A Simple Approximation Algorithm for Nonoverlapping Local Alignments (Weighted Independent Sets of Axis Parallel Rectangles)

Biocomputing ◽  
2002 ◽  
pp. 129-138 ◽  
Author(s):  
Piotr Berman ◽  
Bhaskar DasGupta
Keyword(s):  
Approximation Algorithm ◽  
Independent Sets ◽  
Simple Approximation ◽  
Axis Parallel

scholarly journals FINDING PLANAR REGIONS IN A TERRAIN – IN PRACTICE AND WITH A GUARANTEE

2005 ◽  
Vol 15 (04) ◽  
pp. 379-401 ◽  
Author(s):  
STEFAN FUNKE ◽  
THEOCHARIS MALAMATOS ◽  
RAHUL RAY
Keyword(s):  
Approximation Algorithm ◽  
Unit Disk ◽  
Related Problem ◽  
Linear Time ◽  
Real Data ◽  
Simple Approximation ◽  
Data Sets ◽  
Fixed Angle ◽  
Planar Regions

We consider the problem of computing large connected regions in a triangulated terrain of size n for which the normals of the triangles deviate by at most some small fixed angle. In previous work an exact near-quadratic algorithm was presented, but only a heuristic implementation with no guarantee was practicable. We present a new approximation algorithm for the problem which runs in O(n/∊2) time and—apart from giving a guarantee on the quality of the produced solution—has been implemented and shows good performance on real data sets representing fracture surfaces consisting of around half a million triangles. Further we present a simple approximation algorithm for a related problem: given a set of n points in the plane, determine the placement of the unit disk which contains most points. This algorithm runs in linear time as well.

Feasibility study of a simple approximation algorithm for in-vivo dose reconstruction by using the transit dose measured using an EPID

2015 ◽  
Vol 66 (4) ◽  
pp. 694-699 ◽  
Author(s):  
Ui-Jung Hwang ◽  
Mi Hee Song ◽  
Tae Seong Baek ◽  
Eun Ji Chung ◽  
Myonggeun Yoon
Keyword(s):  
Approximation Algorithm ◽  
Feasibility Study ◽  
Simple Approximation ◽  
Dose Reconstruction ◽  
Transit Dose

scholarly journals An experimental analysis on the similarity of argumentation semantics

2020 ◽  
Vol 11 (3) ◽  
pp. 269-304
Author(s):  
Federico Cerutti ◽  
Matthias Thimm ◽  
Mauro Vallati
Keyword(s):  
Approximation Algorithm ◽  
Experimental Analysis ◽  
Learning Phase ◽  
Decision Problems ◽  
Simple Approximation ◽  
Approximation Approach ◽  
Abstract Argumentation ◽  
Grounded Semantics ◽  
Theoretical Results

In this paper we ask whether approximation for abstract argumentation is useful in practice, and in particular whether reasoning with grounded semantics – which has polynomial runtime – is already an approximation approach sufficient for several practical purposes. While it is clear from theoretical results that reasoning with grounded semantics is different from, for example, skeptical reasoning with preferred semantics, we investigate how significant this difference is in actual argumentation frameworks. As it turns out, in many graphs models, reasoning with grounded semantics actually approximates reasoning with other semantics almost perfectly. An algorithm for grounded reasoning is thus a conceptually simple approximation algorithm that not only does not need a learning phase – like recent approaches – but also approximates well – in practice – several decision problems associated to other semantics.

SEPARATING POINTS BY AXIS-PARALLEL LINES

2005 ◽  
Vol 15 (06) ◽  
pp. 575-590 ◽  
Author(s):  
GRUIA CĂLINESCU ◽  
ADRIAN DUMITRESCU ◽  
HOWARD KARLOFF ◽  
PENG-JUN WAN
Keyword(s):  
Approximation Algorithm ◽  
Separation Problem ◽  
Lp Rounding ◽  
Parallel Lines ◽  
Point Separation ◽  
Axis Parallel ◽  
Minimum Number ◽  
Np Hardness

We study the problem of separating n points in the plane, no two of which have the same x- or y-coordinate, using a minimum number of vertical and horizontal lines avoiding the points, so that each cell of the subdivision contains at most one point. Extending previous NP-hardness results due to Freimer et al. we prove that this problem and some variants of it are APX-hard. We give a 2-approximation algorithm for this problem, and a d-approximation algorithm for the d-dimensional variant, in which the points are to be separated using axis-parallel hyperplanes. To this end, we reduce the point separation problem to the rectangle stabbing problem studied by Gaur et al. Their approximation algorithm uses LP-rounding. We present an alternative LP-rounding procedure which also works for the rectangle stabbing problem. We show that the integrality ratio of the LP is exactly 2.

A Simple Approximation Algorithm for Computing Arrow-Debreu Prices

2012 ◽  
Vol 60 (5) ◽  
pp. 1245-1248 ◽  
Author(s):  
Mehdi Ghiyasvand ◽  
James B. Orlin
Keyword(s):  
Approximation Algorithm ◽  
Simple Approximation
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