The cascade failure theory is introduced into the risk propagation problem of the multimodal transport network in order to study the inherent law of risk propagation and provide theoretical support for the safety management of multimodal transport networks. Firstly, this paper analyses the characteristics of the multimodal transport network and concludes that the risk of the multimodal transport network belongs to failure risk. Secondly, the applicability of cascade failure theory is expounded. Based on cascade failure theory, a risk propagation model of the multimodal transport network is established. Through simulation experiments, the risk propagation of the multimodal transport network is analyzed from the differences of node distribution and node type. The process is analyzed, and the results show that different node distributions and different types of risk source nodes will have an impact on the risk propagation process. The influence of four types of node distributions on the risk propagation effect is in the following order: increasing type > concave-convex type ≈ balanced type > decreasing type. The influence of four types of source nodes on the risk propagation effect is in the following order: transportation type > transporting type > storage type > assistant type.
In order to study the influence of travelers’ self-adaptive adjustment behavior on transportation network under the assumption of bounded rationality, using cellular automaton to discretize the selection model under the analytic paradigm in the existing research, abstract each cell into a traveler, and describe the traveler characteristics with finite rationality characteristics through the travel risk attitude and travel generalized cost budget. Cellular automata and cumulative prospect theory is used to establish the travel route choice model, giving the dynamic evolution process of different reference points for travelers and taking the actual regional transportation network of Sichuan Tibet region in China as the study object, analyzes the impact of bounded rational travel behavior on route choice. The model and algorithm proposed in our study can not only guide the transportation organization of Sichuan Tibet region, but also provide theoretical support for the implementation of regional transportation planning and traffic control scheme in the future.
The multimodal transport network in the region with complex environment and being easily affected by disturbance factors is used as the research object in our work. The characteristics of the cascading failure of such multimodal transport network were analyzed. From the perspective of network load redistribution, the risk control methods for the cascading failure of the multimodal transport network were investigated. This research aims to solve the problem that traditional load redistribution methods usually ignore the original-destination (OD) constraint and uncertain risks. The conditional value-at-risk (CVaR) was improved based on the Bureau of Public Roads (BPR) road impedance function to quantify the uncertainty of the disturbance factors. A nonlinear programming model was established with the generalized travel time as the objective function. A parallelly-running cellular ant colony algorithm was designed to solve the model. Empirical analysis was conducted on the multimodal transport network in Sichuan-Tibet region of China. The results of the empirical analysis verified the applicability of the proposed load redistribution method to such kind of regions and the effectiveness of the algorithm. This research provides theoretical basis and practical reference for the risk control of the cascading failure of multimodal transport networks in some regions.
Aiming at the problem where the dynamic adjustment of reference points under the impact of decision makers’ emotions may lead to different decision-making results, this research proposes a multi-stage emergency decision-making method with the emotion updating mechanism of decision makers. The method of setting dynamic reference points under the influence of decision-makers' emotions is given in this study, and the scenario value of each stage of emergency is calculated by using cumulative prospect theory, so as to describe the emotion renewal mechanism of decision-makers. The scenario weights of each stage are calculated, and the prospect values of alternatives at each stage are calculated according to the prospect value, input costs and start-up time values of the alternatives. Furthermore, by giving a calculation method of the weight of each stage, the overall values of the alternatives are calculated and the ranking of the alternatives is given. Taking Sichuan Tibet emergency rescue in China as an case analysis, the scientific rationality of the theory proposed in this paper is verified.
As a necessary work before risk prevention and control, risk assessment has become increasingly important in multimodal transport networks. On the basis of the idea of quality function deployment (QFD), this paper combines fuzzy G1 method, two-tuple linguistic representation model, and dynamic intuitionistic fuzzy multi-attribute evaluation method to propose a new method for risk assessment. QFD is innovatively used to create an overall framework, which includes the basic importance rating of risk factors, the correlation between risk factors and network failures, the importance rating of network failures, and the comprehensive importance rating of risk factors. The comprehensive importance rating is regarded as an indicator to verify, improve, and modify the basic importance rating, which can make up for the disadvantage of the existing risk assessment methods in proving the credibility of the results. Its result is the key to judging the degree of influence of risk factors on network operation. This paper takes the multimodal transport network in the Sichuan-Tibet region of China as an example for analysis. The results are analyzed and discussed to prove the validity and advancement of the proposed method.
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