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This web tutorial and Java applet ("pgedit") are copyright (C) 2001-2002 Chris Cocosco (crisco@bic.mni.mcgill.ca).
They are available at no-cost under the GNU General Public License (GPL).

Glossary of terms

feature space: A space where each sample (in a pattern recognition problem) is represented as a point. Each measurement ("feature") about the object gives the coordinate of the point along one axis of the space. The dimensionality of the feature space is thus equal to the number of features used (for example, if two features are used, the space will be a plane, with the first feature on the X axis, and the second feature on the Y axis).

classifier: A system or method that given some measurements about an object (the "features") assigns a class membership ("label") to that object.

non-parametric classifier: A classifier that does not incorporate any assumptions about the data distributions in feature space. Such an assumption is typically a parametric model, described by a small number of parameters. For example, see Bayes classifier with Gaussian distributions.

Bayes classifier (with Gaussian distributions): A parametric classifier that assumes multi-variate Gaussian ("Normal") data distributions in the multi-dimensional feature space. The class means and covariance matrix are estimated from the training data, and new samples are labeled as the class having the maximum aposteriori probability.

graph: A set of points in space, together with a set of "edges" (line segments) connecting pairs of points from the set. Typically, not all possible pairs of points are connected.

Relative Neighborhood graph: Given a set of points in the plane, two points are connected by an edge ab if there are no other points inside lune(a,b). The lune of two points is the intersection of the interiors of the two circles centered at a and at b, and both with radius equal to the distance between a and b (see [9], [12])

Beta skeletons: A continuous family of proximity graphs proposed by Kirkpatrick and Radke [10]. These graphs are defined by a positive real parameter Beta. Lower values of Beta give denser graphs (with more edges). There are two types of Beta-skeletons: lune-based (the neighborhood is an intersection of discs), and circle-based (the neighborhood is a union of discs). For Beta=1 the skeleton is in fact the Gabriel graph, and for Beta=2 the (lune-based) skeleton is the Relative Neighborhood graph. See also:


Bibliography

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2
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3
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web course notes.

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http://www1.ics.uci.edu/~eppstein/junkyard/betadil.html .

7
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8
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First Canadian Conference on Computational Geometry (Montreal, PQ, 1989).

9
Jerzy W. Jaromczyk and Godfried T. Toussaint.
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10
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11
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Prototype selection for the nearest neighbour rule through proximity graphs.
Pattern Recognition Letters, 18(6):507-513, Jun 1997.

12
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The relative neighbourhood graph of a finite planar set.
Pattern Recognition, 12(4):261-268, 1980.

13
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The application of Voronoi diagrams to non-parametric decision rules.
In Proc. 16th Symposium on Computer Science and Statistics: The Interface, Atlanta, Georgia, pages 97-108, March 1984.



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