Cutting out cancers
نویسندگان
چکیده
منابع مشابه
Cutting Out Polygons
In this paper, we present approximation algorithms for the problem of cutting out a convex polygon P with n vertices from another convex polygon Q with m vertices by a sequence of guillotine cuts of smallest total length. Specifically, we give an O(n + m) running time, constant factor approximation algorithm, and an O(n+m) running time, O(log n)-factor approximation algorithm for cutting P out ...
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To establish a lysogenic lifestyle, the temperate bacteriophage φC31 integrates its genome into the chromosome of its Streptomyces host, by site-specific recombination between attP (the attachment site in the phage DNA) and attB (the chromosomal attachment site). This reaction is promoted by a phage-encoded serine recombinase Int. To return to the lytic lifestyle, the prophage excises its DNA b...
متن کاملCutting Out Polygons with a Circular Saw
Given a simple (cuttable) polygon Q drawn on a piece of planar material R, we cut Q out of R by a (small) circular saw with a total number of cuts no more than twice the optimal. This improves the previous approximation ratio of 2.5 obtained by Demaine et al. in 2001.
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I) Given a segment-cuttable polygon P drawn on a planar piece of material Q, we show how to cut P out of Q by a (short) segment saw with a total length of the cuts no more than 2.5 times the optimal. We revise the algorithm of Demaine et al. (2001) so as to achieve this ratio. (II) We prove that any collection R of n disjoint1 axis-parallel rectangles drawn on a planar piece of material Q is cu...
متن کاملCutting Out Polygons with Lines and Rays
We present approximation algorithms for cutting out polygons with line cuts and ray cuts. Our results answer a number of open problems and are either the first solutions or significantly improve over previously known solutions. For the line cutting version, we prove a key property that leads to a simple, constant factor approximation algorithm. For the ray cutting version, we prove it is possib...
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ژورنال
عنوان ژورنال: Nature
سال: 1975
ISSN: 0028-0836,1476-4687
DOI: 10.1038/258094a0