With the economic development and the popularity of application of electronic computer, electronic commerce has rapid development. More and more commerce and key business has been carried on the lnternet because Inter...With the economic development and the popularity of application of electronic computer, electronic commerce has rapid development. More and more commerce and key business has been carried on the lnternet because Internet has the features of interaction, openness, sharing and so on. However, during the daily commerce, people worry about the security of the network system. So a new technology which can detect the unusual behavior in time has been invented in order to protect the security of network system. The system of intrusion detection needs a lot of new technology to protect the data of the network system. The application of data mining technology in the system of intrusion detection can provide a better assistant to the users to analyze the data and improve the accuracy of the checking system.展开更多
In this work we compare the DNS results(Fabregat et al.2021,Fabregat et al.2021)for a mild cough already reported in the literarure with those obtained with a compressible URANS equations with a k-ϵturbulence model.In...In this work we compare the DNS results(Fabregat et al.2021,Fabregat et al.2021)for a mild cough already reported in the literarure with those obtained with a compressible URANS equations with a k-ϵturbulence model.In both cases,the dispersed phase has been modelled as spherical Lagrangian particles using the one-way coupling assumption.Overall,the URANS model is capable of reproducing the observed tendency of light particles under 64µm in diameter to rise due to the action of the drag exerted by the buoyant puff generated by the cough.Both DNS and URANS found that particles above 64µm will tend to describe parabolic trajectories under the action of gravitational forces.Grid independence analysis allows to qualify the impact of increasing mesh resolution on the particle cloud statistics as flow evolves.Results suggest that the k-ϵmodel overpredicts the horizontal displacement of the particles smaller than 64µm while the opposite occurs for the particles larger than 64µm.展开更多
文摘With the economic development and the popularity of application of electronic computer, electronic commerce has rapid development. More and more commerce and key business has been carried on the lnternet because Internet has the features of interaction, openness, sharing and so on. However, during the daily commerce, people worry about the security of the network system. So a new technology which can detect the unusual behavior in time has been invented in order to protect the security of network system. The system of intrusion detection needs a lot of new technology to protect the data of the network system. The application of data mining technology in the system of intrusion detection can provide a better assistant to the users to analyze the data and improve the accuracy of the checking system.
基金This work was supported by Spanish Ministerio de Ciencia,Innovación y Universidades(Grants Nos.RTI2018-100907-A-I00 and PID2020-113303GB-C21)the Generalitat de Catalunya(Grant No.2017-SGR-1234).
文摘In this work we compare the DNS results(Fabregat et al.2021,Fabregat et al.2021)for a mild cough already reported in the literarure with those obtained with a compressible URANS equations with a k-ϵturbulence model.In both cases,the dispersed phase has been modelled as spherical Lagrangian particles using the one-way coupling assumption.Overall,the URANS model is capable of reproducing the observed tendency of light particles under 64µm in diameter to rise due to the action of the drag exerted by the buoyant puff generated by the cough.Both DNS and URANS found that particles above 64µm will tend to describe parabolic trajectories under the action of gravitational forces.Grid independence analysis allows to qualify the impact of increasing mesh resolution on the particle cloud statistics as flow evolves.Results suggest that the k-ϵmodel overpredicts the horizontal displacement of the particles smaller than 64µm while the opposite occurs for the particles larger than 64µm.
