A novel iterative channel estimation algorithm for orthogonal frequency-division multiplexing (OFDM) systems in fast time-varying environment is proposed. Instead of directly estimate the original channel taps, the proposed estimation focus on the rest channel part from the original channel taps subtracted by the prior estimation results in the absence of any channel information. The initial re...

Breakfast and Registration: 8:30 9:00 Morning Session I Room 1312 9:00 11:00 9:00 9:20 Eugene Vecharynski The Convergence of Restarted GMRES University of Colorado at Denver for Normal Matrices is Sublinear 9:25 9:45 Adrianna Gillman The Numerical Performace of a Mixed-Hybrid University of Colorado at Boulder Type Solution Methodology for Solving High-Frequency Helmholtz Problems 9:50 10:10 Sri...

This paper is concerned with the identification of the geometrical structure of the boundary shape for a two-dimensional boundary value problem. The output least square identification method is considered for estimating partially unknown boundary shapes. A numerical parameter estimation technique using the spline collocation method is proposed. lThis research was supported by the National Aeron...

Reverse-time de-migration (RTDM) is formulated as the adjoint operator of reverse-time migration (RTM). In acoustic medium, RTM provides a good approximation to the inverse of RTDM, and can be used to iteratively invert for the reflectivity image in least-squares RTM (LSRTM). In viscoelastic medium, however, the adjoint of the RTDM operator is far from its inverse because of amplitude attenuati...

We develop a general convergence theory for the generalized minimal residual method for least squares problems preconditioned with inner iterations. The inner iterations are performed by stationary iterative methods. We also present theoretical justifications for using specific inner iterations such as the Jacobi and SOR-type methods. The theory is improved particularly in the rankdeficient cas...

In this talk we present results of our recent work [2]: We develop and analyze strategies to couple the discontinuous Petrov-Galerkin method with optimal test functions to (i) least-squares boundary elements and (ii) various variants of standard Galerkin boundary elements. The procedure (i) is somehow a natural approach, because the DPG method can also be equivalently written as a least-squares...

In this paper, we extend Bai and Perron’s (1998, Econometrica, p.47-78) framework for multiple break testing to linear models estimated via Two Stage Least Squares (2SLS). Within our framework, the break points are estimated simultaneously with the regression parameters via minimization of the residual sum of squares on the second step of the 2SLS estimation. We establish the consistency of the...

A least-squares finite element method for second-order elliptic boundary value problems having interfaces due to discontinuous media properties is proposed and analyzed. Both Dirichlet and Neumann boundary data are treated. The boundary value problems are recast into a firstorder formulation to which a suitable least-squares principle is applied. Among the advantages of the method are that nonc...

Several models in data analysis are estimated by minimizing the objective function defined as the residual sum of squares between the model and the data.A necessary and sufficient condition for the existence of a least squares estimator is that the objective function attains its infimum at a unique point. It is shown that the objective function for Parafac-2 need not attain its infimum, and tha...