Partial Differential Equations and the Finite Element Method provides a much–needed, clear, and systematic introduction to modern theory of partial differential equations (PDEs) and finite element methods (FEM). Both nodal and hierachic concepts of the FEM are examined. Reflecting the growing complexity and multiscale nature of current engineering and scientific problems, the author emphasizes ...

Electrical and Computer Engineering) A Hybrid Spectral-Element / Finite-Element Time-Domain Method for Multiscale Electromagnetic Simulations by Jiefu Chen Department of Electrical and Computer Engineering Duke University

A finite element wave-packet procedure is presented to solve problems of wave propagation in multiscale behavior. The proposed scheme combines the advantages of the finite element and spectral methods. The basic formulation is presented, and the capabilities of the procedure are demonstrated through the solution of some illustrative problems, including a problem that characterizes the mode-conv...

Gate degradation in high electron mobility transistors (HEMTs) under OFF-state stress results from the high electric field near the gate edge. We investigate the evolution of this field over time in AlGaN/ GaN HEMTs upon OFF-state stress using a combination of electroluminescence (EL) microscopy and spectroscopy. EL analysis suggests that the electric field at the sites of generated surface def...

Recent work on octree-based finite-element systems has developed a multigrid solver for Poisson equations on meshes. While the idea of defining a regularly indexed function space has been successfully used in a number of applications, it has also been noted that the richness of the function space is limited because the function values can be coupled across locally disconnected regions. In this ...

Spectral and pseudo spectral methods for advection equations are investigated. A basic framework is given which allows the application of techniques used in finite element analysis to spectral methods with trigonometric polynomials. Error estimates for semidiscrete spectral and pseudo spectral as well as fully discrete explicit pseudo spectral methods are given. The approximation schemes are sh...

The implementation of high-order (spectral) approximations associated with FEM is an approach to overcome the difficulties encountered in the numerical analysis of complex problems. This paper proposes the use of the spectral finite element method, originally developed for computational fluid dynamics problems, to achieve improved solutions for these types of problems. Here, the interpolation n...

A Poisson equation on a rectangular domain is solved by coupling two methods: the domain is divided in two squares; a finite element approximation is used on the first square and a spectral discretization is used on the second. Two kinds of matching conditions on the interface are presented and compared; in both cases, error estimates are proved.

We examine the dual graph representation of simplicial manifolds in causal dynamical triangulations (CDT) as a means to build observables and propose new based on finite element methods (FEM). In particular, with application FEM techniques, we extract (low-lying) spectrum Laplace-Beltrami (LB) operator Sobolev space ${H}^{1}$ scalar functions piecewise flat compare them corresponding results ob...