Shi Peiteng, Zhang Jiang, Yang Bo, Luo Jingfei
School of Systems Science, Beijing Normal University, Beijing, China.
Ministry of Commerce of the People's Republic of China, Beijing, China.
PLoS One. 2014 Jun 6;9(6):e98247. doi: 10.1371/journal.pone.0098247. eCollection 2014.
With globalization, countries are more connected than before by trading flows, which amounts to at least 36 trillion dollars today. Interestingly, around 30-60 percents of exports consist of intermediate products in global. Therefore, the trade flow network of particular product with high added values can be regarded as value chains. The problem is weather we can discriminate between these products from their unique flow network structure? This paper applies the flow analysis method developed in ecology to 638 trading flow networks of different products. We claim that the allometric scaling exponent η can be used to characterize the degree of hierarchicality of a flow network, i.e., whether the trading products flow on long hierarchical chains. Then, it is pointed out that the flow networks of products with higher added values and complexity like machinary, transport equipment etc. have larger exponents, meaning that their trade flow networks are more hierarchical. As a result, without the extra data like global input-output table, we can identify the product categories with higher complexity, and the relative importance of a country in the global value chain by the trading network solely.
随着全球化的发展，各国通过贸易流动比以往任何时候都联系得更加紧密，如今贸易流动总额至少达36万亿美元。有趣的是，全球约30%至60%的出口产品为中间产品。因此，具有高附加值的特定产品的贸易流动网络可被视为价值链。问题在于我们能否从其独特的流动网络结构中区分这些产品？本文将生态学中发展起来的流动分析方法应用于638个不同产品的贸易流动网络。我们认为，异速生长缩放指数η可用于表征流动网络的层次化程度，即贸易产品是否沿着长层次链流动。然后，指出像机械、运输设备等具有较高附加值和复杂性的产品的流动网络具有更大的指数，这意味着它们的贸易流动网络更具层次性。结果是，无需像全球投入产出表这样的额外数据，我们仅通过贸易网络就能识别出具有较高复杂性的产品类别以及一个国家在全球价值链中的相对重要性。
