全站仪在工程测量中的精度与误差分析

电子全站仪是光电测距仪、电子经纬仪和微处理器的集成,它能在测站上同时测量、计算显示及记录各种测量数据,在工程测量中得到广泛应用。本文结合全站仪在工程测量中的应用,谈谈降低测量误差的几种方法。     

Predicting capacity utilization: Federal Reserve vs time-series models

This study evaluates the Federal Reserve forecasts of manufacturing capacity utilization employing, as benchmarks, the forecasts from a univariate model which utilizes past information in capacity utilization, and from a bivariate model which utilizes past information in both capacity utilization and the federal funds rate. In addition to accurately predicting the directional change in capacity utilization, the Federal Reserve forecasts are “weakly” rational and generally superior to the bivariate forecasts. In light of another finding that monetary policy is non-neutral, we argue the Federal Reserve forecasts of capacity utilization have positively contributed to the Fed’s success in maintaining a low inflationary environment.

精密深孔钻床的设计与实现

针对当前钻孔设备中低档设备精度低、效率低,而高档设备结构复杂、成本高的缺陷,基于PLC技术设计了一种"高精度、高效率、低成本、易操作"的数控高精度钻孔机床,保证了产品质量,提高了生产效率,降低了生产成本。同时,对相关构件进行创新设计,实现了高精度加工和成倍提高钻孔效率。     

供应商集中度影响管理层业绩预告行为吗？——基于业绩预告精确性及其预告态度的视角

基于中国企业间关系信任的历史禀赋与现实情境,以2010-2017年A股公司业绩预告为样本,考察供应商集中度对业绩预告精确性与预告态度的影响。研究发现：供应商集中度越高,管理层业绩预告的精确性越低,预告态度也越倾向乐观。进一步研究发现：供应商集中度对业绩预告的精确性负向影响在业绩预告修正情况下作用更明显,在业绩预告未修正时企业更倾向于乐观的业绩预告;同时企业在自愿披露业绩预告情况下,供应商集中度对业绩预告精确性的反向作用更为显著,企业越倾向于披露乐观的业绩预告。以上研究为理解外部利益相关者与企业未来盈利预测之间的关系提供了直接的经验证据,丰富和拓展了供应商关系型交易影响企业信息披露策略选择的研究。     

培养观察能力对提高学习技巧的作用

学习也有技巧,观察能力也很重要,培养观察能力,要指导学生掌握有序观察,分析观察,逆向观察的观察方法;重视观察的目的性、全面性、精确性、深刻性等良好观察品质的培养。学生的数学学习水平,取决于数学观察能力的强弱。     

The influence of member heterogeneity on dyad judgment: Are two heads better than one?

An experiment is conducted to test the effect of the degree of heterogeneity in individual member judgments on the accuracy of judgments made by dyads. Predictions are made about how (1) homogeneity versus heterogeneity in judgments and (2) task instruction interact to affect a group's judgmental accuracy in average price-estimation tasks. Results indicate that dyads were not more accurate than the average dyad member or than the better member. However, increases in accuracy (relative to the accuracy of the better member of the dyad) occurred more often in dyads whose members were heterogeneous in their prior individual judgments than they did in dyads whose members were more homogeneous. When provided with instructions, heterogeneous dyads improved in accuracy to a greater degree than did homogeneous dyads.     

Making the same mistake all over again: CEO overconfidence and corporate resistance to corrective feedback

Firms often make mistakes, from simple manufacturing overruns all the way to catastrophic blunders. However, there is considerable heterogeneity in the nature of corporate responses when faced with evidence that an error has taken place, and, therefore, in the likelihood that such errors will reoccur in the future. In this paper, we explore an important but understudied influence on firms' responses to corrective feedback—a CEO's level of overconfidence. Using multiple distinct measures of overconfidence and the empirical context of voluntary corporate earnings forecasts, we find strong, robust evidence that firms led by overconfident CEOs are less responsive to corrective feedback in improving management forecast accuracy. We further show that this relationship is moderated by prior forecast error valence, time horizon, and managerial discretion. Copyright © 2014 John Wiley & Sons, Ltd.     

业绩预告的类型会影响其准确性吗?——基于盈余管理动机视角

业绩预告的经验品属性使得资本市场如何预判业绩预告的准确性显得尤为重要,但已有研究难以为资本市场提供简单直接且便于观测的预判标准.本文通过挖掘业绩预告类型可能隐藏的盈余管理动机,以2010-2018年度在资产负债表日后披露业绩预告的A股上市公司为研究对象,实证考察盈余管理动机是否以及如何影响业绩预告准确性.实证研究发现,盈余管理动机越强,业绩预告的准确性越低;作用机制检验发现,审计师对盈余管理动机较强的公司进行了更多的审计调整,使得定期报告中的盈余水平偏离了业绩预告中的盈余水平,从而导致了业绩预告准确性的降低;在控制内生性问题和稳健性测试后实证结果保持不变.研究表明业绩预告类型隐藏的盈余管理动机信息,可以帮助资本市场预判业绩预告的准确性.     

北斗星基增强系统的精确性研究

介绍北斗卫星导航系统的现状以及北斗卫星星基增强系统的工作原理.研究影响卫星导航精度定位的主要来源,确定有3种误差源,分别为卫星钟差、对流层延迟误差、电离层延迟误差.在此之后,对影响定位精度最主要的误差源——电离层延迟进行分析.针对电离层误差提出格网电离层模型的优化算法并通过数据采集和算法仿真对比得到较好的优化模型.通过仿真结果对比证明了优化算法能够有效降低电离层误差值.     

Investor Sentiment,Misstatements, and Auditor Behavior*

High investor sentiment has been linked with opportunistic managerial behavior in the face of more optimistic investors and analysts. We extend this line of work by documenting that the likelihood of misstatements is higher when sentiment is high. Although this would suggest elevated audit risk, we posit that a contemporaneous reduction in auditors' litigation cost could drive down audit fees and going concern opinion (GCO) reporting conservatism in order to please clientele. Consistent with this notion, we document that auditors charge lower fees and report GCOs less conservatively when sentiment is high. However, this reduction in reporting conservatism is unwarranted; results reveal that auditors are less likely to issue GCOs to clients which subsequently file for bankruptcy during high sentiment periods. We conduct additional tests to examine whether auditors' litigation costs indeed vary with sentiment and document that auditors are less likely to be sued and the market reacts less negatively to misstatement announcements when sentiment is high. Collectively, our findings suggest that, although misstatement risk is increasing with sentiment, auditors' litigation risk actually declines.