Re: Bar Code Scheme for Ballot

From: Alan Dechert <adechert_at_earthlink_dot_net>
Date: Fri Aug 22 2003 - 15:51:57 CDT

----- Original Message -----
From: "Arthur Keller" <arthur_at_kellers_dot_org>
To: <voting-project@lists.sonic.net>
Cc: <voting-project@lists.sonic.net>
Sent: Thursday, August 21, 2003 4:49 PM
Subject: Re: Bar Code Scheme for Ballot

> At 4:38 PM -0700 8/21/03, Alan Dechert wrote:
> >Probably, we will be encoding 7 bits with a single character. In this
case,
> >the possibilities for the first 7 bits are:
> >
> >1000000
> >0100000
> >0010000
> >0001000
> >0000100
> >0000010
> >0000001
> >0000000
>
> That encodes eight possibilities. That can more effectively be
> encoded in 3 bits. 7 bits can encode 128 possibilities. If you use
> a bit-dense continuous coding scheme with varying length codes, it
> wouldn't be easy to figure out anything by eye, but easy by computer.
>
Here's what I came up with manually for the sample mockup ballot for the
demo at

http://home.earthlink.net/~adechert/ballot-mockup3.gif

position character
-----------
1 - 16 1
17 - 26 2
27 - 36 3
37 - 44 4
45 - 51 5
52 - 66 6
67 - 79 7
80 - 93 8
94 - 108 9
109 - 116 10

So, the 116 positions (analogous to puch card holes) can be encoded with ten
7-bit characters

A more clever arrangement might be able to get it to nine 7-bit characters,
but that's what I came up with. Can anyone check this?

Alan Dechert

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Received on Sun Aug 31 23:17:14 2003

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