Topological optimization plays a guiding role in the conceptual design process.This paper conducts research on structural topology optimization algorithm within the framework of isogeometric analysis.For multi-compone...Topological optimization plays a guiding role in the conceptual design process.This paper conducts research on structural topology optimization algorithm within the framework of isogeometric analysis.For multi-component structures,the Nitsche’smethod is used to glue differentmeshes to performisogeometricmulti-patch analysis.The discrete variable topology optimization algorithm based on integer programming is adopted in order to obtain clear boundaries for topology optimization.The sensitivity filtering method based on the Helmholtz equation is employed for averaging of curved elements’sensitivities.In addition,a simple averaging method along coupling interfaces is proposed in order to ensure the material distribution across coupling areas is reasonably smooth.Finally,the performance of the algorithm is demonstrated by numerical examples,and the effectiveness of the algorithm is verified by comparing it with the results obtained by single-patch and ABAQUS cases.展开更多
This paper presents a novel approximating method to construct highprecision single-patch representation of B-spline surface from a multi-patch representation for isogeometric applications.In isogeometric analysis,mult...This paper presents a novel approximating method to construct highprecision single-patch representation of B-spline surface from a multi-patch representation for isogeometric applications.In isogeometric analysis,multi-patch structure is not easy to achieve high continuity between neighboring patches which will reduce the advantage of isogeometric analysis in a sense.The proposed method can achieve high continuity at surface stitching region with low geometric error,and this technique exploits constructing the approximate surface with several control points are from original surfaces,which guarantees the local feature of the surface can be well-preserved with high precision.With the proposed approximating method,isogeometric analysis results using the new single-patch can be obtained efficiently compared with the original multi-patch structure.Several examples are presented to illustrate the effectiveness,accuracy and efficiency of the proposed method.展开更多
Recently,deep learning-based image outpainting has made greatly notable improvements in computer vision field.However,due to the lack of fully extracting image information,the existing methods often generate unnatural...Recently,deep learning-based image outpainting has made greatly notable improvements in computer vision field.However,due to the lack of fully extracting image information,the existing methods often generate unnatural and blurry outpainting results in most cases.To solve this issue,we propose a perceptual image outpainting method,which effectively takes the advantage of low-level feature fusion and multi-patch discriminator.Specifically,we first fuse the texture information in the low-level feature map of encoder,and simultaneously incorporate these aggregated features reusability with semantic(or structural)information of deep feature map such that we could utilizemore sophisticated texture information to generate more authentic outpainting images.Then we also introduce a multi-patch discriminator to enhance the generated texture,which effectively judges the generated image from the different level features and concurrently impels our network to produce more natural and clearer outpainting results.Moreover,we further introduce perceptual loss and style loss to effectively improve the texture and style of outpainting images.Compared with the existing methods,our method could produce finer outpainting results.Experimental results on Places2 and Paris StreetView datasets illustrated the effectiveness of our method for image outpainting.展开更多
The bonded repair techniques seem to be the most frequent procedures in the aviation maintenance.The achieved composite repaired perforated thin-walled plate is a complex geometry with high numerical analysis cost.The...The bonded repair techniques seem to be the most frequent procedures in the aviation maintenance.The achieved composite repaired perforated thin-walled plate is a complex geometry with high numerical analysis cost.The NURBS-based Isogeometric Analysis(IGA)proposes a sensible and affordable tool to carry out such geometry analysis.In this context,a well-known technique is to divide the original geometry assembly into number of simple neighbors connected geometries.In the present study the free vibration analysis of the perforated plates repaired on one side with an external bonded composite laminated patch is investigated.A multi-patch geometry modeling approach is implemented in line with the first order shear deformation theory of plates.In order to hold the geometry integrity and uniformity,all the degrees of freedom between adjacent geometry patches are completely tied through implementing a Nitsche method.To show the effectiveness and accuracy of the developed formulation,some representative results are extracted and compared with those from literature.The effects of geometrical as well as material parameters including boundary condition,cutout shape,and repair layup on the dynamic response of the repaired perforated plates are then investigated.展开更多
This paper presents a law of large numbers result,as the size of the population tends to infinity,of SIR stochastic epidemic models,for a population distributed over distinct patches(with migrations between them)and d...This paper presents a law of large numbers result,as the size of the population tends to infinity,of SIR stochastic epidemic models,for a population distributed over distinct patches(with migrations between them)and distinct groups(possibly age groups).The limit is a set of Volterra-type integral equations,and the result shows the effects of both spatial and population heterogeneity.The novelty of the model is that the infectivity of an infected individual is infection age dependent.More precisely,to each infected individual is attached a random infection-age dependent infectivity function,such that the various random functions attached to distinct individuals are i.i.d.The proof involves a novel construction of a sequence of i.i.d.processes to invoke the law of large numbers for processes in,by using the solution of a MacKean-Vlasov type Poisson-driven stochastic equation(as in the propagation of chaos theory).We also establish an identity using the Feynman-Kac formula for an adjoint backward ODE.The advantage of this approach is that it assumes much weaker conditions on the random infectivity functions than our earlier work for the homogeneous model in[20],where standard tightness criteria for convergence of stochastic processes were employed.To illustrate this new approach,we first explain the new proof under the weak assumptions for the homogeneous model,and then describe the multipatch-multigroup model and prove the law of large numbers for that model.展开更多
基金supported by the Fundamental Research Funds for the Cen-tral Universities(No.JUSRP12038)the Natural Science Foundation of Jiangsu Province(No.BK20200611)the National Natural Science Foundation of China(No.12102146).
文摘Topological optimization plays a guiding role in the conceptual design process.This paper conducts research on structural topology optimization algorithm within the framework of isogeometric analysis.For multi-component structures,the Nitsche’smethod is used to glue differentmeshes to performisogeometricmulti-patch analysis.The discrete variable topology optimization algorithm based on integer programming is adopted in order to obtain clear boundaries for topology optimization.The sensitivity filtering method based on the Helmholtz equation is employed for averaging of curved elements’sensitivities.In addition,a simple averaging method along coupling interfaces is proposed in order to ensure the material distribution across coupling areas is reasonably smooth.Finally,the performance of the algorithm is demonstrated by numerical examples,and the effectiveness of the algorithm is verified by comparing it with the results obtained by single-patch and ABAQUS cases.
基金This research was supported by the National Nature Science Foundation of China under Grant Nos.61602138,61772163 and 61761136010the NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(Grant No.U1909210)Zhejiang Provincial Science and Technology Program in China(2018C01030).
文摘This paper presents a novel approximating method to construct highprecision single-patch representation of B-spline surface from a multi-patch representation for isogeometric applications.In isogeometric analysis,multi-patch structure is not easy to achieve high continuity between neighboring patches which will reduce the advantage of isogeometric analysis in a sense.The proposed method can achieve high continuity at surface stitching region with low geometric error,and this technique exploits constructing the approximate surface with several control points are from original surfaces,which guarantees the local feature of the surface can be well-preserved with high precision.With the proposed approximating method,isogeometric analysis results using the new single-patch can be obtained efficiently compared with the original multi-patch structure.Several examples are presented to illustrate the effectiveness,accuracy and efficiency of the proposed method.
基金This work was supported by the Sichuan Science and Technology program(2019JDJQ0002,2019YFG0496,2021016,2020JDTD0020)partially supported by National Science Foundation of China 42075142.
文摘Recently,deep learning-based image outpainting has made greatly notable improvements in computer vision field.However,due to the lack of fully extracting image information,the existing methods often generate unnatural and blurry outpainting results in most cases.To solve this issue,we propose a perceptual image outpainting method,which effectively takes the advantage of low-level feature fusion and multi-patch discriminator.Specifically,we first fuse the texture information in the low-level feature map of encoder,and simultaneously incorporate these aggregated features reusability with semantic(or structural)information of deep feature map such that we could utilizemore sophisticated texture information to generate more authentic outpainting images.Then we also introduce a multi-patch discriminator to enhance the generated texture,which effectively judges the generated image from the different level features and concurrently impels our network to produce more natural and clearer outpainting results.Moreover,we further introduce perceptual loss and style loss to effectively improve the texture and style of outpainting images.Compared with the existing methods,our method could produce finer outpainting results.Experimental results on Places2 and Paris StreetView datasets illustrated the effectiveness of our method for image outpainting.
文摘The bonded repair techniques seem to be the most frequent procedures in the aviation maintenance.The achieved composite repaired perforated thin-walled plate is a complex geometry with high numerical analysis cost.The NURBS-based Isogeometric Analysis(IGA)proposes a sensible and affordable tool to carry out such geometry analysis.In this context,a well-known technique is to divide the original geometry assembly into number of simple neighbors connected geometries.In the present study the free vibration analysis of the perforated plates repaired on one side with an external bonded composite laminated patch is investigated.A multi-patch geometry modeling approach is implemented in line with the first order shear deformation theory of plates.In order to hold the geometry integrity and uniformity,all the degrees of freedom between adjacent geometry patches are completely tied through implementing a Nitsche method.To show the effectiveness and accuracy of the developed formulation,some representative results are extracted and compared with those from literature.The effects of geometrical as well as material parameters including boundary condition,cutout shape,and repair layup on the dynamic response of the repaired perforated plates are then investigated.
文摘This paper presents a law of large numbers result,as the size of the population tends to infinity,of SIR stochastic epidemic models,for a population distributed over distinct patches(with migrations between them)and distinct groups(possibly age groups).The limit is a set of Volterra-type integral equations,and the result shows the effects of both spatial and population heterogeneity.The novelty of the model is that the infectivity of an infected individual is infection age dependent.More precisely,to each infected individual is attached a random infection-age dependent infectivity function,such that the various random functions attached to distinct individuals are i.i.d.The proof involves a novel construction of a sequence of i.i.d.processes to invoke the law of large numbers for processes in,by using the solution of a MacKean-Vlasov type Poisson-driven stochastic equation(as in the propagation of chaos theory).We also establish an identity using the Feynman-Kac formula for an adjoint backward ODE.The advantage of this approach is that it assumes much weaker conditions on the random infectivity functions than our earlier work for the homogeneous model in[20],where standard tightness criteria for convergence of stochastic processes were employed.To illustrate this new approach,we first explain the new proof under the weak assumptions for the homogeneous model,and then describe the multipatch-multigroup model and prove the law of large numbers for that model.
