国际金融危机潜在传染源的识别及其传染力分析

亚洲金融危机和希腊债务危机表明中小国家也可以引发严重危机，这种现象不容忽视。基于复杂网络理论，使用2007年国际贸易数据构建了包含148个国家和地区的全球宏观经济网络；利用S.I.R模型模拟了各国在发生不同等级的金融危机时所影响到的国家数量和经济总量，发现不同国家传染力的差异存在一定的区域特征，许多经济总量不大的国家也具有引发严重危机的潜力；使用动态聚类法对各国的传染力进行分类，处于类别1至类别4的国家为国际金融危机潜在传染源；通过计算传染力与GDP、进口和网络拓扑结构指标的Spearman相关系数发现，GDP、进口较大以及聚类系数小的国家在低危机等级时就表现出一定的负面溢出；而贸易伙伴较多以及处于网络中心位置的国家在较高的危机等级下具备引发严重危机的潜力；使用2009年的数据进行模拟，本文的主要结论依然稳健。

The Identification of Potential Infectious Source of International Financial Crisis and the Analysis of Their Contagiousness

The Asian financial crisis and Greek debt crisis showed that small countries can lead to a severe crisis. Apart from Thailand and Greece, those countries which can trigger a regional financial crisis or international financial crisis should not be ignored. Based on complex network theory, a global macroeconomic network containing 148 countries and regions using international trade data of 2007 is constructed. Moreover, the susceptible infected recovered (S.I.R) epidemic model with a changeable probability of infection is utilized to simulate the financial crisis transmitting through network. By this method, the number of countries and the aggregate economic volume that different countries will affect in different crisis levels can be obtained according to which countries are classified in six categories using dynamic clustering method. By calculating the Spearman correlation coefficients between contagiousness and GDP, import volume and index of network topology comprising degree, closeness centrality, betweenness centrality and clustering coefficients, the major influence factors that can explain the difference of contagiousness are explored. The results show that there is region feature in the difference of contagiousness and many countries with lower GDP can lead to a severe crisis. Countries located in category 1 to category 4 in the global macroeconomic network are potential infectious source. Countries with higher GDP and import will lead to negative spillover when a small crisis occurs, while countries with more trade partners and in the center of the network have the potential to lead to a severe crisis. Then the financial crisis transmitting through network of 2009 is simulated and the results pass the robust test. In this paper, the conclusions make for discovering countries which should be concerned and building a global early warning system to watch for future financial crisis.