An IC-plane graph is a topological graph where every edge is crossed at most once and no two crossed edges share a vertex. We show that every IC-plane graph has a visibility drawing where every vertex is of the form { , , , }, and every edge is either a horizontal or vertical segment. As a byproduct of our drawing technique, we prove that every IC-plane graph has a RAC drawing in quadratic area...

in this research the daily data of 69 climatic variables (wind direction, wind speed, dry temperature, wet temperature, maximum and minimum temperature, average daily temperature, precipitation, relative humidity, station level pressure, cloudiness, horizontal visibility, vapor pressure, …) of abumoosa synoptic station during the years 1362-1388 were studied. initially, a data base of variabl...

Triangulating a simple polygon has been one of the most outstanding open problems in two-dimensional computational geometry. It is a basic primitive in computer graphics and, generally, seems the natural preprocessing step for most nontrivial operations on simple polygons [5,13]. Recall that to triangulate a polygon is t o partition it into triangles without adding any new vertices. Despite its...

OBJECTIVES To investigate whether a 360-degree horizontal turn after oral premedication with simethicone improves the mucosal visibility during gastroendoscopic examination, and to determine the proper time to turn over the patient. METHODS This study involved 993 patients scheduled for gastroendoscopy. Just before gastroendoscopy, after oral premedication with simethicone, patients were rand...

Aerosol Optical Thickness (AOT) is an important parameter in Radiative Transfer Models (RTMs) used for atmospheric correction of remotely-sensed data. It is often estimated from horizontal visibility measurements by use of the Koschmieder formula or other related methods built into RTMs. This paper assesses the accuracy of this estimation, in the context of atmospheric correction, by comparing ...

The study was approved by the institutional review board, and informed consent was obtained. The purpose of the study was to prospectively quantify the angular visibility range, determine the existence of orthogonal viewing pairs, and characterize the conditions that cause artifacts in multipath curved planar reformations (MPCPRs) of the peripheral arterial tree in 10 patients (eight men and tw...

A triangulated polygon is a 2-connected maximal outerplanar graph. A unit bar-visibility graph (UBVG for short) is a graph whose vertices can be represented by disjoint, horizontal, unit-length bars in the plane so that two vertices are adjacent if and only if there is a nondegenerate, unobstructed, vertical band of visibility between the corresponding bars. We give combinatorial and geometric ...

The paper considers representations of unions and products of trees as rectangle-visibility graphs (abbreviated RVGs), i.e., graphs whose vertices are rectangles in the plane, with adjacency determined by horizontal and vertical visibility. Our main results are that the union of any tree (or forest) with a depth-1 tree is an RVG, and that the union of two depth-2 trees and the union of a depth-...