A note on the asymptotic distribution of the process capability index C pmk

Process capability indices have been widely used to evaluate the process performance to the continuous improvement of quality and productivity. The distribution of the estimator of the process capability index C _pmk is very complicated and the asymptotic distribution is proposed by Chen and Hsu [The asymptotic distribution of the processes capability index C _pmk , Comm. Statist. Theory Methods 24(5) (1995), pp. 1279–1291]. However, we found a critical error for the asymptotic distribution when the population mean is not equal to the midpoint of the specification limits. In this paper, a correct version of the asymptotic distribution is given. An asymptotic confidence interval of C _pmk by using the correct version of asymptotic distribution is proposed and the lower bound can be used to test if the process is capable. A simulation study of the coverage probability of the proposed confidence interval is shown to be satisfactory. The relation of six sigma technique and the index C _pmk is also discussed in this paper. An asymptotic testing procedure to determine if a process is capable based on the index of C _pmk is also given in this paper.     

动态视角下中国城市群土地利用TFP测度及影响因素研究

提高城市群土地利用TFP对合理高效利用土地资源,协调好城市群经济发展、资源配置和环境保护具有重大理论和实践意义.文章运用DEA-Malmquist指数对2003—2016年动态视角下中国城市群土地利用TFP进行测度和时空演变分析,并利用Tobit回归模型对影响城市群土地利用TFP变化的因素进行深入研究.结果表明:从时间维度看,城市群土地利用TFP年均上升0.7％,城市群土地利用TFP增长由技术效率和技术进步"双核驱动",技术效率的提升主要与纯技术效率提升有关,规模效率是技术效率和土地利用TFP提升的瓶颈约束;从空间维度看,晋中、哈长、海峡西岸、中原、长江中游、北部湾、成渝、黔中、关中平原和兰西城市群土地利用TFP呈下降趋势,其余城市群土地利用TFP均呈上升趋势,且京津冀、呼包鄂榆、辽中南、长江三角洲、山东半岛和天山北坡城市群土地利用TFP增长为技术进步和技术效率"双核驱动";从影响因素看,人均GDP和年末金融机构人民币各项贷款余额对中国城市群土地利用TFP具有正向促进作用,城市财政支出占本市GDP的比重和人口密度具有负向阻碍作用.     

1981—2014年中国资本服务流量测算——基于截断正态退役分布和几何役龄效率剖面

通过梳理资本核算理论框架,结合中国实际情况测量了1981-2014年资本服务流量。资本分类、组合役龄效率-退役剖面计算、资本回报率确定和初始单位效率生产性资本存量估计等方面与既有研究有所不同。测量结果表明:按照1990年不变价格,各类资本服务流量呈增加趋势,其中无形资产服务流量前期较为波动;设备类服务流量增速最高;总资本服务增长率前期呈V型后期呈倒U型,与GDP增速变动不一致,整体来看前者高于后者;比较发现测量结果高于其它研究,差距先收敛后扩大。     

Scanner Data and the Treatment of Quality Change in Nonrevisable Price Indexes

The recently developed rolling year GEKS procedure makes maximum use of all matches in the data to construct nonrevisable price indexes that are approximately free from chain drift. A potential weakness is that unmatched items are ignored. In this article we use imputation Törnqvist price indexes as inputs into the rolling year GEKS procedure. These indexes account for quality changes by imputing the “missing prices” associated with new and disappearing items. Three imputation methods are discussed. The first method makes explicit imputations using a hedonic regression model which is estimated for each time period. The other two methods make implicit imputations; they are based on time dummy hedonic and time-product dummy regression models and are estimated on bilateral pooled data. We present empirical evidence for New Zealand from scanner data on eight consumer electronics products and find that accounting for quality change can make a substantial difference.     

Partial linear single-index models with additive distortion measurement errors

We study partial linear single-index models (PLSiMs) when the response and the covariates in the parametric part are measured with additive distortion measurement errors. These distortions are modeled by unknown functions of a commonly observable confounding variable. We use the semiparametric profile least-squares method to estimate the parameters in the PLSiMs based on the residuals obtained from the distorted variables and confounding variable. We also employ the smoothly clipped absolute deviation penalty (SCAD) to select the relevant variables in the PLSiMs. We show that the resulting SCAD estimators are consistent and possess the oracle property. For the non parametric link function, we construct the simultaneous confidence bands and obtain the asymptotic distribution of the maximum absolute deviation between the estimated link function and the true link function. A simulation study is conducted to evaluate the performance of the proposed methods and a real dataset is analyzed for illustration.     

Estimation and simulation of conditional hazard function in the quasi-associated framework when the observations are linked via a functional single-index structure

We consider the estimation of the conditional hazard function of a scalar response variable Y given a Hilbertian random variable X when the observations are linked via a single-index structure in the quasi-associated framework. We establish the pointwise almost complete convergence and the uniform almost complete convergence (with the rate) of the estimate of this model. A simulation is given to illustrate the good behavior in the practice of our methodology.     

Causal structure among US corn futures and regional cash prices in the time and frequency domain

This study investigates causal structure among daily Chicago Board of Trade corn futures prices and seven regional cash series from Iowa, Illinois, Indiana, Ohio, Minnesota, Nebraska, and Kansas for January 2006–March 2011. Their wavelet transformed series are further analyzed for causal relationships at different time scales. Empirical results indicate no causality among states or between the futures and a cash series for time scales shorter than one month. As scales increase but do not exceed a year, bidirectional causal flows are determined among all prices. The information leadership role of the futures against a cash price is identified for the scale longer than one year and raw series, at which no interstate causality is found.     

中国收入分配的公平与效率关系测度及评价

首先对公平与效率做出了精确定义,确定其指标,然后测度由于收入分配总量和结构引致的公平与效率的变化量,在此基础上构建了一个公平效率指数,用来反映中国二者关系的变化及其协调程度,最后采用目标优化的方法对收入分配总量和结构进行了优化,根据优化结果提出了改善收入分配关系的建议。     

Charisma as signal: An evolutionary perspective on charismatic leadership

We present an evolutionary perspective on charismatic leadership, arguing that charisma has evolved as a credible signal of a person's ability to solve a coordination challenge requiring urgent collective action from group members. We suggest that a better understanding of charisma's evolutionary and biological origins and functions can provide a broader perspective in which to situate current debates surrounding the utility and validity of charismatic leadership as a construct in the social sciences. We outline several key challenges which have shaped our followership psychology, and argue that the benefits of successful coordination in ancestral environments has led to the evolution of context-dependent psychological mechanisms which are especially attuned to cues and signals of outstanding personal leadership qualities. We elaborate on several implications of this signaling hypothesis of charismatic leadership, including opportunities for deception (dishonest signaling) and for large-scale coordination.     

Estimation of parameters of SDE driven by fractional Brownian motion with polynomial drift

ABSTRACT

Strongly consistent and asymptotically normal estimators of the Hurst index and volatility parameters of solutions of stochastic differential equations with polynomial drift are proposed. The estimators are based on discrete observations of the underlying processes.