Dengue disease is the most common vector borne infectious disease transmitted to humans by infected adult female Aedes mosquitoes. Over the past several years the disease has been increasing remarkably and it has beco...Dengue disease is the most common vector borne infectious disease transmitted to humans by infected adult female Aedes mosquitoes. Over the past several years the disease has been increasing remarkably and it has become a major public health concern. Dengue viruses have increased their geographic range into new human population due to travel of humans from one place to the other. In the present paper, we have proposed a multi patch SIR-SI model to study the host-vector dynamics of dengue disease in different patches including the travel of human population among the patches. We have considered different disease prevalences in different patches and different travel rates of humans. The dimensionless number, basic reproduction number R0 which shows that the disease dies out if R0 < 1 and the disease takes hold if R0 ≥ 1, is calculated. Local and global stability of the disease free equilibrium are analyzed. Simulations are observed considering the two patches only. The results show that controlling the travel of infectious hosts from high disease dominant patch to low disease dominant patch can help in controlling the disease in low disease dominant patch while high disease dominant becomes even more disease dominant. The understanding of the effect of travel of humans on the spatial spread of the disease among the patches can be helpful in improving disease control and prevention measures. In the present study, a patch may represent a city, a village or some biological habitat.展开更多
We focus on the single layer formulation which provides an integral equation of the first kind that is very badly conditioned. The condition number of the unpreconditioned system increases exponentially with the multi...We focus on the single layer formulation which provides an integral equation of the first kind that is very badly conditioned. The condition number of the unpreconditioned system increases exponentially with the multiscale levels. A remedy utilizing overlapping domain decompositions applied to the Boundary Element Method by means of wavelets is examined. The width of the overlapping of the subdomains plays an important role in the estimation of the eigenvalues as well as the condition number of the additive domain decomposition operator. We examine the convergence analysis of the domain decomposition method which depends on the wavelet levels and on the size of the subdomain overlaps. Our theoretical results related to the additive Schwarz method are corroborated by numerical outputs.展开更多
This paper studied a structured model by age of tuberculosis. A population divided into two parts was considered for the study. Each subpopulation is submitted to a program of vaccination. It was allowed the migration...This paper studied a structured model by age of tuberculosis. A population divided into two parts was considered for the study. Each subpopulation is submitted to a program of vaccination. It was allowed the migration of vaccinated people only between the two patches. After the determination of and , the local and global stability of the disease-free equilibrium was studied. It showed the existence of three endemic equilibrium points. The theoretical results were illustrated by a numeric simulation.展开更多
电大尺寸目标高频散射场的仿真一般使用物理光学(physical optics,PO)方法,该方法要求对目标使用尺寸为八分之一倍波长的三角网格进行剖分.然而,随着入射波频率增加,网格数目呈指数增长.本文提出基于一倍波长的二次曲面网格的快速PO(fas...电大尺寸目标高频散射场的仿真一般使用物理光学(physical optics,PO)方法,该方法要求对目标使用尺寸为八分之一倍波长的三角网格进行剖分.然而,随着入射波频率增加,网格数目呈指数增长.本文提出基于一倍波长的二次曲面网格的快速PO(fast PO,FPO)方法,该方法使用线性多项式拟合振幅函数,能够有效降低面片数目.与二次多项式拟合振幅函数的快速物理光学方法相比,本文方法避免了菲涅尔积分的求解,且计算速度快1.22倍.为了进一步降低网格数目,提出了自适应网格技术的快速物理光学(FPO based on the adaptive mesh technique,AFPO)方法,允许使用比标准奈奎斯特采样率更少的网格数目对目标进行离散.通过后验误差估计和数值算例对所提出算法的精度和速度进行了验证,结果表明与采用均匀网格剖分的方法相比,AFPO方法所需的面片数目降低89.58%.展开更多
文摘Dengue disease is the most common vector borne infectious disease transmitted to humans by infected adult female Aedes mosquitoes. Over the past several years the disease has been increasing remarkably and it has become a major public health concern. Dengue viruses have increased their geographic range into new human population due to travel of humans from one place to the other. In the present paper, we have proposed a multi patch SIR-SI model to study the host-vector dynamics of dengue disease in different patches including the travel of human population among the patches. We have considered different disease prevalences in different patches and different travel rates of humans. The dimensionless number, basic reproduction number R0 which shows that the disease dies out if R0 < 1 and the disease takes hold if R0 ≥ 1, is calculated. Local and global stability of the disease free equilibrium are analyzed. Simulations are observed considering the two patches only. The results show that controlling the travel of infectious hosts from high disease dominant patch to low disease dominant patch can help in controlling the disease in low disease dominant patch while high disease dominant becomes even more disease dominant. The understanding of the effect of travel of humans on the spatial spread of the disease among the patches can be helpful in improving disease control and prevention measures. In the present study, a patch may represent a city, a village or some biological habitat.
文摘We focus on the single layer formulation which provides an integral equation of the first kind that is very badly conditioned. The condition number of the unpreconditioned system increases exponentially with the multiscale levels. A remedy utilizing overlapping domain decompositions applied to the Boundary Element Method by means of wavelets is examined. The width of the overlapping of the subdomains plays an important role in the estimation of the eigenvalues as well as the condition number of the additive domain decomposition operator. We examine the convergence analysis of the domain decomposition method which depends on the wavelet levels and on the size of the subdomain overlaps. Our theoretical results related to the additive Schwarz method are corroborated by numerical outputs.
文摘This paper studied a structured model by age of tuberculosis. A population divided into two parts was considered for the study. Each subpopulation is submitted to a program of vaccination. It was allowed the migration of vaccinated people only between the two patches. After the determination of and , the local and global stability of the disease-free equilibrium was studied. It showed the existence of three endemic equilibrium points. The theoretical results were illustrated by a numeric simulation.
文摘电大尺寸目标高频散射场的仿真一般使用物理光学(physical optics,PO)方法,该方法要求对目标使用尺寸为八分之一倍波长的三角网格进行剖分.然而,随着入射波频率增加,网格数目呈指数增长.本文提出基于一倍波长的二次曲面网格的快速PO(fast PO,FPO)方法,该方法使用线性多项式拟合振幅函数,能够有效降低面片数目.与二次多项式拟合振幅函数的快速物理光学方法相比,本文方法避免了菲涅尔积分的求解,且计算速度快1.22倍.为了进一步降低网格数目,提出了自适应网格技术的快速物理光学(FPO based on the adaptive mesh technique,AFPO)方法,允许使用比标准奈奎斯特采样率更少的网格数目对目标进行离散.通过后验误差估计和数值算例对所提出算法的精度和速度进行了验证,结果表明与采用均匀网格剖分的方法相比,AFPO方法所需的面片数目降低89.58%.
