| As the most important mode of transportation in the world,shipping has attracted much attention for its safety issues.Numerous accidents and data show that the impact of heavy weather on the safety of navigation should not be underestimated.In order to reduce risks and ensure the safe navigation of ships,the analysis and evaluation of navigational risk in heavy weather has become an indispensable part in the field of maritime transportation research.In this regard,scholars at home and abroad have conducted a lot of research on ship navigation risks in heavy weather,and have formed a relatively mature theoretical system,but most of them focus on static evaluation research and simulation calculations,lack of dynamic tracking of risk,and cannot reflect change of risk.The rule of risk change presented by the change of risk factors during the ship navigation in heavy weather.Therefore,on the basis of previous studies,this paper proposes a dynamic simulation method for ship navigation risk in heavy weather based on cloud model and Markov chain Monte Carlo method.This research is based on real-time ship navigation statistics,considering the variability,time sequence and uncertainty of risk,and dynamically simulates the ship navigation risk in heavy weather from the perspective of the change of the safety state,obtaining the probability distribution of the risk states.Study on the dynamic changes and evolutionary laws of risk during the ship navigation in heavy weather.This paper first considers the impact of heavy weather on the ship navigational safety and the different navigational waters in which the ship is sailing,analyses the risk factors that affect the ship navigational safety in heavy weather,and summarizes the risk characteristics presented by the continuous change of risk factors during the ship navigation.Secondly,according to the chronological and variability characteristics of the ship navigation risk in heavy weather,the method of combining coefficient of variation and analytic hierarchy process is used to screen the risk indicators under different navigation conditions,and a dynamic risk indicator system is established.Third,divide the ship navigation risk level in heavy weather,and establish a dynamic simulation model of the ship navigation in heavy weather based on the Markov chain.Finally,taking a heavy weather voyage of the "EVER DEVOTE" vessel as an example,the collected data is quantified using a cloud model to determine the initial risk state and dynamic transition matrix of the ship navigation,and the Markov chain Monte Carlo method is used for many times.Through simulation,the dynamic change curve of navigational risk in the heavy weather is obtained,and then analyze the dynamic change law of the risk during the voyage.The analysis of the simulation results shows that the dynamic change rule of the ship navigation risk in heavy weather is in line with the realistic judgment of the actual situation of the voyage,which verifies the feasibility and applicability of the dynamic simulation method proposed in this paper.This method can present the macroscopic law of the overall risk during the navigation process through the microscopic changes of risk influencing factors,and then can accurately reflect the change process of the ship navigation risk over time.The dynamic simulation results can provide a scientific reference for ship pilots and shore managers,pay more attention to high-risk key waters and actively take counter measures to ensure the safe navigation of ships. |
