Study On Assistant Decision-Making Methods For Vessel Traffic Organization In Compound Waterway Areas

With the growing increase of marine cargo throughputs,more and more vessels are entering or leaving ports.As a bottleneck water between the berths and the sea--waterway,in order to improve its traffic capacity,it has gradually developed from one-way,two-way to a compound waterway.Though the compound waterway is an advanced vessel traffic infrastructure,simultaneously many unique problems have gradually emerged in those waters,such as the existence of various traffic organization modes,the occurrence of complex vessel traffic conflicts in multiple legs of waterways,the supply of waterway resources and the demand of vessel users varying with different traffic organization modes and different periods,thus seriously restricting the efficiency and service level of compound waterways.Based on this,the purpose of this study is to improve the level of vessel traffic organization in the compound waterways.By analyzing the characteristics of the components belonging to the compound waterway traffic system and the coupling characteristics among components,the mechanism of the above problems is deeply understood.The aim of this study is to provide a safe,efficient and refined vessel traffic organization scheme for VTSOs(Vessel Traffic Service Operators).The corresponding mathematical model and algorithm are constructed.The main contents of this paper are as follows:The elements and characteristics of vessel traffic system in the compound waterways are analyzed,and traffic organization modes in the compound waterways,the arrival volume of vessels,the characteristics of vessel traffic conflicts and its impact on the traffic organization are analyzed furtherly,so that the objectives and principles of the traffic organization in compound waterways are concluded,which lays the foundation for the model construction.Vessel traffic organization optimization model in a compound waterway is established.Considering the improvement of navigation efficiency and service level,the shortest total occupancy time in a waterway and the shortest total waiting time of vessels are selected as the optimization objectives.The numerous constraints,including large vessels riding the tide,vessel time slot allocation at the entrance of a compound waterway,vessel traffic flow conversion between ends of sub-channels,and traffic flow coordination in intersection waters are designed.Navigation continuity constraint is constructed to ensure vessel speed limits in waterways.An algorithm is designed to solve the model above,furthermore,a multi-objective genetic algorithm is constructed to search the optimal solution for the model.Considering the impact of previous traffic organization stage on the current stage,by laying particular emphasis on one of two objective functions which aim at improving navigation efficiency and service level respectively,the very one solution is selected among a set of pareto optimal solutions.Realization and validation of assistant decision-making method above.Based on MATLAB,the operation interface of vessel traffic organization is designed to manage a large number of input and output parameters,and visualize the outputs.The simulation experiments of 20,30 and 40 vessels entering or leaving a port are designed,and the rationality and validity of the model and algorithm are verified through an analysis of 20 ship experiment in detail.The feasibility and efficiency of the model is further verified by comparing with the experience-based scheduling scheme.The results reveal the method above can provide VTSOs with a safe,efficient and refined traffic organization scheme.