Semiparametric time series regression modeling with a diverging number of parameters

Variable selection and error structure determination of a partially linear model with time series errors are important issues. In this paper, we investigate the regression coefficient and autoregressive order shrinkage and selection via the smoothly clipped absolute deviation penalty for a partially linear model with a divergent number of covariates and finite order autoregressive time series errors. Both consistency and asymptotic normality of the proposed penalized estimators are derived. The oracle property of the resultant estimators is proved. Simulation studies are carried out to assess the finite‐sample performance of the proposed procedure. A real data analysis is made to illustrate the usefulness of the proposed procedure as well.     

China’s international trade development and opening-up policy design over the past four decades

ABSTRACT

China’s opening-up in the past four decades has gone through three waves: the extensive margin of opening-up (1978–2001), the intensive margin of opening-up (2001–2017), and all-around opening-up (since 2017). This paper explores these three stages of the country’s economic reform. China’s gains from trade have been inspired by different economic factors. Before the turn of the century, the large trade volume was due to the realization of comparative advantage based on the country’s factor endowment. However, after its accession to the World Trade Organization, China’s gains from trade have been due, in large part, to the realization of economic scale effects associated with the larger market.     

一种基于SIR结构的三通带带通滤波器

应用双指耦合结构和枝节加载谐振器（Stub-loaded Resonator，SLR）实现了一款基于阶梯阻抗谐振器（Stepped Impedance Resonator，SIR）的滤波器。该滤波器具有3个通带，带外抑制较好，工作频段提高。通过调整阻抗比可调节第二、三通带的谐振频率；SLR结构能够增加通带数量；SLR结构和双指耦合结构均能改善滤波器的S参数。HFSS软件仿真表明，3个通带的中心频率分别为3.5 GHz、6.6 GHz、9.2 GHz，对应的分数带宽分别为5.7%、3%、2%，S11分别为-18 dB、-22 dB、-24 dB，通带内的S21分别为-1.8 dB、-1 dB、-1 dB。电路的测量结果与仿真结果较为吻合。该滤波器在5G通信的低频段具有应用前景。     

Can Direct Payments Facilitate Agricultural Commercialisation: Evidence from a Transition Country

We investigate the impact of direct payments on agricultural commercialisation in Kosovo. Kosovo is one of the poorest countries in Europe but, with European assistance, provides substantial funds to support agriculture, made up of many small and often semi‐subsistence farms. Thus, the effect of this support is a central policy issue. Identifying the effect of direct payments on market participation faces endogeneity issues arising from the possible simultaneous determination of participation in support programmes and market participation. In order to achieve proper identification of the endogenous direct payments, we use a strategy of targeted identification search that employs several different methodological approaches. We find that direct payments for fruit and vegetables, and those for cereals and oilseeds have a positive effect on market participation. However, we cannot identify any definite effect of livestock payments.     

Dynastic Inequality Compared: Multigenerational Mobility in the United States,the United Kingdom,and Germany

Using harmonized household survey data, we analyze long‐run social mobility in the United States, the United Kingdom, and Germany, and test recent theories of multigenerational persistence of socioeconomic status. In this country comparison setting, we find evidence against a universal law of social mobility. Our results show that the long‐run persistence of socioeconomic status and the validity of a first‐order Markov chain in the intergenerational transmission of human capital is country‐specific. Furthermore, we find that the direct and independent effect of grandparents' social status on grandchildren's status tends to vary by gender and institutional context.     

Vicarelli’s Keynes and the New-Keynesian analytical method

This article provides a critical review of the foundations of the new Keynesian apparatus, to evaluate the actual strength of the Keynesian inheritance. As a reference of the Keynesian vision, Fausto Vicarelli’s recognition of the Keynesian message is adopted. The critical recognition of the new Keynesian methodology focuses on its analytical foundations, the recent extensions and on the criticality of its empirical performances and controls. The new Keynesian construction is shown to lack truly Keynesian roots in at least three key theoretical features: the role of the microfoundations, the stability of equilibrium, and expectations formation. The directions of an ongoing research narrowing the new Keynesian theoretical fracture from Keynesian economics are addressed.     

三维价值链视阈下科技成果转化知识供给体系研究

科技成果转化知识供给是指知识沿价值链不同维度，经过耦合与交流，形成知识供给体系，对其探索可推动知识的精准供给和有序流动。基于全程价值链视角，从3个维度剖析科技成果转化知识供给体系的特征与机理。在纵向维度中，知识供给纵贯创意→设计→实验→中试→量产→销售等价值环节，并经历知识分化、加工、增值、包装与应用；在横向维度中，科技成果转化知识供给内含于各价值模块中，具有半自律化特征；在网络维度中，知识供给嵌于价值网络中，具有开放组合性、跨领域交叉性与跨疆界性。     

Selection of influential variables in ordinal data with preponderance of zeros

Presence of excess zero in ordinal data is pervasive in areas like medical and social sciences. Unfortunately, analysis of such kind of data has so far hardly been looked into, perhaps for the reason that the underlying model that fits such data, is not a generalized linear model. Obviously some methodological developments and intensive computations are required. The current investigation is concerned with the selection of variables in such models. In many occasions where the number of predictors is quite large and some of them are not useful, the maximum likelihood approach is not the automatic choice. As, apart from the messy calculations involved, this approach fails to provide efficient estimates of the underlying parameters. The proposed penalized approach includes ?₁ penalty (LASSO) and the mixture of ?₁ and ?₂ penalties (elastic net). We propose a coordinate descent algorithm to fit a wide class of ordinal regression models and select useful variables appearing in both the ordinal regression and the logistic regression based mixing component. A rigorous discussion on the selection of predictors has been made through a simulation study. The proposed method is illustrated by analyzing the severity of driver injury from Michigan upper peninsula road accidents.     

The 2020 Pandemic: Economic repercussions and policy responses

This paper analyses the economic and financial repercussions of the 2020 COVID‐19 pandemic. It argues that the pandemic has inflicted serious injuries to the labor force but has not damaged the physical capital stock. Therefore, the resolution policies of this crisis ought to be carefully tailored to supporting structural adjustments to the labor market. The analysis asserts that the impact of the pandemic crisis is exacerbated by the identification gap between the unobserved and the officially reported cases of COVID‐19. The gap increases financial risks, including market‐, credit‐, default‐, and foreign exchange risks.     

The effect of observables,functional specifications,model features and shocks on identification in linearized DSGE models

The decisions a researcher makes at the model building stage are crucial for parameter identification. This paper contains a number of applied tips for solving identifiability problems and improving the strength of DSGE model parameter identification by fine-tuning the (1) choice of observables, (2) functional specifications, (3) model features and (4) choice of structural shocks. We offer a formal approach based on well-established diagnostics and indicators to uncover and address both theoretical (yes/no) identifiability issues and weak identification from a Bayesian perspective. The concepts are illustrated by two exemplary models that demonstrate the identification properties of different investment adjustment cost specifications and output-gap definitions. Our results provide theoretical support for the use of growth adjustment costs, investment-specific technology, and partial inflation indexation.