Results 1  10
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13
VLSI cell placement techniques
 ACM Computing Surveys
, 1991
"... VLSI cell placement problem is known to be NP complete. A wide repertoire of heuristic algorithms exists in the literature for efficiently arranging the logic cells on a VLSI chip. The objective of this paper is to present a comprehensive survey of the various cell placement techniques, with emphasi ..."
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VLSI cell placement problem is known to be NP complete. A wide repertoire of heuristic algorithms exists in the literature for efficiently arranging the logic cells on a VLSI chip. The objective of this paper is to present a comprehensive survey of the various cell placement techniques, with emphasis on standard ce11and macro
Local Search for the Steiner Tree Problem in the Euclidean Plane
 EUROPEAN J. OPER. RES
, 1997
"... Most heuristics for the Steiner tree problem in the Euclidean plane perform a series of iterative improvements using the minimum spanning tree as an initial solution. We may therefore characterize them as local search heuristics. In this paper, we first give a survey of existing heuristic approa ..."
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Cited by 8 (2 self)
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Most heuristics for the Steiner tree problem in the Euclidean plane perform a series of iterative improvements using the minimum spanning tree as an initial solution. We may therefore characterize them as local search heuristics. In this paper, we first give a survey of existing heuristic approaches from a local search perspective, by setting up solution spaces and neighbourhood structures. Secondly, we present a new general local search approach which is based on a list of full Steiner trees constructed in a preprocessing phase. This list defines a solution space on which three neighbourhood structures are proposed and evaluated. Computational results show that this new approach is very competitive from a costbenefit point of view. Furthermore, it has the advantage of being easy to apply to the Steiner tree problem in other metric spaces and to obstacle avoiding variants.
On the Steiner ratio in 3space
 J. of Combinatorial Theory, A
, 1992
"... The "Steiner minimal tree" (SMT) of a point set P is the shortest network of "wires" which will suffice to "electrically" interconnect P . The "minimum spanning tree" (MST) is the shortest such network when only intersite line segments are permitted. The "Steiner ratio" ae(P ) of a point set P is th ..."
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Cited by 7 (1 self)
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The "Steiner minimal tree" (SMT) of a point set P is the shortest network of "wires" which will suffice to "electrically" interconnect P . The "minimum spanning tree" (MST) is the shortest such network when only intersite line segments are permitted. The "Steiner ratio" ae(P ) of a point set P is the length of its SMT divided by the length of its MST. It is of interest to understand which point set (or point sets) in R d have minimal Steiner ratio. In this paper, we introduce a point set in R d which we call the "ddimensional sausage." The 1 and 2dimensional sausages have minimal Steiner ratios 1 and p 3=2 respectively. (The 2sausage is the vertex set of an infinite strip of abutting equilateral triangles. The 3sausage is an infinite number of points evenly spaced along a certain helix.) We present extensive heuristic evidence to support the conjecture that the 3sausage also has minimal Steiner ratio (ß 0:784190373377122). Also: We prove that the regular tetrahedron minimize...
Steiner Tree Problems
, 2000
"... this article, we will review important developments in 1990s and discuss some open problems which may induce important developments in this centrary ..."
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Cited by 7 (4 self)
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this article, we will review important developments in 1990s and discuss some open problems which may induce important developments in this centrary
Selfprotection for wireless sensor networks
 in Proc. ofthe 26thIEEE International Conference on Distributed Computing Systems (ICDCS'06
, 2006
"... Dynamic proxy treebased data dissemination schemes ..."
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Cited by 7 (2 self)
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Dynamic proxy treebased data dissemination schemes
CAMPINO  A skeletonization method for point cloud processing
 ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
, 2007
"... Available online at www.sciencedirect.com ..."
ConcatenationBased Greedy Heuristics for the Euclidean Steiner Tree Problem
 Algorithmica
, 1997
"... We present a class of O(n log n) heuristics for the Steiner tree problem in the Euclidean plane. These heuristics identify a small number of subsets with few, geometrically close, terminals using minimum spanning trees and other wellknown structures from computational geometry: Delaunay triangulati ..."
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Cited by 3 (2 self)
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We present a class of O(n log n) heuristics for the Steiner tree problem in the Euclidean plane. These heuristics identify a small number of subsets with few, geometrically close, terminals using minimum spanning trees and other wellknown structures from computational geometry: Delaunay triangulations, Gabriel graphs, relative neighbourhood graphs, and higherorder Voronoi diagrams. Full Steiner trees of all these subsets are sorted according to some appropriately chosen measure of quality. A tree spanning all terminals is constructed using greedy concatenation. New heuristics are compared with each other and with heuristics from the literature by performing extensive computational experiments on both randomly generated and library problem instances. Keywords: heuristics, Steiner trees 1 Introduction Given a set Z of n terminals in the Euclidean plane, a shortest network which interconnects Z is called a Steiner minimum tree (SMT). An SMT may contain additional intersection points, ...
Analysis of greedy approximations with nonsubmodular potential functions
"... In this paper, we present two techniques to analyze greedy approximation with nonsubmodular functions restricted submodularity and shifted submodularity. As an application of the restricted submodularity, we present a worstcase analysis of a greedy algorithm for Network Steiner tree adapted from a ..."
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In this paper, we present two techniques to analyze greedy approximation with nonsubmodular functions restricted submodularity and shifted submodularity. As an application of the restricted submodularity, we present a worstcase analysis of a greedy algorithm for Network Steiner tree adapted from a heuristic originally proposed by Chang in 1972 for Euclidean Steiner tree. The performance ratio of Chang’s heuristic is a longstanding open problem due to the nonsubmodularity of its potential function. As an application of the shifted submodularity, we present a worstcase analysis of a greedy algorithm for Connected Dominating Set generalized from a greedy algorithm proposed by Ruan et al. Such generalized greedy algorithm is shown to have performance ratio at most (1 + ε)(1 + ln( ∆ − 1)), which matches the wellknown lower bound (1−ε)ln ∆, where ∆ is the maximum vertexdegree of input graph and ε is any positive constant.
Steiner Trees and Beyond: Approximation Algorithms for Network Design
, 1993
"... We present approximation algorithms for several NPhard optimization problems arising in network design. Almost all of our algorithms run in polynomial time and output solutions with a worstcase performance guarantee on the quality of the output solution. A typical problem that we consider can be s ..."
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Cited by 3 (1 self)
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We present approximation algorithms for several NPhard optimization problems arising in network design. Almost all of our algorithms run in polynomial time and output solutions with a worstcase performance guarantee on the quality of the output solution. A typical problem that we consider can be stated as follows: given an undirected graph and certain connectivity requirements, find a subgraph that satisfies these requirements and has minimum cost. In this thesis, we address many different connectivity requirements such as spanning trees, Steiner trees, generalized Steiner forests, and twoconnected networks. The cost criteria that we consider range from the total cost of the edges in the network, the total cost of the nodes in the network, the maximum degree of any node in the network, the maximum cost of any edge in the network to some combination of these. We also address the maximumleaf spanning tree problem and provide the first approximation algorithms for this problem. In t...
Algorithms for Plane Steiner Tree Problems
, 1998
"... Topological network design is the process of planning the layout of a network subject to constraints on topology. Applications include the design of transportation and communication networks where the construction costs typically are associated with the nodes and/or edges of the network. The Steiner ..."
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Topological network design is the process of planning the layout of a network subject to constraints on topology. Applications include the design of transportation and communication networks where the construction costs typically are associated with the nodes and/or edges of the network. The Steiner tree problem is one of the fundamental topological network design problems. The problem is to interconnect (a subset of) the nodes such that there is a path between every pair of nodes while minimizing the total cost of selected edges. Originally, the Steiner tree problem was stated as a purely geometric problem: Given a set of points (terminals) in the plane, construct a tree interconnecting all terminals such that the total length of all line segments is minimized. In the Euclidean Steiner tree problem, the length of a line segment is the usual Euclidean (or L 2 ) distance between the endpoints of the segment. Correspondingly, in the rectilinear Steiner tree problem distances are measured...