Gomez Michael, Garcia Susana, Rajtmajer Sarah, Grady Caitlin, Mejia Alfonso
Department of Civil and Environmental Engineering, The Pennsylvania State University, State College, USA.
Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, USA.
Appl Netw Sci. 2020;5(1):71. doi: 10.1007/s41109-020-00310-1. Epub 2020 Sep 23.
Supply chains enable the flow of goods and services within economic systems. When mapped for the entire economy and geographic locations of a country, supply chains form a spatial web of interactions among suppliers and buyers. One way to characterize supply chains is through multiregional input-output linkages. Using a multiregional input-output dataset, we build the multilayer network of supply chains in the United States. Together with a network cascade model, the multilayer network is used to explore the propagation of economic shocks along intranational supply chains. We find that the effect of economic shocks, measured using the avalanche size or total number of collapsed nodes, varies widely depending on the geographic location and economic sector of origin of a shock. The response of the supply chains to shocks reveals a threshold-like behavior. Below a certain failure or fragility level, the avalanche size increases relatively quickly for any node in the network. Based on this result, we find that the most fragile regions tend to be located in the central United States, which are regions that tend to specialize in food production and manufacturing. The most fragile layers are chemical and pharmaceutical products, services and food-related products, which are all sectors that have been disrupted by the Coronavirus Disease 2019 (COVID-19) pandemic in the United States. The fragility risk, measured by the intersection of the fragility level of a node and its exposure to shocks, varies across regions and sectors. This suggests that interventions aiming to make the supply-chain network more robust to shocks are likely needed at multiple levels of network aggregation.
供应链使商品和服务在经济系统中得以流通。当针对一个国家的整个经济和地理位置进行映射时，供应链形成了供应商和买家之间相互作用的空间网络。描述供应链的一种方法是通过多区域投入产出联系。利用多区域投入产出数据集，我们构建了美国供应链的多层网络。结合网络级联模型，该多层网络用于探索经济冲击在国内供应链中的传播。我们发现，使用雪崩规模或崩溃节点总数衡量的经济冲击影响，会因冲击的地理位置和起源经济部门的不同而有很大差异。供应链对冲击的反应呈现出类似阈值的行为。在某个特定的故障或脆弱性水平以下，网络中任何节点的雪崩规模都会相对快速增加。基于这一结果，我们发现最脆弱的地区往往位于美国中部，这些地区往往专门从事食品生产和制造业。最脆弱的层级是化学和药品产品、服务以及与食品相关的产品，这些都是在美国受到2019年冠状病毒病（COVID - 19）疫情干扰的所有部门。由节点的脆弱性水平与其遭受冲击的程度交叉衡量的脆弱性风险，在不同地区和部门有所不同。这表明可能需要在网络聚合的多个层面采取旨在使供应链网络对冲击更具韧性的干预措施。
