Incorporating vintage differences and forecasts into Markov switching models

This paper incorporates vintage differences and forecasts into the Markov switching models described by Hamilton (1994). The vintage differences and forecasts induce parameter breaks close to the end of the sample, too close for standard maximum likelihood techniques to produce precise parameter estimates. A supplementary procedure estimates the statistical properties of the end-of-sample observations that behave differently from the rest, allowing inferred probabilities to reflect the breaks. Empirical results using real-time data show that these techniques improve the ability of a Markov switching model based on GDP and GDI to recognize the start of the 2001 recession.     

基于短信技术的销售数据实时采集系统的设计与实现

随着中国移动通信业的高速发展,移动通信的用户量迅速增长,手机及其短信作为一种实用、方便、廉价的通信手段已赢得了广大用户的青睐。现代企业要想提升其产品的市场竞争力与销售终端运营效率,就必须全面、准确、及时地掌握其产品终端销售数据,只有解决了"销售末梢"的终端数据的实时性采集问题,企业管理者才能快速做出正确的生产、经营决策。文章分析了短信技术在企业终端销售数据管理中的应用,提出了新系统所应该具备的功能需求,并在此基础上讨论了系统实现中的关键技术问题及其解决方法。     

深入剖析Compiere ERP & CRM数据模型的研究

设计一个成熟稳定的ERP系统的关键是创建通用的数据模型框架和能够适应企业业务流程的软件体系。本文通过"报价-发票"业务流程中的销售订单业务深入分析Compiere ERP & CRM(Web Application版本)的通用数据模型及其动态数据字典设计思想,为企业导入应用和客户化定制提供基本思路。     

The Greenspan years: an analysis of the magnitude and speed of the equity market response to FOMC announcements

We examine the impact of monetary policy on the S&P 500 using intraday data. The analysis shows an economically and statistically significant relationship between S&P 500 intraday returns and changes in the Fed funds target rate. The significance and magnitude of the response is dependent on whether the change was expected or unexpected. An expected change in the Fed funds target rate has no impact on prices in the broad equity market; however, an unexpected change of 25 basis points in the Fed funds target rate results in an approximate 48 basis points decline in the broad equity market’s return. The speed of these market reactions is rapid with the equity market reaching a new equilibrium within 15 minutes.

Minimum distance estimation of the spatial panel autoregressive model

This paper contributes to the interface literature of new methodological foundation of analyzing historical data with space and spatio-temporal phenomena. In particular, I consider estimating the spatial panel autoregressive model using the minimum distance estimator. Spatial autoregression has important implications for economic system that typifies correlatedness across many spatial locations and which could evolve over long span of time. To overcome computational difficulties, I suggest a two-stage estimation procedure based on minimum distance estimators. A striking feature of the proposed model is that minimum distance estimates are derived under common slopes and complete equality of parameters across spatial units. Assumption of common slopes across spatial units is an empirical and theoretical plausibility as many spatial units are observed to share common trend and typology of changes occurring to the individual system under which equality of parameters are possibilities. The estimation strategy allows various restrictions on time-varying vector parameters. Moreover, those restrictions can easily be tested. I apply this procedure to the residential demand for water of 115 French municipalities over the biannual period 1988–1993. The primary contribution of the paper is to the methodological side of cliometrics while the empirical application (with shorter time period) has been presented for illustrative purpose although, it can nonetheless be readily applied to historical data with long-time horizon allowing for restrictions such as spatio-temporal common vector and structural break in parameter estimates.

战斗机航空电子系统最新的发展趋势-网络化

在分析未来战斗机面临的空中作战特点以及战斗机航空电子系统发展现状的基础上,根据未来信息化战争对航空电子系统发展需求的重大变化,提出未来战斗机航空电子系统在完成从"三代综合化"向"四代综合化"的转变以后,重点是朝着"网络化"方向发展的观点,并重点分析外军为实现这种网络化所采取的技术措施。     

A note on why more West than East German firms export

Germany is one of the most important exporters of manufacturing goods in the world, but by far not all manufacturing firms in Germany are exporters, and there is a remarkable gap between the share of exporters in all manufacturing firms between West Germany and East Germany. While in West Germany in 2004 about two in three manufacturing plants were exporters, fourteen years after re-unification this share was less than fifty percent in the former communist East Germany. Given that exports play a key role in shaping business cycles and growth in Germany, and the much higher unemployment in East compared to West Germany, promotion of exports by East German firms figure prominently on the policy agenda. However, the reasons for the large difference in the propensity to export between East and West German firms are not yet well understood, not least due to a lack of comprehensive micro data. Using unique new data and a recently introduced non-linear decomposition technique this paper shows that the huge difference in the propensity to export between West and East German plants can only partly be explained by differences in firm size, productivity, and technology intensity.

多步数据加密技术及应用

数据加密是保护数据安全的一种有效的方法,它是将一段明文按某种算法进行处理,使其成为密文,以保护数据不被非法人窃取、阅读。数据加密技术常分为"对称式"加密与"非对称式"加密两类。多步加密算法属对称式加密,由于安全性高得到广泛应用。     

魔术在数据结构教学中的运用

数据结构是大学计算机相关专业的核心课程,但其内容抽象、理论性强、难于理解,传统教学方法按部就班地教学,往往会使学生感到厌倦无味。在实际教学中,笔者结合"魔术思想"来教学数据结构,通过分析揭密魔术来实现对课程知识的教学,提高学生学习兴趣和激发学习动机,获得了较好的效果。     

中国转型期生产性服务业发展与制造业竞争力关系研究——基于面板数据的实证分析

本文在中国特殊的情境中研究生产性服务业发展与制造业竞争力的关系．文章围绕如下关键点进行了探讨：在我国特殊的体制背景下，对于提升制造业竞争力而言．生产性服务业究竟在充当什么样的角色；在不同地区，生产性服务业所起的作用是否有差别；在当前阶段，不同生产性服务行业发挥的功能是否一样。文章通过理论分析和基于面板数据的实验检验得出的结论是：在我国经济转型期，发展生产性服务业有利于提升制造业的竞争力；东部地区生产性服务业发挥的作用最充分；金融保险业最能发挥提升制造业竞争力的功能．