The Research On Model Of Vessel To Ship Lock And Lockage Scheduling Optimization Algorithm

Double-line five-grade ship lock in Three Gorges is the largest ship lock all over the world.It has operated safely and efficiently since 2003,which effectively promotes the rapid development of Yangtze river transportation and economy along the river.However,the Three Gorges ship lock(TGSL)has met the design capacity 19 years ahead of time,in order to enhance the operating efficiency of the whole ship lock,it is necessary to do a systematic and scientific research on it.This paper studies models of vessel to the lock and lockage scheduling,the former contains the ship lock pressure index and the distribution of vessel to the lock.The main work is as follows:Firstly,a new quantification method for lockage demanding,called the ship lock pressure index,is proposed based on the index constructing idea,which is widely used in economic and financial field.Using Dynamic Factor Model(DFM)to study the construction of ship lock pressure index,and then improving weight's estimation by introducing Gaussian kernel function,and also comparing with traditional straight objective weighting method(SOWM).We extract three variables through original down line recording data of TGSL in 2012 to 2014,which are daily freight volume to the lock,daily amounts of arriving vessel and average waiting time.Empirical analysis results show that improved weighting estimation performs better on fitting precision and the index constructed by DFM is more sensitive than SOWM.Meanwhile,the ship lock pressure index indicates the increase of lockage pressure,which makes it necessary to do deeper research on simulation of vessel traffic flow to the lock and lockage scheduling.Secondly,because single distribution is not comprehensive to describe the arrival process at the lock,this paper uses mixture distribution to model it.We study parameter estimation of mixture distribution based on EM Algorithm and summary expectation-variance iterative expressions for any finite dimension mixture distribution,then use it to model time interval distribution of vessel's arrival at the lock,vessel types distribution,and the arriving time distribution of different vessel types.Research results show that mixture distribution is more effective to fitdistribution of vessel arrival process,paving the way for research on simulation and scheduling.Thirdly,an algorithm is proposed for simulating vessel traffic flow to the lock based on time interval distribution and vessel types distribution.For the lockage scheduling problem,we improve the Heuristic Search Algorithm by adding a length-width filter from the point of operating efficiency,and also add a effective filter to permutable point in Rapid Arranging Algorithm in order to decrease searching space.This paper proposes a decomposition algorithm for lockage scheduling.This algorithm divides the scheduling process into three parts,which contains the preliminary screening,refunding and supplying.And it effectively solve the problem between the vessel priority and the area utilization ratio of lock chamber.Testing the algorithm validation by using simulation data and real data,results show that the decomposition algorithm and the Heuristic Search Algorithm has the same effect,but the former is more efficient.