The algorithms of convex hull have been extensively studied in literature, principally because of their wide range of applications in different areas. This article presents an efficient algorithm to construct approximate convex hull from a set of n points in the plane in O(n+ k) time, where k is the approximation error control parameter. The proposed algorithm is suitable for applications prefe...

In this paper, we cope with the following problem: compute the size of the convex hull of a configuration C, where the given data is the number of separating lines between any two points of the configuration (where the lines are generated by pairs of other points of the configuration). We give an algorithm for the case that the convex hull is of size 3, and a partial algorithm and some directio...

Rappaport D., A convex hull algorithm for discs, and applications, Computational Geometry: Theory and Applications 1 (1992) 171-187. We show that the convex hull of a set of discs can be determined in @(n log n) time. The algorithm is straightforward and simple to implement. We then show that the convex hull can be used to efficiently solve various problems for a set of discs. This includes O(n...

Recently the invariant (copoint) pre-hull number ph(G) of a graph G that measures the nonconvexity of a convex space was introduced by Polat and Sabidussi in [18]. We introduce a similar invariant called convex pre-hull number which is a natural upper bound for the copoint pre-hull number and consider in this work both on the lexicographic product of graphs. We present exact values with respect...

In this paper, we consider the problem of computing a convex hull of bounded curvature of a set S of points in the plane, i.e. a set containing S and whose boundary is a curve of bounded curvature of minimal length. We prove that, if the radius of the smallest disk that contains S is greater than 1, such a hull is unique. We show that the computation of a convex hull of bounded curvature reduce...

This paper considers the problem of computing the real convex hull of a finite set of ndimensional integer vectors. The starting point is a finite-automaton representation of the initial set of vectors. The proposed method consists in computing a sequence of automata representing approximations of the convex hull and using extrapolation techniques to compute the limit of this sequence. The conv...

Classic convexity can be extended to graphs in a natural way by considering shortest paths, also called geodesics: a set S of vertices of a graph is convex if it contains all the vertices lying in some geodesic with endpoints in S and the convex hull of a set S of vertices is the minimum convex set containing S. Farber and Jamison [9] characterized the graphs such that every convex set is the c...

The convex hull of a planar point set is the smallest convex polygon containing each point in the set. The dynamic convex hull problem concerns efficiently maintaining the convex hull of a set of points subject to additions and removals. One algorithm for this problem uses two external balanced binary search trees (BSTs) [16]. We present the first concurrent solution for this problem, which use...

In this paper, we study the distributed containment control problem for networked Lagrangian systems with multiple dynamic leaders in the presence of parametric uncertainties under a directed graph that characterizes the interaction among the leaders and the followers. We propose a distributed adaptive control algorithm combined with distributed sliding-mode estimators. A necessary and sufficie...

The dynamic maintenance of the convex hull of a set of points in the plane is one of the most important problems in computational geometry. We present a data structure supporting point insertions in amortized O(log n · log log log n) time, point deletions in amortized O(log n · log log n) time, and various queries about the convex hull in optimal O(log n) worst-case time. The data structure req...