LET K C R3 be a simple closed curve, and K be its convex hull. In [l], Almgren and Thurston define the (oriented) convex hull genus of K to be the minimal genus of an (oriented) surface contained in g and bounded by K. They give examples showing that even if K is unknotted both the orientable and non-orientable convex hull genus of K may be arbitrarily large. In 43 of this paper we show that th...

This paper presents a new O(nlog(n)) algorithm for computing the convex hull of a set of 3 dimensional points. The algorithm first sorts the point in (x,y,z) then incrementally adds sorted points to the convex hull using the constraint that each new point added to the hull can 'see' at least one facet touching the last point added. The reduces the search time for adding new points. The algorith...

In this paper, convex hull based features are used for recognition of isolated Roman numerals using a Multi Layer Perceptron (MLP) based classifier. Experiments of convex hull based features for handwritten character recognition are few in numbers. Convex hull of a pattern and the centroid of the convex hull both are affine invariant attributes. In this work, 25 features are extracted based on ...

ci = 1, and all Pi in Σ. For example, the line segment between two points P and Q is the convex hull of those two points. This is clearly convex. An extremal point of a convex region is a point that does not lie on the interior of a line segment in the region. Any convex region is the convex hull of its extremal points. As was proved in [Weyl:1935], the convex hull of any finite set of points a...

• Sd: A d-Simplex The simplest convex polytope in R. A d-simplex is always the convex hull of some d + 1 affinely independent points. For example, a line segment is a 1− simplex i.e., the smallest convex subspace which contains two points. A triangle is a 2 − simplex and a tetrahedron is a 3− simplex. • P: A Simplicial Polytope. A polytope where each facet is a d− 1 simplex. By our assumption, ...

For a self{similar or self{aane tile in R n we study the following questions: 1) What is the boundary? 2) What is the convex hull? We show that the boundary is a graph directed self{aane fractal, and in the self{similar case we give an algorithm to compute its dimension. We give necessary and suucient conditions for the convex hull to be a polytope, and we give a description of the Gauss map of...

We develop efficient algorithms for problems in computational geometry—convex hull, smallest enclosing box, ECDF, two-set dominance, maximal points, all-nearest neighbor, and closest-pair—on the OTIS-Mesh optoelectronic computer. We also demonstrate the algorithms for computing convex hull and prefix sum with condition on a multi-dimensional mesh, which are used to compute convex hull and ECDF ...

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