Study On The Choice Of Urban Logistics Distribution Routes Considering Carbon Emissions Under Time-varying Network

In recent years,with the rapid development of the national economy and the promotion of urbanization,the flow of people and logistics activities around the needs of people's production,life and urban development are increasing day by day.As the main carrier of the realization of human and material displacement,the number of cars is increasing day by day,which is followed by serious urban traffic congestion problems,which leads to continuous changes in the speed of road vehicles.At the same time,due to the sharp increase in car ownership,the carbon dioxide generated by vehicle exhaust emissions is increasing,which results in a continuous increase in the "greenhouse effect".Urban logistics is the "driver" of the urban economy,and it has important responsibilities in terms of"energy saving,emission reduction and carbon reduction",which puts new demands on logistics distribution under the new situation.The changes of vehicle speed of time-varying road networks in different time periods and the choice of urban logistics distribution route under carbon emissions constraints are studied in this thesis.Firstly,some related theories about logistics distribution,distribution route problem and carbon emission are summarized in the thesis,on the basis of this,considering the changes in vehicle speed of time-varying road networks in different time periods and carbon emissions,taking "the least number of vehicles used","the highest customer's satisfaction of the system" and "the minimum carbon dioxide emission" in the distribution process as the optimization target within an acceptable time window,the three optimization targets are respectively represented as cost models and weighted,the "fixed cost of vehicles" is used to reflect the "number of vehicles used",and the "penalty cost" is used to reflect "the system customer's satisfaction",the "cost of carbon dioxide emissions"is used to reflect the problem of "carbon dioxide emissions during the distribution process",the dynamic change of the road network is represented by time-varying speed,and then a mathematica model of urban logistics distribution route selection which considers carbon dioxide emissions under time-varying road network is established.Then the genetic algorithm is designed to solve the model.Finally,the actual road network simulation experiment is built to simulate the actual distribution situation,the objective function values under static speed and time-varying speed are calculated by Matlab software.Through the comparison and analysis of the calculation results,the superiority and effectiveness of the urban logistics distribution route selection model which considers carbon dioxide emissions under time-varying road network are fully verified.In the actual logistics distribution process,distribution company can combine the characteristics of real-time road traffic speed and consider the emissions of carbon dioxide to make the number of vehicles used by the company,the customer's time satisfaction and envirovment protection be optimum,by this way,it can provide reference for enterprises to achieve low carbon distribution in the real road network.