This paper addresses the problem of surface reconstruction of highly noisy point clouds. The surfaces to be reconstructed are assumed to be 2-manifolds of piecewise C1 continuity, with isolated small irregular regions of high curvature, sophisticated local topology or abrupt burst of noise. At each sample point, a quadric field is locally fitted via a modified moving least squares method. These...

Article history: Received 24 February 2010 Received in revised form 4 June 2010 Accepted 6 July 2010 Available online 16 July 2010

errors, and are essentially independent of the 25 larger errors. This is shown clearly by the fact that the SNTLN1 solution is changed only slightly byachange in .I n contrast, the VarPro solution nal error is determined primarily by the largest data errors, and will increase in proportion to ,a s is increased. This will also be true for any approximation method based on L 2 norm minimization. ...

Article history: Received 10 December 2012 Received in revised form 26 July 2013 Accepted 30 July 2013 Available online 17 August 2013

We examined an econometric model of counts of worker absences due to illness. The underlying theoretical model is of a sluggishly adjusting hedonic labor market. We compared results from three parametric estimators, nonlinear least squares plus Poissonand negative binomial pseudo maximum likelihood, to generalized least squares using nonparametric estimates of the conditional variance. Our data...

This note calls attention to a variant formulation of the least-squares adjustment procedure [1] that should prove increasingly attractive as electronic dataprocessing equipment becomes ever more widely available. It indicates that the statistician need not concern himself with the two rituals featured in traditional textbook presentations—namely, the construction and solution of the convention...

Article history: Received 1 March 2010 Accepted 2 May 2010 Available online 9 June 2010

presents a modiied Chebyshev pseudospec-tral method, involving mapping of the Chebyshev points, for solving rst-order hyperbolic initial boundary value problems. It is conjectured that the time step restriction for the modiied method is O(N ?1) compared to O(N ?2) for the standard Chebyshev pseudospectral method, where N is the number of discretization points in space. In the present paper we s...

Least squares problems minx ‖b−Ax‖2 where the matrix A ∈ Cm×n (m ≥ n) has some particular structure arise frequently in applications. Polynomial data fitting is a well-known instance of problems that yield highly structured matrices, but many other examples exist. Very often, structured matrices have huge condition numbers κ2(A) = ‖A‖2 ‖A†‖2 (A† is the Moore-Penrose pseudo-inverse ofA) and, the...