NLOS环境下移动台位置与速率估计

NLOS (Non-line of Sight)误差是定位中的主要误差来源,直接影响了定位的精度 。在MIMO（Multiple Input Multiple Output）系统中,基于NLOS信道模型的定位方法成为 解决NLOS定位误差问题的利器。基于此提出一种新颖的几何方法,仅采用两条NLOS路径就可 计算MS(Mobile Station)的位置,并且只需要利用单个基站便可完成MS的定位,克服了基站 数目过少无法准确定位MS的缺陷。在此基础上,还给出了最小二乘与最大似然算法利用多条 NLOS路径来改善定位精度的方法,并利用它对NLOS环境下运动的MS进行定位跟踪。理论分析 和仿真结 果都证明该定位方法在NLOS环境中对MS定位的有效性与精确度。     

基于Mathematica的中心极限定理的实验分析

基于Mathematica讨论了二项分布与正态分布之间的关系,对棣莫弗-拉普拉斯中心极限定理进行实验研究,通过图像演示和相对误差分析,给出二项分布的极限分布及其相应的准确度分析,并得出了一些计算概率的近似公式.     

基于主成分分析和支持向量机的个人信用评估

本文针对信用评估指标维数较高的问题,运用主成分分析与支持向量机理论建立了一个新的个人信用评估预测模型。为反映该模型在信用评估分类方面的优越性,又分别建立了基于神经网络、K近邻判别分析等多种理论的信用评估模型,并用同一组数据对不同的模型分别进行训练,然后比较其预测分类正确率。实验结果表明,基于主成分分析与支持向量机理论的个人信用评估模型具有较优的预测分类正确率。     

调性感与音程感的有机结合

具有明确调性扩展意识的音乐作品（简称为“调性扩展类作品”）可以说是现代音乐试图走出调性音乐的第一步.它在音准的把握上有别于传统的调性音乐,但与其又有着千丝万缕的联系.该类作品中仍有明确的调号和较为鲜明的调性音,但如何在视唱时处理好作品中出现的音准问题,则应从分析调性感与音程感之关系入手.     

时差型卫星定位系统目标位置标校算法的误差分析

针对时差型卫星定位系统位置标校算法中标校源选择的问题,首先建立了基于单个标校源的标校方法的误差分析模型,分析了参数的系统性误差和随机测量误差对标校效果的影响;其次,定义了两类定位误差改善因子,用来定量描述标校算法对定位精度的改善能力,并可以通过理论计算评价标校源的标校效果,从而为标校源的选择提供了依据。最后,仿真分析验证了误差分析模型及定位误差改善因子的有效性。     

Are more able managers good future tellers? Learning from Japan

Baik et al. (2011) find that high-ability managers in the U.S. are more likely to issue accurate management earnings forecasts. Focusing on Japan, where management earnings forecasts are effectively mandated, we extend the literature by exploring (1) whether the relationship between managerial ability and forecast accuracy is unique to the U.S. disclosure system, where management forecasts are voluntary, and (2) how high-ability managers increase their forecast accuracy. We find that managerial ability is negatively associated with forecast errors based on initial forecasts, suggesting that high-ability managers are more likely to issue accurate forecasts at the beginning of the fiscal year. We then show that high-ability managers are less likely to revise their initial earnings forecasts and less likely to use earnings management to improve the accuracy of their earnings forecasts. Our findings show that, while high-ability managers are more likely to issue accurate initial management forecasts, low-ability managers are more likely to revise their forecasts and conduct earnings management to reduce their forecast errors.     

An examination of the congruence and incongruence between employee actual and customer perceived emotional labor

This study examines the effects of the congruence and incongruence between employee actual and customer perceived emotional labor on customer trust. Based on data collected from 510 service employee and customer dyads in restaurants, the results of response surface modeling indicate that customer trust is higher when employee deep acting and customer perceived deep acting are both high rather than both low. Customer trust is also higher when customer perceived deep acting is higher than employee actual deep acting rather than vice versa. The effects are different in surface acting: as employee surface acting and customer perceived surface acting increase, customer trust initially decreases, then increases, exhibiting a U‐shaped effect. Implications for both theory and practice are discussed.     

Assessing the uncertainty in central banks’ inflation outlooks

Recent research has found that macroeconomic survey forecasts of uncertainty exhibit several deficiencies, such as horizon-dependent biases and lower levels of accuracy than simple unconditional uncertainty forecasts. We examine the inflation uncertainty forecasts from the Bank of England, the Banco Central do Brasil, the Magyar Nemzeti Bank and the Sveriges Riksbank to assess whether central banks’ uncertainty forecasts might be subject to similar problems. We find that, while most central banks’ uncertainty forecasts also tend to be underconfident at short horizons and overconfident at longer horizons, they are mostly not significantly biased. Moreover, they tend to be at least as precise as unconditional uncertainty forecasts from two different approaches.     

Do survey joiners and leavers differ from regular participants? The US SPF GDP growth and inflation forecasts

If ‘learning by doing’ is important for macro-forecasting, newcomers might be different from regular, established participants. Stayers may also differ from the soon-to-leave. We test these conjectures for macro-forecasters’ point predictions of output growth and inflation, and for their histogram forecasts. Histogram forecasts of inflation by both joiners and leavers are found to be less accurate, especially if we suppose that joiners take time to learn. For GDP growth, there is no evidence of differences between the groups in terms of histogram forecast accuracy, although GDP point forecasts by leavers are less accurate. These findings are predicated on forecasters being homogeneous within groups. Allowing for individual fixed effects suggests fewer differences, including leavers’ inflation histogram forecasts being no less accurate.     

An alternative benchmark for the validity of China’s GDP growth statistics

The veracity of China’s official statistics on GDP growth rates is a matter of debate in both the popular media and academic literature. Given the level of institutional development, its size, complexity and fast pace of change as an emerging economy, there are good reasons to expect that producing reliable and consistent estimates for GDP is difficult. An alternative benchmark would therefore be useful. We propose a benchmark index for the nominal GDP growth constructed bottom-up from publically available and audited total Revenue numbers of 150 major Chinese listed companies covering 19 industry sectors. This benchmark index closely tracks the official statistics, but with some interesting deviations. Validation by using Gross Margin numbers for our Chinese sample and US data produced similar results. The methodology also allowed us to produce estimates of growth at the industry level, which highlights some important changes underway in the structure growth patterns of the Chinese economy.