Study On Traffic Assignment Problem Based On The Interval Cross Entropy

Traffic assignment is an important means of traffic network analysis,but in the traditional assignment method,the demand is usually regarded as deterministic.However,in real life,due to the influence of many factors,the traffic demand is undeterministic.On the other hand,if the traveler route choice is undeserved,the traveler may suffer unnecessary losses.Therefore,in this thesis,the interval number is used to measure the uncertainty of demand,and the traffic assignment problem under the interval demand is studied,it has a good theoretical and practical significance for the analysis of the uncertainty of the traffic network.Because of the demand is the interval number,the link resistance must be the interval number,and the robust shortest path under the interval resistance becomes the core problem of the research.In this thesis,the reference system theory of the behavioral economics is used,the interval shortest path is obtained by calculation with lower and upper bounds of the resistance,and takes this as the reference,consider the worst case,two judgment criteria of the robust effective path is constructed and the set of effective path is get.Based on the cross entropy theory,the cross entropy between the effective path and the reference interval shortest path is calculated,and the robust shortest path model is constructed based on the minimum cross entropy.On this basis,the interval demand user equilibrium assignment model is constructed and the method of successive averages is used to solve it.Finally,the above methods are analyzed by a simple example of the road network,the results show that the proposed model and algorithm is reasonable and effective.In this thesis,reference system theory,entropy theory and interval analysis are combined,robust shortest path and user equilibrium assignment method is proposed,this can not only deal with uncertain traffic demand,and also can be applied to dynamic traffic demand and imprecise data of traffic network analysis,moreover,can expand the application in the field of public transportation network,logistics network and related network.