International reserves: Facing model uncertainty

The abundant literature on the competing motives for holding international reserves stresses different factors, giving rise to a problem called model uncertainty. In this paper we search for the most important determinants of reserve holdings using data for 104 countries over the period 1999–2010 and evaluate their importance using Bayesian model averaging (BMA). We enrich the ongoing empirical discussion by examining the role of financial globalization and monetary policy and by introducing new variables and searching for alternatives to the traditional ones. The results confirm that trade openness and the broad-money-to-GDP ratio are the key determinants with a positive link to the level of reserves. On the other hand, financial development seems to lower the need for reserves.     

A stochastic dynamic model of trade and growth: Convergence and diversification

There is a growing literature that studies the properties of models that combine international trade and neoclassical growth theory, but mostly in a deterministic setting. In this paper we introduce uncertainty in a dynamic Heckscher-Ohlin model and characterize the equilibrium of a small open economy in such an environment. We show that, when trade is balanced period-by-period, the per capita output and consumption of a small open economy converge to an invariant distribution that is independent of the initial wealth. Further, at the invariant distribution, there are periods in which the small economy diversifies. Numerical simulations show that the speed of convergence increases with the size of the shocks. In the limit, when there is no uncertainty, there is no convergence and countries may specialize permanently. The paper highlights the role of market incompleteness, as a result of the period-by-period trade balance, in this setup. Through an analytical example we also illustrate the importance of country specific risk in delivering our results.     

国际货币政策协调:理论研究、实践进展及中国的选择

开放经济下一国货币政策会产生溢出效应,因此各国需要通过货币政策的国际协调来增进共同福利;目前,国际货币政策协调的实践已形成了几种重要的区域协调模式,并在解决国际经济事务中发挥关键作用;对于我国而言,在新一轮汇率制度改革后,也更加需要通过货币政策的国际协调来解决与其他国家或经济区的政策冲突。     

Supply chain planning of vaccine and pharmaceutical clusters under uncertainty: The case of COVID-19

As an abrupt epidemic occurs, healthcare systems are shocked by the surge in the number of susceptible patients' demands, and decision-makers mostly rely on their frame of reference for urgent decision-making. Many reports have declared the COVID-19 impediments to trading and global economic growth. This study aims to provide a mathematical model to support pharmaceutical supply chain planning during the COVID-19 epidemic. Additionally, it aims to offer new insights into hospital supply chain problems by unifying cold and non-cold chains and considering a wide range of pharmaceuticals and vaccines. This approach is unprecedented and includes an analysis of various pharmaceutical features such as temperature, shelf life, priority, and clustering. To propose a model for planning the pharmaceutical supply chains, a mixed-integer linear programming (MILP) model is used for a four-echelon supply chain design. This model aims to minimize the costs involved in the pharmaceutical supply chain by maintaining an acceptable service level. Also, this paper considers uncertainty as an intrinsic part of the problem and addresses it through the wait-and-see method. Furthermore, an unexplored unsupervised learning method in the realm of supply chain planning has been used to cluster the pharmaceuticals and the vaccines and its merits and drawbacks are proposed. A case of Tehran hospitals with real data has been used to show the model's capabilities, as well. Based on the obtained results, the proposed approach is able to reach the optimum service level in the COVID conditions while maintaining a reduced cost. The experiment illustrates that the hospitals' adjacency and emergency orders alleviated the service level significantly. The proposed MILP model has proven to be efficient in providing a practical intuition for decision-makers. The clustering technique reduced the size of the problem and the time required to solve the model considerably.     

多重目标下的跨国银行FDI动机和区位选择——基于跨国银行面板数据变截距固定效应模型的检验

依据1986年-2008年期间以外国金融直接投资的形式在我国设立商业存在的跨国银行数据、运用Panel Data变截距固定效应模型GLS估算方法,检验了跨国银行进入我国的动机和区位选择的影响因素.结果发现,跨国银行进入我国"追求利润"的动机比"客户追随"的动机更加强烈;而制度质量上接近的程度则是跨国银行进行区位选择的决定性因素.     

A discrete-time model for daily S & P500 returns and realized variations: Jumps and leverage effects

We develop an empirically highly accurate discrete-time daily stochastic volatility model that explicitly distinguishes between the jump and continuous-time components of price movements using nonparametric realized variation and Bipower variation measures constructed from high-frequency intraday data. The model setup allows us to directly assess the structural inter-dependencies among the shocks to returns and the two different volatility components. The model estimates suggest that the leverage effect, or asymmetry between returns and volatility, works primarily through the continuous volatility component. The excellent fit of the model makes it an ideal candidate for an easy-to-implement auxiliary model in the context of indirect estimation of empirically more realistic continuous-time jump diffusion and Lévy-driven stochastic volatility models, effectively incorporating the interdaily dependencies inherent in the high-frequency intraday data.     

Linking green purchasing capabilities to environmental and economic performance: The moderating role of firm size

This study identifies firms’ green purchasing capabilities, classified into operational capabilities and dynamic capabilities, and measures their effects on the environmental and economic performance of a firm. We developed instruments to measure operational green purchasing capabilities and dynamic green purchasing capabilities. This study also investigates the moderating effect of firm size on the relationship between green purchasing capabilities and firm performance. The structural equation model (SEM) is used to analyse 239 responses from Japanese manufacturing companies. The results indicate that their green purchasing capabilities positively affect environmental and economic performance. Operational capabilities and dynamic capabilities have different levels of effects on green purchasing performance. A further analysis of the moderating effect of firm size shows that the high economic performance of green purchasing relies on the level of dynamic capabilities rather than firm size.