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。     

发动机汽缸压力测试方法探析

发动机的汽缸压力是评价发动机动力性能的一项重要指标,在对发动机进行检查、评价和维修时需要经常测试。文章从汽车实践技术的角度阐述了发动机汽缸压力的测试仪器、测试方法与技巧,并在理论上对测试的数据和测试误差加以科学系统地分析,提出解决办法,为汽车发动机的技术维修提供科学合理的依据。     

The Stambaugh bias in panel predictive regressions

This paper analyzes predictive regressions in a panel data setting. The standard fixed effects estimator suffers from a small sample bias, which is the analogue of the Stambaugh bias in time-series predictive regressions. Monte Carlo evidence shows that the bias and resulting size distortions can be severe. A new bias-corrected estimator is proposed, which is shown to work well in finite samples and to lead to approximately normally distributed t-statistics. Overall, the results show that the econometric issues associated with predictive regressions when using time-series data to a large extent also carry over to the panel case. The results are illustrated with an application to predictability in international stock indices.     

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.

粤港澳大湾区发展机遇下茂名的优势及发展对策研究

本文用世界上大湾区的特点分析茂名的优势,利用城市间的列车次数绘制广东城市中心度网络图,结合灯光地图分析广东城市的GDP排名,提出粤港澳大湾区发展机遇下茂名的发展对策。     

基于STM32的石油管材测厚系统设计

针对现有石油管材检测存在的不足,设计了一种石油管材实时检测与数据处理的智能测厚系统。该系统以STM32为主控芯片,以TDC-GP22为采集芯片经过计算得到管道厚度,以I2C总线方式实现主从机通信,以HLK-RM04嵌入式模块实现与上位机应用软件的数据传输与采集功能,同时配合控制多个42步进电机与直流喷液电机实现运动、耦合、温湿度检测等功能,给出了硬件部分与上位机软件的设计与实现。与传统的人工作业效率相比,大大提升了安全系数、工作效率。     

数据足迹视域下的南粤古驿道旅游地形象感知研究——以河源粤赣古驿道为例

随着互联网技术的发展及自媒体时代的到来,移动互联网的旅游消费比例日益增长,游客体验交互效应及价值共创成为常态。旅游数字足迹挖掘与研究,有利于以游客体验核心价值、最佳利益为出发点,构建服务型企业管理制度层面的口碑及业界诚信,从而实现企业、员工与游客最终的共赢。基于南粤古驿道旅游地形象感知研究视角,选取河源粤赣古驿道为研究区域,运用ROST网络文本分析、百度指数等数据挖掘方法,从多维度、多视角开展旅游地形象感知研究,对河源粤赣古驿道及其沿线景区开发、游客满意度优化提供针对性策略。     

Cash Management, Payment Patterns and the Demand for Money

We analyse cash management and payments behaviour using 1990–1994 panel data for Dutch households. The results largely confirm the transactions demand for money theory, including an income elasticity of substantially less than one, and they are consistent with the hypothesis of technology resulting in households' economizing on currency balances. The results indicate up to 40 per cent lower transactions balances in the future, which is affirmed by direct questioning on future expectations. The effect on total money outstanding is considerably lower, due to significant amounts of missing money in hoards, which are insensitive to new developments in the payments system.     

Bartlett correction to the likelihood ratio test for MCAR with two‐step monotone sample

Assuming that two‐step monotone missing data is drawn from a multivariate normal population, this paper derives the Bartlett‐type correction to the likelihood ratio test for missing completely at random (MCAR), which plays an important role in the statistical analysis of incomplete datasets. The advantages of our approach are confirmed in Monte Carlo simulations. Our correction drastically improved the accuracy of the type I error in Little's (1988, Journal of the American Statistical Association, 83 , 1198–1202) test for MCAR and performed well even on moderate sample sizes.     

Conditional assessment of the impact of a Hausman pretest on confidence intervals

In the analysis of clustered and longitudinal data, which includes a covariate that varies both between and within clusters, a Hausman pretest is commonly used to decide whether subsequent inference is made using the linear random intercept model or the fixed effects model. We assess the effect of this pretest on the coverage probability and expected length of a confidence interval for the slope, conditional on the observed values of the covariate. This assessment has the advantages that it (i) relates to the values of this covariate at hand, (ii) is valid irrespective of how this covariate is generated, (iii) uses exact finite sample results, and (iv) results in an assessment that is determined by the values of this covariate and only two unknown parameters. For two real data sets, our conditional analysis shows that the confidence interval constructed after a Hausman pretest should not be used.