The SPectrogram Analysis and Cataloguing Environment (SPACE) tool is an interactive python designed to label radio emission features of interest in a time-frequency map (called “dynamic spectrum”). program uses Matplotlib’s Polygon Selector widget allow user select edit undefined number vertices on top the dynamic spectrum before closing shape (polygon). Multiple polygons may be drawn any spect...

Circle graphs are intersection graphs of chords in a circle and kpolygon graphs are the intersection graphs of chords in a convex ksided polygon where each chord has its endpoints on distinct sides. Every k-polygon graph is a circle graph and every circle graph is a kpolygon graph for some k. The polygon number ψ(G) of a circle graph G is the minimum k such that G is a k-polygon graph and the p...

The dark-line defect problem in the conventional polygon computer-generated hologram (CGH) is addressed. To resolve this problem, we clarify the physical origin of the defect and address the concept of phase-regularization. A novel synthesis algorithm for a phase-regularized polygon CGH for generating photorealistic defect-free holographic images is proposed. The optical reconstruction results ...

This paper presents a new approach to visibility culling. We propose a conservative visibility preprocessing method for complex virtual environments. The proposed method deals with general 3D graphical models and invisible polygons jointly blocked by multiple occluders. The proposed method decomposes volume visibility from the predefined volume into the area visibility from rectangles surroundi...

The dynamics of a binary mixture of large and small discs are studied at temperatures approaching the glass transition using an analysis based on the topology of the Voronoi polygon surrounding each atom. At higher temperatures we find that dynamics is dominated by fluid-like motion that involves particles entering and exiting the nearest-neighbour shells of nearby particles. As the temperature...

This paper is Part 2 of a four-part series of our research on the development of a general framework for error analysis in measurement-based geographic information systems (MBGIS). In this paper, we discuss the problem of point-in-polygon analysis under randomness, i.e., with random measurement error (ME). It is well known that overlay is one of the most important operations in GIS, and point-i...

os-Nagy Theorem and its Rami cations Godfried Toussaint School of Computer Science McGill University Montr eal, Qu ebec, Canada June 29, 1999 Abstract Given a simple polygon in the plane, a ip is dened as follows: consider the convex hull of the polygon. If there are no pockets do not perform a ip. If there are pockets then re ect one pocket across its line of support of the polygon to obtain a...

We present an order n algorithm which computes the convex hull of a two-dimensional non-selfintersecting polygon. The algorithm recovers much of the simplicity of the one presented by Sklansky (Sklansky, 1972), and subsequently disproved. Unlike several algorithms which have been found since then, the modified algorithm executes a truly uniform (modeless) traversal of all the vertices of the po...

We present a diagram that captures containment information for scalable translations of a convex polygon. For a given polygon P and contact point q in a set S, the diagram parameterizes possible translations and scales of the polygon in order to represent containment regions for each other point v in S. We present geometric and combinatorial properties for this diagram, and describe how it can ...

Introduction: The detection of subsurface ice at the po-lygonally-patterned Phoenix landing site [1] is the culmination of over thirty years of Mars permafrost and polygons research [2-6]. The exploration of martian polygonally pat-terned ground addresses several critical questions related to recent martian habitability and climate processes: 1) what is the origin of ice in the shallow martian ...