Research On Risk Assessment And Early Warning At Key Nodes Of Sea Lines Of Communication

The safety and security of key nodes is one of the important factors that restrict the safe,stable and efficient completion of cargo trade in the sea transportation system.It is one of the important topics to conduct safety and security research at the key nodes which can ensure the safe transportation of trade goods.Such as analyzing the risk influencing factors affecting the key nodes,evaluating the risk situation of the key nodes and realizing the risk warning of the key nodes.It is of great practical significance and theoretical value to carry out research on the risks of key nodes to reduce the risks of sea transportation,guarantee the safety of the sea lines of communication and enrich the theory of risk evaluation and early warning.There are relatively few relevant studies on risk assessment and risk early warning at key nodes of sea lines of communication from the perspective of non-traditional security threats.Most of the literature mainly analyzes and evaluates the risks encountered during the transportation activities carried out by vessels from the perspective of traditional security threats such as maritime traffic accidents and fire and explosion.In addition,the existing literature on the risk assessmnet and early warning of maritime transportation risks seldom comprehensively considers the problems of missing historical case data,uncertainty of risk indicators,and the existence of state transfer process of risk influencing factors.Therefore,how to integrate non-traditional security threat factors into risk assessment and risk early warning models,how to adopt appropriate methods to deal with the problem of missing historical case data,and how to scientifically and rationally express the uncertainty of risk evaluation indicators and the state transfer process of risk influencing factors between different moments are the current challenges faced by this topic.In view of the above problems,this paper explores and researches the identification,risk evaluation and risk warning of risk influencing factors at key nodes of sea lines of communication.The main research contents are as follows:(1)Reserch on the topic of definition of the concepts related to the safety of sea lines of communication and the application of the theoretical methods.According to the concepts related to the safety of sea lines of communication in literature and the characteristics of the research object,the basic concepts related to it are defined.The current situation of the distribution of major sea lines in China is analyzed according to the main sea transport routes,the share and structure of international trade imports and exports.the theoretical basis of the method used in this paper and its specific application in the field of risk evaluation and risk warning of key nodes are analyzed,which lay the foundation for the subsequent identification of risk influencing factors,risk evaluation and risk early warning at key nodes.(2)Research on the topic of identifying factors influencing the risk of key nodes of sea lines of communication.The key nodes studied in this paper are screened out according to the distribution of major sea lines of communication in China,the distribution of international trade cargoes and transport vessels.All factors that may affect the risk of key nodes are analyzed and counted,including non-traditional security threat factors.A Bayesian network-based model is constructed to identify the risk influencing factors of key nodes,which can effectively deal with the problem of missing historical case data using the EM algorithm.The ranking of risk influencing factors on the risk status is realized,which lays the foundation for the construction of subsequent risk evaluation and risk warning model.(3)Research on the topic of risk evaluation of key nodes of sea lines of communication.The risk evaluation index system is constructed and the index weights are determined according to the results of risk influence factors identification.The input and output variables of the model are represented by the membership function of the fuzzy set,which effectively expresses the fuzziness and uncertainty of the risk evaluation index.A fuzzy reliability rule base is constructed to establish the nonlinear relationship between input variables and output variables,which maximizes the expression of the true nonlinear relationship between the independent and dependent variables without losing important information.The risk values of key nodes are obtained by using evidential reasoning theory and utility function.Horizontal comparative analysis of risk status of key nodes is realized.(4)Research on the topic of risk early warning of key nodes of sea lines of communication.The initial topology of the risk warning model is constructed based on the results of risk influencing factors identification.The EM algorithm is applied to determine the conditional probability and state transfer probability parameters of the dynamic Bayesian network,which effectively expresses the state transfer process of risk influencing factors between different moments.The risk early warning model based dynamic Bayesian network is then constructed.The dynamic early warning of the risk of key nodes is realized.The effectiveness of the model constructed in this paper is verified by using the traditional Bayesian model and Markov model.This study is the intersection of system engineering theory,safety science,risk analysis and risk warning theory in penetration.It is a useful exploration of the important topic of securing key nodes of sea lines of communication.This research on risk influencing factor identification,risk evaluation and risk early warning technologies can provide maritime stakeholders decision support for the work of securing key nodes.