# Vulnerability Analysis of a Multilayer Logistics Network against Cascading Failure
## 5 Discussion and Conclusions
Therefore, it is an effective measure to improve the destruction resistance of the urban network system of logistics hubs and a potential way to improve the reliability of the network to strengthen the logistics coupling relationship between cities, increase the direct dependence of different network layers on functions and improve the complexity of the network structure. Due to the diversity and uncertainty of risk sources for logistics hub cities, most of the impact and diffusion paths of risk shocks do not follow a regular pattern in advance. Therefore, the three-step response strategy of \"Prewarning-Response-Postrepair\" is the main pathway to improving the adjustment ability and adaptability of logistics hub cities in response to external shocks. First, we should actively promote preventive medical examinations, risk monitoring and early warning mechanisms and strengthen the redundancy and modularity of infrastructure construction in logistics hub cities to identify the contingencies and risks that logistics hub cities may face, carry out security risk assessment of logistics hub cities, and form personalized physical examination reports of logistics hub cities to identify the shortcomings of logistics hub cities. The logistics needed during a crisis period should be considered to avoid the various risks faced by the logistics hub city proactively during the course of operation. Second, action guidelines should be developed to promote active feedback and active response mechanisms during an attack event to enhance the logistics hub city's comprehensive emergency logistics security capacity. Governments at all levels should consider the resource endowment, network layout and emergency security of logistics hub cities and formulate action guidelines or action plans for emergency capacity building of logistics hub cities under the impact of emergencies, mainly involving short board identification, system construction, key technologies, policy initiatives and risk response checklists, such as optimizing the stock of logistics hub cities with the advantages of their network functions and trunk line transit capacity. The layout of emergency material reserve facilities thus reduces the losses caused by shocks to a minimum level. For example, Shenzhen, China, has maintained regular cargo flights, launched international air cargo charter services, and implemented measures such as \"passenger to cargo\" contribution to flight increase to cope with the impact of the COVID-19 epidemic. Third, timely reflection and optimization should be promoted, and post-event repair and dynamic adjustment mechanisms should be actively promoted. On the one hand, it is necessary to introduce improved policies and initiatives and continuously absorb the lessons learned by itself and other cities in response to the crisis to reduce the vulnerability of logistics hub cities and improve the \"immunity\" and reliability of logistics hub cities in response to emergencies; on the other hand, it is necessary to improve the emergency response function of the comprehensive information platform and make use of big data technology for assessments. On the other hand, it is necessary to improve the emergency functions of comprehensive information platforms, make use of big data technology to evaluate whether there is a logistics supply gap or redundancy and its real logistics de mand, quantify and rank the urgency of supply and demand in terms of strategy, value and urgency, further realize the information sharing and cooperative operation ability of suppliers, logistics enterprises and government departments, promote matching resources and regulation processes, and improve the collection and deployment of materials, transportation and transit, distribution and delivery to ensure the normal operation of the logistics hub city under the risk impact. The research offers an extensive examination of cascading failures within multilayer global logistics networks.