Oracle data mining - O-cluster
From: szalas <gszalach_at_hotmail.com>
Date: Mon, 12 Jan 2004 19:21:44 +0100
Message-ID: <btuoef$8ia$1_at_julia.coi.pw.edu.pl>
Hi,
I've implemented O-cluster algorithm and during doing some tests I've noticed strange results. I hope that someone had something to do with this alghoritm and is able to answer for my questions : 1. O-cluster uses data histograms. Are the bins' values computed in usual way for histograms :
number of points in bin range/(number of all points*bin width) 2. Is the equation for chi-square test correct ?? 2*((observed-expected)^2)/expected, where observed is the value of histogram valley and expected is the average of the histogram counts of the valley and the lower peak. 3. I compute bin width as 3.49*standard_deviation*number of points^(-1/3)
Date: Mon, 12 Jan 2004 19:21:44 +0100
Message-ID: <btuoef$8ia$1_at_julia.coi.pw.edu.pl>
Hi,
I've implemented O-cluster algorithm and during doing some tests I've noticed strange results. I hope that someone had something to do with this alghoritm and is able to answer for my questions : 1. O-cluster uses data histograms. Are the bins' values computed in usual way for histograms :
number of points in bin range/(number of all points*bin width) 2. Is the equation for chi-square test correct ?? 2*((observed-expected)^2)/expected, where observed is the value of histogram valley and expected is the average of the histogram counts of the valley and the lower peak. 3. I compute bin width as 3.49*standard_deviation*number of points^(-1/3)
My problem is that I've never reached min statistical significance(3.843) for none of my data sets.It is possible that i have wrong data (maybe too small for o-cluster, too few dimensions) but some other clustering alghoritms were able to obtain some clusters from my data sets.
Thank you very much for any clues, ideas and places where i can find some
additional help.
Szalas
Received on Mon Jan 12 2004 - 19:21:44 CET