Study On The Operation And Adjustment Of High-speed Railway Based On Discrete Firefly Algorithm

In recent years,high-speed railway has developed rapidly and become one of the most popular means of transportation.At the same time,it meets higher requirements for punctuality,security and stability.It is inevitable that trains will be affected by the external environment in the daily operation and leads to trains delay of varying degree.If the adjustment measures are not taken,it may result in a large area delay of the following trains and affect the operation safety and transportation efficiency.Traditional operation command was planned and adjusted by the train dispatcher manually.This kind of adjustment method with heavy workload is less predictable and is difficult to adapt to high real-time requirements with the fast development of high-speed railway.Therefore,intelligent and automatic operation adjustment becomes a trend in this field.Recently,intelligent optimization algorithm provides a better way for solving train operation adjustment problem,but the deficiencies of the existing algorithm make it necessary to explore the application of other algorithms in this field.Based on the characteristics of high-speed railway,this thesis,combing the existing research results,studies the train operation adjustment problem from the following steps.First,mathematical methods are applied to describe train operation diagram and the operation condition under the influence of interference factors.Considering the difference of train grades,the thesis establishes the train operation adjustment mathematical model and give the relevant constraints.The objective function of the model is the total weighted arrival delay time.Then,firefly algorithm is used as the basic algorithm because it is easy to understand and program,and has fewer parameters and faster convergence rate.Standard firefly algorithm is suitable for the problem of continuous space optimization.Train operation adjustment is combinatorial optimization problem,therefore,the standard firefly algorithm needs to be discretized.Thus,the discrete firefly algorithm is used to solve the problem.The process of discretization is carried out in three aspects:distance calculation,movement mode and disturbance mechanism.The disturbance mechanism based on variable neighborhood search algorithm is used to increase the diversity of the fireflies group and avoid algorithm being trapped in local optimization.In order to verify the effectiveness of the discrete firefly algorithm,it is compared with one of the heuristic algorithms based on greedy thought.Finally,based on the simulation test platform of our laboratory,the train operation adjustment simulation system is designed using C#and selects the downward direction data of Beijing-Shanghai high-speed railway as numerical example.It adjusts two types delay and analyzes the adjustment results.Through comparative analysis of two algorithms,the discrete firefly algorithm,which uses the departure order of each station as variate,has the better adjustment result and can reduce the resolution space vastly and converge to the optimal solution in smaller population size and fewer iterations.The simulation system proves that the discrete firefly algorithm can give an effective solution to the adjustment problem in a reasonable time to help the train operation gradually recover to the scheduled state and achieve the purpose of the train operation adjustment.Therefore,the discrete firefly algorithm provides a new way to solve the problem of train operation adjustment.