Research On Feeder Liner Shipping Schedule Optimization Based On Sail Time And Port Time Adjustment

With the sharp increase in the size of containerships,the small and medium ports can never be the port call of trunk liner shipping.Then the feeder liner shipping is more and more developed in worldwide.And a number of policy documents for the support of feeder liner shipping have been published by the government of China.However,due to the downturn of container transportation market in recent years,the development of feeder liner shipping has also been limited.With the weakness of freight demand,shippers take an active part when face the liner shipping companies,and start to pursue the higher service quality of container transportation.In order to gain more and more freight demand,the feeder liner shipping companies try their best to improve the schedule reliability.But considering the fact that the schedule reliability of feeder liner shipping is worse than the reliability of trunk liner shipping,we need to focus on the schedule reliability of feeder liner shipping.The researches on liner shipping schedule reliability include the schedule optimization issue in tactical level and the schedule recovery issue in operational level.Among of these two issues,the schedule optimization issue adopts the prevention measure,and concentrates on the schedule optimality.The schedule recovery issue adopts the recovery measure,and concentrates on schedule reliability.Although these two issues have their own research emphases,there are also strong correlations between these two issues.Specifically,the liner shipping schedule determines the occurrence frequency of schedule recovery action.And the ability of schedule recovery also has influence on the reserve time of liner shipping schedule.Once the research findings of schedule optimization issue and schedule recovery issue have be combined,the optimal liner shipping schedule will have balance on the optimality and reliability.As for this,based on the sail time and port time adjustment method provided by the schedule recovery issue,we studied the feeder liner shipping schedule optimization issue.Then on the basis of the research findings of schedule optimization issue and schedule recovery issue,according to the progressive relation of gradually improving the sail time and port time adjustment method,three main parts of this paper have been studied.(1)Using the sail time adjustment method to study the feeder liner shipping schedule optimization issue.Compared with the difficulty of implementation on port time adjustment,it is easier to request captains to adjust the uncertain sail time.So we will use the sail time adjustment method to study the feeder liner shipping schedule optimization issue.In our study,we introduced the speed adjustment measure for small-scale disturbance and the port skipping measure for large-scale disturbance into the feeder liner shipping schedule optimization issue.As for this,one multi-stage nonlinear stochastic programming model has been proposed,for optimizing the feeder liner shipping schedule with the goal of minimizing operation cost.And then we defined one multi-distribution nonlinear synthesis problem in our model.This problem was hard to tackle by using determination and linearization algorithm.So we have solved our model by using simulation method.In the numerical experiments,the feasibility of the Monte Carlo simulation,the speed adjustment simulation and the port skipping simulation have been verified,the influence of the speed adjustment measure and port skipping measure on the feeder liner shipping schedule have be analyzed.Finally,the feasibility and effectiveness of our model have been confirmed.(2)Using the sail time improved adjustment method to study the feeder liner shipping schedule optimization issue.The previous literature has little research on the source and influence of sail time uncertainty,which means that the speed loss phenomenon caused by meteorological and hydrological condition has been ignored.Due to this speed loss phenomenon,the actual ship speed has been decreased compared with the planned speed,and the ability of sail time adjustment produced by speed adjustment measure will be declined.So we will have research on the speed loss phenomenon for improving the sail time adjustment method,and then use the sail time improved adjustment method to study the feeder liner shipping schedule optimization issue.In our study,the machine learning method was adopted to train the speed loss data,for the purpose of fitting the calculation formula of speed loss.In addition,the speed adjustment interval consisted of minimum speed and maximum speed has been optimized,with the goal of minimizing late arrival compensation and bunker cost.And then we proposed the feeder liner shipping schedule optimization model based on the improved speed adjustment measure,for the joint optimization of speed adjustment interval and liner shipping schedule.In the numerical experiments,the feasibility of the neural network training for speed loss law has been verified,the influence of the training process for speed loss law and the optimization process for speed adjustment interval on the feeder liner shipping schedule have be analyzed.Finally,the feasibility and effectiveness of our model have been confirmed.(3)Using the port time and sail time combined adjustment method to study the feeder liner shipping schedule optimization issue.The previous literature often adopts the sail time adjustment method to absorb port time uncertainty,but has little research on the port time adjustment method.Even the above improved adjustment method has been used,not all the time delay can be recovered,and a lot of adjustment cost may be produced in the meantime.So we will combine the sail time adjustment and port time adjustment to improve the ability of uncertainty control,and then use the port time and sail time combined adjustment method to study the feeder liner shipping schedule optimization issue.In our study,we proposed the waiting berth time control measure to absorb port time uncertainty.And we formulated the optimal control model of uncertain waiting berth time,for the optimization of waiting berth time with the goal of minimizing late arrival compensation and waiting berth time control cost.Then we proposed the feeder liner shipping schedule optimization model based on the optimal control of waiting berth time,for the joint optimization of waiting berth time and liner shipping schedule.In the numerical experiments,the feasibility and effectiveness of the waiting berth time control measure have be verified,the influence of the waiting berth time control measure on the feeder liner shipping schedule have be analyzed.Finally,the feasibility and effectiveness of our model have been confirmed.Based on the above-mentioned numerical experiments about the feasibility and effectiveness of sail time and port time adjustment method and the influence of these adjustment methods on the feeder liner shipping schedule,some research findings have been obtained.As for these research findings on the feeder liner shipping schedule optimization based on sail time and port time adjustment,they help to supplement the research findings of schedule optimization issue and schedule recovery issue,and contribute to provide decision support for the operation practice of liner shipping schedule.In addition,these research findings help to promote the development of feeder liner shipping and container foreign trade,and contribute to provide container transportation support for national economy and foreign trade.