| As the passenger transporting mission of high-speed railways(HSR)is increasingly heavy,keeping high punctuality of HSR has become a challenge on which people pay more attention.The disturbance happens randomly during the train’s operation,which is inevitable,leading to the delay of trains.Therefore,how to manage and increase the ability of trains of transferring invalid operation time(buffer time)to valid operation time when encountering the delay is a noteworthy problem.This paper study on the optimization of buffer time allocation cooperated with delay halting,which means optimizing the distribution of buffer time to stop delay propagation as soon as possible.The summarization of major work is as follows:1.Analyzing theories relating to the buffer time allocation,which includes the definition of buffer time,the categories of buffer time depending on the location of train diagram,the functional principle of delay halting based on direct buffer time allocation,and four ways to allocate the buffer time.2.After obtaining the present situation and statistical analysis of train’s departure delay and arrival delay,the disturbance and the recovery data based on the Wuhan-Guangzhou HSR enormous number of real-world operation records,we conclude that the original buffer time allocation cannot halt the delay immediately once the disturbance occurred.3.Introducing the theory of Markov Chain,combined with non-aftereffect property of train’s operation,we create the state transition matrix of delay to describe the delay propagation on the operation line.We also take three matrices as example to show how the transition matrix of delay is able to reflect the delay propagation and the disturbance distribution during the train’s operation.4.Based on the work in previous chapters,we create the model frame of the buffer time allocation optimization cooperated with delay halting and the mathematical model to maximize the time profit gained from the process which buffer time successfully cancel out the delay time as early as possible.After the detailed description of model,we introduce the genetic algorithm to find the optimum solution of our model.5.Choosing three trains from the scheduled diagram and getting their original buffer time distribution from our records as the optimization object,using random sampling method to get 500 kinds of departure and arrival delay information from transition matrix of delay,and with all these information,we are able to resolve the problem with genetic algorithm.The optimization process prove that genetic algorithm is efficient enough to find the optimum solution and the solution converges steadily and the optimum solution,which shows that as the total buffer time decreases,the time profit increases at the same time,can testify that our model is capable of optimizing the buffer time allocation to halt the delay propagation. |
