The Experts below are selected from a list of 855 Experts worldwide ranked by ideXlab platform
Burkhard Monien - One of the best experts on this subject based on the ideXlab platform.
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Upper bounds on the Bisection Width of 3- and 4-regular graphs
Journal of Discrete Algorithms, 2006Co-Authors: Burkhard Monien, Robert PreisAbstract:Abstract We derive new upper bounds on the Bisection Width of graphs which have a regular vertex degree. We show that the Bisection Width of sufficiently large 3-regular graphs with | V | vertices is at most ( 1 6 + e ) | V | , e > 0 . For the Bisection Width of sufficiently large 4-regular graphs we show an upper bound of ( 2 5 + e ) | V | , e > 0 .
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New spectral lower bounds on the Bisection Width of graphs
Theoretical Computer Science, 2004Co-Authors: S. Bezrukov, Burkhard Monien, Robert Preis, R. Elsässer, J.-p. TillichAbstract:AbstractThe communication overhead is a major bottleneck for the execution of a process graph on a parallel computer system. In the case of two processors, the minimization of the communication can be modeled using the graph Bisection problem. The spectral lower bound of λ2|V|/4 for the Bisection Width of a graph is widely known. The Bisection Width is equal to λ2|V|/4 iff all vertices are incident to λ2/2 cut edges in every optimal Bisection.We present a new method of obtaining tighter lower bounds on the Bisection Width. This method makes use of the level structure defined by the Bisection. We define some global expansion properties and we show that the spectral lower bound increases with this global expansion. Under certain conditions we obtain a lower bound depending on λ2β|V| with 12⩽β
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MFCS - Upper Bounds on the Bisection Width of 3- and 4-Regular Graphs
Mathematical Foundations of Computer Science 2001, 2001Co-Authors: Burkhard Monien, Robert PreisAbstract:We derive new upper bounds on the Bisection Width of graphs which have a regular vertex degree. We show that the Bisection Width of large 3-regular graphs with |V| vertices is at most 1/6 |V|. For the Bisection Width of large 4-regular graphs we show an upper bound of 2/5 |V|.
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upper bounds on the Bisection Width of 3 and 4 regular graphs
Mathematical Foundations of Computer Science, 2001Co-Authors: Burkhard Monien, Robert PreisAbstract:We derive new upper bounds on the Bisection Width of graphs which have a regular vertex degree. We show that the Bisection Width of large 3-regular graphs with |V| vertices is at most 1/6 |V|. For the Bisection Width of large 4-regular graphs we show an upper bound of 2/5 |V|.
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WG - New Spectral Lower Bounds on the Bisection Width of Graphs
Graph-Theoretic Concepts in Computer Science, 2000Co-Authors: S. Bezrukov, Burkhard Monien, Robert Preis, R. Elsässer, J.-p. TillichAbstract:The communication overhead is a major bottleneck for the execution of a process graph on a parallel computer system. In the case of two processors, the minimization of the communication can be modeled by the graph Bisection problem. The spectral lower bound of λ2|V|/4 for the Bisection Width of a graph is well-known. The Bisection Width is equal to λ2|V|/4 iff all vertices are incident to λ2/2 cut edges in every optimal Bisection. We discuss the case for which this fact is not satisfied and present a new method to get tighter lower bounds on the Bisection Width. This method makes use of the level structure defined by the Bisection. Under certain conditions we get a lower bound depending on λ2β|V| with 1/2 ≤ β < 1. We also present examples of graphs for which our new bounds are tight up to a constant factor. As a by-product, we derive new lower bounds for the Bisection Widths of 3- and 4-regular graphs. We use them to establish tighter lower bounds for the Bisection Width of 3- and 4-regular Ramanujan graphs.
Nicholas C. Wormald - One of the best experts on this subject based on the ideXlab platform.
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Minimum Power Dominating Sets of Random Cubic Graphs
Journal of Graph Theory, 2016Co-Authors: Liying Kang, Nicholas C. WormaldAbstract:We present two heuristics for finding a small power dominating set of cubic graphs. We analyze the performance of these heuristics on random cubic graphs using differential equations. In this way, we prove that the proportion of vertices in a minimum power dominating set of a random cubic graph is asymptotically almost surely at most 0.067801. We also provide a corresponding lower bound of using known results on Bisection Width.
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Bounds on the Bisection Width for random d -regular graphs
Theoretical Computer Science, 2007Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the Bisection Width of random d-regular graphs, for any value of d. The upper bounds are obtained from the analysis of the performance of a randomized greedy algorithm to find Bisections of d-regular graphs. We provide bounds for 5≤d≤12. We also give empirical values of the size of the Bisection found by the algorithm for some small values of d and compare them with numerical approximations of our theoretical bounds. Our analysis also gives asymptotic lower bounds for the size of the maximum Bisection.
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Computation of the Bisection Width for random d-regular graphs
Lecture Notes in Computer Science, 2004Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the Bisection Width of random d-regular graphs, for any value of d. We provide the bounds for 5 < d < 12. The upper bounds are obtained from the analysis of the performance of a randomized greedy algorithm to find Bisections of d-regular graphs. We also give empirical values of the size of Bisection found by the algorithm for some small values of d and compare it with numerical approximations of our theoretical bounds. Our analysis also gives asymptotic lower bounds for the size of the maximum Bisection.
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LATIN - Computation of the Bisection Width for Random d-Regular Graphs
LATIN 2004: Theoretical Informatics, 2004Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the Bisection Width of random d-regular graphs, for any value of d. We provide the bounds for 5 ≤ d ≤ 12. The upper bounds are obtained from the analysis of the performance of a randomized greedy algorithm to find Bisections of d-regular graphs. We also give empirical values of the size of Bisection found by the algorithm for some small values of d and compare it with numerical approximations of our theoretical bounds. Our analysis also gives asymptotic lower bounds for the size of the maximum Bisection.
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Bounds on the max and min Bisection of random cubic and random 4-regular graphs
Theoretical Computer Science, 2003Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper, we present a randomized algorithm to compute the Bisection Width of cubic and 4-regular graphs. The analysis of the proposed algorithms on random graphs provides asymptotic upper bounds for the Bisection Width of random cubic and random 4-regular graphs with n vertices, giving upper bounds of 0.174039n for random cubic, and of 0.333333n for random 4-regular. We also obtain asymptotic lower bounds for the size of the maximum Bisection, for random cubic and random 4-regular graphs with n vertices, of 1.32697n and 1.66667n, respectively. The randomized algorithms are derived from initial greedy algorithm and their analysis is based on the differential equation method.
Robert Preis - One of the best experts on this subject based on the ideXlab platform.
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Upper bounds on the Bisection Width of 3- and 4-regular graphs
Journal of Discrete Algorithms, 2006Co-Authors: Burkhard Monien, Robert PreisAbstract:Abstract We derive new upper bounds on the Bisection Width of graphs which have a regular vertex degree. We show that the Bisection Width of sufficiently large 3-regular graphs with | V | vertices is at most ( 1 6 + e ) | V | , e > 0 . For the Bisection Width of sufficiently large 4-regular graphs we show an upper bound of ( 2 5 + e ) | V | , e > 0 .
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New spectral lower bounds on the Bisection Width of graphs
Theoretical Computer Science, 2004Co-Authors: S. Bezrukov, Burkhard Monien, Robert Preis, R. Elsässer, J.-p. TillichAbstract:AbstractThe communication overhead is a major bottleneck for the execution of a process graph on a parallel computer system. In the case of two processors, the minimization of the communication can be modeled using the graph Bisection problem. The spectral lower bound of λ2|V|/4 for the Bisection Width of a graph is widely known. The Bisection Width is equal to λ2|V|/4 iff all vertices are incident to λ2/2 cut edges in every optimal Bisection.We present a new method of obtaining tighter lower bounds on the Bisection Width. This method makes use of the level structure defined by the Bisection. We define some global expansion properties and we show that the spectral lower bound increases with this global expansion. Under certain conditions we obtain a lower bound depending on λ2β|V| with 12⩽β
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MFCS - Upper Bounds on the Bisection Width of 3- and 4-Regular Graphs
Mathematical Foundations of Computer Science 2001, 2001Co-Authors: Burkhard Monien, Robert PreisAbstract:We derive new upper bounds on the Bisection Width of graphs which have a regular vertex degree. We show that the Bisection Width of large 3-regular graphs with |V| vertices is at most 1/6 |V|. For the Bisection Width of large 4-regular graphs we show an upper bound of 2/5 |V|.
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upper bounds on the Bisection Width of 3 and 4 regular graphs
Mathematical Foundations of Computer Science, 2001Co-Authors: Burkhard Monien, Robert PreisAbstract:We derive new upper bounds on the Bisection Width of graphs which have a regular vertex degree. We show that the Bisection Width of large 3-regular graphs with |V| vertices is at most 1/6 |V|. For the Bisection Width of large 4-regular graphs we show an upper bound of 2/5 |V|.
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WG - New Spectral Lower Bounds on the Bisection Width of Graphs
Graph-Theoretic Concepts in Computer Science, 2000Co-Authors: S. Bezrukov, Burkhard Monien, Robert Preis, R. Elsässer, J.-p. TillichAbstract:The communication overhead is a major bottleneck for the execution of a process graph on a parallel computer system. In the case of two processors, the minimization of the communication can be modeled by the graph Bisection problem. The spectral lower bound of λ2|V|/4 for the Bisection Width of a graph is well-known. The Bisection Width is equal to λ2|V|/4 iff all vertices are incident to λ2/2 cut edges in every optimal Bisection. We discuss the case for which this fact is not satisfied and present a new method to get tighter lower bounds on the Bisection Width. This method makes use of the level structure defined by the Bisection. Under certain conditions we get a lower bound depending on λ2β|V| with 1/2 ≤ β < 1. We also present examples of graphs for which our new bounds are tight up to a constant factor. As a by-product, we derive new lower bounds for the Bisection Widths of 3- and 4-regular graphs. We use them to establish tighter lower bounds for the Bisection Width of 3- and 4-regular Ramanujan graphs.
Josep Díaz - One of the best experts on this subject based on the ideXlab platform.
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Bounds on the Bisection Width for random d -regular graphs
Theoretical Computer Science, 2007Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the Bisection Width of random d-regular graphs, for any value of d. The upper bounds are obtained from the analysis of the performance of a randomized greedy algorithm to find Bisections of d-regular graphs. We provide bounds for 5≤d≤12. We also give empirical values of the size of the Bisection found by the algorithm for some small values of d and compare them with numerical approximations of our theoretical bounds. Our analysis also gives asymptotic lower bounds for the size of the maximum Bisection.
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Computation of the Bisection Width for random d-regular graphs
Lecture Notes in Computer Science, 2004Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the Bisection Width of random d-regular graphs, for any value of d. We provide the bounds for 5 < d < 12. The upper bounds are obtained from the analysis of the performance of a randomized greedy algorithm to find Bisections of d-regular graphs. We also give empirical values of the size of Bisection found by the algorithm for some small values of d and compare it with numerical approximations of our theoretical bounds. Our analysis also gives asymptotic lower bounds for the size of the maximum Bisection.
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LATIN - Computation of the Bisection Width for Random d-Regular Graphs
LATIN 2004: Theoretical Informatics, 2004Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper we provide an explicit way to compute asymptotically almost sure upper bounds on the Bisection Width of random d-regular graphs, for any value of d. We provide the bounds for 5 ≤ d ≤ 12. The upper bounds are obtained from the analysis of the performance of a randomized greedy algorithm to find Bisections of d-regular graphs. We also give empirical values of the size of Bisection found by the algorithm for some small values of d and compare it with numerical approximations of our theoretical bounds. Our analysis also gives asymptotic lower bounds for the size of the maximum Bisection.
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Bounds on the max and min Bisection of random cubic and random 4-regular graphs
Theoretical Computer Science, 2003Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:In this paper, we present a randomized algorithm to compute the Bisection Width of cubic and 4-regular graphs. The analysis of the proposed algorithms on random graphs provides asymptotic upper bounds for the Bisection Width of random cubic and random 4-regular graphs with n vertices, giving upper bounds of 0.174039n for random cubic, and of 0.333333n for random 4-regular. We also obtain asymptotic lower bounds for the size of the maximum Bisection, for random cubic and random 4-regular graphs with n vertices, of 1.32697n and 1.66667n, respectively. The randomized algorithms are derived from initial greedy algorithm and their analysis is based on the differential equation method.
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RANDOM - Bisection of Random Cubic Graphs
Randomization and Approximation Techniques in Computer Science, 2002Co-Authors: Josep Díaz, Maria Serna, Nicholas C. WormaldAbstract:We present two randomized algorithms to bound the Bisection Width of random n-vertex cubic graphs. We obtain an asymptotic upper bound for the Bisection Width of 0.174039n and a corresponding lower bound of 1.325961n. The analysis is based on the differential equation method.
Antonio Fernández Anta - One of the best experts on this subject based on the ideXlab platform.
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Bisection (Band)Width of Product Networks with Application to Data Centers
IEEE Transactions on Parallel and Distributed Systems, 2014Co-Authors: Jordi Arjona Aroca, Antonio Fernández AntaAbstract:The Bisection Width of interconnection networks has always been important in parallel computing, since it bounds the speed at which information can be moved from one side of a network to another, i.e., the Bisection bandWidth. Finding its exact value has proven to be challenging for some network families. For instance, the problem of finding the exact Bisection Width of the multidimensional torus was posed by Leighton [1, Problem 1.281] and has remained open for almost 20 years. We provide two general results that allow us to obtain upper and lower bounds on the Bisection Width of any product graph as a function of some properties of its factor graphs. The power of these results is shown by deriving the exact value of the Bisection Width of the torus, as well as of several d-dimensional classical parallel topologies that can be obtained by the application of the Cartesian product of graphs. We also apply these results to data centers, by obtaining bounds for the Bisection bandWidth of the d-dimensional BCube network, a recently proposed topology for data centers.
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Bisection band Width of product networks with application to data centers
Theory and Applications of Models of Computation, 2012Co-Authors: Jordi Arjona Aroca, Antonio Fernández AntaAbstract:The Bisection Width of interconnection networks has always been important in parallel computing, since it bounds the amount of information that can be moved from one side of a network to another, i.e., the Bisection bandWidth. The problem of finding the exact Bisection Width of the multidimensional torus was posed by Leighton and has remained open for 20 years. In this paper we provide the exact value of the Bisection Width of the torus, as well as of several d -dimensional classical parallel topologies that can be obtained by the application of the Cartesian product of graphs. To do so, we first provide two general results that allow to obtain upper and lower bounds on the Bisection Width of a product graph as a function of some properties of its factor graphs. We also apply these results to obtain bounds for the Bisection bandWidth of a d -dimensional BCube network, a recently proposed topology for data centers.
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Bisection (Band)Width of Product Networks with Application to Data Centers
arXiv: Networking and Internet Architecture, 2012Co-Authors: Jordi Arjona Aroca, Antonio Fernández AntaAbstract:The Bisection Width of interconnection networks has always been important in parallel computing, since it bounds the amount of information that can be moved from one side of a network to another, i.e., the Bisection bandWidth. Finding its exact value has proven to be challenging for some network families. For instance, the problem of finding the exact Bisection Width of the multidimensional torus was posed by Leighton and has remained open for almost 20 years. In this paper we provide the exact value of the Bisection Width of the torus, as well as of several d-dimensional classical parallel topologies that can be obtained by the application of the Cartesian product of graphs. To do so, we first provide two general results that allow to obtain upper and lower bounds on the Bisection Width of a product graph as a function of some properties of its factor graphs. We also apply these results to obtain bounds for the Bisection bandWidth of a d-dimensional BCube network, a recently proposed topology for data centers.
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TAMC - Bisection (band)Width of product networks with application to data centers
Lecture Notes in Computer Science, 2012Co-Authors: Jordi Arjona Aroca, Antonio Fernández AntaAbstract:The Bisection Width of interconnection networks has always been important in parallel computing, since it bounds the amount of information that can be moved from one side of a network to another, i.e., the Bisection bandWidth. The problem of finding the exact Bisection Width of the multidimensional torus was posed by Leighton and has remained open for 20 years. In this paper we provide the exact value of the Bisection Width of the torus, as well as of several d -dimensional classical parallel topologies that can be obtained by the application of the Cartesian product of graphs. To do so, we first provide two general results that allow to obtain upper and lower bounds on the Bisection Width of a product graph as a function of some properties of its factor graphs. We also apply these results to obtain bounds for the Bisection bandWidth of a d -dimensional BCube network, a recently proposed topology for data centers.
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Bisection Width of Multidimensional ProductGraphs
2011Co-Authors: Jordi Arjona Aroca, Antonio Fernández AntaAbstract:In this paper we will provide two general results that allow to obtain upper and lower bounds on the Bisection Width of a product graph as a function of some properties of its factor graphs. The most interesting contribution of this paper is the exact value of the Bisection Width of a d-dimensional torus, as this problem has been open for almost 20 years [2]. Our work is partially based on the work by Azizo�glu and E�gecio�glu. In [1] they study the relation between the isoperimetric number and the Bisection Width of diff�erent product networks and obtained and exact value for the Bisection Width of the d-dimensional array studying it as a product of paths. Similarly, we have been able to provide a lower and an upper bound for the Bisection Width of product graphs whose factor graphs have the same maximal congestion with multiplicity r, for the former case, or the same central cut, for the latter one. The general results provided are used to obtain exact bounds on the Bisection Width of several product graphs. The factor graphs used are paths, rings, complete binary trees (CBTs), and extended trees (which are CBTs with the leaves connected as a path). Then, we show that the Cartesian product of rings (i.e., the torus) of sizes k1 � : : : � kd has Bisection Width 2 Pei =1 Ci, where Ci = Qdj =i+1 kj for i 2 [1; e], and e being the lowest dimension with an even number of vertices. (If there is no such dimension, e = d.). Additionally, we show that the Cartesian product of a mixture of XTs and rings has the same Bisection Width. (When all factor graphs are XTs, e = d.) Finally, we show that the Cartesian product of a mixture of CBTs and paths has Bisection Width Pei =1 Ci. (When all factor graphs are CBTs, e = d.)