[FoRK] Kernel Density Technique (Parzen Window) help

Damien Morton dmorton at bitfurnace.com
Sat Apr 26 12:04:16 PDT 2014

Hi everyone,

I am trying to implement a technique described in the following paper,


I have struck a problem and am looking for some help.

on page 7, function S4 is defined

Part of that is function pw(ai)

The right hand term inside the summation has a denominator |a[i] - a[i+w]|

 The kernel density technique (also called Parzen window)  is being used

The problem is that the denominator is 0 when a[i]==a[i+w] - I want to know
how best to handle this event

 now, I have searched all kinds of material on the kernel density technique
and nowhere do i see the denominator defined this way

 from what I can see, the denominator is usually expressed as a constant
proportional to the standard deviation of the samples

 I _think_ the term  |a[i] - a[i+w]| is being used as some kind of adaptive
kernel width. Its really not clear to me why this term is being used and
what it means

I tried contacting the author, but got no response

If anyone can point me in the right direction or give me some advice, t
would be very much appreciated

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