sábado, 21 de noviembre de 2009

Erratum to: MIR closures of polyhedral sets


Erratum to: MIR closures of polyhedral sets


  • Content Type Journal Article
  • Category Erratum
  • DOI 10.1007/s10107-009-0328-z
  • Authors

    • Sanjeeb Dash, IBM, T.J. Watson Research Center P.O. Box 218 Yorktown Heights NY 10598 USA
    • Oktay Günlük, IBM, T.J. Watson Research Center P.O. Box 218 Yorktown Heights NY 10598 USA
    • Andrea Lodi, DEIS, University of Bologna viale Risorgimento 2 40136 Bologna Italy





Numerical Studies of Adaptive Finite Element Methods for Two Dimensional Convection-Dominated Problems


Abstract  In this paper, we study the stability and accuracy of adaptive finite element methods for the convection-dominated convection-diffusion-reaction
problem in the two-dimension space. Through various numerical examples on a type of layer-adapted grids (Shishkin grids),
we show that the mesh adaptivity driven by accuracy alone cannot stabilize the scheme in all cases. Furthermore the numerical
approximation is sensitive to the symmetry of the grid in the region where the solution is smooth. On the basis of these two
observations, we develop a multilevel-homotopic-adaptive finite element method (MHAFEM) by combining streamline diffusion
finite element method, anisotropic mesh adaptation, and the homotopy of the diffusion coefficient. We use numerical experiments
to demonstrate that MHAFEM can efficiently capture boundary or interior layers and produce accurate solutions.




Gaussian quadrature rules using function derivatives


For finite positive Borel measures supported on the real line we consider a new type of quadrature rule with maximal algebraic degree of exactness that involves function derivatives. We prove the existence of such quadrature rules and describe their basic properties. We also give an application of these quadrature rules to the solution of a Cauchy problem without solving it directly. Numerical examples are included as well.