Panel LM unit root tests with level and trend shifts

This paper considers a Lagrange multiplier (LM) based panel unit root test that allows for heterogeneous structural breaks in both the intercepts and slopes of a series. We note that many popular time series variables are likely to exhibit changing means and/or trends over time. Given that the usual tests will depend on the nuisance parameters indicating the locations of the trend breaks, we adopt a transformation procedure that makes our new panel unit root tests invariant to the nuisance parameters. To illustrate the importance of the power gain provided by our test, we examine the convergence hypothesis using relative ratios of per capita health care expenditures in 20 OECD countries. Our results provide evidence that the convergence hypothesis is supported.     

我国商品流通的变迁与发展趋势

计划体制下形成的是与高度集权的经济体制相适应的分配式商品流通组织体系。转轨时期商品流通呈现“三多一少”的格局，流通的低层次性和非系统化。未来的商品流通呈现出弱化二元经济特征、批发业革新、信息化等趋势。     

关于中国服装教育若干问题的思考

古老而先进的服装文明建设遭遇了浮躁而滞后的服装教育 ;博大精深的服装文化被简单而肤浅地诠释了。功利主义将服装教育引入了重重误区 ,服装教育的管理体制、院校布局、教育理念、层次划分、专业设置等 ,亟待规范。为此 ,本文提出了中国服装教育标本兼治的思路和一些对策。     

重载交通柔性路面结构设计研究与应用

车辆超载是一个普遍存在的问题,对道路路面的正常使用具有很大影响,是道路路面使用初期产生严重破坏的主要原因.结合深南路的路面修缮工程,分析重载交通柔性路面结构修缮所面临的实际问题.     

Evaluation of the social and economic impact of carbon dioxide (CO2) emissions on sustainable mobility using cumulative ordinal models: trend odds model

In the context of environmental sustainability evaluation, grouped under climate change, health and ecosystem themes, an impact that could be investigated is the Global Warming Potential (GWP), whose sources are a multitude. In urban areas the evaluation of real vehicles emissions is an essential activity in order to suggest possible solution to local administrators. They still express the need to improve and maintain the characteristics of the breathing air at the best possible quality level. Moreover, these solutions, such as planning measures or traffic control management in respect of pollution, would be apply at different geographical levels, i.e. national, regional or urban scale. Another factor to be investigated is the effect of technologies and emission control systems to comply more stringent limits (Euro 4/5/6) and improve air quality to a lower environmental impact. GWP, indicator of climate change, is measured in terms of CO₂ equivalency emission values variable. To perform this activity an experimental campaign was carried out with several vehicles from different manufacturers and with a wide variety in terms of mass, power, engine displacement and type approval technology. The experimental plan includes some repetitions of the urban section in Naples city centre.The purpose of this paper is twofold: first, to provide a strategy on the choice of a logistic model with ordinal data and with trend, and, second, to evaluate the usefulness of such models for environmental sustainability (CO₂ and other vehicular pollutant emissions), with particular emphasis on model formulation, the interpretation of model coefficients, and the implications of such models.     

浅谈高性能沥青路面

文章主要介绍美国SHRP计划中高性能沥青路面(Superpave)的研究方法和Superpave在实际应用中的技术问题。     

水泥混凝土路面板破坏的原因及其防治

根据我国已建成通车的高等级公路的使用情况，从路基施工前准备、路基施工、台背处理、路面施工及路表面排水处理等方面较全面地分析了水泥混凝土路面破坏的原因及其防治。     

曲面响应法预测砂浆性能的试验研究

本试验以砂浆性能为研究对象,采用Box-Behnken的中心组合实验设计及响应面分析方法对腻子粘结强度进行预测研究。试验选用三因素三水平的响应曲面分析法,建立了粘结强度的二次多项数学模型,并以粘结强度为响应值作响应面和等高线,考察了水粉比、灰粉比和胶粉比对粘结强度的影响,并根据实际选择响应曲面方程,利用最小二乘法估计相应的系数,剔除最不显著因素,建立最终的数学方程。结果表明:该预测模型能很好地描述粘结强度与水粉比、灰粉比和胶粉比之间的关系,可以对腻子粘结强度进行分析和预测,为砂浆性能研究提供一种新方法。     

Modelling the implied volatility surface based on Shanghai 50ETF options

We develop a dynamic factor model to forecast the implied volatility surface (IVS) of Shanghai Stock Exchange 50ETF options. Based on the assumption that dynamic change in IVS is mean-reverting and Markovian, we use a state space model to capture the dynamics of IVS, and set the latent factors to be the Ornstein–Uhlenbeck processes. We obtain the optimal estimations of parameters using the Kalman filter algorithm. Empirical results show that our model performs better than the traditional IVS model in terms of fitting ability and prediction performance.     

Growth and real business cycles in Vietnam and the Asean-5. Does the trend shock matter?

We examine Vietnam’s economy in comparison with its closest trade partners. We show that capital accumulation has been the primary growth engine since the start of its transition to the pro-market economy in 1986 – the Doi Moi. We also show that the cyclical behavior of its macro aggregates is similar to that of its ASEAN-5 peers and other developing countries. We extend the standard small open economy RBC model by considering habit persistence and government consumption, which allows a close match of the moments of the growth variables. At the business cycle frequency, transitory productivity shocks account for approximately one-half of Vietnam’s output variance, while country risk and non-transitory productivity shocks account to close to one-fifth each. Regarding the Solow residual’s volatility, we find that the trend component merely accounts for 12 % of this variance in Vietnam, while in Thailand it is only 6 %. These findings refute the “the cycle is the trend” hypothesis in Aguiar and Gopinath (2007) and align with the hypotheses in García-Cicco et al. (2010) and Rhee (2017), where the stationary component is overwhelmingly dominant. We claim that technological progress and productivity-enhancing measures are fundamental for Vietnam’s economy to sustain high growth.