影响蒙汉双语生普通话成绩的原因与对策

利用统计工具和分析方法,通过对1462份蒙汉双语生普通话水平测试试卷的分析,进一步明确了影响测试总分的原因。结果表明,蒙汉双语生的声调、识字量、语流音变、词汇语法、语调是影响普通话水平测试成绩的主要因素,今后在推普工作中应采取相应对策,就会更好地提高蒙汉双语生普通话水平及测试成绩。     

Testing Chaos Based on Empirical Distribution Function: A Simulation Study

It is well known that many classical statistical tests of randomness generally fail to distinguish chaos generated by some lower-dimensional deterministic dynamical systems from independent and identically distributed (i.i.d.) random series. In this paper, we suggest a powerful statistical testing method based on empirical distribution function that can well detect chaos and i.i.d. random series.     

多维多层尺度下移动服务质量测度的实证研究

本文基于广泛的文献综述和定量研究,同时结合移动商务的独特性,提出了多维度多层次的移动服务质量模型,并根据服务质量研究的一般文献和移动服务方面的研究成果,提取了43个测度项用来度量模型中的结构变量.之后,从中国移动和中国联通两家公司选取了217份有效样本,通过使用部分分散技术(Partial Disaggregation Technique)对模型进行了三阶段检验.结果显示,模型达到了很好的拟合数据的要求,这使得本文提出的层次结构模型得到强有力的验证.并且.企业形象作为调节变量,对环境质量与服务质量之间和结果质量和服务质量之间的关系具有显著的调节作用,但对于交互质量和服务质量之间的调节作用不显著.     

A note on the deterministic EPQ with partial backordering

In a recent paper published in Omega [Pentico DW, Drake MJ, Toews C. The deterministic EPQ with partial backordering: a new approach. Omega 2009; 37(3):624–36], the authors proposed an EPQ model with partial backordering. In the EPQ model, a critical value of backordering rate was developed, below which the optimal production policy is either to lose all sales or meet all demand, above which the optimal policy is to allow stockouts with partial backordering and meet fractional demand. However, there exists a flaw in the critical value of backordering rate, which will be amended in this note.     

Partial groups ranked set sampling and mean estimation

Ranked set sampling (RSS) is an advanced sampling method which is very effective for estimating mean of the population when exact measurement of observation is difficult and/or expensive. Balanced Groups RSS (BGRSS) is one of the modification of RSS where only the lowest, the median and the largest ranked units are taken into account. Although BGRSS is advantageous and useful for some specific cases, it has strict restrictions regarding the set size which could be problematic for sampling plans. In this study, we make an improvement on BGRSS and propose a new design called Partial Groups RSS which offers a more flexible sampling plan providing the independence of the set size and sample size. Partial Groups RSS also has a cost advantage over BGRSS. We construct a Monte Carlo simulation study comparing the performance of the mean estimators of the proposed sampling design and BGRSS according to their sampling costs and mean squared errors for various type of distributions. In addition, we give a biometric data application for investigating the efficiency of Partial Groups RSS in real life applications.     

FISIM核算之参考利率的比较与选择

现有核算体系中,间接测算的金融中介服务（FISIM）出现核算漏洞,致使SNA内部出现核算的不一致性以及FISIM负值。因此,SNA（2008）建议参考利率应反映存贷款的风险和期限结构。随之,国际与欧洲FISIM工作组探讨了各种经风险和期限调整的参考利率以改进FISIM核算,包括加权参考利率、匹配参考利率、长短期双参考利率、中点参考利率与SNA建议的参考利率。为了检验他们在中国的适用性,本文从利率的波动性、FISIM负值发生的可能性以及对FISIM生产与使用造成的影响等方面,对这些参考利率进行实证检验。研究发现,期限调整方面,加权参考利率与长短期双参考利率相对稳定,发生FISIM负值的可能性也较小。其中加权参考利率更为简单,实践操作性也更强。中国账面价值参考利率在稳定性、FISIM负值、风险调整方面都有着比较优势,缺点是没有考虑参考利率的期限调整。     

Prequential omnibus goodness-of-fit tests for stochastic processes: A numerical study

This article is a contribution to the study of an omnibus goodness-of-fit (Gof) test based on Rosenblatt Probability Integral Transform (RPIT) within Dawid's prequential framework. This Gof test is easy to use since it has a common test statistic (with apparently the same asymptotic distribution) for a wide range of stochastic models. Intensive Monte-Carlo simulations are presented to investigate the behavior of this test for several stochastic models: renewal, autoregressive (AR, ARMA, ARCH, GARCH) and Poisson processes, generalized linear models... These simulations suggest that the RPIT test could be used to test the fit of a wide range of stochastic models but it may be not powerful when compared to Gof tests specifically designed for the tested processes. It is also conjectured that this test is still appropriate for testing the Gof of any discrete-time stochastic process provided that efficient estimators are used.     

Testing the validity of the exponential model for hybrid Type-I censored data

The exponential distribution has been used in life-testing and reliability studies. In this article, we first express the entropy of Type-I hybrid censoring scheme in terms of hazard function and provide an estimate of the entropy of Type-I hybrid censored data. Then, we construct a goodness-of-fit test statistic based on Kullback–Leibler information for Type-I hybrid censored data. The test statistic is used to test for exponentiality. A Monte Carlo simulation is conducted to obtain the power of the proposed test against various alternatives. Finally, a data example is presented for illustrative purpose.     

基于回归的时变偏度和时变峰度识别检验

资产收益率时变高阶矩建模的首要前提是资产收益率的偏度和峰度具有时变性,即资产收益率存在类似于异方差性的异偏度和异峰度特征。目前文献中的时变偏度和时变峰度识别检验存在适用性较差且检验功效较低等不足。本文提出基于回归的检验方法识别资产收益率偏度和峰度的时变性。该检验一方面利用概率积分变换缓解了拉格朗日乘数检验对资产收益率序列的高阶矩存在性的限制,另一方面考虑了检验统计量中参数估计的不确定性对其统计性质的影响,具有良好的渐近统计性质且适用性更广。蒙特卡洛模拟表明该检验具有良好的有限样本性质,具有合适的检验水平和较高的检验功效。最后,将基于回归的检验运用于上证综指和深圳成指收益率的时变建模研究中。     

普通话水平测试中的"轻声"问题

"轻声"是普通话里的一种特殊变调,是普通话水平测试中必须考查的语言点之一.由于轻声的不确定性(音变调值和轻声词数量的不确定性),使得轻声成了测试中令人困惑的问题.本文针对笔者临场测试所收集到的轻声问题,从语音理论的角度,对如何把握好"轻声"作了初步探讨.