THE FOURIER SPECTRAL ELEMENT METHOD FOR VIBRATION AND POWERFLOW ANALYSIS OF COMPLEX DYNAMIC SYSTEMS byHONGAN XUMay 2011Advisor: Dr. Wen LiMajor: Mechanical EngineeringDegree: Doctor of PhilosophyA general numerical method, the so-called Fourier-Space Element Method (FSEM), isproposed for the vibration and power flow analyses of complex built-up structures. In...

In mathematical programming, constraint qualifications are essential elements for duality theory. Recently, necessary and sufficient constraint qualifications for Lagrange duality results have been investigated. Also, surrogate duality enables one to replace the problem by a simpler one in which the constraint function is a scalar one. However, as far as we know, a necessary and sufficient cons...

We develop a fast discrete algorithm for computing the sparse Fourier expansion of a function of d dimension. For this purpose, we introduce a sparse multiscale Lagrange interpolation method for the function. Using this interpolation method, we then design a quadrature scheme for evaluating the Fourier coefficients of the sparse Fourier expansion. This leads to a fast discrete algorithm for com...

Periodic elements play important roles in genomic structures and functions, yet some complex periodic elements in genomes are difficult to detect by conventional methods such as digital signal processing and statistical analysis. We propose a periodic power spectrum (PPS) method for analyzing periodicities of DNA sequences. The PPS method employs periodic nucleotide distributions of DNA sequenc...

We consider the so-called Babuska method of finite elements with Lagrange multipliers for numerically solving the problem Au = f in il, u = g on 3Í2, iî C Rn, 7i > 2. We state a number of local conditions from which we prove the uniform stability of the Lagrange multiplier method in terms of a weighted, mesh-dependent norm. The stability conditions given weaken the conditions known so far and a...

In [Mu1] we underlined the motifs of holomorphic subspaces in a complex Finsler space: induced nonlinear connection, coupling connections, and the induced tangent and normal connections. In the present paper we investigate the equations of Gauss, H−and A−Codazzi, and Ricci equations of a holomorphic subspace. We deduce the link between the holomorphic curvatures of the Chern-Finsler connection ...

A new parameterized binary relation is used to define minimality concepts in vector optimization. To simplify the problem of determining minimal elements the method of scalarization is applied. Necessary and sufficient conditions for the existence of minimal elements with respect to the scalarized problems are given. The multiplier rule of Lagrange is generalized. As a necessary minimality cond...

A geometrically exact membrane formulation is presented that is based on curvilinear coordinates and isogeometric finite elements, and is suitable for both solid and liquid membranes. The curvilinear coordinate system is used to describe both the theory and the finite element equations of the membrane. In the latter case this avoids the use of local cartesian coordinates at the element level. C...

We present new rectangular mixed finite elements for linear elasticity. The approach is based on a modification of the Hellinger-Reissner functional in which the symmetry of the stress field is enforced weakly through the introduction of a Lagrange multiplier. The elements are analogues of the lowest order elements described in Arnold, Falk and Winther [ Mixed finite element methods for linear ...