Research On Wagon-flow Allocation For Marshalling Yard Based On TPr/T_system

The content of wagon-flow allocation of marshalling yard,wich constitute an indispensable part in the stage plan,is to make the sure wagon source and marshalling formation of the departure trains,according to the available wagon information and departure plan in the stage plan.Optimizing the wagon-flow allocation plan is significant for marshalling yard to command shunting work,improve the operation efficiency,decrease the berthing time and ensure transportation tasks for marshalling yard.Based on introducing the content of wagon-flow allocation,existing relating researches and trends are summarized and analyzed in the paper,besides,the usefull references and shortcomings about research results are alse simply indicated.Bying analyzing the infulenceing factors and content of wagon-flow allocation,the marshalling yard is considered as a discrete cargo processing system from perspective of Petri net,and the theory of TPr/T_system about Petri net is used to research the wagon-flow allocation.The main research content is following.(1)The influencing factors about wagon-flow allocation are analied intensively,such as time,space,resource and freight organization reform.It is pointed out that the marshalling yard is a tipical discrete cargo processing system integrating parallel system and tanden system together.After building basic Petri net model about freight organization,inadaptability is analyzed to research wagon-flow allocation by using basic Petri net theory according to wagon organization in marshalling yard.So,the Pr/T_system is introduced form advanced Petri net theory,and a TPr/T_system model about wagon-flow allocation for marshalling yard is build by extending Pr/T_system to TPr/T_system.Based on the model,the related system factors and transition rules are explained and illustrated.(2)According to the TPr/T_system model about wagon-flow allocation for marshalling yard,the relationship between the model and optimization for wagon-flow allocation is analyzed and pointed.After that,the optimization algorithms are designed to humping transition and marshalling transition respectively by analyzing the optimal objection about wagon-flow allocation.Based on the humping transition process,nearest neighbor search algorithm and aenetic algorithm are designed to humping transition form perspective of local search and global search respectively.Besides,considering the decision behavior to the planner,the prospect theory is used and the prospect value is regarded as the evaluation basis for the train to be humped in nearest neighbor search algorithm and aenetic algorithm.(3)According to the TPr/T_system model about wagon-flow allocation for marshalling yard and case demonstration,verification and analization are carried out under the condition of certainty and uncertainty respectively.Under the certain condition,the wagon-flow allocation plan,the rationality and feasibility of the algorithms proposed,related parameter value and the system performance are evaluated and analyzed.Under the uncertainty condition,the influence on wagon-flow allocation,cased by operating time uncertatain and freight organization reform,are perturbed and analyzed.Based on this,wagon-flow allocation plans with preferable robustness are presented to satisfy the different departure plan.The research shows that TPr/T_system theory can describe the process of marshalling yard operation very well,and it has an advantage in simulating and reconstructing the process of wagon-flow allocation.Finally,the shortcomings and prospects in the paper are proposed.