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RE: VMs: Follow-up

Gabriel: As a sometime user of signal analysis, I'm very interested in your
correlation analysis!  I'm sure reference to it passed through the list
conversation, but I must have been occuped.  Could you send me a .pdf
please?  Thanks very much.

Dr. Don J. Latham
Street:  17850 Six Mile Road
Mail:    POBox 460134
City:    Huson, MT, 59846
VOX:     406-626-4304
Email:   djl@xxxxxxxxxxx
Web:     http://www.lightningforensics.com
Web:     http://www.sixmilesystems.com

-----Original Message-----
From: owner-vms-list@xxxxxxxxxxx [mailto:owner-vms-list@xxxxxxxxxxx]On
Behalf Of Gabriel Landini
Sent: Tuesday, June 22, 2004 5:42 AM
To: vms-list@xxxxxxxxxxx
Subject: Re: VMs: Follow-up

On Tuesday 22 June 2004 11:58, Diego Rybski wrote:
> 2) correlations depend on the order of the symbols. If you shuffle the
> symbols, the distribution remains, but the correlation structure vanishes.
> Correlations mean, that there is a dependence between the elements of the
> series. In numbers, a big is more probably follwed by another big, and a
> small by another small one. The often mentioned long-range correlations
> are a special kind of correlation. Unfortunately I have not yet found
> the references related to this topic. The correlation function decays like
> a power-law, thus the mean correlation length diverges. It is simple to
> create long-range correlated sequences with gaussian distribution, but
> even today it is a rather difficult task to create long-range correlated
> power-low distributed sequences. I know that it is possible for
> exponential distributed.

As you are aware, symbolic sequences are not good candidates to correlation
analysis because symbols do not have a quantity associated.
There are some ways round, though. I did some long correlation analysis of
vms text using Voss' method of applying fft to binary "same-symbol"
(and of other texts).
The reference is: Landini, G. Evidence of linguistic structure in the
Manuscript using spectral analysis. Cryptologia, October 2001, Volume XXV,
Number 4, (pp.275-295), 2001.
I can send you a pdf preprint if you cannot get the journal.


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