The problem of endogeneity in statistics and econometrics is often handled by introducing instrumental variables (IV) which fulfill the mean independence assumption, i.e. unobservable independent instruments. When full IV’s assumed, nonparametric IV regression models demand lead to nonlinear integral equations with unknown kernels. We prove convergence rates for integrated square error iterativ...

Point-based models are gaining lately considerable attention as an alternative to traditional surface meshes. In this context, Point Set Surfaces (PSS) were proposed as a modeling and rendering method with important topological and approximation properties. However, ray-tracing PSS is computationally expensive. Therefore, we propose an interactive ray-tracing algorithm for PSS implemented compl...

In this paper we analyze the local and global boundary rigidity problem for general Riemannian manifolds with boundary (M, g) whose boundary is strictly convex. We show that the boundary distance function, i.e. dg |∂M×∂M , known over suitable open sets of ∂M determines g in suitable corresponding open subsets of M , up to the natural diffeomorphism invariance of the problem. We also show that i...

Natural illuminant and reflectance spectra can be roughly approximated by a linear model with as few as three basis functions, and this has suggested that the visual system might construct a linear representation of the spectra by estimating the weights of these functions. However, such models do not accommodate nonlinearities in color appearance, such as the Abney effect. Previously, we found ...

abstractbackground: polymer gels are an emerging new class of dosimeters which are being applied to the challenges of modern radiotherapy modalities. research on gel dosimetry involves several scientific domains, one of which is the imaging techniques with which dose data is extracted from the dosimeters. in the current work, we present our preliminary results of investigating capability of x-r...

This paper presents a new method for progressively previewing a raytraced image while it is being computed. Our method constructs and incrementally updates a constrained Delaunay triangulation of the image plane. The points in the triangulation correspond to all of the image samples that have been computed by the ray tracer, and the constraint edges correspond to various important discontinuity...

This paper presents a new method for progressively previewing a raytraced image while it is being computed. Our method constructs and incrementally updates a constrained Delaunay triangulation of the image plane. The points in the triangulation correspond to all of the image samples that have been computed by the ray tracer, and the constraint edges correspond to various important discontinuity...

BACKGROUND The objectives of this systematic review are to examine how researchers report missing data in questionnaires and to provide an overview of current methods for dealing with missing data. METHODS We included 262 studies published in 2010 in 3 leading epidemiologic journals. Information was extracted on how missing data were reported, types of missing, and methods for dealing with mi...