| The ship routing system,which is an important part of the maritime ship traffic management system,can well standard the navigation order of the ships,and make the ships navigate in accordance with the recommended route,which will finally cause the encounter situation occur frequently for the ships with the same directions.From the statistical data,ship overtaking is a common ship behavior in the water area of the routing system,which accounts around 30% of the encounter behavior.As the ship overtaking is significantly influenced by the ship speed,ship maneuverability,port of destination and tide,and the large number of ship traffic flow,it is significant to study the ship overtaking behavior and risk assessment within the ship routing system to propose methods for assisting overtaking decisions.This thesis utilizes the data processing,behavior factor modeling and fuzzy theory to study the influencing factors identification,ship behavior modeling and decisionmaking method within the ship routing system,separately.Consequently,the typical ship overtaking behavior is derived and the ship overtaking choice of the right moment can also be obtained.The main research contents are as follows:First,the recognition of ship overtaking and the extraction of ship overtaking data.After preprocessing the collected Automatic Identification System(AIS)data,the thesis analyzes the relative movement situation of the ship,calculates the moving distance between the ships and analyzes the ship speed based on the ship overtaking characteristics.Afterwards,the overtaking and being overtaken ships can be identified.Second,analysis of influencing factors of ship overtaking behavior.According to the navigation characteristics of the water area of the routing system,the navigation behavior of ship overtaking is analyzed.The static distribution of overtaking behavior is analyzed in terms of space,time,ship length and other factors.The dynamic characteristics of overtaking behavior are analyzed in terms of speed,course and distance.To obtains the ship overtaking risk level,the main influencing factors of overtaking behavior are obtained.Third,the development of ship overtaking risk assessment model.Based on the influencing factors of the ship overtaking,the index system of influencing factors of ship overtaking is established.The fuzzy logic method is introduced to fuzzify the identified influencing factors.Then,the fuzzy risk assessment model is constructed based on ship characteristics movement situation.Finally,the fuzzy reasoning rules is established to obtains the overtaking risk level.From the demonstration results,this method can not only provide reasonable suggestions for the existing navigation safety of ships,but also provide theoretical support for the navigation of intelligent ships in the future. |
