A decision-maker can specify the input- and output-values subjectively without any support or (s)he can use a multiple criteria support system to assist him/her to find those values on the efficient frontier. The underlying assumption is that the most preferred values maximize the decision-maker's implicitly known value function in a production possibility set or a subset. The purpose of value efficiency analysis is to estimate a need to increase outputs and/or decrease inputs for reaching the indifference contour of the value function at the optimum. In this paper, we briefly review the main ideas in value efficiency analysis and discuss practical aspects related to the use of value efficiency analysis. We also consider some extensions.     

Evolving Market Efficiency with an Application to Some Bulgarian Shares

With new technically advanced methods and computers at our disposal, the efficient market hypothesis is once again being debated. At the same time, we are witnessing an unprecedented growth in both existing and new financial markets. These new markets are often in economies which have just recently embraced free market economics; we term these stock markets infant markets. Such stock markets are obviously not efficient in allocating the supply of savings to productive capital. We do not test whether or not these infant markets are informationally efficient, but instead examine whether and how they are becoming more efficient. We propose modelling the excess returns of individual securities using a multi-factor model with time-varying coefficients and generalised auto-regressive conditional heteroskedastic (GARCH) errors. If the markets are becoming more informationally efficient or the agents are learning, we would expect this to manifest itself as the time-varying coefficients becoming more stable as time increases. We test our model using data on four Bulgarian shares. First, we estimate an AR(2) model and a GARCH-M(1,1) model for the shares. Then, we estimated our AR(2) model with time varying coefficients and GARCH type errors. We find varying levels of efficiency and varying speeds of movement towards efficiency within our sample of four shares. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Reliability of Impairment Tests： The Case of Vessels

For a shipping company, the vessel is the most valuable and important asset. In most cases, the value of the vessel is the bigger part of total assets. Under International Accounting Standards （IAS） and also United States Generally Accepted Accounting Principles （US GAAP） （IAS 36 and Statement of Financial Accounting Standards （SFAS） 144 respectively）, entities are required to conduct impairment tests where there is an indication of impairment of an asset. It is of high importance that the assumptions and the methodology of these tests be right, in order for the results of these tests to be valid. Always, there is the risk that the accountant manipulates the test in order to avoid any impairment losses. Our purpose is to examine the way that the results from these tests are related with market values. Also, we aim to examine under what test assumptions the results from these tests are close enough to market values of vessels.     

效率工资、效率工资增长模型

本文首先介绍了效率工资的经典模型——夏皮罗一斯蒂格里兹模型,探讨了效率工资的形成以及非自愿失业出现的原因,及失业的“威胁”作用。另外,本文在符合效率工资模型的基本假定条件下,融合代理理论和强制性储蓄假说,构建了效率工资增长模型,提出了效率工资增长模型的关键等式,且由等式隐含地决定了效率工资的最优增长率。此外,还分别分析了效率工资的最优增长率与贴现率、厂商生产技术和工人偏好之间的关系。最后,探讨了最优就业路径和调整成本问题等等。     

协整向量误设对相关检验的影响

常用于检验既定协整关系的统计量有tDF和tECM两种，但由于真实数据生成过程未知，估计模型中可能存在一定程度的协整向量误设，从而使统计量的分布特征受到影响。本文首先探讨tDF检验的隐含系数约束α=γ，即短期弹性等于先验长期弹性；其次分析零假设下两种统计量的分布特征，以及先验设定γ对信号噪声比q进而对tECM分布特征的影响；最后在局部备择假设下，给出两种统计量的渐近分布，并表明向量误设会降低协整检验的势，其程度与设定误差d正相关。     

人格测验在人事测评中的应用

文章强调了人格测验在人事测评中的必要性,在此基础上介绍了四种经典人格测验和三种管理情境中的人格测验,分析了人格测验在预测个体未来工作表现、工作风格以及实现人岗匹配方面所发挥的作用。     

Long Window Tests of China＇s Stock Market Efficiency in Different Sectors around the Disclosure of Annual Report

10 stock sectors are selected in Shanghai and Shenzhen stock market＇s as samples. By event study, the change of stock＇s cumulative abnormal return rate around the data of annual report disclosure was analyzed among the year 2004-2008. The market reaction pattern of such kind of news was summarized in order to test the efficiency of China＇s stock market and its trend before and after the comprehensive completion of the Share-trading Reform and the imple- mentation of new Accounting Standards. The conclusion is that Chinese stock markets response more accurately to ROE and EPS; its efficiency continued to decline in 2005 and 2006, but there was a gradual increase in 2007 and in 2008; and in general the capital market do not reach the semi-strong efficiency, but the machinery industry and biopharmaceutical industry have done.     

中国艺术表演企业的效率现状及动态效率评价

利用数据包络分析(DEA)和Malmquist生产率指数对我国艺术表演企业2004-2009年的经营效率及其变动进行分析。结果表明,中国艺术表演企业整体运营效率较高,但内部差异较大,存在不平衡特征;大多数企业存在严重的投入拥挤与产出不足现象;我国艺术表演企业纯技术效率出现下降趋势。这些给我们的启示是:要从根本上提高艺术表演企业经营效率必须合理整合企业资源,防止行业规模的盲目扩大。     

效率工程技术研究

本文在系统分析、功能分析等基础上提出效用分析法,又在价值工程基础上引出效率工程的基本概念,并以效用分析为核心阐述了效率工程的运用程序和方法.效率工程的突出优点是能方便分析宏观问题,该理论可认为是价值工程基础理论的研究与探讨.     

军事物流效益评价初探

军事物流作为连接军用物资供给与消费需求的纽带，其效益的好坏在很大程度上影响着军用物资保障能力的强弱。本文运用供应链管理思想阐述了军事物流效益评价的基本原则，旨在建立一套评价军事物流效益的指标体系，并给出了相应的评价方法。     

华晨宝马：高效背后的源动力

华晨宝马不仅见证、参与和推动了主重汽车工业的发展,更是形成了自身独特的人才造血机制——而这也是这一合资企业迅速成长的驱动力。