Correlation properties of continuous-time autoregressive processes delayed by the inverse of the stable subordinator

Abstract

We define the delayed Lévy-driven continuous-time autoregressive process via the inverse of the stable subordinator. We derive correlation structure for the observed non-stationary delayed Lévy-driven continuous-time autoregressive processes of order p, emphasizing low orders, and we show they exhibit long-range dependence property. Distributional properties are discussed as well.     

Control charts based on dependent count data with deflation or inflation of zeros

The process of serially dependent counts with deflation or inflation of zeros is commonly observed in many applications. This paper investigates the monitoring of such a process, the first-order zero-modified geometric integer-valued autoregressive process (ZMGINAR(1)). In particular, two control charts, the upper-sided and lower-sided CUSUM charts, are developed to detect the shifts in the mean process of the ZMGINAR(1). Both the average run length performance and the standard deviation of the run length performance of these two charts are investigated by using Markov chain approaches. Also, an extensive simulation is conducted to assess the effectiveness or performance of the charts, and the presented methods are applied to two sets of real data arising from a study on the drug use.     

Simultaneous sparse model selection and coefficient estimation for heavy-tailed autoregressive processes

We propose a sparse coefficient estimation and automated model selection procedure for autoregressive processes with heavy-tailed innovations based on penalized conditional maximum likelihood. Under mild moment conditions on the innovation processes, the penalized conditional maximum likelihood estimator satisfies a strong consistency, O_P(N^?1/2) consistency, and the oracle properties, where N is the sample size. We have the freedom in choosing penalty functions based on the weak conditions on them. Two penalty functions, least absolute shrinkage and selection operator and smoothly clipped average deviation, are compared. The proposed method provides a distribution-based penalized inference to AR models, which is especially useful when the other estimation methods fail or under perform for AR processes with heavy-tailed innovations [Feigin, Resnick. Pitfalls of fitting autoregressive models for heavy-tailed time series. Extremes. 1999;1:391–422]. A simulation study confirms our theoretical results. At the end, we apply our method to a historical price data of the US Industrial Production Index for consumer goods, and obtain very promising results.     

Oracle GMM estimation for misspecified models via thresholding

We propose a thresholding generalized method of moments (GMM) estimator for misspecified time series moment condition models. This estimator has the following oracle property: its asymptotic behavior is the same as of any efficient GMM estimator obtained under the a priori information that the true model were known. We propose data adaptive selection methods for thresholding parameter using multiple testing procedures. We determine the limiting null distributions of classical parameter tests and show the consistency of the corresponding block-bootstrap tests used in conjunction with thresholding GMM inference. We present the results of a simulation study for a misspecified instrumental variable regression model and for a vector autoregressive model with measurement error. We illustrate an application of the proposed methodology to data analysis of a real-world dataset.     

Structural Change Monitoring for Random Coefficient Autoregressive Time Series

A monitoring scheme is proposed to sequentially detect a structural change in random coefficient autoregressive time series of order p (RCA(p)) after a training period of size T. It extends structural change monitoring to RCA(p) time series. The asymptotic properties of our monitoring statistic are established under both the null of no change in parameters and the alternative of a change in coefficient. The finite sample properties are investigated by a simulation study.     

Asymptotic Distributions of Quasi‐Maximum Likelihood Estimators for Spatial Autoregressive Models

This paper investigates asymptotic properties of the maximum likelihood estimator and the quasi‐maximum likelihood estimator for the spatial autoregressive model. The rates of convergence of those estimators may depend on some general features of the spatial weights matrix of the model. It is important to make the distinction with different spatial scenarios. Under the scenario that each unit will be influenced by only a few neighboring units, the estimators may have ‐rate of convergence and be asymptotically normal. When each unit can be influenced by many neighbors, irregularity of the information matrix may occur and various components of the estimators may have different rates of convergence.     

数字经济、空间效应与全要素生产率

当前,数字经济蓬勃发展,已成为经济增长的新动能。本文从数字产业化与产业数字化 两个维度,采用主成分分析法构建了数字经济发展水平的指标体系,并利用2004-2017年我国省际面板 数据,在克服内生性问题的基础上,实证分析了数字经济发展对全要素生产率的影响。研究发现,数字 经济发展显著促进了全要素生产率的提升。但较之高生产率地区和东部地区,数字经济发展对低生产率地区和中西部地区全要素生产率的提升作用更大。就机制而言,人力资本投资与产业结构升级是数 字经济影响全要素生产率的两个渠道。进一步的空间计量分析表明,数字经济发展不仅会提升本地区 的全要素生产率,还存在显著的空间溢出效应,有助于提升邻近地区的全要素生产率。本文的研究为评估数字经济发展的影响效果提供了数据支撑和分析视角,也为探寻全要素生产率的提升路径提供了政策参考。     

Reexamining the ethnic hierarchy of locational attainment: Evidence from Los Angeles

Because of a lack of data, the locational attainment literature has not incorporated documentation status into models examining group differences in neighborhood quality. I fill this void by using the Los Angeles Family and Neighborhood Survey, which permits the identification of undocumented respondents, allowing a reexamination of the ethnic structure of locational attainment in this important immigrant-receiving city. Results first suggest that while undocumented Latinos live in the poorest quality communities, blacks live in neighborhoods that are similar to native-born Latinos and better than foreign-born Asians and Latinos. Second, the effects of education are strongest for blacks, allowing the highly educated an opportunity to reside in communities that are of better quality than educated Latinos and Asians. Thus, undocumented Latinos replace blacks at the bottom of the locational attainment hierarchy, allowing educated blacks in Los Angeles to reside in better neighborhoods than blacks in the nation at large.