Predictive regressions under asymmetric loss: Factor augmentation and model selection

This paper discusses the specifics of forecasting using factor-augmented predictive regressions under general loss functions. In line with the literature, we employ principal component analysis to extract factors from the set of predictors. In addition, we also extract information on the volatility of the series to be predicted, since the volatility is forecast-relevant under non-quadratic loss functions. We ensure asymptotic unbiasedness of the forecasts under the relevant loss by estimating the predictive regression through the minimization of the in-sample average loss. Finally, we select the most promising predictors for the series to be forecast by employing an information criterion that is tailored to the relevant loss. Using a large monthly data set for the US economy, we assess the proposed adjustments in a pseudo out-of-sample forecasting exercise for various variables. As expected, the use of estimation under the relevant loss is found to be effective. Using an additional volatility proxy as the predictor and conducting model selection that is tailored to the relevant loss function enhances the forecast performance significantly.     

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.     

卫星通信地球站终端技术的发展

本文介绍了卫星通信地球站终端技术的发展过程,初步论述了新技术应用的环境,为今后研制卫星通信设备提供某些参考。     

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。     

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.     

入世后我国中小企业发展的机遇、挑战与对策

中小企业准确认识加入WTO带来的机遇和挑战，是制定正确应对措施的前提。我国中小企业在激烈的国际竞争中立于不败之地的关键是，提高企业的综合素质和竞争能力，优化企业组织结构、深化企业改革，建立新的企业制度、建立创新机制。     

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.     

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。     

中国经济增长与能源消费空间面板分析

近年来面板数据广泛应用于各类统计分析,但变量的空间相关并没有引起足够的重视。本文引入空间面板回归模型研究中国各省市区经济增长和能源消费的关系。利用matlab软件及其spatial econometric模块建立和比较传统面板回归模型与空间面板回归模型,结果表明空间面板回归模型较传统面板回归模型优越,本文的研究为空间面板数据分析提供了一个应用实例。