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NodeWeighted Steiner Tree and Group Steiner Tree in Planar Graphs
"... Abstract. We improve the approximation ratios for two optimization problems in planar graphs. For nodeweighted Steiner tree, a classical networkoptimization problem, the best achievable approximation ratio in general graphs is Θ(log n), and nothing better was previously known for planar graphs. We ..."
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Cited by 22 (1 self)
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Abstract. We improve the approximation ratios for two optimization problems in planar graphs. For nodeweighted Steiner tree, a classical networkoptimization problem, the best achievable approximation ratio in general graphs is Θ(log n), and nothing better was previously known for planar graphs
Online Nodeweighted Steiner . . .
"... We obtain the first online algorithms for the nodeweighted Steiner tree, Steiner forest and group Steiner tree problems that achieve a polylogarithmic competitive ratio. Our algorithm for the Steiner tree problem runs in polynomial time, while those for the other two problems take quasipolynomia ..."
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We obtain the first online algorithms for the nodeweighted Steiner tree, Steiner forest and group Steiner tree problems that achieve a polylogarithmic competitive ratio. Our algorithm for the Steiner tree problem runs in polynomial time, while those for the other two problems take quasi
NodeWeighted Prize Collecting Steiner Tree and Applications
"... I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii The Steiner Tree problem has appeared in the Karp’s li ..."
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list of the first 21 NPhard problems and is well known as one of the most fundamental problems in Network Design area. We study the NodeWeighted version of the Prize Collecting Steiner Tree problem. In this problem, we are given a simple graph with a cost and penalty value associated with each node
A nearly bestpossible approximation algorithm for nodeweighted Steiner trees
, 1993
"... We give the first approximation algorithm for the nodeweighted Steiner tree problem. Its performance guarantee is within a constant factor of the best possible unless ~ P ' NP . Our algorithm generalizes to handle other network design problems. ..."
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Cited by 139 (11 self)
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We give the first approximation algorithm for the nodeweighted Steiner tree problem. Its performance guarantee is within a constant factor of the best possible unless ~ P ' NP . Our algorithm generalizes to handle other network design problems.
A ptas for nodeweighted steiner tree in unit disk graphs
 in COCOA, 2009
"... Abstract. The nodeweighted Steiner tree problem is a variation of classical Steiner minimum tree problem. Given a graph G =(V,E)withnode weight function C: V → R + and a subset X of V, the nodeweighted Steiner tree problem is to find a Steiner tree for the set X such that its total weight is minim ..."
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Cited by 1 (0 self)
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Abstract. The nodeweighted Steiner tree problem is a variation of classical Steiner minimum tree problem. Given a graph G =(V,E)withnode weight function C: V → R + and a subset X of V, the nodeweighted Steiner tree problem is to find a Steiner tree for the set X such that its total weight
Packing Steiner trees
"... The Steiner packing problem is to find the maximum number of edgedisjoint subgraphs of a given graph G that connect a given set of required points S. This problem is motivated by practical applications in VLSIlayout and broadcasting, as well as theoretical reasons. In this paper, we study this p ..."
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Cited by 106 (5 self)
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this problem and present an algorithm with an asymptotic approximation factor of S/4. This gives a sufficient condition for the existence of k edgedisjoint Steiner trees in a graph in terms of the edgeconnectivity of the graph. We will show that this condition is the best possible if the number
Approximation schemes for nodeweighted geometric Steiner tree problems
"... Abstract. In this paper we introduce a new technique for approximation schemes for geometrical optimization problems. As an example problem, we consider the following variant of the geometric Steiner tree problem. Every point u which is not included in the tree costs a penalty of pi(u) units. Furth ..."
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Cited by 1 (0 self)
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Abstract. In this paper we introduce a new technique for approximation schemes for geometrical optimization problems. As an example problem, we consider the following variant of the geometric Steiner tree problem. Every point u which is not included in the tree costs a penalty of pi(u) units
Graph Theory
 MATHEMATISCHES FORSCHUNGSINSTITUT OBERWOLFACH REPORT NO. 16/2007
, 2007
"... This week broadly targeted both finite and infinite graph theory, as well as matroids, including their interaction with other areas of pure mathematics. The talks were complemented by informal workshops focussing on specific problems or particularly active areas. ..."
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Cited by 1203 (5 self)
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This week broadly targeted both finite and infinite graph theory, as well as matroids, including their interaction with other areas of pure mathematics. The talks were complemented by informal workshops focussing on specific problems or particularly active areas.
A polylogarithmic approximation algorithm for the group Steiner tree problem
 Journal of Algorithms
, 2000
"... The group Steiner tree problem is a generalization of the Steiner tree problem where we ae given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimumweight connected subgraph containing at least one vertex from each group. The problem was introduced by Reich a ..."
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Cited by 155 (10 self)
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The group Steiner tree problem is a generalization of the Steiner tree problem where we ae given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimumweight connected subgraph containing at least one vertex from each group. The problem was introduced by Reich
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