منابع مشابه
Flying over a polyhedral terrain
We consider the problem of computing shortest paths in three-dimensions in the presence of a single-obstacle polyhedral terrain, and present a new algorithm that for any p ≥ 1, computes a (c + ε)approximation to the Lp-shortest path above a polyhedral terrain in O( ε log n log log n) time and O(n log n) space, where n is the number of vertices of the terrain, and c = 2(p−1)/p. This leads to a F...
متن کاملGeodesic Spanners for Points on a Polyhedral Terrain
Let S be a set S of n points on a polyhedral terrain T in R, and let ε > 0 be a fixed constant. We prove that S admits a (2 + ε)-spanner with O(n log n) edges with respect to the geodesic distance. This is the first spanner with constant spanning ratio and a near-linear number of edges for points on a terrain. On our way to this result, we prove that any set of n weighted points in R admits an ...
متن کاملPractical Approaches to Partially Guarding a Polyhedral Terrain
We study the problem of placing guard towers on a terrain such that the terrain can be seen from at least one tower. This problem is important in many applications, and has an extensive history in the literature (known as, e.g., multiple observer siting). In this paper, we consider the problem on polyhedral terrains, and we allow the guards to see only a fixed fraction of the terrain, rather th...
متن کاملPlacing observers to cover a polyhedral terrain in polynomial time
The Art Gallery Problem is the problem of determining the number of observers necessary to cover an art gallery room such that every point is seen by at least one observer. This problem is well known and has a linear solution for the 2 dimensional case, but little is known in the 3-D case. In this paper we present a polynomial time solution for the 3-D version of the Art Gallery Problem. Becaus...
متن کاملRecirculation over complex terrain
This study generated eddy covariance data to investigate atmospheric dynamics leeward of a small, forested hillside in upstate New York. The causes and effects of recirculation eddies were examined to support the larger goal of improving measurement of the exchange of energy, moisture, and trace gases between the terrestrial biosphere and the atmosphere over complex terrain. Sensors operated at...
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ژورنال
عنوان ژورنال: Information Processing Letters
سال: 2008
ISSN: 0020-0190
DOI: 10.1016/j.ipl.2007.08.008