The cycle packing number ve(G) of a graph G is the maximum number of pairwise edgedisjointcycles in G. Computing ve(G) is an NP-hard *** present approximation algorithms for computing v e(G) in both undirected and dir...
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The cycle packing number ve(G) of a graph G is the maximum number of pairwise edgedisjointcycles in G. Computing ve(G) is an NP-hard *** present approximation algorithms for computing v e(G) in both undirected and directed graphs. In the undirected case we analyze a variant of the modified greedy algorithm suggested by Caprara et al. [2003] and showthat it has approximation ratio Θ(√log n), where n = |V(G)|. This improves upon the previous O(log n) upper bound for the approximation ratio of this algorithm. In the directed case we present √n-approximation algorithm. Finally, we give an O(n2/3)- approximation algorithm for the problem of finding a maximum number of edge-disjoint cycles that intersect a specified subset S of *** also study generalizations of these problems. Our approximation ratios are the currently best-known ones and, in addition, provide upper bounds on the integrality gap of standard LP-relaxations of these problems. In addition, we give ower bounds for the integrality gap and approximability of ve(G) in directed graphs. Specifically, we prove a lower bound of Ω( log n log log n) for the integrality gap of edge-disjoint cycle packing. We also show that it is quasi-NP-hard to approximate ve(G) within a factor of O(log1-Ε n) for any constant Ε > 0. This improves upon the previously known APX-hardness result for this problem.
In this paper we consider the following time constrained scheduling problem. Given a set of jobs J with execution times e(j) E (0, 1] and an undirected graph G = (J, E), we consider the problem to find a schedule for ...
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This paper studies the stochastic variant of the classical k-TSP problem where rewards at the vertices are independent random variables which are instantiated upon the tour’s visit. The objective is to minimize the e...
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We consider a generalization of the connected facility location problem where the clients must be connected to the open facilities via shared capacitated (tree) networks instead of independent shortest paths. This pro...
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In role based access control (RBAC), minimizing the descriptive set of roles (specified as Basic-RMP) and minimizing the administrative assignments for roles (specified as Edge-RMP) can greatly decrease the management...
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We give a polynomial-time(formula presented)-approximation algorithm for minimum-time broadcast and minimum-time multicast in n-node networks under the single-port vertex-disjoint paths mode. This improves a previous ...
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k orthogonal line center problem computes a set of k axis-parallel lines for a given set of points in 2D such that the maximum among the distance between each point to its nearest line is minimized. A 2-factor approxi...
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We study the problem of routing and scheduling requests of limited durations in an all-optical network. The task is servicing the requests, assigning each of them a starting time and a wavelength, with restrictions on...
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We address the problem of finding viewpoints that preserve the relational structure of a three-dimensional graph drawing under orthographic parallel projection. Previously, algorithms for finding the best viewpoints u...
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The dominating set problem in graphs asks for a minimum size subset of vertices with the following property: each vertex is required to either be in the dominating set, or adjacent to at least one node in the dominati...
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