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。     

基于协整分析的东北区域产业结构优化与金融支持关系研究

基于1978—2003年的统计数据,采用协整关系检验法和格兰杰(Granger)因果检验法对东北地区金融发展与产业结构优化之间的关系进行了实证检验。分析结果表明东北区域产业结构优化与金融发展之间存在长期动态均衡关系及单向因果关系,即金融发展对东北区域产业结构优化具有支持作用,从而为政府经济决策提供了政策依据。     

Enders-Granger方法在协整检验中的应用研究

本文将协整检验由传统的线性协整检验扩展到线性协整检验和阈值协整检验,并在Enders和Granger(1998)方法的基础上提出了一个新的检验协整是否存在的Sup-F和Sup-F*统计量。通过MC仿真研究发现:在线性协整下,ADF方法比Sup-F法具有更高的检验势,但在"持久性"较强时,Sup-F检验比ADF检验法具有更高的检验势;Sup-F统计量在Three-Regime的阈值协整检验中比ADF法有更高的检验势;Sup-F*在检验协整(包括线性协整和阈值协整)时都具有较低的检验势;随着在不同Regime中自回归系数差距的增大(非对称程度增大),sup-F统计量的检验势提高很快,且比ADF法的检验势高。     

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.     

商品流通与产业升级的关系研究：理论与实证

商品流通与产业升级是两个密切联系的概念,商品流通对产业升级的影响主要是通过对社会财富的增量与存量调整来实现的。本文通过建立基于新兴古典经济学的理论模型,分析商品流通的发展所引起的交易效率的提高对产业升级的影响,然后利用我国的经验数据对两者进行协整分析、误差修正模型检验和因果关系检验。结果表明:我国的商品流通与产业升级之间存在长、短期稳定的正向关系,通过G ranger因果关系检验,我国的商品流通的发展是产业升级的G ranger原因,而反之却不成立。     

公司债务期限结构影响因素的实证分析

本文以上市公司板面数据及横截面数据为基础,利用混合时间序列回归、横截面回归和固定效果回归等方法,对影响我国上市公司债务期限结构的因素进行了实证检验。结果发现,除契约成本假说中成长机会外,绝大部分因素的检验结果与预期一致,进而验证了其适用性;经验证据不支持信息不对称假说;对税负假说相关因素的检验结果表现出不确定性;期限匹配假说得到了支持。研究还证明,具有较少自由现金流量、杠杆水平较高、规模大、受到管制和资产期限长的公司具有更多的长期债务。     

Asymptotic behaviour of regression pre-test estimators with minimal Bayes risk

Pre-test estimators (PTE) are considered which are optimal under a Bayes risk among PTE with general measurable sets as “regions of significance” for the test statistic t associated with the estimate of a given regression coefficient. Asymptotic and some finite sample results are stated and numerical experiments are commented on.     

我国公共投资规模效率实证分析

我国公共投资规模连年扩大,改善了生活环境和生产条件,但是否存在投资过度的风险?本文运用生产函数模型分析了公共投资规模效率存在的条件,使用协整的方法分析了大口径和小口径公共投资规模的最优规模,得出我国公共投资规模不足的结论。     

Lp空间上线性回归方程回归系数的估计

本文讨论了多元线性回归方程参数的L^p估计问题。首先采取消除方程中参数“。的技术，化参数估计为对回归系数的估计，然后进一步将问题转化为一个单目标数学规划模型，利用能自动搜索最优解的电脑软件，十分方便地求出规划模型的最优解。特别对一元回归方程，在消除参数a0后，还可以直接利用普通一元函数求极值的方法，求出回归系数的估计。