Research On The Measurement Of Spatial And Temporal Characters Of Vessel Traffic Flow In Busy Waters Based On AIS Data

With a gradual prosperity of waterborne economic activities,the on-water traffic situation is getting complex.Vessel traffic flow is getting denser,larger and more complicated;routes are crisscrossing;nearmiss and accidents happen frequently.Obviously,the safety and maintenance of water traffic is under great pressure,and higher requirements are set in analyzing and judging traffic situation in busy waters.What's more,the analysis and exploration of traffic flow patterns in busy waters have become the basis of improving navigation capacity,operating efficiency and ensuring the safety of navigation.Thus research on the measurement of spatial and temporal characters of vessel traffic flow in busy waters based on AIS data is of tremendous significance.Firstly,the macroscopic characters of vessel traffic flow are analyzed,and the spatial-temporal characters are put forward,including interarrival time distribution,traffic flow,speed and density.Secondly,when exploring vessel interarrival time distribution,a mixed model with higher adaptability is established;at the same time,vessel traffic flow macroscopic characters are extracted and studied.A vessel traffic flow macroscopic characters model is built.Finally,a full time-space master of vessel traffic flow characters in busy waters is realized.The specific research is done as follows:(1)The interarrival time distribution model is established.Considering the water traffic operation features,constraints are set for vessels to berth and in channel separately.For vessels navigating to berth,constraints are safety distance and loading & unloading efficiency;for vessels navigating in channel,constraint are safety factors and lack of opportunities for overtaking.Then the Generalized Queuing Model(GQM)is proposed.(2)Parameter estimation is carried out based on intelligent algorithm.Due to the complexity of GQMs,the parameters of ?-GQM,LNM-GQM and Burr-GQM can hardly be calculated by derivation.Therefore,the Generalized Pattern Search algorithm(GPS)is selected to optimize the parameters.(3)Macroscopic operation characteristics of vessel traffic flow is extracted.Based on preprocessed AIS data,each vessel's three dimention trajectory is constructed and boundary interpolation algorithm is proposed.Then,the vessel track's start and end points can be calculated,and as a result,the time and distance interval can be extracted.(4)The characters and realationship model of regional traffic flow are studied.With the help of previous similar study on road and pedestrian traffic area,the Eide model is proposed and is diementional extended,considering the vessels' motion featuers.Then the definition of vessel traffic flow characters are proposed.After extracting those charaters from data,the relationship model between regional vessel traffic flow macroscopic characters can be established.In the Tianjin port and the Yangtze Estuary cases study,the superiority of the ?-GQM,LNM-GQM and Burr-GQM is verified,since the study results show that GQMs present better fitting results than single models and GQMs are good at describing features,having a better adaptability.On the other hand,in the Yangtze Estuary and the Yantai port cases study,similar patterns between traffic flow characters with those in road traffic are found.Thus,it is believde that the regional traffic flow characters' extraction and modeling are of feasibility and the foudamental diagram is valid in water traffic applications.The research results enrich the regional traffic flow theory,and at the same time,the research results can effectively reflect the target waters' traffic situation.And the study can be useful for regional water traffic planning and management.