Every set of disjoint line segments admits a binary tree, Discrete Comput Geom (2008)
Michael E. Houle, Godfried T. Toussaint
z Abstract Given a set of n disjoint line segments in the plane, we show that it is always possible to form a tree with the endpoints of the segments such that each line segment is an edge of the...
Revised Submission to Special Issue of Algorithmica: (2008)
Vladimir Estivill-castro, Michael E. Houle
Topic: Optimization algorithms applied to geographical data, geostatistics, mathematical modeling of geographic problems.
Extracting Spatial Knowledge from the Web (2008)
Yasuhiko Morimoto (contact, Masaki Aono, Michael E. Houle, Kevin S. Mccurley
The content of the world-wide web is pervaded by information of a geographical or spatial na-ture, particularly such location information as addresses, postal codes, and telephone numbers. We present...
Best of Both: A Hybridized Centroid-Medoid Clustering Heuristic (2008)
Although each iteration of the popular k-Means clustering heuristic scales well to larger problem sizes, it often requires an unacceptably-high number of iterations to converge to a solution. This...
Token Distribution on Tree-Connected Architectures (2007)
Michael E. Houle, Antonios Symvonis, David R. Wood
Load balancing on a multi-processor system involves redistributing tasks among processors so that each processor has roughly the same amount of work to perform. The token-distribution problem is a...
Every set of disjoint line segments admits a binary tree, Discrete Comput Geom (2007)
Prosenjit Bose, Michael E. Houle, Godfried Toussaint
Given a set of n disjoint line segments in the plane, we show that it is always possible to form a tree with the endpoints of the segments such that each line segment is an edge of the tree, the tree...
Two Voronoi Variants with Applications to Viewing Three-Dimensional Graph Drawings (2007)
Peter Eades, Michael E. Houle, Richard Webber
In this paper we address the problem of finding good viewpoints for three-dimensional straightline graph drawings. We define goodness in terms of preserving the relational structure of the graph, and...
Dimension-exchange algorithms for token distribution on tree-connected architectures (2004)
Michael E. Houle, A Antonios Symvonis
Load balancing on a multi-processor system involves redistributing tasks among processors so that each processor has roughly the same amount of work to perform. The token-distribution problem is a...
Graph Drawing in Motion II (2002)
Friedrich, Carsten, Houle, Michael E.
Enabling the user of a graph drawing system to preserve the mental map between two different layouts of a graph is a major problem. Whenever a layout in a graph drawing system is modified, the mental...
Graph Drawing in Motion II (2002)
Friedrich, Carsten, Houle, Michael E.
Enabling the user of a graph drawing system to preserve the mental map between two different layouts of a graph is a major problem. Whenever a layout in a graph drawing system is modified, the mental...
Graph Drawing in Motion II (2002)
Friedrich, Carsten, Houle, Michael E.
Enabling the user of a graph drawing system to preserve the mental map between two different layouts of a graph is a major problem. Whenever a layout in a graph drawing system is modified, the mental...
Dimension-Exchange Algorithms for Load Balancing on Trees (2002)
Michael E. Houle, Antonios Symvonis, David R. Wood
This paper considers dimension-exchange algorithms for load balancing on trees with finitely-divisible loads (token distribution). We present improved analysis of an existing protocol, and in...
On local transformation of polygons with visibility properties (2002)
Carmen Hernando, Michael E. Houle, Ferran Hurtado
One strategy for the enumeration of a class of objects is local transformation, in which new objects of the class are produced by means of a small modication of a previously-visited object in the...
Dimension-Exchange Algorithms for Load Balancing on Trees (2002)
Michael E. Houle, Antonios Symvonis, David R. Wood
This paper considers dimension-exchange algorithms for load balancing on trees with finitely-divisible loads (token distribution). We present improved analysis of an existing protocol, and in...
Dimension-Exchange Algorithms for Load Balancing on Trees (2002)
Michael E. Houle, Antonios Symvonis, David R. Wood
This paper considers dimension-exchange algorithms for load balancing on trees with finitely-divisible loads (token distribution). We present improved analysis of an existing protocol, and in...
Approximating Proximity for Fast and Robust Distance-Based Clustering (2002)
Estivill-Castro, Vladimir, Houle, Michael E.
Distance-based clustering results in optimization problems that typically are NP-hard or NP-complete and for which only approximate solutions are obtained. For the large instances emerging in data...
Approximating Proximity for Fast and Robust Distance-Based Clustering (2002)
Estivill-Castro, Vladimir, Houle, Michael E.
Distance-based clustering results in optimization problems that typically are NP-hard or NP-complete and for which only approximate solutions are obtained. For the large instances emerging in data...
Robust Distance-Based Clustering with Applications to Spatial Data Mining (2001)
Estivill-Castro, Vladimir, Houle, Michael E.
In this paper we present a method for clustering geo-referenced data suitable for applications in spatial data mining, based on the medoid method. The medoid method is related to k-MEANS, with the...
Robust Distance-Based Clustering with Applications to Spatial Data Mining (2001)
Estivill-Castro, Vladimir, Houle, Michael E.
In this paper we present a method for clustering geo-referenced data suitable for applicationsin spatial data mining, based on the medoid method. The medoid method is related to k-MEANS, with...
Robust Distance-Based Clustering with Applications to Spatial Data Mining (2001)
Estivill-Castro, Vladimir, Houle, Michael E.
In this paper we present a method for clustering geo-referenced data suitable for applications in spatial data mining, based on the medoid method. The medoid method is related to k-MEANS, with the...
Robust Distance-Based Clustering with Applications to Spatial Data Mining (2001)
Estivill-Castro, Vladimir, Houle, Michael E.
In this paper we present a method for clustering geo-referenced data suitable for applications in spatial data mining, based on the medoid method. The medoid method is related to k-MEANS, with the...
Robust Distance-Based Clustering with Applications to Spatial Data Mining (1999)
Vladimir Estivill-Castro, Michael E. Houle
In this paper, we present a method for clustering geo-referenced data suitable for applications in spatial data mining, based on the medoid method. The medoid method is related to k-Means, with the...
Finding the Best Viewpoints for Three-Dimensional Graph Drawings (1998)
Eades, Peter, Houle, Michael E., Webber, Richard
In this paper we adress the problem of finding the best viewpoints for three-dimensional straight-line graph drawings. We define goodness in terms of preserving the relational structure of the graph,...
Fekete, Sándor P., Houle, Michael E., Whitesides, Sue
The logic engine technique has been used in the past to establish the NP-hardness of a number of graph representations. The original technique can only be applied in those situations in which...
Approximation Algorithms for Finding Best Viewpoints (1998)
Houle, Michael E., Webber, Richard
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...
Finding the Best Viewpoints for Three-Dimensional Graph Drawings (1998)
Eades, Peter, Houle, Michael E., Webber, Richard
In this paper we adress the problem of finding the best viewpoints for three-dimensional straight-line graph drawings. We define goodness in terms of preserving the relational structure of the graph,...
Fekete, Sándor P., Houle, Michael E., Whitesides, Sue
The logic engine technique has been used in the past to establish the NP-hardness of a number of graph representations. The original technique can only be applied in those situations in which...
Approximation Algorithms for Finding Best Viewpoints (1998)
Houle, Michael E., Webber, Richard
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...
Finding the Best Viewpoints for Three-Dimensional Graph Drawings (1998)
Eades, Peter, Houle, Michael E., Webber, Richard
In this paper we adress the problem of finding the best viewpoints for three-dimensional straight-line graph drawings. We define goodness in terms of preserving the relational structure of the graph,...
Fekete, Sándor P., Houle, Michael E., Whitesides, Sue
The logic engine technique has been used in the past to establish the NP-hardness of a number of graph representations. The original technique can only be applied in those situations in which...
Approximation Algorithms for Finding Best Viewpoints (1998)
Houle, Michael E., Webber, Richard
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...
On a visibility representation for graphs in three dimensions (1998)
Prosenjit Bose, Sdndor P. Fckete, Anna Lubiw, Thomas C. Shetruer, Michael E. Houle, Henk Meijer, ...
This paper proposes a 3-dimensional visibility representation of graphs G (V, E) in which vertices are mapped to rectangles floating in [R 3 parallel to the x, y-plane, with edges represented by...
On a visibility representation for graphs in three dimensions (1998)
Prosenjit Bose, Hazel Everett, Sándor P. Fekete, Michael E. Houle, Anna Lubiw, Henk Meijer, ...
This paper proposes a 3-dimensional visibility representation of graphs G = (V,E) in which vertices are mapped to rectangles floating in R 3 parallel to the x, y-plane, with edges represented by...
On a visibility representation for graphs in three dimensions (1998)
Prosenjit Bose, Hazel Everett, Sándor P. Fekete, Michael E. Houle, Anna Lubiw, Henk Meijer, ...
This paper proposes a 3-dimensional visibility representation of graphs G = (V,E) in which vertices are mapped to rectangles floating in R 3 parallel to the x, y-plane, with edges represented by...
Angewandte Mathematik und Informatik Universit at zu K oln (1997)
Report No On, Hazel Everett, Hazel Everett, S'andor P. Fekete, S'andor P. Fekete, Michael E. Houle, ...
This paper proposes a 3-dimensional visibility representation of graphs G = (V; E) in which vertices are mapped to rectangles floating in R 3 parallel to the x; y-plane, with edges represented by...
Sándor P. Fekete, S'andor P. Fekete, Michael E. Houle, Michael E. Houle, Michael E. Houle, Sue Whitesides, ...
In this paper we describe a general technique for establishing NPhardness of graph representations. This technique is a generalization of the tool called the logic engine. We show that it is possible...
On a Visibility Representation of Graphs in 3D (1997)
Prosenjit Bose, Hazel Everett, Hazel Everett, Sandor P. Fekete, S'andor P. Fekete, Michael E. Houle, ...
This paper proposes a 3-dimensional visibility representation of graphs G = (V; E) in which vertices are mapped to rectangles floating in R 3 parallel to the x; y-plane, with edges represented by...
Finding the Best Viewpoints for Three-Dimensional Graph Drawings (1997)
Peter Eades, Michael E. Houle, Richard Webber
In this paper we address the problem of finding the best viewpoints for three-dimensional straight-line graph drawings. We define goodness in terms of preserving the relational structure of the...
Approximation Algorithms for Finding Best Viewpoints (1997)
Michael E. Houle, Richard Webber
. 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...
Optimal Dimension-Exchange Token Distribution on Complete Binary Trees (1997)
Michael E. Houle, Ewan Tempero, Gavin Turner
Load balancing on a multi-processor systems involves shifting work around the system so that each processor has about the same amount of processing to perform. The token-distribution problem is a...
New Results on a Visibility Representation of Graphs in 3D (1996)
Fekete, Sándor P., Houle, Michael E., Whitesides, Sue
This paper considers a 3-dimensional visibility representation of cliques K_n. In this representation, the objects representing the vertices are 2-dimensional and lie parallel to the x, y-plane, and...
New Results on a Visibility Representation of Graphs in 3D (1996)
Fekete, Sándor P., Houle, Michael E., Whitesides, Sue
This paper considers a 3-dimensional visibility representation of cliques K_n. In this representation, the objects representing the vertices are 2-dimensional and lie parallel to the x, y-plane, and...
New Results on a Visibility Representation of Graphs in 3D (1996)
Fekete, Sándor P., Houle, Michael E., Whitesides, Sue
This paper considers a 3-dimensional visibility representation of cliques K_n. In this representation, the objects representing the vertices are 2-dimensional and lie parallel to the x, y-plane, and...
New Results on a Visibility Representation of Graphs in 3D (1996)
Sandor P. Fekete, S'andor P. Fekete, S'andor P. Fekete, Michael E. Houle, Michael E. Houle, Michael E. Houle, ...
This paper considers a 3-dimensional visibility representation of cliques K n . In this representation, the objects representing the vertices are 2dimensional and lie parallel to the x; y-plane, and...
New Results on a Visibility Representation of Graphs in 3D (1996)
Sandor P. Fekete, S'andor P. Fekete, S'andor P. Fekete, Michael E. Houle, Michael E. Houle, Michael E. Houle, ...
This paper considers a 3-dimensional visibility representation of cliques K n . In this representation, the objects representing the vertices are 2dimensional and lie parallel to the x; y-plane, and...
On Zones of Flats in Hyperplane Arrangements (1992)
Michael E. Houle, Takeshi Tokuyama
Let H be a set of n hyperplanes in R d , let A(H) be its arrangement, and let b be an m-dimensional flat. The zone of b in the arrangement A(H) is the set of open d-dimensional cells of A(H) which...
Computational Aspects of Helly's Theorem and its Relatives (1991)
This paper investigates computational aspects of the well-known convexity theorem due to Helly, which states that the existence of a point in the common intersection of n convex sets is guaranteed by...
Computing the Width of a Set (1988)
Michael E. Houle, Godfried T. Toussaint
Given a set of points P = {p 1 , p 2 ,..., p n } in three dimensions, the width of P, W(P), is defined as the minimum distance between parallel planes of support of P. It is shown that W(P) can be...
Fast Randomized Algorithms for Robust Estimation of Location
Vladimir Estivill-Castro, Michael E. Houle
. A fundamental procedure appearing within such clustering methods as k-Means, Expectation Maximization, Fuzzy-C-Means and Minimum Message Length is that of computing estimators of location. Most...