Study On Models And Algorithms For Empty Wagons Distribution Among Railway Network Nodes

The adjustment of empty wagon is one of the cardinal elements of railway transportation technical program and is also significant guidance to transport production. It represents technically an optimizing problem of reasonably operating wagons, research on models and algorithms of which possesses important meaning in whether theory or practice.The paper focuses on theoretical research, plentifully uses former results for reference, introduces systematic science analogy and means of mathematic models, and combines theoretics of correlated knowledge, such as discrete math, optimization and computation etc. to deeply analyze the optimizing problem of empty wagon distribution among railway nodes to achieve the purpose of providing a new modeling thought and resolving algorithm.The main content and conclusion includes:(1) Depicting and analyzing the sources, adjusting principles and ways of empty wagons in detail.(2) Ascertaining two core problem of the empty wagon distribution: quantity distribution and network matching flow, and so making certain two different studying ways.(3) Based on the analysis of existing models, the problem of empty wagon distribution is abstractly described from varied studying viewpoint, TP model and EWDCO model are constructed.(4) It is found that identical path constraint doesn't correspond with EWDCO model through analysis and convection constraint won't affect the optimal solution via proving the theorem. Thus, EWDCO model can be described as linear integer programming model which is essentially the minimum rate flow model subjected to capacity.(5) Introducing principle, forms and application circs of ACO which is selected to be the method to solve the optimizing model of empty wagondistribution among railway nodes.(6) Based on the analysis of the existing algorithm, ACO algorithm of empty wagon distribution is devised. At the same time, parameters in the algorithm and its convergence and time-complexity are analyzed. With instances, the paper compares the validity of varied algorithms and draws the conclusion that ACO is superior for TP model.The research work and conclusion of the paper are hopeful to advance more development in the empty wagon distribution problem.