The anchor words algorithm performs provably efficient topic model inference by finding an approximate convex hull in a high-dimensional word co-occurrence space. However, the existing greedy algorithm often selects poor anchor words, reducing topic quality and interpretability. Rather than finding an approximate convex hull in a high-dimensional space, we propose to find an exact convex hull i...

For a self similar or self a ne tile in R we study the following questions What is the boundary What is the convex hull We show that the boundary is a graph directed self a ne fractal and in the self similar case we give an algorithm to compute its dimension We give necessary and su cient conditions for the convex hull to be a polytope and we give a description of the Gauss map of the convex hull

We investigate the utility of the convex hull ofmany Lagrangian tracers to analyze transport properties of turbulent flowswith different anisotropy. In direct numerical simulations of statistically homogeneous and stationaryNavier–Stokes turbulence, neutral fluid Boussinesq convection, and MHDBoussinesq convection a comparisonwith Lagrangian pair dispersion shows that convex hull statistics cap...

An application of Fourier descriptors and convex hull for shape analysis is presented. Convex hull is used for dividing a shape into small parts. Amplitude spectrum which is invariant to scaling, translation and choosing a starting point is obtained from the Fourier descriptors (see e.g [1-3]) and used for comparison. All calculations are performed with the author's software and some algorithms...

This work focusses on boundary detection of target objects by extracting conngurations of straight lines. Hough transformation is used as basic voting technique for extracting the image lines. To nd the appropriate peaks in the bin array of the Hough transform and thus estimating the line parameters a three-step procedure is involved. First, the Hough transform is constrained appropriately by t...

The objective of this report is to explore the algorithmic and architectural optimization of the Hough Transform. The design of proposed Hough Transform algorithm will particularly suit small and mobile systems like tiny robots. Comparisons with ordinary point to point Hough Transform will be made and it will be shown that the proposed method produces accurate and faster results where memory co...

An algorithm for computing the convex hull of a simple polygon is presented. Its correctness and complexity are also shown. Computational geometry Convex hull Simple polygon Algorithm

We consider the problem of reporting convex hull points in an orthogonal range query in two dimensions. Formally, let P be a set of n points in R. A point lies on the convex hull of a point set S if it lies on the boundary of the minimum convex polygon formed by S. In this paper, we are interested in finding the points that lie on the boundary of the convex hull of the points in P that also fal...

In this paper, an effective and reliable skew estimation technique for machine printed documents and photos using radon transform is proposed and is compared with other methods used for skew estimation such as Fast Fourier Transform (FFT), Hough Transform (HT), combination of Horizontal Projection Profile (HPP) and Hough Transform, combination of Gabor filter and Radon transform, combination of...

In this paper, the polar Hough transform (PHT) is considered as a track initiator in a track before detect (TBD) system. The study is performed in the presence of impulse interference. The algorithm under study includes a parametric CFAR detector, which works successfully in conditions of impulse interference and uses the polar Hough transform. The proposed Hough detector improves the detection...