In this paper, we present a new algorithm for vertex guarding of a triangulated surface, which takes into account the heights of the vertices and considers the global visibility of the guards. In this algorithm, the initial surface is reduced to a collection of simple polygons and trivial triangulated surfaces. This is done by assigning guards to some vertices and removing the faces covered by ...

In the area of motion planning, considerable work has been done on guarding problems, where “guards”, modelled as points, must guard a polygonal space from “intruders”. Different variants of this problem involve varying a number of factors. The guards performing the search may vary in terms of their number, their mobility, and their range of vision. The model of intruders may or may not allow t...

We study the problem of finding optimal covers of polygonal regions using multiple mobile guards. By our definition, a point is covered if, at some time, it lies within the convex hull of the guards from which it is visible. The definition captures our desire that guards both “see” and “surround” points that they cover. Guards move along continuous timeparameterized curves within a polygonal re...

A revolutionary entrepreneur strategically chooses the revolutionary agenda to maximize the likelihood of revolution. Citizens have different preferences and can contribute varying degrees of support. This presents the revolutionary entrepreneur with a tradeoff between extensive and intensive margins of support. We show: (1) Extremists exert a disproportionate influence over the revolutionary a...

BACKGROUND The participation of children and adolescents in sports, including basketball, is becoming increasingly common, and this increased involvement raises concerns about the potential risk of sports injuries. OBJECTIVE To analyze the occurrence of sports injuries among young basketball players according to their position on the court and to associate these injuries with risk factors. ...

Workflow management systems (WfMSs) frequently use data to coordinate the execution of workflow instances. A WfMS evaluates conditions defined on data to make the control flow decisions i.e. selecting the next activity or deciding on an actor. However, data within and outside of a running workflow instance may change dynamically. Modifications of data needed for past control flow decisions may ...