Illumination by floodlights
نویسندگان
چکیده
منابع مشابه
Illumination by floodlights
We consider three problems about the illumination of planar regions with oodlights of prescribed angles. Problem 1 is the decision problem: given a wedge W of angle , n points p 1 ; ; p n in the plane and n angles 1 ; ; n summing up to , decide whether W can be illuminated by oodlights of angles 1 ; ; n placed in some order at the points p 1 ; ; p n and then rotated appropriately. We show that ...
متن کاملIllumination with Orthogonal Floodlights ? (extended Abstract)
We provide the rst tight bound for covering a polygon with n vertices and h holes with vertex guards. In particular, we provide tight bounds for the number of oodlights, placed at vertices or on the boundary , suucient to illuminate the interior or the exterior of an orthogonal polygon with holes. Our results lead directly to simple linear, and thus optimal, algorithms for computing a covering ...
متن کاملContinuous Surveillance of Points by Rotating Floodlights
Let P and F be sets of n ≥ 2 and m ≥ 2 points in the plane, respectively, so that P ∪ F is in general position. In this paper we study the problem of finding the minimum angle α ∈ [2π/m, 2π] such that one can install at each point of F a stationary rotating floodlight with illumination angle α, initially oriented in some direction, in such a way every target point of P is illuminated at any tim...
متن کاملContinuous Surveillance of Points by rotating Floodlights
Let P and F be sets of n ≥ 2 and m ≥ 2 points in a plane, respectively. We study the problem of finding the minimum angle α ∈ [2π/m, 2π] such that one can install at each point of F a stationary rotating floodlight with illumination angle α, initially oriented in a suitable direction, in such a way that, at all times, every target point of P is illuminated by at least one floodlight. All floodl...
متن کاملThe Inapproximability of Illuminating Polygons by α-Floodlights
We consider variants of the art gallery problem where guard visibility is limited to a certain angular aperture α. We show that the problem is NP-hard even when guards can be located in the interior of the polygon. We then proceed to prove that both this problem and its vertex variant, where guard placement is restricted to the vertices of the polygon, are APX-hard. We observe that earlier cons...
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ژورنال
عنوان ژورنال: Computational Geometry
سال: 1998
ISSN: 0925-7721
DOI: 10.1016/s0925-7721(97)00027-8