半参数空间ZISF的估计及反馈分类

本文引入空间效应、非参函数和非连续分布技术无效率项,构建了半参数空间0无效率随机前沿模型(简称为半参数空间ZISF),模型的适用性更广,可有效避免函数形式误设和忽略内生性问题导致的有偏和不一致估计量.对非参函数采用B样条逼近,使用极大似然方法和JLMS法可得到参数(含非参数函数)和技术效率的估计.基于伯努利大数定律提出反馈分类,可将技术无效率项分类.蒙特卡罗模拟表明:①本文方法的估计精度较高.增加样本容量后,估计精度更优.忽略任意一种效应将导致估计精度降低.②分类阈值的跨度较大,主观判断贝叶斯后验概率的大小进而将技术无效率项分类的可靠性较低.反馈分类的准确率较高且必要.     

基于Copula函数的空间统计模型估计与应用

在空间数据分析中,由于空间预测在很大程度上依赖于对空间变化的现象分布的假设,因此建立空间数据分布模型是非常重要的问题.Stein(1999)指出,传统的方法利用变差函数描述插值的空间依赖性结构和基于似然方法的模型相比是相当不精确的.对于非正态分布的空间数据而言,Copula函数提供了一种可以分别指定相关结构和边缘分布而建立联合分布的可能性.文章基于Copula函数的非正态分布数据的空间插值方法,讨论模型参数的极大似然估计并运用生态环境数据进行实证研究.     

空间自回归模型及其估计

一、概述在经济问题研究中,处理的数据分为时间序列数据、截面数据以及截面时间序列数据(paneldata)。应用回归模型研究变量之间的关系时,假设模型满足Gauss_Markov条件,当研究的数据是时间序列时,通常会存在序列相关,针对这类数据的问题可以结合时间序列分析的方法加以处理;如     

平滑转移空间随机前沿模型的贝叶斯估计

经济数据常存在空间相关性,忽略空间相关性会引发内生性问题,导致相应估计量有偏且不一致。空间随机前沿模型在随机前沿模型的基础上考虑了生产单元的空间相关性,更利于效率测算。然而现有空间随机前沿模型的生产函数形式单一,适用性较差,实证分析存在局限性。文章在空间随机前沿模型中引入平滑转移效应,构建了平滑转移空间随机前沿模型,该模型同时考虑了空间相关性和个体异质性,适用性较佳。为丰富估计方法,同时采用极大似然方法和贝叶斯方法估计模型,其中极大似然估计的核心在于推导对数似然函数、对数似然函数的最优化以及使用JLMS法估计技术效率,贝叶斯估计的核心在于推导未知参数的后验分布及执行MCMC抽样。数值模拟结果显示：（1）极大似然估计和贝叶斯估计的估计精度均较高,其中贝叶斯估计的估计精度略高于极大似然估计;增加样本容量,贝叶斯估计和极大似然估计的估计精度更高。（2）若忽略空间效应或者平滑转移效应,则估计精度较低。     

时变系数空间自回归面板数据模型的极大似然估计

本文对扰动项存在跨时期的异方差、但不存在序列相关的时变系数空间自回归模型提出了极大似然的估计方法,并证明了该估计量的一致性,同时,证明了该估计量渐进服从正态分布,由此说明该估计量具有优良的大样本性质。同时,我们还对本文所提出估计量的小样本性质进行了数值模拟。本文研究表明,估计量虽然在N较小时偏差较大,但是随着N的不断增加,估计量偏差减小,体现了比较优良的渐进性质。同时,估计量的偏差会随着时期数的增加而变大,这说明本文所提出的估计方法适用于个体数较多、时期数较少的短面板数据。     

季节指数的极大似然估计

文章探索运用数理统计的极大似然估计法计算季节指数,得出的计算公式与传统的算术方法完全一致,从直观上保持了与传统算法的衔接性,又可以得出季节指数的区间估计,提高了季节指数计算的完备性.     

浅谈极大似然估计的教学方法

在数理统计中,当随机变量X的分布类型已知时,一个很重要的问题就是要对分布中所含的参数θ进行估计,即所谓的参数估计。在参数估计方法中有一种常用的点估计方法——极大似然估计方法（以下简称极大似然估计）。该方法最早是由高斯（C.F.Gauss）提出来的,后来费雷（R.A.Fisher）在1912年又重新提出该方法,并证明了该方法的一些优良性质。极大似然估计方法的背后有着非常朴素的哲理,但是,如果不把握其精髓,则很难让初学者理解和接受。笔者在多年从事概率与数理统计教学中发现,这部分既是数理统计（参数估计）教学中的一个难点又是重点。     

随机效应变系数空间自回归面板模型的估计

具有良好可读性和稳健性的变系数模型在各学科领域应用广泛.本文构建了一种新的随机效应变系数空间自回归面板模型,运用截面极大似然估计方法,导出了模型的估计量,证明其具备一致性和渐近正态性,蒙特卡洛模拟研究显示估计量的小样本表现效果良好.     

空间滞后面板平滑转换模型的估计及数值模拟

将空间滞后项引入面板平滑转换模型,构建了空间滞后面板平滑转换模型,通过综合应用拟极大似然法和非线性最小二乘法,构造了该模型的参数估计方法,并通过蒙特卡洛数值模拟探讨了参数估计方法的小样本性质;数值模拟结果显示,提出的估计方法在小样本条件下表现良好,参数估计值随着样本容量的增大而收敛到参数的真值。     

证券市场中板块联动效应的空间计量分析

收益率之间的联动效应广泛存在于证券市场中,文章用空间计量的方法对同板块股票收益率的联动效应进行了定量分析,在CAPM模型的基础上,通过使用空间权重矩阵将联动影响因素纳入了解释变量之中,并推导出极大似然估计方法克服了内生性问题,然后通过蒙特卡洛模拟证明了这种方法的可行性。     

双重滞后随机前沿模型技术效率的估计

首次在随机前沿模型中同时引入因变量间(或双边误差间)和技术效率间的空间相关性并构造了双重滞后随机前沿模型,使用极大似然估计方法和JLMS方法得出参数和技术效率的估计。蒙特卡罗模拟表明:忽略技术效率的空间相关性,参数估计和技术效率的估计均表现欠佳。本研究能以较高的精度估计参数和技术效率。随着样本容量的增加,估计效果更优。     

随机前沿生产函数非效率项不同衡量方式的一致性问题——基于蒙特卡罗模拟的分析

 摘　　要:本文应用蒙特卡罗模拟方法，在定义单次模拟程序时，假设数据产生机制是一个超越对数随机前沿生产函数的10模型，由此创造出模拟样本，并用一个超越对数的00模型（scaling-property模型）计算出有关参数、特别是非效率项的估计值。又进一步判定了所得到的估计值和原来10模型中的“真实”非效率项的一致性。研究发现，真实非效率项与从scaling-property模型中计算出来的非效率估计值之间的各种相关系数均为负值。因此，效率秩估计值和“真实”效率秩是不一致的     

On the Convergence of the Monte Carlo Maximum Likelihood Method for Latent Variable Models

While much used in practice, latent variable models raise challenging estimation problems due to the intractability of their likelihood. Monte Carlo maximum likelihood (MCML), as proposed by Geyer & Thompson (1992 ), is a simulation-based approach to maximum likelihood approximation applicable to general latent variable models. MCML can be described as an importance sampling method in which the likelihood ratio is approximated by Monte Carlo averages of importance ratios simulated from the complete data model corresponding to an arbitrary value of the unknown parameter. This paper studies the asymptotic (in the number of observations) performance of the MCML method in the case of latent variable models with independent observations. This is in contrast with previous works on the same topic which only considered conditional convergence to the maximum likelihood estimator, for a fixed set of observations. A first important result is that when is fixed, the MCML method can only be consistent if the number of simulations grows exponentially fast with the number of observations. If on the other hand, is obtained from a consistent sequence of estimates of the unknown parameter, then the requirements on the number of simulations are shown to be much weaker.     

Improved Monte Carlo inference for models with additive error

Some statistical models defined in terms of a generating stochastic mechanism have intractable distribution theory, which renders parameter estimation difficult. However, a Monte Carlo estimate of the log-likelihood surface for such a model can be obtained via computation of nonparametric density estimates from simulated realizations of the model. Unfortunately, the bias inherent in density estimation can cause bias in the resulting log-likelihood estimate that alters the location of its maximizer. In this paper a methodology for radically reducing this bias is developed for models with an additive error component. An illustrative example involving a stochastic model of molecular fragmentation and measurement is given.     

空间误差自相关随机前沿模型及其估计

将空间计量经济学的思想引入随机前沿分析，构建了基于横截面数据的空间误差自相关随机前沿模型，推导出模型的似然函数以求得参数估计，并给出了各生产单元技术效率的估计。     

Monte Carlo Likelihood Estimation for Three Multivariate Stochastic Volatility Models

Estimating parameters in a stochastic volatility (SV) model is a challenging task. Among other estimation methods and approaches, efficient simulation methods based on importance sampling have been developed for the Monte Carlo maximum likelihood estimation of univariate SV models. This paper shows that importance sampling methods can be used in a general multivariate SV setting. The sampling methods are computationally efficient. To illustrate the versatility of this approach, three different multivariate stochastic volatility models are estimated for a standard data set. The empirical results are compared to those from earlier studies in the literature. Monte Carlo simulation experiments, based on parameter estimates from the standard data set, are used to show the effectiveness of the importance sampling methods.     

Monte Carlo Likelihood Estimation for Three Multivariate Stochastic Volatility Models

Estimating parameters in a stochastic volatility (SV) model is a challenging task. Among other estimation methods and approaches, efficient simulation methods based on importance sampling have been developed for the Monte Carlo maximum likelihood estimation of univariate SV models. This paper shows that importance sampling methods can be used in a general multivariate SV setting. The sampling methods are computationally efficient. To illustrate the versatility of this approach, three different multivariate stochastic volatility models are estimated for a standard data set. The empirical results are compared to those from earlier studies in the literature. Monte Carlo simulation experiments, based on parameter estimates from the standard data set, are used to show the effectiveness of the importance sampling methods.     

A Comparison Between Maximum Likelihood and Bayesian Estimation of Stochastic Frontier Production Models

In this paper, the finite sample properties of the maximum likelihood and Bayesian estimators of the half-normal stochastic frontier production function are analyzed and compared through a Monte Carlo study. The results show that the Bayesian estimator should be used in preference to the maximum likelihood owing to the fact that the mean square error performance is substantially better in the Bayesian framework.     

Semiparametric Estimation of Stochastic Production Frontier Models

This article extends the linear stochastic frontier model proposed by Aigner, Lovell, and Schmidt to a semiparametric frontier model in which the functional form of the production frontier is unspecified and the distributions of the composite error terms are of known form. Pseudolikelihood estimators of the parameters characterizing the two error terms of the model are constructed based on kernel estimation of the conditional mean function. The Monte Carlo results show that the proposed estimators perform well in finite samples. An empirical application is presented. Extensions to a partially linear frontier function and to more flexible one-sided error distributions than the half-normal are discussed     

Bayesian Estimation for the Exponentiated Weibull Model via Markov Chain Monte Carlo Simulation

Bayesian estimation for the two unknown parameters and the reliability function of the exponentiated Weibull model are obtained based on generalized order statistics. Markov chain Monte Carlo (MCMC) methods are considered to compute the Bayes estimates of the target parameters. Our computations are based on the balanced loss function which contains the symmetric and asymmetric loss functions as special cases. The results have been specialized to the progressively Type-II censored data and upper record values. Comparisons are made between Bayesian and maximum likelihood estimators via Monte Carlo simulation.