我国物价总水平波动路径研究

利用时间序列分析方法研究了PPI和CPI的结构突变特征,并通过建立时间序列模型刻画了我国物价水平(CPI)的波动路径。结果表明,CPI序列在2003年7月、2007年5月以及2008年7月三个时间点上存在结构突变现象,从而将CPI的运行过程分为四个阶段。另外,PPI的结构突变时点一般较CPI滞后1-2个月,这说明CPI触发了PPI的上涨,而PPI又会给予CPI以上涨支撑。最后,分别对以上四个子样本区的CPI序列波动性进行了建模研究,结果表明1997年1月至2003年6月间的CPI波动具有条件异方差性,可由GARCH(1,1)模型来描述。而其他阶段的CPI波动均可由AR(1)模型描述。     

The 1990s: prescription for success

MCH materiel management has successfully utilized an information system to achieve the objectives of the past decade, and it is now well into accomplishing the objectives of the 1990s. Those objectives revolved around revenue enhancement, which will occur through further integration of the information system throughout the institution. Currently the information system links accounts payable, general ledger, budgeting, and, to a lesser degree, nursing and the ancillaries. However, the plan is to enhance its integration to all departments in order to control and track not only official inventory but all patient chargeable items. This system will be able to ensure that all patient chargeable items are infact billed. One should consider, for example, the revenue effect in the surgery department, considering the dollar volume of noninventory purchases. Thus it becomes apparent that for materiel management in the 1990s there are many opportunities and challenges. Management must be able to utilize the resources available to find success and excel toward achievement of future goals.     

总体经验模式分解视角下的PPI与CPI波动特征及传导关系研究

本文采用总体经验模式分解（EEMD）和计量分析的方法,对国内PPI和CPI的波动特征和传导关系进行了深入研究。结果显示,二者均由高频分量、低频分量和趋势项构成,其中,高频分量体现的是国内物价中随机波动的信息;低频分量传递的是一定时期内的物价变动信息;趋势项反映的是物价中不轻易变动的信息。对上述结构分量的Granger因果检验表明,PPI和CPI之间的传导关系主要受低频分量和趋势项影响：低频分量中只存在PPI到CPI的单向因果关系;而在趋势项中存在不对称的传导方式,即在1%的水平上CPI到PPI存在单向因果关系,在5%的水平上二者互为因果。     

Testing for structural stability in the whole sample

The paper examines a Lagrange Multiplier type test for the constancy of the parameter in general models with dependent data without imposing any artificial choice of the possible location of the break. In order to prove the asymptotic behaviour of the test, we extend a strong approximation result for partial sums of a sequence of random variables. We also present a Monte-Carlo experiment to examine the finite sample performance of the test and how it compares with tests which assume some knowledge of the possible location of the break.     

Distribution-free and link-free estimation for the sample selection model

The prevalent estimation methods for the sample selection model rely heavily on parametric assumptions and are sensitive to departures from the underlying parametric assumptions [see, e.g., Goldberger (1983)]. We propose an alternative estimation method, the corrected maximum likelihood estimate, which is consistent for the slope vector in the outcome equation up to a multiplicative scalar, even through the parametric model on which the estimate is based might be misspecified. As an important corollary, it follows from our result that Olsen's (1980) corrected ordinary least squares estimate is consistent if the outcome equation is linear, without requiring Olsen's assumptions on the joint error distribution.     

Some remarks concerning the quotient of sample median and sample range for a sample of size 2n+1 from a normal distribution

Consider an ordered sample ₍₁₎, ₍₂₎,…, _(2n+1) of size 2 n +1 from the normal distribution with parameters μ and . We then have with probability one
₍₁₎ < ₍₂₎ < … < (2 n +1).
The random variable
_n =_(n+1)/_(2n+1)-(1)
that can be described as the quotient of the sample median and the sample range, provides us with an estimate for μ/, that is easy to calculate. To calculate the distribution of h _n is quite a different matter***. The distribution function of h₁, and the density of h₂ are given in section 1. Our results seem hardly promising for general h_n. In section 2 it is shown that h_n is asymptotically normal.
In the sequel we suppose μ= 0 and = 1, i.e. we consider only the "central" distribution. Note that h_n can be used as a test statistic replacing Student's t. In that case the central h_n is all that is needed.     

对技术经济评价指标的改进

一、对技术经济指标经济涵义的再认识 净现值(NPV)定义为项目寿命期内各年的净现金流量按照应达到的基准收益率i_0。贴现到项目开始时点上的现值之和。NPV反映了项目所占用的尚未收回的资金在以基准收益率i_0的递增幅度获利之外,在整个项目寿命期内所获收益现值的大小。 从净现值的表现形式上看,一般认为净现值是一个绝对数指标,仅能反映项目的盈利总额,而不能反映项目所用资金的利用效率。但将NPV作为绝对数指标运用时,应注意NPV有别于统计学中所定义的绝对数指标,它有其特殊性。实际上NPV的大小,在项目的其他条件不变的前提下,完全取决于基准收益率i_0的大小,NPV是在一定i_0的基础上所得的一个“余值”,而i_0是收益率指标,是相对数。因此可以说,NPV的大小,不仅     

A large deviation result for the difference in sample medians

Let X_m and Y_n denote the medians of independent samples from continuous populations F and G respectively. In Theorem 1 of this note, a large deviation result for the difference d_mn= X_m- Y_n is established under the assumption that F and G arc symmetric about 0. The result is then used to define a sequential rule based on medians for selecting the best of K symmetric populations.     

提高上市公司质量的对策

上市公司作为证券市场的基石,其质地如何关系到证券市场的安危,如果出现上市公司失控,屡屡发生违规行为和恶性事件,就会动摇证券市场的根基,     

Finite sample inference for quantile regression models

Under minimal assumptions, finite sample confidence bands for quantile regression models can be constructed. These confidence bands are based on the “conditional pivotal property” of estimating equations that quantile regression methods solve and provide valid finite sample inference for linear and nonlinear quantile models with endogenous or exogenous covariates. The confidence regions can be computed using Markov Chain Monte Carlo (MCMC) methods. We illustrate the finite sample procedure through two empirical examples: estimating a heterogeneous demand elasticity and estimating heterogeneous returns to schooling. We find pronounced differences between asymptotic and finite sample confidence regions in cases where the usual asymptotics are suspect.     

Small sample corrections for LTS and MCD

The least trimmed squares estimator and the minimum covariance determinant estimator [6] are frequently used robust estimators of regression and of location and scatter. Consistency factors can be computed for both methods to make the estimators consistent at the normal model. However, for small data sets these factors do not make the estimator unbiased. Based on simulation studies we therefore construct formulas which allow us to compute small sample correction factors for all sample sizes and dimensions without having to carry out any new simulations. We give some examples to illustrate the effect of the correction factor.     

基于EEMD-JADE模型的PMI与PPI结构分析及传导机制

研究目标：构建采购经理指数PMI和生产者价格指数PPI结构分量间的传导机制。研究方法：使用PMI和PPI同比序列进行集合经验模态分解（EEMD）得到固有模态序列作为观察信号,采用特征矩阵联合近似对角化算法（JADE）提取独立信号分量序列并通过游程判定法重构出不同频率的结构分量,最后进行Granger因果检验。研究发现：PMI和PPI重构出的高中低频三个结构分量分别反映短期波动、中期波动和长期波动。Granger因果检验表明,高频分量中PPI和PMI互为因果关系,传导时长为1期;中频分量中PMI是PPI的因且先行4期;低频分量PPI是PMI的因且先行10期。研究创新：将时频分析方法EEMD-JADE联合算法引入经济领域。研究价值：为经济量化调控政策提供导向和理论依据。     

如何利用质量管理体系进行业绩改进

在当今的市场环境中，大部分组织面临着棘手的条件，包括来自对手的扩张性竞争战略、令人胆怯的法律法规和全球化的压力。但最后，组织的经营一般都会归结到简单的问题，比如，以更低的价格提供比竞争对手更好的产品和服务。     

On the estimation of location parameters in the multivariate one sample and two sample problems

Summary In this paper we consider the problem of estimating the vectors of location parameters in the multivariate one sample and two sample problems. These estimators are obtained through the use of the multivariate rank order statistics such as theWilcoxon or the normal scores statistic considered by the authors inPuri, Sen [1966] andSen, Puri [1967] for the corresponding testing problems. The distribution of these estimators is shown to be symmetric with respect to the parameters being estimated. These estimators are translation invariant, robust and asymptotically normal. Their asymptotic relative efficiencies with respect to the estimators based on the vector of means and medians are discussed by applying the criterion ofWilks generalized variance [Anderson, p. 166]. In particular, it is shown that the estimators based on the multivariate normal scores statistics are asymptotically as efficient as the ones based on the method of least squares when the parent distributions are normal. Research sponsored by National Science Foundation Grant No. GP-12462, and by Research Grant, GM-12868 from the N.I.H., Public Health Service.     

一种提高轧辊加工精度的方法

在机加工过程中,很多轧辊辊身精度要求非常高,在加工工艺中如何使产品满足一些高精度轧辊的一些设计要求,提高产品的质量扩大其竞争力是我们努力的方向,本文简单介绍了一种提高轧辊表面精度的加工方法,使轧辊在生产过程中使产品达到了一定的高精度要求。