Economic interpretations of DEA

Research on productive efficiency at the firm level has developed as an important and active strand of research the last decades, both within operations research, management science and economics. Two apparently different definitions of efficiency are examined, but it is shown that when both estimation methods are based on solving linear programming problems the definitions of efficiency are identical. The purpose of the paper is to give the basic ideas of efficiency analyses using DEA as a tool for researchers not so familiar with efficiency analysis and DEA. The concept of shadow prices is given special attention.     

用AD9852与FPGA结合实现中频线性调相

本文介绍了直接数字频率合成（DDS）芯片AD9852与可编程门阵列（FPGA）相结合采用数字方法实现中频线性相位调制（PM）及试验结果。     

改革开放以来广州经济增长因素分析

本文从实证角度建立计量模型,利用主成分分析方法和最小二乘回归的方法,对广州改革开放30多年以来的经济增长因素进行了具体分析,研究表明改革开放30多年来,广州经济增长的促进因素主要是劳动力数量的增长,经济制度的变革,产业结构的升级,以及人力资本增长的作用,物质资本不是促进广州经济增长的主要因素。     

Use of minimum risk approach in the estimation of regression models with missing observations

This article considers a linear regression model with some missing observations on the response variable and presents two estimators of regression coefficients employing the approach of minimum risk estimation. Small disturbance asymptotic properties of these estimators along with the traditional unbiased estimator are analyzed and conditions, that are easy to check in practice, for the superiority of one estimator over the other are derived. Received May 2001     

中国外商直接投资的区位决定因素分析:城市数据

本文以全国210个地级以上城市为对象,分析了外商直接投资的区位决定因素。本文采用OLS和逐步回归分析方法以及2002年的横截面数据,在以往研究的基础上选择四项区位决定因素包括三种成本因素、三种市场因素、四种集聚因素和四种制度因素进行实证研究。结果表明,劳动力成本对各城市的外商直接投资的区位选择影响不明显,而市场规模、基础设施、教育和研究开发条件以及地方金融规模对外商直接投资的区位选择的影响具有显著性。本文的逐步回归分析结果还表明,就东部地区而言,能源条件和市场规模是较重要的区位决定因素;就中西部地区而言,市场规模、基础设施、教育和研究开发条件以及地方金融成为较重要的区位决定因素。     

Linear Programming Models for the Measurement of Environmental Performance of Firms—Concepts and Empirical Results

I use linear programming models to define standardised, aggregate environmental performance indicators for firms. The best practice frontier obtained corresponds to decision making units showing the best environmental behaviour. Results are obtained with data from U.S. fossil fuel-fired electric utilities, starting from four alternative models, among which are three linear programming models that differ in the way they account for undesirable outputs (pollutants) and resources used as inputs. The results indicate important discrepancies in the rankings obtained by the four models. Rather than contradictory, these results are interpreted as giving different, complementary kinds of information, that should all be taken into account by public decision-makers.     

Pseudo empirical likelihood method in the presence of missing data

In this paper, we propose an estimator for the population mean when some observations on the study and auxiliary variables are missing from the sample. The proposed estimator is valid for any unequal probability sampling design, and is based upon the pseudo empirical likelihood method. The proposed estimator is compared with other estimators in a simulation study.     

商业银行盈利能力影响因素的实证分析——基于偏最小二乘回归（PLSR）算法

运用偏最小二乘回归模型及其辅助分析手段对商业银行盈利能力影响因素进行一次深入、细致、系统的梳理。研究表明,影响商业银行盈利能力的前六大因素依次为净息差、资产质量、成本收入比、风险承受能力、金融创新及存贷比,而银行资产规模对盈利能力的贡献度最低。为提升商业银行盈利能力,必须强化金融创新能力、防控商业银行风险、完善金融监管体制。     

回归分析法在经济预测中的应用浅析

回归分析法是在经济预测中常用的方法之一，它是在观察和分析经济发展的历史和现状的基础上，按照一定的方式建立反映其关系的数学模型，然后根据自变量在未来的变化来计算预测变量的变化，从而对未来的经济发展趋势进行预测。其关键是建立回归模型，并进行相关分析和结果预测。