| The sudden outbreak of COVID-19 in 2019 has left the entire world under a viral haze.The series of measures to cope with the spread of COVID-19,such as extended Chinese New Year holidays,postponement of work and school hours,city closures,traffic control and calls for home quarantine measures,have curbed the spread of the virus to a certain extent,but they have also severely affected numerous manufacturing companies and caused huge losses to society and the economy.In the face of the onslaught of the COVID-19 epidemic,it is important to study the spatio-temporal spread of the COVID-19,to construct a COVID-19 transmission model to simulate the virus transmission process from different geographical and spatial scales,and to analyse the spatial and temporal transmission characteristics of COVID-19,which is an important reference value for urban infectious disease departments to make effective prevention and control decisions.The main work of this paper is as follows:Firstly,in order to clarify the transmission characteristics of COVID-19 in the same space,an agent based spatio-temporal transmission model of COVID-19 in a finite spatial region was constructed based on the transmission mode and mechanism of COVID-19.The model mainly consisted of defining agent attributes,agent movement rules and infection mechanism.The results show that,in the absence of any control measures,the disease spreads in all directions over time until it infects everyone in the spatial area.Further simulations of different intervention scenarios show that as the population density increases,so does the rate of infection,with the rate of individual infection decreasing as the proportion of people wearing masks and the rate of vaccination increases.As vaccination rates and vaccine protection rates in China are not yet adequate for herd immunity,and as the new coronavirus continues to mutate,therefore,non-pharmaceutical interventions(NPIs)such as maintaining social distance,reducing population congregation and wearing a mask can reduce the risk of viral infection.Secondly,the movement of individuals within the epidemic area will lead to the continuous spread of the epidemic within the city.Further,we construct an intelligent body-based model for the spread of COVID-19 in urban space,considering that the virus spread mainly occurs in fixed social networks,and use a small-world network to represent the social relationships between agents to simulate the spread process of COVID-19 in urban space.In order to verify the accuracy of the model,the Wuhan urban area was selected as the test area,and the Wuhan urban communities were regarded as agents with their own attributes and behavioural rules.The model parameters were quantified based on the actual data using the Runge-Kutta method combined with the SEIR model.The experimental results show that the difference between the average number of infected agents and the actual number of infected agents for one hundred times is 12.27%,and the duration of infection is also similar to the real situation,which shows that the simulation results of the COVID-19 transmission model considering social networks are realistic.In addition,the model can also simulate the impact of different NPIs on the development of the epidemic,which can help cities to build a safe epidemic prevention and control system.Finally,to explore the radiation process of the epidemic in Wuhan City under actual circumstances,and to analyse the transmission characteristics of the initial outbreak of COVID-19 in China at provincial spatial scales using correlation analysis and GIS map representation methods based on COVID-19 data from 20 January to 12 March 2020,and to assess the effectiveness of NPIs in China in the early stage.The results showed that the epidemic was more severe in provinces with a high inflow of people from Wuhan.The spread of the epidemic in China non-Hubei Province can be divided into five stages,the first stage was the initial phase of the COVID-19 outbreak;in the second stage,a new peak of the epidemic was observed;in the third stage,the epidemic was controlled with fewer new cases;the fourth stage saw a rebound and the fifth stage levelled off.The virus spread rapidly through the movement of people,with confirmed cases appearing in all provinces of China within a short period of time.The cumulative confirmed cases were mainly concentrated in the southeastern region where the population is more concentrated.To evaluate the NPIs,we simulated the prevalence of the COVID-19 based on an improved SIR model and under different prevention intensity.It was found that our simulation results were compatible with the observed values and the parameter of the time function in the improved SIR model for China is a=-0.0058.and that there were large differences in the number of COVID-19 cases with different intensities of NPIs.China’s successful control measures to contain the epidemic can be used as a reference for fight against COVID-19 and even other respiratory diseases around the world. |
PDF Full Text Request