| Although ship foundering accident,as one of the significant maritime traffic accidents,accounts for a small proportion in all types of accidents,it often features in high speed,difficulty in rescue,easy to cause serious casualties and property losses,thus posing major threats to the safety of navigation and people.At the same time,ships carrying dry bulk cargoes are the most crucial ship type in ship foundering accidents.The reasons for the frequent occurrence of accidents are not only related to the characteristics of the cargo they carry,such as concentrate powder or the fluidization risk of cargoes such as clay,etc.,but also comes from the factors such as whether the loading and unloading operation of the cargo by the personnel is reasonable,the loading condition of the ship,the structural strength of the ship itself,the heavy weather encountered by the ship in the course of navigation,etc.All of these are the important inducement for the frequent ship foundering accidents of dry bulk carrier.This paper,with a view to solving problems of frequent ship foundering accidents of dry bulk carrier,found the main influencing factors of the accidents by employing Bayesian network,the principles of system safety engineering and AHP.It analyzed from"people-ship-environment-cargo" to find the causes and chains of accidents,the correlation between the various factors,and the factors that have a critical impact on the accident.Meanwhile,risk control measures were proposed in a targeted manner.The paper was carried out as follows:(1)According to the definition of the concept of ship foundering accident,the qualitative analysis and excavation of the factors that caused the accident from"people-ship-environment-cargo" were conducted,in which the human factors were divided into human errors and personal factors that cause human errors;the impact of the cargo factor took into account the danger of the fluidization of the cargo,the stowage of the cargo,the lashing,trimming,and whether the cargo is overloaded;the ship factor mainly considers the structural defects of the hull itself,the age of the ship,the impact of ship tonnage and ship equipment failure;the environmental factors mainly consider the influence of factors in the natural environment and navigation environment.For the sorted-out factors,this paper established a hierarchical model of risk factors,used the analytic hierarchy process to determine the weight of each risk factor,identified the risk factors,and provided a theoretical basis for the Bayesian network analysis of applied factors in the following.(2)Through the learning of the probability theory basis of Bayesian network and the determination of the model construction steps,and taking each maritime institution and maritime accident cases as sample data,each risk factor was extracted and converted into Bayesian network nodes and node value range was defined.Bayesian network structure learning and Bayesian network parameter learning were conducted during the structure learning process,in which the fault tree method in system safety engineering theory was introduced to facilitate the construction of the network,the index weights obtained by the analytic hierarchy process were modified to the conditional probabilities of some nodes during the parameter learning process,so as to better fuse expert knowledge with data learning together.(3)The Bayesian visual modeling software GeNIe was used to verify and extrapolate the established Bayesian network.By verifying the validity of the accident sample data,the posterior probability of the accident was deduced,which proved that the established network structure was correct.Through diagnostic reasoning,the largest cause chain affecting the ship foundering accident of dry bulk carrier was extracted,and meanwhile the impact of various risk factors on the accident was determined,after which the risk control measures for reducing the occurrence of ship foundering accident of dry bulk carrier were put forward. |
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