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Difference between revisions of "Redundancy"

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A measure of the possible increase in the transmission rate of information by using a statistical dependence between the components of the information processed at the source of information. The redundancy of a stationary source of information in discrete time processing the information <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804601.png" /> generated by a stationary stochastic process
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A measure of the possible increase in the transmission rate of information by using a statistical dependence between the components of the information processed at the source of information. The redundancy of a stationary source of information in discrete time processing the information $\xi = ( \ldots, \xi_{-1}, \xi_0, \xi_1, \ldots )$ generated by a stationary stochastic process
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$$
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\xi_k\,,\ \ \ k = \ldots, -1,0,1, \ldots
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$$
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where$\xi_k$ takes values in some finite set $X$ with $N$ elements, is defined to be
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$$
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1 - \frac{\bar H(U)}{H_{\mathrm{max}}}
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$$
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where $\bar H(U)$ is the rate of generation of information by the given source $U$ (see [[Information, rate of generation of|Information, rate of generation of]]) and $H_{\mathrm{max}} = \log N$ is the maximum possible speed of generation of information by a source in discrete time whose components take $N$ different values.
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804602.png" /></td> </tr></table>
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For references, see at [[Communication channel|Communication channel]].
  
where <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804603.png" /> takes values in some finite set <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804604.png" /> with <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804605.png" /> elements, is defined to be
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<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804606.png" /></td> </tr></table>
 
 
 
where <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804607.png" /> is the rate of generation of information by the given source <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804608.png" /> (see [[Information, rate of generation of|Information, rate of generation of]]) and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r0804609.png" /> is the maximum possible speed of generation of information by a source in discrete time whose components take <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/r/r080/r080460/r08046010.png" /> different values.
 
 
 
For references, see ,
 
 
 
at [[Communication channel|Communication channel]].
 

Revision as of 18:14, 19 October 2014

A measure of the possible increase in the transmission rate of information by using a statistical dependence between the components of the information processed at the source of information. The redundancy of a stationary source of information in discrete time processing the information $\xi = ( \ldots, \xi_{-1}, \xi_0, \xi_1, \ldots )$ generated by a stationary stochastic process $$ \xi_k\,,\ \ \ k = \ldots, -1,0,1, \ldots $$ where$\xi_k$ takes values in some finite set $X$ with $N$ elements, is defined to be $$ 1 - \frac{\bar H(U)}{H_{\mathrm{max}}} $$ where $\bar H(U)$ is the rate of generation of information by the given source $U$ (see Information, rate of generation of) and $H_{\mathrm{max}} = \log N$ is the maximum possible speed of generation of information by a source in discrete time whose components take $N$ different values.

For references, see at Communication channel.

How to Cite This Entry:
Redundancy. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Redundancy&oldid=11410
This article was adapted from an original article by R.L. DobrushinV.V. Prelov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article