Research On Simulation Of Large-scale Disease Spread And Evaluation Of Mitigation Strategies Based On Geographic Information

The spread of infectious diseases poses a huge threat to human health and the stable development of society.For example,the Black Death that broke out in 1347,the cholera that broke out in 1817,and the COVID-19（Corona Virus Disease）that broke out in 2019are all major disasters in human history.Due to the limitations of moral ethics and conditions,it is impossible to carry out real experiment to study the mechanisms and laws of the spread infectious diseases.Existing epidemic mitigation and response measures are often carried out based on the experience and intuition of decision-makers,and lack reasonable assessment and scientific basis.Therefore,using computational experimental approaches to study large-scale disease transmission and assisting decision-makers in tailoring epidemic mitigation strategies has become an urgent research issue.The thesis studies the simulation of large-scale disease transmission in cities and the evaluation of mitigation strategies,and proposes a community network model based on geographic information,a disease course and transmission model for asymptomatic patients,and an evaluation model for the economic cost of mitigation strategies.The main work and innovations of this paper can be summarized as follows:（1）Based on geographic information,this paper creatively proposes a community size and distance priority mechanism and based on this,proposes community network models:MoncSid-N and MoncSid-E.MoncSid-N traditionally generates a network by adding nodes and connecting edges one by one,while MoncSid-E separates the operations of adding nodes and adding edges,so that the generation of the network can be carried out in parallel,making the generation of large-scale networks possible.（2）To generate a large-scale network,this paper designs the idea of parallelizing the MoncSid-E model based on the Pregel graph computing framework.Regarding the network community as a Pregel node,the internal evolution of the community can be realized by sending messages through the self-connected edge of the Pregel node,and the evolution between communities can be realized by sending messages through the Pregel non-self-connected edge.Parallelization can greatly reduce the time consumption of network generation.（3）Considering the characteristics of disease transmission in asymptomatic patients,this paper establishes a disease course model and a transmission model for asymptomatic patients.On the basis of the SEIR model,adding the distinction between asymptomatic and symptomatic patients,the SEIs Ia RD model is proposed.The infection status of a person changes between susceptible,latent,symptomatic,asymptomatic,recovery and death.And combined with the prevention and control of such diseases,a transmission model has been established.The transmission model describes the process of disease transmission from one individual to another.（4）Based on the emission data of CO₂,this paper proposes an evaluation model of the economic cost of mitigation strategies.The economic cost evaluation model of mitigation strategies includes two parts,medical expenditure and GDP loss.The calculation of the two parts is based on the number of infected persons,and the calculation of GDP loss is based on the emission of CO₂,and the mapping of the number of infected persons to GDP is established to obtain the GDP loss value.This evaluation model can effectively reflect the economic costs of adopting different prevention and control measures.（5）On the basis of the above research,this paper designs a prototype computational experiment system for large-scale epidemic transmission.Based on this prototype system,a calculation experiment was carried out to compare strict and loose mitigation strategies of COVID-19,and to compare the lockdown measures in advance and postponement.The experimental results show that the strict mode has advantages in controlling economic costs,and also shows the necessity of advanced blockade measures.The thesis focuses on the research of large-scale disease transmission and prevention and control,constructs a community network model based on geographic information,and designs a large-scale disease transmission calculation experimental prototype system.The research results can be used to support decision-making for large-scale disease prevention and control.