[aklug] Re: [OT] Re: random bits vs random Hex

Bryan is right, if you have saved the binary data poorly, in an odd way,
there is potential for fluff that would be easily be trimmed by a
compression algorithm.

As for pattern recognition, a random stream will hopefully have no
patterns, so further compression won't work. If it does then the stream
wasn't random.

On Wed, May 29, 2013 at 1:12 PM, <bryanm@acsalaska.net> wrote:

> On Wed, May 29, 2013 12:26 pm, Arthur Corliss wrote:
> > On Wed, 29 May 2013, bryanm@acsalaska.net wrote:
> >
> >> I don't know enough to address entropy, but I can say that changing
> >> from binary triplets to decimal digits leaves some of the pattern space
> >> unused (i.e. 8 and 9). In other words, the same data takes up more
> space,
> >> leaving open the possibility for an algorithm to compress it back to
> close
> >> to its original size.
> >
> > If this were true that we'd be able to get great compression on any data,
> > random or not. By your logic, compressing binary data should be awesome,
> > since there's only two choices: 1 or 0.
>
> That's not what I'm saying at all. I'm talking about unused pattern space.
> As an extreme example, imagine representing binary data by letting each
> *byte* represent either a 0 or a 1. Obviously, there would be tremendous
> opportunity for compression. The same thing happens (to a lesser degree)
> in my binary triplet -> decimal digit conversion. In each case, there
> are some possible values for each data element that will *never* be used.
>
> I'm speaking mathematically, and don't claim to know how to implement an
> algorithm to take advantage of this property.
>
> > You can't cheat around the basic problem of pattern recognition by
> changing
> > how the same data is presented. Choosing to evaluate smaller chunks of
> data
> > is a zero sum game because you either have to inflate your translation
> maps
> > or look for longer pattern strings than you would in larger chunks. In
> the
> > end, it's the repeatability of data chunks, regardless of presentation,
> > which will determine compressability.
>
> The idea of pattern recognition for the purpose of data compression
> intrigues me, though I've never fully researched the details.
>
> --
> Bryan Medsker
> bryanm@acsalaska.net
>
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Received on Wed May 29 13:17:32 2013