检索结果-南通市图书馆

Preface to the Focused Issue on WENO schemes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2023年第1期5卷 1-2页

作者： sigal Gottlieb jan s.hesthaven Jianxian Qiu Chi-Wang shu Qiang Zhang Yong-Tao Zhang Department of Mathematics University of Massachusetts DartmouthNorth DartmouthMA 02747USA Ecole Polytechnique Federale de Lausanne(EPFL) CH-1015 LausanneSwitzerland school of Mathematical sciences Xiamen UniversityXiamen 361005FujianChina Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Department of Mathematics Nanjing UniversityNanjing 210093JiangsuChina Department of Applied and Computational Mathematics and statistics University of Notre DameNotre DameIN 46556USA

The weighted essentially-oscillatory(WENO)schemes are a class of finite volume and finite difference methods for solving convection-dominated problems,mainly hyperbolic conservation *** idea comes from the earlier essentially-oscillatory(ENO)schemes,first developed in[1]in finite volume version and in[6]in finite difference version,for solving hyperbolic conservation laws.

关键词： hyperbolic finite essentially

Preface to Focused Issue on Discontinuous Galerkin Methods

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2022年第1期4卷 1-2页

作者： jan s.hesthaven Jennifer Ryan Chi-Wang shu Jaap van der Vegt Yan Xu Qiang Zhang Zhimin Zhang Ecole Polytechnique Federale de Lausanne(EPFL) 1015 LausanneSwitzerland Department of Applied Mathematics and statistics Colorado School of MinesGoldenCO 80401USA Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Department of Applied Mathematics University of Twente7500AE EnschedeThe Netherlands school of Mathematical sciences University of Science and Technology of ChinaHefei 230026AnhuiChina Department of Mathematics Nanjing UniversityNanjing 210093JiangsuChina Department of Mathematics Wayne State UniversityDetroitMI 48202USA

The discontinuous Galerkin(DG)method is a class of finite element methods using com-pletely discontinuous piecewise smooth functions(typically polynomials)as basis and test *** its inception in 1973[10],it has seen a sustained development,both in the computational mathematics community and in many scientific and engineering application *** DG methods have several advantages,such as its extreme flexibility in dealing with complex geometry and adaptive computation(both h-and p-adaptivities are easy to implement),extremely high parallel efficiency,good stability properties(energy and entropy stability has been established for DG methods in many situations),nice con-vergence and superconvergence properties,and capability to solve hyperbolic and convec-tion-dominated problems effectively.

关键词： discontinuous stability piecewise

Efficient solution of Ordinary Differential Equations with High-Dimensional Parametrized Uncertainty

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2011年第7期10卷 253-278页

作者： Zhen Gao jan s.hesthaven Research Center for Applied Mathematics Ocean University of ChinaQingdao 266071ShandongChina Division of Applied Mathematics Brown University182 George StreetProvidenceRI 02912USA

The important task of evaluating the impact of random parameters on the output of stochastic ordinary differential equations(sODE)can be computationally very demanding,in particular for problems with a high-dimensional parameter *** this work we consider this problem in some detail and demonstrate that by combining several techniques one can dramatically reduce the overall cost without impacting the predictive accuracy of the output of *** discuss how the combination of ANOVA expansions,different sparse grid techniques,and the total sensitivity index(TsI)as a pre-selective mechanism enables the modeling of problems with hundred of *** demonstrate the accuracy and efficiency of this approach on a number of challenging test cases drawn from engineering and science.

关键词： sparse grids stochastic collocation method ANOVA expansion total sensitivity index

Characterization of image spaces of Riemann-Liouville fractional integral operators on sobolev spaces W^(m,p)(Ω)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

science China Mathematics 2021年第12期64卷 2611-2636页

作者： Lijing Zhao Weihua Deng jan s.hesthaven school of Mathematics and statistics Northwestern Polytechnical UniversityXi'an 710129China school of Mathematics and statistics Gansu Key Laboratory of Applied Mathematics and Complex SystemsLanzhou UniversityLanzhou 730000China EPFL-sB-MATHICsE-MCss Ecole Polytechnique Federale de LausanneLausanne CH-1015Switzerland

Fractional operators are widely used in mathematical models describing abnormal and nonlocal *** there are extensive numerical methods for solving the corresponding model problems,theoretical analysis such as the regularity result,or the relationship between the left-side and right-side fractional operators is seldom *** of considering the fractional derivative spaces,this paper starts from discussing the image spaces of Riemann-Liouville fractional integrals of L_(p)(Ω) functions,since the fractional derivative operators that are often used are all *** the high regularity situation-the image spaces of Riemann-Liouville fractional integral operators on the W^(m,p)(Ω) space is *** characterizations of the defined spaces,as well as those of the intersection of the left-side and right-side spaces are *** behavior of the functions in the defined spaces at both the nearby boundary point/points and the points in the domain is demonstrated in a clear ***,tempered fractional operators are shown to be reciprocal to the corresponding Riemann-Liouville fractional operators,which is expected to contribute some theoretical support for relevant numerical ***,we also provide some instructions on how to take advantage of the introduced spaces when numerically solving fractional equations.

关键词： image space Riemann-Liouville integral regularity property approximation

Modeling 3D Magma Dynamics Using a Discontinuous Galerkin Method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2015年第6期18卷 230-246页

作者： seshu Tirupathi jan s.hesthaven Yan Liang Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA IBM Research DublinDamastown Industrial ParkMulhuddartDublin 15Ireland EPFL-sB-MATHICsE-MCss Ecole Polytechnique Fédérale de Lausanne(EPFL)LausanneSwitzerland Department of Geological sciences Brown UniversityProvidenceRI 02912USA

Discontinuous Galerkin(DG)and matrix-free finite element methods with a novel projective pressure estimation are combined to enable the numerical modeling of magma dynamics in 2D and 3D using the library *** physical model is an advection-reaction type system consisting of two hyperbolic equations to evolve porosity and soluble mineral abundance at local chemical equilibrium and one elliptic equation to recover global pressure.A combination of a discontinuous Galerkin method for the advection equations and a finite element method for the elliptic equation provide a robust and efficient solution to the channel regime problems of the physical system in 3D.A projective and adaptively applied pressure estimation is employed to significantly reduce the computational wall time without impacting the overall physical reliability in the modeling of important features of melt segregation,such as melt channel bifurcation in 2D and 3D time dependent simulations.

关键词： magma dynamics discontinuous Galerkin method finite element method matrixfree method

Modeling Magma Dynamics with a Mixed Fourier Collocation-Discontinuous Galerkin Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2011年第7期10卷 433-452页

作者： Alan R.schiemenz Marc A.Hesse jan s.hesthaven Department of Geological sciences Brown UniversityProvidenceRI 02910USA Division of Applied Mathematics Brown UniversityProvidenceRI 02910USA Department of Geological sciences University of Texas at AustinAustinTX 78712USA Department of Earth and Environmental sciences GeophysicsMunich UniversityTheresienstr.4180333 MunichGermany

A high-order discretization consisting of a tensor product of the Fourier collocation and discontinuous Galerkin methods is presented for numerical modeling of magma *** physical model is an advection-reaction type system consisting of two hyperbolic equations and one elliptic *** high-order solution basis allows for accurate and efficient representation of compaction-dissolution waves that are predicted from linear *** discontinuous Galerkin method provides a robust and efficient solution to the eigenvalue problem formed by linear stability analysis of the physical *** insights into the processes of melt generation and segregation,such as melt channel bifurcation,are revealed from two-dimensional time-dependent simulations.

关键词： Magma dynamics discontinuous Galerkin method Fourier collocation method numerical simulations linear stability analysis

Non-Intrusive Reduced OrderModeling of Convection Dominated Flows Using Artificial NeuralNetworkswithApplication to Rayleigh-Taylor Instability

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2021年第6期30卷 97-123页

作者： Zhen Gao Qi Liu jan s.hesthaven Bao-shan Wang Wai sun Don Xiao Wen school of Mathematical sciences Ocean University of ChinaQingdaoChina Mathematics Institute of Computational science and Engineering ´Ecole Polytechnique F´ed´erale de LausanneLausanneSwitzerland College of Mathematics and systems science Shandong University of Science and TechnologyQingdaoChina

.A non-intrusive reduced order model(ROM)that combines a proper orthogonal decomposition(POD)and an artificial neural network(ANN)is primarily studied to investigate the applicability of the proposed ROM in recovering the solutions with shocks and strong gradients accurately and resolving fine-scale structures efficiently for hyperbolic conservation *** accuracy is demonstrated by solving a high-dimensional parametrized ODE and the one-dimensional viscous Burgers’equation with a parameterized diffusion *** two-dimensional singlemode Rayleigh-Taylor instability(RTI),where the amplitude of the small perturbation and time are considered as free parameters,is also *** adaptive sampling method in time during the linear regime of the RTI is designed to reduce the number of snapshots required for POD and the training of *** extensive numerical results show that the ROM can achieve an acceptable accuracy with improved efficiency in comparison with the standard full order method.

关键词： Rayleigh-Taylor instability non-intrusive reduced basis method proper orthogonal decomposition artificial neural network adaptive sampling method

A Local Discontinuous Galerkin Method for Two-Dimensional Time Fractional Diffusion Equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2020年第4期2卷 689-709页

作者： somayeh Yeganeh Reza Mokhtari jan shesthaven Department of Mathematical sciences Isfahan University of TechnologyIsfahan 84156-83111Iran EPFL-sB-MATHICEs-MCss École Polytechnique Fédéral de Lausanne1015 LausanneSwitzerland

For two-dimensional(2D)time fractional diffusion equations,we construct a numerical method based on a local discontinuous Galerkin(LDG)method in space and a finite differ-ence scheme in *** investigate the numerical stability and convergence of the method for both rectangular and triangular meshes and show that the method is unconditionally *** results indicate the effectiveness and accuracy of the method and con-firm the analysis.

关键词： Two-dimensional(2D)time fractional difusion equation Local discontinuous Galerkin method(LDG) Numerical stability Convergence analysis

Recurrent evolution of seaweed body plan complexity among photosynthetic eukaryotes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2024年第7期17卷 999-1001页

作者： Elisa s.Goldbecker Iker Irisarri jan de Vries Department of Applied Bioinformatics Institute for Microbiology and GeneticsUniversity of GottingenGoldschmidtstr.137077 GottingenGermany section Phylogenomics Center for Molecular Biodiversity ResearchLeibniz Institute for the Analysis of Biodiversity Change(LIB)Museum of Nature HamburgMartin-Luther-King-Platz 320146 HamburgGermany Department of Applied Bioinformatics Campus Institute Data Science(CIDAS)University of GottingenGoldschmidtstr.137077 GottingenGermany Department of Applied Bioinformatics Gottingen Center for Molecular Biosciences(GZMB)University of GottingenGoldschmidtstr.137077 GottingenGermany

The evolutionary origin of multicellularity is an age-old question in biological *** studies have delved into the evolutionary processes that led to the evolution of multicellular life forms from unicellular *** beauty and the challenge about this topic are that evolution has brought forth various forms of multicellular life,multiple times independently,scattered across the evolutionary tree of *** to the challenge,multicellular organisms exist in a diversity of forms and complexities,and the mechanisms by which multicellularity emerged are also likely different between animals,algae,or fungi(Niklas and Newman,2020).Recently,Nelson et al.(2024)presented a large-scale comparative genomics study focused on particularly intricate multicellular organisms:macroalgae(seaweeds),which emerged independently in three distinct eukaryotic lineages-green algae(Chlorophyta),red algae(Rhodophyta),and brown algae(Phaeophyceae).

关键词： algae seaweed evolution