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The Path Optimization Of Military Railway Transportation Under Major Emergencies

Posted on:2017-01-27Degree:MasterType:Thesis
Country:ChinaCandidate:X GuoFull Text:PDF
GTID:2346330518467189Subject:Transportation engineering
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Since 2008 WenChuan earthquake occurred,in recent years,natural disasters,mass incidents and other major emergencies occured frequently.These events not only constitute a great threat to society's economic development and physical safety of life,but also put forward higher requirements to the military transport security,and how to overcome become a hot topic in the field of military transport.How to formulate scientific and rational transportation security plan and finding the optimal delivery pathways,and to meet the needs of the national economy and a certain share of military transport,with the shortest time rescue workers and emergency supplies transported to the disaster,it became the key to enhance the efficiency of military transport.Wenchuan earthquake rescue operations,railway transport volume accounted for more than 48% of the total volume,has become the backbone of emergency relief operations,especially in the long haul level,thus making the military security research program under the rail transport modes has Significance.Thus rail transport route optimization is an important part of military transport security programs,what it first needs to be considered is the emergency possess destructive dynamics,randomness,complexity,and other characteristics of causality,as well as major emergencies time military transport on railways raised a series of requirements,such as urgent,huge traffic,the direction of centralized,multi-source and multi-point meeting point,and more troops.According to the above military transport characteristic analysis,it can be targeted selected the main influence factors of path optimization,such as transport efficiency,transport costs,time value and thus.In this paper,the author first defines major emergencies and introduction of railway transport military to define the concept,as well as a detailed analysis of demand characteristics emergencies,as well as higher requirements for the case of the railway military transport raised.The above study shows Railway transport is the main military force all kinds of integrated modes of transport,but also an important guarantee to achieve rapid mobility and material supply under emergency,these studies provide the main theoretical in accordance for the choice of objectives and constraints in path optimization model in later.This paper describes existing models and algorithms of vehicle routing optimization problems,including the exact algorithms and heuristic algorithms(two-stage method,the improved algorithm,incomplete optimization algorithms,etc.),and the advantages and disadvantages and conditions for each algorithm were discussed in detail,and then focus on the main content of the genetic algorithm,the key parameters and operational processes were studied.Thirdly,major emergencies presented a detailed regional demand for railway traffic,transport sequences,transport pathways,the locations of loading and unloading,and other needs of the national economy in military railway transportation.And based on the railway route capacity constraints and certain military,the minimum time operation under conditions of share-cost flow model is established.The form of constructing the railway network map,objectives and constraints of the optimization model do specifically addressed.Finally,based on the sequential assignment method,in the capacity as a basis for arc capacity constraints,the priority of each troop and railway traffic through the flow sequence segment has been determined,the priority of the traffic chromosome coding genetic algorithm as the initial population.t The successive flow method with a transfer time of each set of pathways as a fitness function of chromosomes,and chromosome crossover and mutation operations,eventually got the highest optimum adaptation pathways collection.This article assumes a specific example,and use Matlab programming to calculate and verify the algorithm,it proved the feasibility of the algorithm.
Keywords/Search Tags:Path Optimization, the Minimum time-Minimum Cost Flow Model, Genetic Algorithm, Sequential Assignment Method
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