电路实验中的若干问题及其解决办法

对电路实验教学中遇到的一些实际问题进行分析讨论，并提出解决问题的办法。     

人民币汇率波动对中国物价水平影响的实证研究

近年来人民币不断升值与物价水平普遍上涨的"双高"现象,使汇率和价格的关系成为研究的热点问题.通过构建汇率价格传递效应的VAR模型和VEC模型,文章分析检验了人民币汇率波动对中国物价水平的影响程度以及二者变化的方向,最后在实证分析的基础上解释其经济学意义并探讨汇率传递效应对中国的政策启示.     

从错误分析反思英语写作教学

反思性教学理论是近年来在各国教育界备受重视的一种促进专业发展的教师教育理论。错误分析理论旨在分析学习者出现的错误从而揭示语言学习中的一些规律。利用错误分析反思写作教学的过程,探讨更优化的写作教学方法,可以更好地提高写作教学质量。     

我国财产保险市场的空间统计分析

以我国31个省(市、自治区)的保险密度和保险深度为属性数据,利用ArcGIS和GeoDa软件,运用空间统计方法,对我国财产保险市场的地区空间差异进行实证分析。结果表明:我国财产保险的保险密度与保险深度的分布特征在南北方向上基本一致,在东西方向上不一致;各地区保险密度的分离度高于保险深度的分离度;我国财产保险发展存在显著的空间自相关和空间聚集现象。     

Subjective well-being and the family: Results from an ordered probit model with multiple random effects

The previous literature on the determinants of individual well-being has failed to fully account for the interdependencies in well-being at the family level. This paper develops an ordered probit model with multiple random effects that allows to identify the intra-family correlation in well-being. The parameters of the model can be estimated with panel data using Maximum Marginal Likelihood. The approach is illustrated in an application using data for the period 1984–1997 from the German Socio-Economic Panel in which both inter-generational and intra-marriage correlations in well-being are estimated.First version received: May 2003/Final version received: August 2004I would like to thank Andrew Clark, Daniel S. Hamermesh, seminar participants at Tilburg University, and three anonymous referees for helpful comments.     

On the Lp error of the Grenander-type estimator in the Cox model

We consider the Cox regression model and study the asymptotic global behavior of the Grenander-type estimator for a monotone baseline hazard function. This model is not included in the general setting of Durot (2007). However, we show that a similar central limit theorem holds for L_p-error of the Grenander-type estimator. As an illustration of application of our main result, we propose a test procedure for a Weibull baseline distribution, based on the L_p-distance between the Grenander estimator and a parametric estimator of the baseline hazard. Simulation studies are performed to investigate the performance of this test.     

Estimating elasticities of residential energy demand from panel county data using dynamic random variables models with heteroskedastic and correlated error terms

A dynamic random variables model correcting for heteroskedastic and correlated error terms over time and space and dynamic demand and using panel county data offers consistent and efficient elasticity estimates of residential electricity and natural gas demands. The model developed by Swamy [Swamy, P.A.V.B., 1974. Linear models with random coefficients. In: P. Zarembka (Eds.), Frontiers in Econometrics, Academic Press, London, pp. 143–168.] with a modification suggested by Maddala et al. [Maddala, G.S., Trost, R.P., Li, H., Joutz, F., 1997. Estimation of short-run and long-run elasticities of energy demand from panel data using shrinkage estimators. Journal of Business and Economic Statistics 15, 90–100.] uses a panel of selected California counties for the years 1983–1997 to yield elasticity estimates that differ from those obtained from more standard panel data procedures.     

Mixed random forest,cointegration, and forecasting gasoline prices

One of the most successful forecasting machine learning (ML) procedures is random forest (RF). In this paper, we propose a new mixed RF approach for modeling departures from linearity that helps identify (i) explanatory variables with nonlinear impacts, (ii) threshold values, and (iii) the closest parametric approximation. The methodology is applied to weekly forecasts of gasoline prices, cointegrated with international oil prices and exchange rates. Recent specifications for nonlinear error correction (NEC) models include threshold autoregressive models (TAR) and double-threshold smooth transition autoregressive (STAR) models. We propose a new mixed RF model specification strategy and apply it to the determinants of weekly prices of the Spanish gasoline market from 2010 to 2019. In particular, the mixed RF is able to identify nonlinearities in both the error correction term and the rate of change of oil prices. It provides the best weekly gasoline price forecasting performance and supports the logistic error correction model (ECM) approximation.     

Cyclical common factors in cointegrated systems

When working with vectors of time series which fluctuate regularly we may possibly want to consider the presence of common factors characterized by cyclical or seasonal behavior as well as trend. For example, Deaton89 provides a hint of a theoretical model where cointegration at the annual frequency may exist between consumption and income in addition to the usual secular cointegration. It is well known that a non-cyclical system cointegrated at frequency zero has a common trend (CT) representation Stock-Watson: 88. In this paper we show that a time series vector that is cointegrated at one or several frequencies simultaneously (e.g. seasonal data) has a common factors (CF) representation which belongs to a class of common factor models that encompasses many cointegrating situations found in the literature. We study these issues and extend the method proposed by Gonzalo-Granger: 95 to the estimation and testing of common factors which may combine trend as well as cyclical or seasonal characteristics. Two illustrative applications are also provided. JEL Classification: C10, C32, C50 Javier Fernández-Macho: Financial support from research group grant 9/UPV00038.321-13503/2001 of UPV/EHU is gratefully acknowledged by both authors and from research project BEC2003-02028 of Ministerio de Ciencia y Tecnología by the first author. We are also indebted to two anonymous referees for their helpful comments.     

中外学生写作中的语用偏误对比

中式英语是中国大学生英语写作中很普遍的现象,与之相类似的是英语国家留学生汉语写作中的各种语用偏误。基于HSK动态作文语料库中的详实语料,运用二语习得中的中介语理论、语言迁移理论及偏误分析理论,尝试研究英国、美国、澳大利亚、加拿大留学生实际写作中的语用偏误现象并与中式英语进行对比分析。通过使用语料库定量分析法、语言对比分析法和偏误分析法,深入分析了这些语用偏误现象及中式英语出现的原因并针对性地提出相关对策,以期对英语国家留学生和中国大学生的第二语言写作以及相关的教学实践提供借鉴,纠正和减少偏误的发生,帮助其提高写作能力。