Complexity analysis and algorithms for the Program Download Problem

In this paper, we consider the Program Download Problem (PDP) which is to download a set of desired programs from multiple channels. When the problem is to decide whether the download can be done by a given deadline d and each program appears in each of the n channels at most once, denoted as PDP (...

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Vydané v:Journal of combinatorial optimization Ročník 29; číslo 1; s. 216 - 227
Hlavní autori: Peng, Chao, Zhou, Jie, Zhu, Binhai, Zhu, Hong
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Boston Springer US 01.01.2015
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ISSN:1382-6905, 1573-2886
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Shrnutí:In this paper, we consider the Program Download Problem (PDP) which is to download a set of desired programs from multiple channels. When the problem is to decide whether the download can be done by a given deadline d and each program appears in each of the n channels at most once, denoted as PDP ( n , 1 , d ) , we prove that PDP ( n , 1 , d ) is NP-complete by a reduction from 3-SAT(3). We can extend the NP-hardness proof to PDP ( 2 , 3 , d ) where there are only two channels but each program could appear in each channel at most 3 times, although PDP ( 2 , 1 , d ) and PDP ( 2 , 2 , d ) are both in P . We show that the aligned version of the problem (APDP) is polynomially solvable by reducing it to a maximum flow problem. For a different version of the problem, MPDP, where the objective is to maximize the number of program downloaded before a given deadline d , we prove that it is fixed-parameter tractable. Finally, we devise an approximation algorithm for MPDP ( 2 , p , d ) , p ≥ 3 , which aims to maximize the number of desired programs downloaded in two channels.
ISSN:1382-6905
1573-2886
DOI:10.1007/s10878-013-9702-0