We consider two-cost network design models in which edges of the input graph have an associated cost and length. We build upon recent advances in hop-constrained oblivious routing to obtain two sets of results. We add...
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We study two problems for a given n-point set in 3-space: Finding a largest subset with diameter at most one, and finding a subset of k points with minimum diameter. For the former problem we suggest several polynomia...
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In the aversion k-clustering problem, given a metric space, we want to cluster the points into k clusters. The cost incurred by each point is the distance to the furthest point in its cluster, and the cost of the clus...
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ISBN:
(纸本)9783959770132
In the aversion k-clustering problem, given a metric space, we want to cluster the points into k clusters. The cost incurred by each point is the distance to the furthest point in its cluster, and the cost of the clustering is the sum of all these per-point-costs. This problem is motivated by questions in generating automatic abstractions of extensive-form games. We reduce this problem to a "local" k-median problem where each facility has a prescribed radius and can only connect to clients within that radius. Our main results is a constant-factor approximation algorithm for the aversion k-clustering problem via the local k-median problem. We use a primal-dual approach;our technical contribution is a non-local rounding step which we feel is of broader interest.
Malleable tasks consist in considering the tasks of a parallel program as large computational units that may be themselves parallelized. In this paper we investigate the problem of scheduling a set of n independent ma...
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In this paper, we study the maximum bounded connected bipartition problem (2-BCBP): given a vertex-weighted connected graph G= (V, E; w) and an upper bound B, the vertex set V is partitioned into two subsets denoted a...
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A mixed shop is to process a mixture of a set of flow-shop jobs and a set of open-shop jobs. Mixed shops are in general much harder than flow-shops and open-shops, and have been studied since the 1980’s. We consider ...
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We present a 2-approximation algorithm for a class of directed network design problems. The network design problem is to find a minimum cost subgraph such that for each vertex set S there are at least f(S) arcs leavin...
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The Generalized Traveling Salesman Problem (GTSP) is a generalization of the well known Traveling Salesman Problem (TSP), where along with a weighted graph G = (V, E, w) we are given by a partition of its node set V =...
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In recent years, data examples have been at the core of several different approaches to schema-mapping design. In particular, Gottlob and Senellart introduced a framework for schema-mapping discovery from a single dat...
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In recent years, data examples have been at the core of several different approaches to schema-mapping design. In particular, Gottlob and Senellart introduced a framework for schema-mapping discovery from a single data example, in which the derivation of a schema mapping is cast as an optimization problem. Our goal is to refine and study this framework in more depth. Among other results, we design a polynomial-time log(n)- approximation algorithm for computing optimal schema mappings from a given data example, for a restricted class of schema mappings;moreover, we show that this approximation ratio cannot be improved.
We present an O(√nlogn)-approximation algorithm for the problem of finding the sparsest spanner of a given directed graph G on n vertices. A spanner of a graph is a sparse subgraph that approximately preserves distan...
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