We propose a new estimator for the error variance in a nonparametric regression model. We estimate the error variance as the intercept in a simple linear regression model with squared differences of paired observations as the dependent variable and squared distances between the paired covariates as the regressor. Our method can be applied to nonparametric regression models with multivariate fun...

We propose a fast and non-stiff approach for the solutions of the Immersed Boundary Method, for Newtonian, incompressible flows in two or three dimensions. The proposed methodology is built on a robust semi-implicit discretization introduced by Peskin in the late 70’s which is solved efficiently through the novel use of a fast, treecode strategy to compute flow-structure interactions. Optimal m...

This paper develops least-squares methods for the solution of linear elastic problems in both two and three dimensions. Our main approach is defined by simply applying the L2 norm least-squares principle to a stress-displacement system: the constitutive and the equilibrium equations. It is shown that the homogeneous least-squares functional is elliptic and continuous in the H(div; Ω)d × H1(Ω)d ...

An analytical solution is presented that reconstructs residual stress field from limited and incomplete data.  The inverse problem of reconstructing residual stresses is solved using an appropriate form of the airy stress function.  This function is chosen to satisfy the stress equilibrium equations together with the boundary conditions for a domain within a convex polygon.  The analytical solu...

In this paper, we focus on a class of dual-rate sampled-data systems in which all the inputs u(t) are available at each instant while only scarce outputs y(qt) can be measured (q being an integer more than unity). To estimate the parameters of such dual-rate systems, we derive amathematicalmodel by using the polynomial transformation technique, and apply the extended least squares algorithm to ...

Abbreviations 3D D three-dimensional; C D molar concentration of a drug; CBG D corticosteroid binding globulin; CoMFA D comparative molecular field analysis; CoMSIA D comparative molecular similarity indices analysis; GOLPE D generating optimal linear PLS estimations; PLS D partial least squares; PRESS D predictive residual sum of squares; RMS D root mean squares; TBG D testosterone binding glo...

We develop and analyze a negative norm least-squares method for the compressible Stokes equations with an inflow boundary condition. Least-squares principles are derived for a first-order form of the equations obtained by using ω = ∇ × u and φ = ∇ ·u as new dependent variables. The resulting problem is incompletely elliptic, i.e., it combines features of elliptic and hyperbolic equations. As a ...

In this paper, we extend Bai and Perron’s (1998, Econometrica, pp. 47-78) method for detecting multiple breaks to nonlinear models. To that end, we consider an unstable univariate nonlinear least squares (NLS) model with a limited number of parameter shifts occurring at unknown dates. In our framework, the break-dates are simultaneously estimated with the parameters via minimization of the resi...