专家荐股信息的实证研究

对荐股信息发布后股票回报率的研究,显示分析师并没有预测股票未来走势的能力,依照他们的推荐来买卖股票不能提供超额的回报。荐股信息对投资人的投资决策有显著的影响。     

Root n consistent and optimal density estimators for moving average processes

Abstract.  The marginal density of a first order moving average process can be written as a convolution of two innovation densities. Saavedra & Cao [Can. J. Statist. (2000), 28, 799] propose to estimate the marginal density by plugging in kernel density estimators for the innovation densities, based on estimated innovations. They obtain that for an appropriate choice of bandwidth the variance of their estimator decreases at the rate 1/ n . Their estimator can be interpreted as a specific U -statistic. We suggest a slightly simplified U -statistic as estimator of the marginal density, prove that it is asymptotically normal at the same rate, and describe the asymptotic variance explicitly. We show that the estimator is asymptotically efficient if no structural assumptions are made on the innovation density. For innovation densities known to have mean zero or to be symmetric, we describe improvements of our estimator which are again asymptotically efficient.     

古代边塞诗派的成熟兴盛与大西北

关于边塞诗的概念存在混乱现象。我们所说的边塞应该是指古代中央政权统一时候的边塞 ,即主要指沿着长城的走向所形成的地域。在国家处于分裂状态的割据政权之间的边界是不能算作一般意义上的边塞的。边塞诗的成熟和兴盛离不开大西北。没有大西北边塞卫国战事和奇丽风光 ,就不会有唐代的边塞诗派的兴盛与成熟。边塞诗在宋、元、明三代衰落了。边塞诗在清代取得堪与唐代媲美的成绩。     

Stochastic Production Frontier and Technical Inefficiency: A Sensitivity Analysis

The present paper focuses attention on the sensitivity of technical inefficiency to most commonly used one-sided distributions of the inefficiency error term, namely the truncated normal, the half-normal, and the exponential distributions. A generalized version of the half-normal, which does not embody the zero-mean restriction, is also explored. For each distribution, the likelihood function and the counterpart of the estimator of technical efficiency are explicitly stated (Jondrow, J., Lovell, C. A. K., Materov, I. S., Schmidt, P. ([1982]), On estimation of technical inefficiency in the stochastic frontier production function model, J. Econometrics19:233-238). Based on our panel data set, related to Tunisian manufacturing firms over the period 1983-1993, formal tests lead to a strong rejection of the zero-mean restriction embodied in the half normal distribution. Our main conclusion is that the degree of measured inefficiency is very sensitive to the postulated assumptions about the distribution of the one-sided error term. The estimated inefficiency indices are, however, unaffected by the choice of the functional form for the production function.     

我国省区服务业综合竞争力的DEA组合评价

我国服务业发展的地区不平衡及服务业内部的结构性不平衡问题较为突出,本文运用超效率DEA的两阶段法对我国各省区第三产业、传统服务业和新兴服务业的发展状况进行了分析评价,并进一步分析指出影响服务业发展的深层次因素。     

湖北省主要农产品技术效率与规模经济性的实证考察

采用超越对数生产函数形式的随机前沿模型,对湖北省2003年农产品生产的规模经济性和技术效率进行了分析比较,得出以下结论：（1）物质费用和播种面积是重要的生产投入要素,对产量的贡献基本上为正;（2）劳动投入的产出弹性有正有负;（3）各农产品的平均规模经济效果不明显,只有小麦的生产规模经济递增;（4）各种农产品的技术效率水平存在较大差距,其中棉花、蔬菜、禽肉最高,而水果、生猪最低。最后,得出两点政策建议：一是应克服技术创新的障碍因素,调动科研、推广和生产三方面的积极性,使农业科技在今后的农业增长中得到最大的发挥;二是建立新型的经营组织,以解决农业基础技术设施的投资问题。     

多目标规划Hartley真有效解的自身对偶性

本文在Ｈａｒｔｌｅｙ真有效解的意义下讨论自身对偶性，得到了类似于［１］和［２］中的结果。     

国家构建视域下的边疆地区政治整合

国家构建是现代国家走上现代化、民主化发展的必由之路,边疆的客观存在与具体状态的呈现能够在某种程度上影响国家构建的效果。为了将边疆地区更好地纳入国家管理的序列当中,使其形成最为基本的国家认同,达成基础的政治共识,需要运用政治整合的手段来进行推动与转化。这种政治整合行为需要权威的政府或政党进行主导,并且通过合理有效的路径达成政治整合的目标。边疆对于现代绝大多数国家都有着重要的意义,于内部而言,它是国家稳定与安全的节拍器,是现代化建设进程中的重要组成部分;于外部而言,它是国际间交往的门户,是区域安全与发展的桥头堡。在国家构建的整体视域下,通过合理的路径针对边疆地区进行政治整合是强化政治共同体意识的需要,是维护边疆稳定乃至区域安全的需要,是促进边疆发展乃至国家现代化的需要。通过特定的政治权威来推动对“异质性”较强的边疆地区的整合,从而形成基本的国家认同,达成基础的政治共识,接受有序的政治安排。这就要求政治主体克服边疆地区固有的社会文化与民族心理之“分化”趋向,现实距离与情感距离之“疏远”态势,达成资源禀赋与多元一体之“整合”目标。     

Central bank credibility and monetary policy in Indonesia

This paper examines the role of central bank credibility in achieving an inflation target and proposes monetary policy rules for Indonesia. Towards that end, we construct and estimate a forward-looking small scale macroeconomic model (SSMM) of the Indonesian economy by adapting the theoretical underpinnings of the well-known Batini–Haldane model, along with the Taylor policy rule. Our results indicate that it is crucial for the Indonesian central bank to bolster its credibility in order to achieve a lower inflation rate. The inflation–output volatility trade-off frontier we derived from the SSMM shows that a monetary policy rule that targets both inflation and output gaps will result in less macroeconomic volatility. We also found that the inclusion of the exchange rate into the rule as an additional feedback variable warrants consideration in the future course of monetary policy management.     

随机前沿面模型构造过程中数据包络分析在数据过滤中的应用

对模型具体形式的依赖，且具有对于多种经济问题的普遍适应性和对于大样本研究的实用性，因而得到了广泛的应用和迅速的发展〔’巧〕。2.数据包络分析的基本模型及其经济含义设有K个决策单元，每个决策单元含有N种投人，M种产出，决策单元j的投人和产出向量分别为，2，…，K，2