Relevance weighted likelihood for dependent data

The relevance-weighted likelihood function weights individual contributions to the likelihood according to their relevance for the inferential problem of interest. Consistency and asymptotic normality of the weighted maximum likelihood estimator were previously proved for independent sequences of random variables. We extend these results to apply to dependent sequences, and, in so doing, provide a unified approach to a number of diverse problems in dependent data. In particular, we provide a heretofore unknown approach for dealing with heterogeneity in adaptive designs, and unify the smoothing approach that appears in many foundational papers for independent data. Applications are given in clinical trials, psychophysics experiments, time series models, transition models, and nonparametric regression. Received: April 2000     

电子商务、物流配送效率与城乡消费差距——基于面板数据联立方程的研究

电子商务的日益常态化正在改变城乡居民的消费水平,而物流配送效率对电子商务良好发展与居民最终消费体验又发挥着不可忽视的作用.采用面板数据联立方程模型,分别从全国层面与区域层面研究电子商务、物流配送效率与城乡消费差距三者之间的联动效应.研究发现,电子商务的发展与物流配送效率之间呈现双向促进的关系,且电子商务通过提高物流配送效率能够间接缩小城乡消费差距,同时三者之间的关系存在显著区域差异.     

农业服务业与农业生产区域专业化的协同效应研究

[目的]探索农业服务业和农业生产区域专业化之间的相互关系,从而为农业服务业持续发展和农业生产区域专业化水平提升寻找可能路径。[方法]文章运用2003—2015年全国28个省的面板数据建立联立方程组模型检验农业服务业和农业生产区域专业化之间的协同效应。[结果](1)从全国层面来看,农业服务业产值增加1%使得农业生产的区域集中度指数提高0. 08%,结果在1%的水平上显著;前一期农业生产区域集中度指数提高1%使得当期农业服务业产值提高5. 348%,结果在5%的水平上显著;(2)西部地区农业服务业产值增加1%使得农业生产的区域集中度指数提高0. 342%,前一期农业生产区域集中度指数提高1%使得当期农业服务业产值提高7. 474%,结果分别在10%和5%的水平上显著;(3)东部地区农业服务业产值增加1%使得农业生产的区域集中度指数提高0. 099%,前一期农业生产区域集中度指数提高1%使得当期农业服务业产值提高5. 874%,结果均在5%的水平上显著;(4)中部地区农业服务业产值增加没有显著影响农业生产区域集中度指数,前一期农业生产区域集中度指数对当期农业服务业产值有5%水平上显著正向的影响,影响弹性为4. 531。[结论](1)农业服务业和农业生产区域专业化在全国层面表现出互相促进的协同效应,但是,该协同效应在东部、中部和西部地区表现出明显的差异;(2)西部地区农业服务业和生产区域专业化的协同效应最强烈;(3)东部地区农业服务业和生产区域专业化表现出协同效应,但不及西部强烈;(4)中部地区农业服务业和生产区域专业化没有表现出明显的协同效应。据此该文认为进一步优化农业产业布局应当重视农业服务业和区域生产专业化的协同效应及其地区差异。     

我国地区产业多样化、技术创新与经济发展--基于面板数据联立方程模型的研究

在分析我国地区产业多样化、技术创新与经济发展之间相互影响机制的基础上,构建联立方程组模型,并利用2003-2011年我国31个省份的面板数据进行实证检验。结果表明,产业多样化通过技术创新促进地区经济发展;相邻地区产业多样化与创新水平对地区经济发展影响显著为正,表明存在空间依赖效应;进一步将产业多样化划分为相关和无关多样化,发现相关多样化是创新产出的主要原动力,无关多样化的影响效应不显著。     

我国消费、投资及净出口与经济增长研究--基于资源与环境的双重约束

基于我国1998-2010年的宏观经济数据,文章通过建立联立方程模型,对我国消费、投资及净出口与经济增长进行实证分析。结果表明：我国的经济增长与资源消耗之间存在着“倒U型”的非线性曲线关系;消费、投资及净出口增长对我国经济增长的拉动效应不同,其中居民消费的拉动效率最强;产业结构升级对资源消耗的抑制作用较为显著。     

Measuring Structural Unemployment: NAWRU Estimates in the Nordic Countries

The non-accelerating wage rate of unemployment (NAWRU indicator), used by the OECD as a measure of structural unemployment, has risen for the four Nordic countries Denmark, Finland, Norway and Sweden. In this paper we present stable empirical wage equations for the same countries over the period 1964–1994, in sharp contrast to the increased NAWRU estimates. The instability of the NAWRU estimates is an artefact of a misspecified underlying wage equation, and not due to instability in wage setting itself.
JEL classification : E 24; E 31; E 64; J 51     

Optimal Consumption-Portfolio Policies With Habit Formation1

This is a companion paper to the authors ‘Asset Prices in an Exchange Economy with Habit Formation” in Econometrica which focuses on consumption demand and asset pricing when preferences are habit forming. Here we prove existence of optimal consumption-portfolio policies for (i) utility functions for which the marginal cost of consumption (MCC) interacts with the habit formation process and satisfies a recursive integral equation with forward functional Lipschitz integrand and (ii) utilities for which the MCC is independent of the standard of living and satisfies a recursive integral equation with locally Lipschitz integrand. Result (i) is demonstrated here for the first time. Result (ii) is novel and enables us to consider Cobb-Douglas utilities without placing lower bounds on the system of Arrow-Debreu prices. We also review and extend our earlier results in the linear case; in particular, we provide new insights about the structure of optimal portfolios. Additional new features of the model include the possibility of finite marginal utility of consumption at zero and habit formation mechanisms with stochastic coefficients. an extension to a financial market model with general processes is outlined. A byproduct of the analysis is a set of fixed-point theorems for recursive integral equations with forward functional Lipschitz or locally Lipschitz integrands.     

基于C语言对三次样条函数的求解及程序

在解三次样条函数时,最后都要归结为求解三对角型方程组。根据此类方程组的特点,该文介绍了一种追赶法,推导了使用这种方法的消元过程和回代过程,并给出了求解此类方程组的通用C语言程序,大大地节省了计算机工作量和计算机存贮单元。