Relative diffuse reflection measurements from the original and ground surfaces using a He-Ne laser are reported. The intensity measurements for the metallic, transparent dielectric, matte plastic surfaces and colored papers are presented. Our results indicate that among metallic surfaces tested, aluminum has the highest diffuse reflectance; while the original stainless steel surface shows the l...

relative diffuse reflection measurements from the original and ground surfaces using a he-ne laser are reported. the intensity measurements for the metallic, transparent dielectric, matte plastic surfaces and colored papers are presented. our results indicate that among metallic surfaces tested, aluminum has the highest diffuse reflectance; while the original stainless steel surface shows the l...

Most of the physically based techniques for rendering translucent objects use the diffusion theory of light scattering in turbid media. The widely used dipole diffusion model [JMLH01] applies the diffusion-theory formula derived for the planar surface to objects of arbitrary shapes. This paper presents first results of our investigation of how surface curvature affects the diffuse reflectance f...

This lecture is an introduction to cosmological tests with clusters of galaxies. Here I do not intend to provide a complete review of the subject, but rather to describe the basic procedures to set up the fitting machinery to constrain cosmological parameters from clusters, and to show how to handle data with a critical insight. I will focus mainly on the properties of X–ray clusters of galaxie...

Let s be a source point and t be a destination point inside an n-vertex simple polygon P . Euclidean shortest paths [Lee and Preparata, Networks, 1984; Guibas et al. , Algorithmica, 1987] and minimum-link paths [Suri, CVGIP, 1986; Ghosh, J. Algorithms, 1991] between s and t inside P have been well studied. Both these kinds of paths are simple and piecewise-convex. However, computing optimal pat...

The HESS instrument has observed a diffuse flux of ∼ TeV γ-rays from a large solid angle around the Galactic center (GC). This emission is correlated with the distribution of gas in the region suggesting that the γ-rays originate in

We prove a conjecture of Aanjaneya, Bishnu, and Pal that the maximum number of diffuse reflections needed for a point light source to illuminate the interior of a simple polygon with n walls is bn/2c − 1. Light reflecting diffusely leaves a surface in all directions, rather than at an identical angle as with specular reflections.

We construct a subset A of the unit disc with the following properties. (i) The set A is the finite union of disjoint line segments. (ii) The shadow of A is arbitrarily close to the shadow of the unit disc in “most” directions. (iii) If the line segments are considered to be mirrors reflecting light according to the classical law of specular reflection then most light rays hitting the set emerg...

This is the first of a series of papers in which we initiate and develop the theory of reflection monoids, motivated by the theory of reflection groups. The main results identify a number of important inverse semigroups as reflection monoids, introduce new examples, and determine their orders.